US2069315A - Internal combustion engine - Google Patents

Description

Feb. 2, 1937. F. 'r. lRG ENS INTERNAL COMBUSTION ENGINE Filed April 5, 1935 I l I. .55- /5 AZ O INVENTOR a w 1% W ATTORNEYS Patented Feb. 2, 1937 UNITED STATES PATENT OFFICE INTERNAL COMBUSTION ENGINE Application April 5,' 1935, Serial No. 14,875

9 Claims. (01. 123-73) This invention relaties to improvements in internal combustion engines of a type particularly adapted for use in outboard motors.

It is one of the broad general objects of the invention to reduce the weight of an internal combustion engine by providing in a single unit a fuel tank and carburetor jet, thus eliminating the carburetor bowl and float and conveniently disposing the fuel reservoir for the convenience of the operator.

More specifically, it is my purpose to locate the fuel tank at the front of the motor, including the meter valve and charge forming means unitarily therewith, and to provide a novel and improved set of controls for equalizing the feed of fuel at different engine speeds.

In the drawing:

Figure 1 is a view of a complete outboard motor including an internal combustion engine embodying the present invention and illustrated partially in side elevation and partially in axial section.

Figure 2 is a plan view of the fuel reservoir as it appears with the cover of the charge forming device removed.

Figure 3 is a detail view in section taken on the line 3-3 of Figure 2.

Figure 4 is a fragmentary plan view of a portion of the timer and a portion of the choke member of the charge forming device.

Figure 5 is a fragmentary detail partially in front elevation and par ially in transverse section through a portion of the fuel reservoir and the cover applied thereto.

Like parts are identified by the same reference characters throughout the several views.

The outboard motoi comprises an engine having a crank case 6, crank shaft 1, connecting rod 8, piston 9, cylinder It, fly-wheel magneto I l, timer plate l2, and spark plug !3, all of which may be of conventional design except as hereinafter specified.

The crank case 6 is disposed av the upper end of a shaft housing l5 for the drive shaft l6 connected with the engine crank shaft. At the lower end of the shaft housing is a lower unit assembled, preferably, from die cast parts as explained in my companion application No. 728,645 filed June 2, 1934. There is a gear casing II, a propeller l8 operatively connected in the usual manner with the drive shaft I6, and a clamp I9 applied about the shaft housing and supporting a water pump 20, an anti-cavitation plate 2|, and an exhaust discharge fitting 22, to which the exhaust pipe 23 leads from the cylinder I ll.

From the pump 20 a pipe 2 l 0' leads to the jacket 220 of the cylinder ID for the cooling of the engine cylinder.

The entire motor assembly as above described is dirigibly mounted in a swivel bearing comprising the two bearing sections 24 and 25 integrally 5 joined by an arm 26 which is pivoted by bolt 21 to a bracket member 28 having a single clamp at 29 to engage the transom of the boat.

The side of the swivel bearing sleeve 24 is provided with a boss shown in dotted lines at 30, 10 which is threaded to receive a set screw 3| engageable with the upper margin of the bracket 28 to determine the angular position of the bracket and motor assembly upon the fulcrum bolt 21, from which position the entire motor assembly is 15 freely tiltable upwardly to clear submerged obstacles.

The front side of the crank case 6 is formed to provide a seat to which the top section 35 of the fuel reservoir 36 is secured. The screws 3'! shown in Fig. 2 support the lower section of the fuel reservoir from the upper section thereof.

The tiller by which the entire outboard motor is dirigibly controlled is mounted directly on the top member 35 of the fuel tank reservoir, thus further economizing in weight by eliminating a special tiller arm. In practice this tiller preferably comprises a handle 32 made of elastical y yieldable rubber or the like, the rear end of which is engaged under compression by a washer 3o 38 retained by the head 39 of a cap screw in threaded engagement with the fuel tank cover 35. By loosening the cap screw 39, the tiller handle may be adjusted to any convenient angle, and when the cap screw is tightened down the adjust- 35 ment is made permanent. The flexibility of the handle grip 32 per se takes up all torque vibration. The upper and lower sections of the fuel reservoir are'preferably both made of die castings and consequently are comparatively rigid. 40 Also, by reason of this fact, they may readily be varied in thickness as required to provide the various ducts and passages hereinafter to be described. A removable closure is provided at 40 for the introduction of the fuel.

In the lower unit of the fuel reservoir there is an annular flange 4| (see Fi 3) threaded to receive a clean-out plug 42. Through the opening thus provided, a fuel supply pipe 43 may be introduced for connection with a boss 44 formed on the under side of the top section of the reservoir. The inlet at the lower end of pipe 43 is preferably covered by a screen 45.

At its upper end the fuel pipe 43 communicates with a duct 46 in the interior of a plug 41 with which a needle valve 48 is in screw threaded connection. The plug 41 provides a suitable seat for the needle valve and also carries conventional packing for the stem thereof.

Beyond the needle valve the duct 46 has an upward extension 49 (Figs. 2 and 3) terminating in a jet opening 50 at the upper face of the top section 35 of the fuel reservoir.

The longitudinally extending boss 52 in the top section 35 of the fuel reservoir through which duct extension 49 leads to jet opening 50, has an air admission port 53 leading to an interior air passage 54 opening adjacent the jet 50 through a U-shaped port 55 in the substantially planiform upper surface 56 of the section 35 of the reservoir. Beyond this point there is another duct 51 leading downwardly and communicating with a duct 58 which carries the mixture to the interior of the crankcase.

Applied to the flat surface 56 of the top member 35 of the fuel reservoir is a cap 59 channeled at 60 to provide a passage communicating with passages 51 and 58 which lead to the crankcase, and also potentially communicating with the jet port 50 and the passage 54 through which the fuel and air are respectively supplied. It is in the passage 60 that carburetion actually occurs.

Confined between the cap 59 and the top section 35 of the fuel reservoir is a. mixing valve comprising a flat spring plate 65 which covers the U-shaped air port 55 and the fuel jet port 50. The end of the spring valve plate above the fuel port is free and the other end is fixed. Thus the pressure differential between the crankcase and the atmosphere during the compression stroke of the piston in its cylinder will cause atmospheric air to pass under the margins 61 of cap 59 and through port 53 and passage 54 to port 55, where the air pressure will cause valve 65 to flex upwardly, thus admitting air to the mixing passage 60 and directing its flow across the jet orifice 50. The greater the pressure differential, the greater will be the upward movement of the spring mixing valve 65 and the greater will be the vacuum on the fuel orifice, thereby producing increased flow of both air and gasoline to supply the increased demand. The mixing valve 65 comprises a fairly light spring plate and serves as a check valve to prevent the escape of mixture when the mixture is compressed in the crankcase.

It has been found that the shape of port 55 and passage 51, as clearly shown in Fig. 2, is admirably adapted to ensure a proper proportion of fuel and air subject, of course, to the control of the fuel by means of the needle valve. The exact type of spring must be determined by experiment since the