WO1998030787A1

WO1998030787A1 - A device for controlling the valves of an internal combustion engine

Info

Publication number: WO1998030787A1
Application number: PCT/FI1997/000013
Authority: WO
Inventors: Tapio Stenman
Original assignee: Tapio Stenman
Priority date: 1996-01-26
Filing date: 1997-01-13
Publication date: 1998-07-16
Also published as: FI102691B1; FI960352A0; FI101998B; FI973212A0; FI102691B; FI973212L; FI101998B1; FI960352A7

Abstract

The invention is about a hydraulic device for controlling the function of the valve of an internal combustion engine. The device includes discharge channels (20, 20A, 20B), which are closed by the cam end piston (4); and discharge channels (13A, 11A, 11B), which are opened by the valve end piston (6). When discharge is enabled through the discharge channels mentioned first, among other things, the opening time of the valve is retarded, and the timing is later than when discharge is enabled through the discharge channels mentioned later, as this will make the closing time of the valve earlier. In certain implementations of the device it is possible to maintain the opening stroke of the valve practically the same when open discharge channel (16) discharges transmitting fluid while control valve (20D) is closed; whereas when control channel (20D) is open the rise of the valve remains sufficient due to the high cam (2) on camshaft (1). Additionally, the device can measure and/or adjust the operating balance or operating levels between different valve control system units and/or damp and adjust the impact between the valve ant its seating. In addition, a cam can be included in the device with additional lift parts, the functions of which can be enabled or disabled. It is also possible to temporarily incapacitate the valve.

Description

A Device for Controlling the Valves of an Internal Combustion Engine

The subject of the invention is a device defined in the introduction of patent claim 1 for controlling valves in an internal combustion engine.

The cams of a camshaft are alone insufficient in controlling the function of the valves, since once the shape of the cam is determined it is always a result of several compromises. Therefore the purpose of this invention is to modify the the valve function after the cam shape has been defined. The background for this invention is a valve operation system for internal combustion engines, where the cam controlling the function of the valve is functionally connected with the cam end piston, and the valve end piston is controlled by releasing transmitting fluid, like oil, from the chamber connecting the pistons, as well as by the movement provided by the cam. Several similar devices are known.

In several devices mentioned above there are only one filling hole and one discharge hole, along with some system controlling the discharge. An example of a device with more than one discharge hole, as in the invention in question, is a device presented in the German patent publication DE 26 36 944 Al. From this patent publication, concerning a device with two discharge holes from the space between the pistons, can be seen that it is possible to remove transmitting fluid from the space between the valve end piston and the cam end piston, shut by the cam end piston, with a non-return valve only to ensure a good refill of fluid. Moreover, the above mentioned patent publication presents a possibility to discharge transmitting fluid with an adjusting valve further away from the space between the said pistons, at a location which neither of the said pistons opens or closes. The space for pressu- rized oil can thus be opened with an adjusting valve without making up enough pressure to open the engine valve, hence the engine valve is made idle. Contrary to the invention under discussion, this known solution does not achieve alteration in the timing of the valve. Furthermore, this known device contains a valve end piston, which is equipped with a hydraulic damping system, where a damping component connected to the valve end piston settles in a socket made for it. In this case a flow resistance is achieved for the return motion of the piston in question and hence for the closing travel of the valve; which is needed after discharging the transmitting fluid. However, there is no graduation in the damping as there is in the invention under discussion, where the first the part of the piston with a smaller diameter creates a larger annular space, and then the part of the piston with a larger diameter creates a smaller annular space. Moreover, the damping does not include a possibility to adjust the resistance that is made up, whereas the different type of damping structure of the invention in question does, as is seen in patent claim no. 5.

Another example is PCT publication WO 85/01984, which also has two discharge holes from the space between the pistons. The cam end piston closes one discharge channel for transmitting fluid controlled by a controlling valve. What is achieved is the opening of the valve, and also a change in the timing of the closing and a change in the amount of the lift. However, there is no possibility to change the opening moment of the valve in relation with the rotation angle of the crankshaft. This is because there is no channel with control valves to open the valve end piston and/or some other way to merely to make the closing of the valve earlier, without the opening of the valve being at the same time delayed. In addition to the said channel it is possible to discharge transmitting fluid from the space between the cam end piston and the valve end piston with another control valve through another channel, which will not be closed by the cam end piston, or opened by the valve end piston. The means mentioned last is not associated with controlling the timing of the valve. The valve end piston is larger than the cam end piston in the implementation of the known device. However, the opportunity to damp the stroke of the valve made possible by the implementation is not used, so that the said piston would enter the smaller space partially forming a diminishing annular space, as a device conforming to the invention in question does, to say nothing of there being stepless adjusting linked with the entering, whereas the invention in question includes also this feature.

The purpose of the invention under discussion is to achieve an improved controlling device, with more diversified control of the function of the valves of an internal combustion engine, especially so that there is a possibility to change the open time of the valve in relation to the rotation angle of the crankshaft in addition to the length of the open time of the valves.

This purpose of the invention is achieved with an invention of which the characteristic fea- tures are presented in the attached patent claim no. 1. This invention makes it possible to choose the time of the discharge of the transmitting fluid. The timing takes place generally as follows. The opening of the engine's valve is delayed, that is, the open time of the valve is reduced from the beginning, when transmitting fluid shut up by the cam end piston is released at the beginning of movement of the controlled valve provided by the camshaft cam, although this moves also the closing of the engine's valves earlier. Dis-charging transmitting fluid opened by the valve end piston during the opening movement of the valves causes the closing of the engine's valve to be made earlier, in other words, it shortens the open time of the valve only in the end of the valve's movement. In this case the open time of the engine's intake or exhaust valve is earlier compared with the previous case. In both cases the said discharge hole is closed and opened by the said piston, so that the discharge is limited to the part of the movement controlled by the said cam end piston, or the valve end piston. The control valves can remain open or closed for extended periods of time, if the running condition of the engine so demands, without having to make wearing reciprocation motion.

Beneficial applications of the invention are presented in dependent patent claims 2 - 18. The invention is described in more detail with the help of sample applications by referring to enclosed figures where:

Figure group 1 represents the invention in an implementation where the camshaft is under the cylinder cover and is not displayed in the figures. Figure group 1 includes figures IA - ID, which differ from each other in switching systems for releasing transmitting fluid, plus figure IE where end 48 of piston 6 has been slimmed. In the said group of figures the cam end piston is lowermost resting on the pushrod and the valve end piston is topmost bounded by a control screw, which can for instance be part of a rocker arm depressing the valve. If the end of the cam end piston is shaped differently, it can have direct contact with the cam of the camshaft, and the camshaft can be at the level of the cover to one side, instead of a pushrod, which demonstrates the system's versatility.

In figure group 2A - 2E the cam end piston is topmost and the valve end piston lowermost, so the functions in it are inverted, compared with figure group IA - IE. The main functions are or could be the same as in figure group 1, although the cylinder arrangement in figure group 2 is different comprising inner cylinder 7 and outer cylinder 21. Corresponding parts and channels are identically numbered for easy comparison and to make it clear that the same invention is in question, only in a different environment.

Figure group 2 displays an implementation of the invention with an overhead camshaft. Figure group 2 includes figures 2A - 2E plus specification 2F of the device's measuring component, which is presented as a diagram in figure 2D. The said components of device 2F measure and adjust in each channel that all the discharges from the channels for initial discharge of the corresponding units remain of equal amount. The systems in figures 2A - 2E of figure group 2 differ only in the way of controlling the transmitting fluid.

Figure group 3 - 8 describe camwheels that can be used with the invention to utilize some of their benefits better, except figure 6, where the valve movements caused by camwheels 3 and 4 are presented as functions A2a and A2b of the rotation angle of the crankshaft.

Figures 9 - 11 present the structure damping the strike of the inner end of the valve end piston presented in figure group IA - IE and the valve connected to it into its sleeve during the "lost motion". Figure 12 presents the cylinder cut open and spread out by its discharge channels.

Figure 13 presents a set of curves conforming to a certain cam shape of the intake and exhaust cams, where the valve motions are represented as a function of the rotation angle of the crankshaft.

Figures 14A - 14D loosely represent a basic cam shape corresponding to figure 13 and in particular the effects on the valve motions achieved by solutions conforming to the inven- tion, when the effects are described by presenting the motions of the valves as a function of the rotation angle of the crankshaft.

Figures 15 A and 15B represent the valve motion in devices in which the valve lift is not substantially reduced regardless of whether the initial discharge is opened or not. Figure 15 A can in a certain way be linked with figure 2E. The valve function described in figures 15 A, 15B can be achieved in the way referred to in patent claim 7.

Figures IA - IE and 2 A - 2E aim to illustrate two different types of solutions; both of them apply, however, to the same invention as regards their means of control and their principles of functioning.

When the ignition key (not displayed in the figures), which in a system described in figures IA - IE is placed between the battery and the pressure switch, is turned, power from the battery turns on the electric motor 38, which runs oil pump 38B. The pressure of transmit- ting fluid is directed to pressure switch 39 through control channel 40, and when the pressure is sufficiently high, it will make a connection between starter motor 43 and its power source, in this case battery 35. The pressure switch can alternatively transmit for example a control impulse which opens a connection for pressurised air produced by a separate air pump to enter into the starter system. Pressure, measured by pressure switch 39, is directed through a distribution network to channels 8, 9, and 10 of the valve control system units. Starting the engine is therefore not possible until the pressure of transmitting fluid is sufficient. The pressure of the transmitting fluid can be possible in lubrication points if the capacity of oil pump 38B is chosen in the design stage with this in mind.

When the engine is run by starter motor 43, the engine's own oil pump 41 will start rotating in order to take care of lubricant pressure and also oil pressure in the valve control system, if motor oil is used as transmitting fluid. The engine's starter and oil feed system 37 include also pressure regulator 42, oil filter 45, and intake filter 44. Also one or more pres- sure accumulators, like for example pressure accumulators 28 and 29, can be included in the oil feed line. Figure group 2A - 2E does not define the oil feed system in more detail.

Figure group IA - IE displays control unit CU21, which controls the function of the system with the help of input information 221.

Figures IA - IE as well as figures 2 A - 2E endeavor to illustrate that all the figures in the figure groups have at least one discharge hole for initial discharge, such as 20, or 20A, and 20B, which is closed by piston 4 at the beginning of the motion of the intake or exhaust valve; and at least one discharge hole for final discharge, 13A,11 A, 1 IB, which is opened by piston 6 at the end of the motion of the intake or exhaust valve. The opening in question can be either allowed or not allowed with control valve 15D, 16D, 20D, 20F. Throttling device 20E, seen in figures 2B and 2E, can also be used, instead of the control valve; in this device discharge is throttled, for instance, so that the relative amount of discharge for each working motion of piston 4 reduces as the running speed grows. Instead of or in addition to the intake or exhaust valve, in an engine using gaseous fuel, for example, the valve controlling the gaseous fuel can be controlled. These functions are expressed in patent claims 1 - 4.

Under discussion, therefore, is a device for controlling the function of the valves of an internal combustion engine, where the engine includes in each cylinder at least one intake valve and/or at least one exhaust valve or at least one control valve for gaseous fuel. The device includes a camshaft 1 cam 2 end piston 4 and a valve end piston 6, as well as a cylinder space 5 between pistons 4, 6; which is connected to a filling channel 8, 9, 10 for fluid transmitting power between the pistons, and a discharge channel 20, 20A, 20B, or 20C with their discharge holes 20, 20A, 20B, which the cam end piston 4 closes at the beginning of the opening motion of the valve. The device is such that the cam end piston 4 closes one or more discharge holes 20, 20A, 20B of the first discharge channel 20, 20A, 20B, or 20C at the beginning of the opening motion of the valve, whereupon the opening moment of the valve can be made later and correspondingly the closing moment can be made earlier by allowing discharge flow through the first discharge channel 20, 20 A, 20B, or 20C. Besides the function in connection with said piston 4, the other, valve end, piston 6 opens one or more discharge holes 13A, 11 A, 11B of the other discharge channel 15, 16, at the end of the opening motion of the valve, whereupon the opening distance of the valve can be shortened and the closing moment be made earlier by allowing discharge flow through the said other discharge channel 15, 16. Hence, in the case of discharge in connection with piston 6, the open time of the intake, exhaust, or gas control valve of the engine compared to the rotation angle of the crankshaft, will be earlier than in the case mentioned before, involving piston 4.

This change in timing can be seen by comparing the curves caused by opening the said initial and final discharges, as displayed in exemplary figures 14A - 14D. Curves II, III 1, 14, 15, III4, III5, caused by opening the initial discharges (through channels 20, 20 A, 20B, 20C), show, for example, the valve beginning to open later than in curves 12, 13, III2, III3, caused by opening the final discharges (through channels 15, 16), which show, for example, earlier closing of the valve. These curves and corresponding functions will be returned to later, as the explanation of the invention progresses.

In addition, the device is designed so that at least two discharge channels 15, 16, 20, 20A, 20B, 20C are connected to discharge flow adjusting devices 15D, 16D, 20D, 20F, 20E, 20G, with which the discharge flows of channels 15, 16, 20, 20A, 20B, 20C can be separately adjusted. The controls of the device include controllable valves 15D, 16D, 20D, 20F for opening or closing the discharge channels. These function as control valves for the system.

The controls of the device include a throttling device 20E, 20G for adjusting the amount of discharge flow, at least in the discharge channel 20, 20A, 20B, 20C, controlling the beginning of the motion of the valve.

Also the following components can be seen in the device. In figures IA - IE grooves 46 on piston 6 and grooves 47 on piston 4, with functions of spreading and distributing oil, for example. Discharge route 19 to reduce pressure around piston 6 at the end 49 of piston 6. Annular groove 19C, which, among other things, lubricates piston 6. Cylinder support edging 19B. Springs 4J, 5J, and locking device 17B, seen in figures IA- IE and 2A - 2E. Discharge holes 13A, 11 A, 1 IB, inner annular groove 12A and outer annular groove 12B. In figures 2A - 2E a discharge route 23 for excess oil, air venting 116, lock rings 17A, 17C, mounting 22. Discharge route 19, function same as 19 in figures IA - IE.

Patent claim 5 expresses a means of damping the impact of the intake or exhaust valve, for instance, on its seating. The means is displayed in figure group 1 A - IE. How this happens is seen in more detail in figure group 9 - 11. The flow route of oil is reduced as piston 6 approaches its tolerance 48A, when, for example, the intake or exhaust valve of the engine approaches its closed postition. In this case the flow route is reduced from flow route 48E in figure 10 to flow route 48F in figure 11.

In the device presented in figure group IA - IE, the cam end piston 4 is smaller in diameter than the valve end piston 6. Hence, the motion distance of the cam end piston 4 is longer than the motion distance of the valve end piston 6, caused by cam end piston 4 through transmitting fluid. The end 48 of the valve end piston 6 and its parts 48D and 48C together with step 18A connected with the change in diameter 18C - 18B of the cylinder 18 of the pistons border a larger annular space 48E, which is reduced to the designated size by ad- justing screw 4S. This adjusting screw can determine how deep into the cylinder section 18B, with a smaller diameter, the adjusting screw 4S pushes parts 48D, 48C of the end 48 of piston 6, pressed by the valve spring. In this case flow takes place, if it is so adjusted, partially or completely through the smaller annular space 48F as the valve approaches its closed position. The flow resistance of flow from annular space 48E, 48F into cylinder space 5, that can be adjusted with adjusting screw 4S in the manner presented above, increases significantly by the designated motion distance before the closing of the valve, if the speed of the valve exceeds a certain limit. Thus the impact of the valve on its seating is reduced, which is needed during the phenomenon known as the "lost motion", which happens when transmitting fluid is allowed out of the space 5 between the pistons.

The device includes channel 15 for larger final discharge, and channel 16 for smaller final discharge, as well as respective control valves 15D and 16D, or at least control valve 15D for larger final discharge. Larger final discharge 15 makes, for instance, the closing of the valve earlier than smaller final discharge 16.

Figure 2E shows an example of the device that in addition to the features presented can also include following features. The device includes channel 15 for larger final discharge and open channel 16 for smaller or small final discharge. As an alternative, it can include only open channel 16 for small final discharge. The lift part of cam 2 on camshaft 1 has been made higher than, for example, the valve spring structure in connection with the device in question would allow, if there were no discharge flow out of cylinder space 5. In this case the lift caused by the lift part of cam 2 on camshaft 1 remains sufficient also when the amount of discharge through throttling device 20E and/or 20G is large, due to small running speed, and/or when the control channel 20D, 20F of one of the discharge channels 20, 20A, 20B, 20C for initial discharge is open. This principle can be applied to any of the presented implementations of the device.

Without control valve 16D, channel 16 remains an open channel. In this case, preventing discharge flow with adjusting device 20D, 20F for initial discharge, or with throttling device 20E, 20G, included in the controls, causes transmitting fluid to discharge through channel 16 for final discharge. This prevents piston 6 from moving too far, thus preventing lift excessive to the opening system structure of the valve, during the lift of the high lift part on cam 2 on camshaft 1, when the initial discharge is closed, or significantly throttled. Allow- ing discharge flow with adjusting device 20D, 20F, or increasing discharge relatively through throttling device 20E, 20G as running speed is reduced, reduces the said discharge through channel 16, or ends the discharge in question. In both cases the inner end 48 of the valve end piston 6 rises, with reasonable amounts of discharge, almost to the level of the inner entrance of discharge hole 1 IB of channel 16 in question. In this case the rise height of the valve remains also the same or almost the same as the relation of the length of the open time and timing of the valve to the rotation angle AM of the crankshaft changes. The ways in question of maximizing the lift of the valve work best, when at least some transmitting fluid is discharged, either through the route opened by the valve end piston of the device, or by the route closed by the cam end piston, or through both, as long as the engine is running, and the discharge is not at least completely disabled in any operation situation.

An example of the achieved valve function can be seen in the sets of curves 15 A and 15B. In both sets of curves the basic curve IIIO, caused by a cam on the camshaft (not displayed), is not achieved, because channel 16 is not closed. Basic curve IIIO begins at point 20K and merges with curve III2, presenting the actual lift of the valve, at point 16E, when control valves 20D, optional 20F, and 15D, are closed. Curve III2 is achieved by final discharge through open channel 16. In figure 15 A the height and end part of curve IIIl, which is achieved by opening control valve 20D, are the same as in curve III2, which merges with it at point 16F. In this case the valve opens later, at point 20 J as shown by curve IIIl.

Alternatively, the rise of the valve remains on the level of curve III3. When for example control valve 20D is closed, the curve begins at point 20K, and when control valve 15D is open, the discharge of transmitting fluid begins at point 15F through channel 15. When cont- rol valve 20 is open, and control valve 15D is opened simultaneously, the curve begins at point 20J, and follows curve III3 from point 15H. Either curve IIIl, or the different curve III2, matching curve IIIO at its first part, or alternatively curve 1113, the lowest and displaying the earliest closing, starting at point 20K or 20J, can be achieved similar as regards to the rise of the valve.

In figure 15B, with functions and numbering corresponding with figure 15 A, curve III3 does nor exist, because here channel 15 with its components have been left out of the structure of the device conforming to the invention. The device (not displayed) achieving the curves in figure 15B includes only channel 20, controlled by control valve 20D, and the open channel 16. In this case curve IIIl, beginning at point 20 J, is achieved with control valve 20D being open. When control valve 20D is closed, the first part of curve IIIO (solid line), starting at point 20K, and curve III2 (broken line), connected to it, beginning at point 16E, are achieved. The part presented with a broken line in curve III2 shows the greatest possible opening and latest possible closing of the valve. Figure group 3 - 8 presents as diagrams camwheels on the camshaft, which include in addition to the main lift part at least one additional lift part, either connected to the main lift part or separate of it, or an additional part. Patent publication FI 67130 gives an account on improving the efficiency ratio of an engine equipped with exhaust camwheels including main lift parts 2 and additional lift parts 3, like in figures3 or 4. This method is represented in the set of curves describing the function of the valves in figure 6, where curve A2b corresponds to the camwheel in figure 3 and curve A2a corresponds to the camwheel in figure 4. A method like this, for example, can be employed better, when the function conforming to additional lift part 3 can be disabled when needed and the valves of the engine can function in accordance with the main lift part 2.

The camwheels in question, as in figures 3, 4, and also in figures 5, 7, and 8, can function in connection with the system conforming to figures IA - IE, for instance. The function con- trolled by an additional part connected to them, or an additional lift part, can be disabled either completely or partially with a device conforming to the invention. Figure 5 presents as a diagram the known cam shape of the camwheel used in connection with a compression pressure brake. It includes a main lift part 3, and gradual additional lift parts 1 and 2 in order to lead the exhaust pressure caused by a throttling device out of the discharge distribution pipework back into the cylinder for the duration of the compression stroke (1) and out of the cylinder for the duration of the working stroke (2). For example, one must at all times be able to, some way, switch off the compression pressure brake for most of the time while the engine is running. Figures 7 and 8 describe cams equipped with additional parts 1, or 1 and 3, like additional lift parts, connected to the main lift part 2. All additional parts on the cam- wheel or additional lift parts, mentioned above, can be disabled from their function of lifting the valve, while the main lift part of the camwheel remains in its function of lifting the valve, by opening one or more of the control valves 20D, 20F, controlling initial discharge. In this case the part of the cam in question, or the one preceding it, will cause discharge of transmitting fluid into the reservoir, but the cam part in question will cause no valve lift at all, or at least not the usual extent of valve lift. The cam parts in question are re-enabled to their function of lifting the valve by closing the control valves mentioned above, 20D and/or alternatively 20F. If disabling additional part 3, in figure 8, following main lift part 2 in its rotation direction, from its function of moving the valve, is desired, it can also be done by opening one of the control valves 15D, 16D, controlling final discharge. This applies also to other cam parts connected to the main lift part 2, following main lift part 2 in its rotation direction, like camwheel part 3 in figure 3. The additional function caused by additional lift part 3 in figure 3 achieves, when desired, four different positions of the valve of the engine, for instance. First, when all control valves 15D, 16D, and 20D are closed, the valve of the engine opens according to the height of the additional lift part 3. Secondly, control valve 16D achieves a position, where the valve of the engine is slightly more closed than the height of additional lift part 3 determines. Thirdly, control valve 20D achieves an almost closed position. Fourthly, control valve 15D achieves a complete closed position.

The effect of opening control valve 15D or 16D does not reach, however, the function caused by, for example, the additional part 1 on the camwheel, located before the main lift part 2 in its rotation direction, as seen in figure 8. Hence, the closing of the valve can be controlled with additional part 3 and control valves 15D, 16D without the effect of additional part 1, located before the main lift part 2 of the camwheel in its rotation direction, reaching the opening of the valve. The effect of initial discharge 20D, 20F reaches the valve motion caused by both additional parts 1 and 3.

The main lift part 3 of the camwheel in figure 5, for example, remains in its function of moving the valve, when the control valve 20D, 20F mentioned above is open, even though the rise of the valve of the engine is somewhat reduced and the additional lift parts 1 and 2 are not lifting the valve. If the ways maximizing the rise of the valve mentioned before are applied here, the device will be equipped with open channel 16 and the camwheel in question will be equipped with a main lift part 3, which is made higher, and both components are appropriately dimensioned. In this case, also additional lift parts 1 and 2 can be made somewhat higher in relation to the camwheel than is shown, yet they still can be disabled from their function of moving the valve by opening initial discharge 20D, 20F in a sufficiently large amount. By closing the control valve 20D, 20F in question, the additional lift parts 1 and 2 of the camwheel in question can be re-enabled to their function of moving the valve.

Also, when needed, the main lift part 2 of a camwheel with an additional lift part in figure 3 or 4, for example, can be made higher than the valve spring structure, for example, would allow without additional arrangements, whereupon the rise of the valve caused by the main lift part remains sufficient even when control valves 20D, 20F are opened in order to disable additional lift part 3. Control valve 20D, and/or 20F is closed in order to enable any of the additional lift parts mentioned above or to enable additional part 1, 3. In this case transmitting fluid is discharged through discharge hole 11B, of the smaller final discharge 16, into annular groove 12B and further through discharge channel 16 into the reservoir during the lift of the main lift part. This cancels the damaging lift effect of the high main lift part, as required, in a way similar to already described in connection with a camwheel without additional lift parts.

Discharge of transmitting fluid can be measured in the way presented in figure 2C by allowing it through valve 106, located between throttling device 20E, of the initial discharge, and closed control valve 20D, into the measuring device. Discharge can be adjusted by changing the flow aperture of throttling device 20E. In this case the function of the valves between the cylinders can be balanced, when it is needed when imbalance in the function of the valves of the engines is caused, for example, by varying degrees of stiffness in the valve springs, so that reducing the flow aperture of throttling device 20E decreases the amount of transmitting fluid reaching the measuring device, increases the rise of the valve and extends the open time of the valve. Enlarging the flow aperture, on the other hand, increases the amount of transmitting fluid reaching the measuring device, reduces the rise of the valve and shortens the open time of the valve. In this way a desired open time level can be adjusted for the entire engine, and hence, a desired operating level for the engine achieved in a function where control valves 20D are kept open.

The balancing of the function of the valves between the cylinders of the engines can also be done continually. This is done by adding into the channel for initial discharge, like into channel 20 after control valve 20D, as seen in figure 2D, of the control devices of the valves in all the cylinders of the engine, a retreating piston 107, performing constant measuring. More details are seen in figure 2F. Piston 107 moves from its location in cylinder space 113 into a position, where discharge holes 114 are essentially closed. This retreating motion allows a certain amount of fluid in place of piston 107. The amount is determined mainly by the size and position of holes 114 and 111, and the dimensions of piston 107. However, the retreating motion mentioned above will not allow more transmitting fluid in place of piston 107 from space 5 between the valve end piston 6 and the cam end piston 4 than designed. The discharge route from the bottom of the cylinder space 113 through channel 111, with a smal diameter, into the groove 109 encircling the device and channel 110 for circulating oil remains open. Spring 108, the pressure of circulating oil, and flow from channel 20 through hole 115 into space 113, cause piston 107 to return back to measuring position. Correspond- ing motion and measuring the amount of fluid takes place at the beginning of each opening motion of each valve for as long as the control valve 20D, for the said initial discharge, is kept open. Component 117 holds the measuring device in its proper location.

Figure 12 shows cylinder 18, 7 cut open and unrolled on a plane. Examining both figure 12 and the figures in either figure group IA - IE or figure group 2 A - 2E reveals that when the inner end of valve end piston 6 opens a pressure connection, transmitting fluid is allowed, through venting and discharge holes 13 A distributed on the circumference of cylinder 18, 7, into circular groove 12 A. Through circular groove 12 A the transmitting fluid is allowed, through discharge holes 11 A, for larger final discharge, distributed on the circumference of cylinder 18, 7, into a pressure connection around the valve end piston (6). This situation is repeated when the discharge holes 1 IB, for smaller final discharge, are opened by the inner end of piston 6 in question. In this case a connection to outer circular groove 12B and further to pressure holes 13B is formed. The pressure centers piston 6, pushing piston 6 symmetrically away from the walls of cylinder 18, 7, from three directions, and thus prevents wear between components. The centering takes place best when control valves 15D, 16D are closed, or when some component of discharge route 15, 16 causes counter- pressure to the discharge of transmitting fluid into the reservoir.

The valve of the engine can be disabled from opening completely or partially in the way seen in figures IB and 2B. From the space 5 between pistons 4 and 6 a sufficient connection to the reservoir of transmitting fluid is opened, through the filling channel 10 of transmitting fluid, equipped with check valve 10 A. This is done with control valve 23D for filling channel 10 in question. Alternatively, or additionally, the discharge of transmitting fluid can be done with control valve 15D, for larger final discharge, through discharge hole 13 A (not displayed), enlarged for that particular purpose, and through circular groove 12A, to which a connection is partly open, for example, in the way presented in figure IE through the slimmed end 48 of piston 6, or opened by piston 6. The function last mentioned could cause, when used alone, the low curve 13 of the exhaust valve, seen for example in figures 14C, 14D. The function can be secured in both mentioned implementations by partially closing the feed of transmitting fluid from oil pump 41 with control valve 24D. The solutions in question could in some operating circumstances be advantageous in an engine, for instance, with more than one intake and/or exhaust valve for each cylinder, or, among other things, in cold circumstances when one desires at times to leave some exhaust gas in the cylinder in rhythmical intervals to raise the running temperature of the ignition chamber of a compression ignition engine.

It can be seen in both figure group 1 A - IE and figure group 2 A - 2E, that despite the differences in implementation between the figure groups, a similar structure causing whirl slowing down and preventing reflux of transmitting fluid is formed in both. Filling channel 8 and boosting channel 9 are connected to the space 5 between the cam end piston 4 and the valve end piston 6, so that an appropriate structure causing whirl in reflux is formed, such as a stepped structure, for example, suitable in relation with holes 8, 9, and channel 8A. When the presuure of transmitting fluid is greater in the space 5 between the pistons in ques- tion than in filling channels 8, 9, and when either one or both of the filling channels has an open connection to the space between pistons in question, reflux toward the oil pump deliberately causes whirling and flow resistance in some section of the filling channels in question. This will reduce reflux toward the oil pump. This can be achieved regardless of whether the channels in question are equipped with check valves. If check valves are used, their wear is reduced, because the pressure stroke on them will not be as sharp. A connection can be made from the channels in question to a third filling channel 10, which is equipped with check valve 10A. The inner entrance of channel 10 will not be closed by either of the pistons 4, 6 in question. This makes it possible for space 5 to be filled after a running halt, for instance, after sufficient pressure of transmitting fluid is produced, but channels 8 and 9 are closed by piston 4.

Figure IE reveals, that it is identical with figure 1 A, except for the end 48 of piston 6, which is made slimmer. This achieves a similar effect in connection with channel 16 as discharge channels 13 A achieve when control valve 15D is opened in connection with channel 15 in figures IA - ID. The discharge begins with a smaller amount already through discharge channels 13 A into channel 15, when control valve 15D is open as the end 48 of the piston opens the holes in question. With a slimmer end 48 of piston 6, the pressure that is present in the space 5 between the pistons, when the valve of the engine is opened, will also discharge into channel 16 while control valve 16D is open, or when control valve 16D does not exist, starting gradually, so that the discharge begins earlier and with a smaller amount at first, as the slimmed part reaches entrances 11B. The discharge begins in full only when the end 48 of piston 6 completely opens discharge holes 1 IB. In this case the pressure stroke on the discharge channel and possible discharge pipeworks is not as sudden and powerful. This re- duces disadvantageous vibration in the possible discharge pipework. If one desires even greater graduality of the opening, the end 48 of piston 6 can be made conical. Alternatively or additionally the entrance of discharge hole 11 A, 11B can be made in the shape of a triangle standing on one corner, or an oval or ellipse, so that the discharge increases gradually as the end 48 of piston 6 opens the hole in question. As a further alternative, if there are, for example, three discharge holes in the same cylinder 18, 7, the inner entrances of discharge holes 11 A, 1 IB can be placed on slightly different levels in their cylinder in question, so that the end 48 of the piston reveals them, at least partly, at different moments.

The curves describing the basic principle of valve motion in figures 14A - 14D are formed within the limits of cam geometry and the limits set by each device, when the amounts of discharge of transmitting fluid and/or the position of discharge holes are designed in specific ways, differing from each other. Also curves 10 and IIIO are achieved differing from figures 15A and 15B, because also channel 16 can be closed with control valve 16D. The curves caused by final discharges can merge at their intersecting point with curves IIIO, 10, deter- mined by cam shape alone, and/or with curves caused by initial discharges, with a similar mechanism as in figures 15A, 15B. For example, in figure 14A, curve III3 merges with curve IIIl. In figure 14D curve 12 merges with curve 10, II, and 14, whereupon in addition to the timing of the other valves in view three different opening moments can be selected, while the closing moment remains the same, conforming to curve 12. The curves, the valve control system, and controlling the system can be connected with each other in the following way: Curves 10 and IIIO: no discharge of transmitting fluid. Curves 12 and III2: discharge of transmitting fluid through channel 16. Curves 13 and III3: discharge of transmitting fluid through channel 15. In connection with curves 13 and III3, in some curves, like for example in figure 14 A, the effect of discharge hole 13 A is presented, which, for instance causes curve 13 to begin gradually along curve 10, and to separate from it at point A15. Furthermore, curve III3 merging with curve IIIl in figure 14 A is formed, when control valves 20D and 15D are open at the same time and the amount of discharge through channel 15 is relatively large. The initial discharges achieve following curves: Curves II and IIIl: discharge through channel 20, or 20A in figures IA, IB, ID, IE, 2 A - 2E, for example. Figure 14D, curves 14 and III4: discharge through channel 20C with control valve 20F in figure 1C; or through channel 20B in figure ID; in both figures through throttling device 20G while the flow aperture of the mentioned throttling device or the discharge of transmitting fluid is larger than the discharge through throttling device 20E. In figures 1C and ID curve II, IIIl is achieved with control valve 20D. Figure 14D, curves 15 and III5: discharge in figures 1C, ID simultaneously through both control valve 20D and control valve 20F through both throttling devices 20E and 20G. Curve 13 in figures 14C, 14D: discharge through enlarged channel 13A and the inner circular groove 12A with control valve 15D.

The initial discharge of the device, through channel 20, 20A, 20B, 20C, primarily, and/or also the final discharge through channel 15, 16, can be equipped with a throttling device 20E, 20G, or a part of the discharge route functioning as a throttling device, which limits the largest discharge possible. Alternatively, the limiting of the mentioned discharge and/or at what stage of its motion piston 4, 6 closes the corresponding discharge hole 20, 20A, 20B, 11 A, 1 IB, is dimensioned so that the amount of discharge through the limiting component is significantly larger per each working motion of piston 4, 6 in low running speeds of the engine than in higher running speeds. This can be achieved because, among other things, the flow time for each motion of piston 4, 6 is reduced as the running speed grows. In this case, for example, the open time of the valve controlled by the device presented in figure 2E increases as the running speed of the engine grows. Correspondingly, the open time of the valve is shortened automatically as the running speed of the engine is reduced, when discharge takes place increasingly through throttling device 20E, as the duration of the dis- charge grows, and decreasingly through channel 16, which limits the greatest rise of the valve. The open time of the valve is adjusted in this case by the running speed while the rise of the valve remains constantly almost unchanged, except when control valve 15D is opened. Changing the valve timing in this way and simple structure is advantageous in several engine types.

As a simple example a device (not displayed) can be mentioned, which includes one initial discharge 20, and one final discharge 15. The function is controlled, for example, with a control valve which, while opening the other channel 15 closes the other channel 20, and while opening channel 20 closes channel 15. The device has only one filling channel 8. As an example of more versatile valve control, in figure 1C an opportunity to use control valve 20D, 20F to select either one or both of throttling devices 20E, 20G, with different sized flow apertures. In figure ID one can choose whether to open discharge channel 20A, closing earlier, or discharge channel 20B, closing later, or both. Throttling devices 15E, 112, some throttling devices 20E, and throttling points in certain control valves function as parts of the air venting route, but the flow resistance caused by the mentioned throttles can, when desired, be dimensioned so that the opening time of the valve can be somewhat limited in low running speeds of the engine.

It is obvious, that the invention is not limited to the displayed implementations, but several variations can be achieved as different combinations of the controlling and adjusting methods presented in this explanation and in the following claims.

Claims

Patent Claims

1. A device for controlling the function of the valves of an internal combustion engine, when the engine contains at least one intake valve and/or at least one exhaust valve and/or at least one control valve for gaseous fuel for each cylinder, the device containing a camshaft (1) cam (2) end piston (4) and a valve end piston (6) as well as a cylinder space (5) between the pistons (4, 6), which is connected to a filling channel (8, 9, 10) for fluid transmitting power between the pistons, and a discharge channel (20, 20A, 20B, 20C) with its discharge holes (20, 20A, 20B), which the cam end piston (4) closes at the beginning of the opening motion of the valve, c h a r a c t e r i z e d by the cam end piston (4) closing one or more discharge holes (20, 20A, 20B) of the first discharge channel (20, 20A, 20B, 20C) at the beginning of the of the opening motion of the valve, whereupon the opening moment of the valve can be made later and correspondingly the closing moment of the valve can be made earlier by allowing discharge flow through the first discharge channel (20, 20 A, 20B, 20C); and by the valve end piston (6) opening one or more discharge holes (13 A, 1 IA, 1 IB) of the second discharge channel (15, 16) at the end of the opening motion of the valve, whereupon the opening distance of the valve can be reduced and the closing moment can be made earlier by allowing discharge flow through the said second discharge channel (15, 16).

2. A device conforming to patent claim 1, c h a r a c t e r i z e d by that at least two discharge channels (15, 16, 20, 20A, 20B, 20C) are connected to discharge flow control devices (15D, 16D, 20D, 20F, 20E, 20G), with which the discharge flows of the channels (15, 16, 20, 20A, 20B) can be controlled separately.

3. A device conforming to patent claims 1 and 2, c h a r a c t e r i z e d by that the control devices include controllable valves (15D, 16D, 20D, 20F), in order to open or close the discharge channels.

4. A device conforming to patent claims lto3, characterized by that the control devices include a throttling device (20E, 20G) to adjust the amount of discharge flow, at least in the discharge channel (20, 20A, 20B, 20C) controlling the beginning of the opening motion.

5. A device conforming to any of patent claims lto4, characterized by that the cam end piston (4) is smaller in diameter than the valve end piston (6), whereupon the traveling distance of the cam end piston (4) is longer than the traveling distance of the valve end piston (6) that is caused by the cam end piston (4) and transmitted with transmitting fluid; and that the end (48) of the valve end piston, together with a step (18 A) in connection with the changing of diameter of the cylinder (18) of the pistons, confines a larger annular space (48E), which is made smaller with an adjusting screw (4S) down to the designated size when the flow occurs, if the flow is so adjusted, partially or completely through the smaller annu- lar space (48F) as the valve nears its closed position and the flow resistance of the flow from the annular space (48E, 48F) into the cylinder space (5), adjusted by the control screw (4S) in the way mentioned above, grows significantly before the closing of the valve by the designated traveling distance, if the speed of the valve exceeds a certain limit, thus reducing the valve's impact power on its seat.

6. A device conforming to patent claim 1, characterized by that the device includes a channel (15) for a larger amount of final discharge and a channel (16) for a smaller amount of final discharge and also control valves (15D and 16D) corresponding with both said chan- nels, respectively, or at least the corresponding control valve (15D) for a larger amount of final discharge.

7. A device conforming to patent claim lor6, characterized by that the device includes the channel (15) for a larger amount of final discharge and the channel (16) for a smaller amount of final discharge, or alternatively, only a channel (16) for a small amount of final discharge, and that the lift part of the camshaft cam is made higher than, for example, the valve spring structure would allow without discharge flow from the cylinder space (5), whereupon the lift of the valve caused by the lift part in question remains sufficient even when one of the channels (20, 20A, 20B, 20C) for initial discharge is open, and the channel (16) for a smaller or small amount of final discharge has been left without control devices as an open channel, whereupon excessive lift of the valve is prevented, when needed, while the channel (20, 20A, 20B, 20C) for initial discharge is partially or completely closed.

8. A device conforming to patent claim 1 or 7, c h a r a c t e r i z e d by that when using an additional camshaft cam lift part (3) separate from the main lift part (2) of the cam, or an additional part (1, 3) of the main lift part, the said part can be partially or completely dis- abled from its function of lifting the valve, while the main lift part (2) of the cam remains in its function of lifting the valve, by opening one or more of the control valves (20D, 20F) controlling initial discharge, and that then the main lift part (2) of the camwheel can, when needed, be made higher than the valve spring structure, for example, would allow without additional arrangements, whereupon the lift of the valve caused by the main lift part (2) remains sufficient also when the control valves in question (20D, 20F) are opened in order to partially or completely disable the additional lift part (3) or the additional part (1, 3) from its function of lifting the valve, and that while the said control valves (20D, 20F) are closed in order to enable the additional lift part (3) or the additional part (1, 3), transmitting fluid is discharged through the discharge hole (UB) of the channel (16) for a smaller amount of final discharge into an annular groove (12B) and through the discharge channel (16) into a reservoir, during the lift of the main lift part, thus reversing the harmful lift effects of the high main lift part.

9. A device conforming to patent claim 1, c h a r a c t e r i z e d by that the discharge of transmitting fluid can be measured by allowing it through a valve (106), placed between the throttling device (such as 20E) for initial discharge and the control valve (such as 20D) for initial discharge, into a measuring device; and it can be adjusted by changing the flow aperture of the throttling device (such as 20E), whereupon balancing valve function between the cylinders of the engine, when it is needed when imbalance in the function of the valves of the engines is caused, for example, by varying degrees of stiffness in the valve springs, can be achieved by reducing the flow aperture of the throttling device (such as 20E) which reduces the amount of transmitting fluid reaching the measuring device, adds to the lift of the valve, and lengthens the open time, whereas enlarging the flow aperture increases the amount of transmitting fluid reaching the measuring device, reduces the lift of the valve, and shortens the open time.

10. A device conforming to patent claim 1, c h a r a c t e r i z e d by that the balancing of valve function between the cylinders of the engine can be done continually by adding into the discharge channel (20) for initial discharge, after the control valve (20D), in corresponding valve control system units of all the cylinders, a retreating piston (107), performing continual measuring, moving from its location in its cylinder space (113) into a position where discharge holes (114) are essentially closed allowing transmitting fluid into the location of the moved piston (107) from the space (5) between the valve end piston (6) and the cam end piston (4) at the beginning of each opening motion of the valve for as long as the said control valve (20D) for initial discharge is kept open.

11. A device conforming to patent claim ^ c h a r a c t e r i z e d by that the additional parts (1) connected to the main lift part (2) of the camwheel or the additional lift parts (1, 2, 3) of the cam, separate of the main lift part (2, 3) of the camwheel, located on the camwheel of the camshaft before the main lift part (2) in the direction of rotation, can completely or partially be disabled from their function of moving the valve by opening the control valve (20D, 20F) for initial discharge, while the main lift part (2, 3) of the camwheel remains in its function of moving the valve; and the said additional parts and the additional lift parts can be re-employed in order to resume their function of moving the valve by closing the control valve (20D, 20F) in question.

12. A device conforming to patent claim 1, c h a r a c t e r i z e d by that by opening one of the control valves (20D, 20F) controlling initial discharge, or one of the control valves (15D, 16D) controlling final discharge, the lower additional part (3) connected to the main lift part (2) of the cam of the camshaft, located after the main lift part (2) in the rotation direction of the cam, or the additional lift part (3), can be either completely or partially disabled from its function of lifting the valve, while the main lift part (2) remains in its function of lifting the valve, and, when desired, by adjusting the amount of discharge of transmitting fluid an effect can be achieved, where the valve either closes completely or remains open to the de- sired degree when the cam part in question lifts the valve, whereas when the control valve (16D) for smaller final discharge or the control valve (15D) for larger discharge is opened, the effect of the said discharge does not reach the lift of the valve caused by the additional part (1) located before the main lift part in its rotation direction or the additional lift part, but the effect of the said discharge does reach the lift of the valve caused by the additional part (3) connected to the main lift part, located after the main lift part (2) in its rotation direction, or the additonal lift part (3), whereupon the effect of the discharge of transmitting fluid can be targeted, with the help of initial discharge, on the valve motions caused by camwheel parts located before or after the main lift part, in the rotation direction of the camwheel, or, with the help of a larger final discharge or a smaller final discharge, only on the valve motions caused by the additional parts (3) connected to the main lift part, located after the main lift part (2), in the rotation direction of the camwheel, or the additional lift parts (3).

13. A device conforming to patent claim 1, c h a r a c t e r i z e d by that when the inner end of the valve end piston (6) opens a connection through the venting and discharge holes (13A) distributed on the circumference of the cylinder (18, 7) and through the inner annular groove (12A), through the discharge holes (HA), for larger final discharge, distributed on the circumference of the cylinder (18, 7), transmitting fluid is allowed into a pressure connection around the valve end piston (6), and the situation is repeated when the discharge holes (UB), for smaller final discharge, are opened by the inner end of the piston (6) in question, whereupon a connection to the outer annular groove (12B) and further into pressure holes (13B) is formed, whereupon the pressure in both cases mentioned centers the piston (6) by pushing the piston (6) from three directions away from the walls of the cylinder (18, 7) and hence prevents wear between components.

14. A device conforming to patent claim 1, c h a r a c t e r i z e d by that the valve of the engine can be disabled from opening, partially or completely, during running, for example, by opening a sufficient connection to the reservoir of transmitting fluid through a filling channel (10) for transmitting fluid, equipped with a check valve, with the control valve (23D) for the filling channel (10) in question, and/or through the discharge hole (13 A), enlarged for this particular purpose, closest to the cylinder space (5), opened by the valve end piston (6) into the inner annular groove (12A), whereupon the discharge is controlled by the control valve (15D) for larger final discharge, and in both cases the function can be secured by partially closing the feed of transmitting fluid from an oil pump (41) with a control valve (24D), and the function can be used, among other things, in cold circumstances when one desires at times to leave some exhaust gas in the cylinder in rhythmical intervals to raise the running temperature of the ignition chamber of a compression ignition engine, for instance.

15. A device conforming to patent claim 1, c h a r a c t e r i z e d by that the space (5) between the cam end piston (4) and the valve end piston (6) is connected to a feed channel

(8) and a boosting channel (9), so that when the pressure is greater in the space (5) between the pistons in question than in the filling channels in question, and one or both of the said filling channels have an open connection to the said space between pistons, the reflux toward the oil pump deliberately causes whirling and flow resistance in some section of the said filling channels, and reduces reflux towards the oil pump, regardless of whether the said channels are equipped with a check valve or not; and that a connection can be made from the channels in question to a third filling channel, which is equipped with a check valve (10A), and the inner entrance of which will not be closed by either of the pistons in question.

16. A device conforming to patent claim 1, c h a r a c t e r i z e d by that the discharge holes for final discharge (13A, 11A, 11B) can be shaped so, or placed on different levels in their cylinder (18, 7), or that the end (48) of the piston (6) can be slimmed or conically shaped in a way that the discharge of transmitting fluid begins with a smaller amount, which increases little by little or gradually, whereupon the pressure impact on the system of discharge channels or discharge pipework will not be as powerful and/or sharp as without the structure in question.

17. A device conforming to patent claim l or 7, c h a r a c t e r i z e d by that the initial discharge through channel (20, 20A, 20B, 20C) and/or the final discharge (15, 16) is equipped with the throttling device (20E, 20G), or a section of the discharge route functioning as a throttling device, which is dimensioned so that the amount of discharge through the component throttling flow is larger with each working stroke of the piston (4, 6) in low running speeds than in higher running speeds, whereupon the open time of the valve controlled with the said throttling is extended as the running speed of the engine grows and the open time of the valve is shortened as the running speed of the engine is reduced, when discharge takes place through the said throttling component.

18. A device conforming to patent claim 1, characterized by that the engine can only be started when there is certain sufficient pressure of transmitting fluid in the filling channel (8, 9, 10) of the device in question.

AMENDED CLAIMS

[received by the International Bureau on 10 October 1997 (10.10.97); original claim 1 amended; remaining claims unchanged (1 page)]

1. A device for controlling the function of the valves of an internal combustion engine, when the engine contains at least one intake valve and/or at le ast one exhaust valve and/or at least one control valve for gaseous fuel for each cylinder, the device containing a camshaft (1) cam (2) end piston (4) and a valve end piston (6) as well as a cylinder space (5) between the pistons (4, 6), which is connected to a filling channel (8, 9, 10) for fluid transmitting power between the pistons, and a discharge channel (20, 20A, 20B, 20C) with its discharge holes (20, 20A, 20B), which the cam end piston (4) closes at the beginning of the opening motion of the valve, c h a r a c t e r i z e d by the cam end piston (4) closing from the opened state one or more discharge holes (20, 20A, 20B) of the first discharge channel (20, 20A, 20B, 20C) during the motion caused by the cam (2), directed away from the cam (2) at the beginning of the of the opening motion of the valve, whereupon the opening moment of the valve can be made later and correspondingly the closing moment of the valve can be made earlier by allowing discharge flow through the first discharge channel (20, 20A, 20B, 20C) before the said closing; and by the valve end piston (6) opening one or more discharge holes (13 A, 1 1 A, 1 IB) of the second discharge channel (15, 16) at the end of the opening motion of the valve, whereupon the opening distance of the valve can be reduced and the closing moment can be made earlier by allowing discharge flow trough the said second discharge channel (15, 16), and the discharge flow can be prevented either completely or partially by keeping closed or by partially or completely closing the said second discharge channel (15, 16) by means of a control device or control valve (15D, 16D, 15E).

2. A device conforming to patent claim 1, c h a r a c t e r i z e d by that at least two discharge channels (15, 16, 20, 20A, 20B, 20C) are connected to discharge flow control devices (15D,

16D, 20D, 20F, 20E, 20G), with which the discharge flows of the channels (15, 16, 20, 20A, 20B) can be controlled separately.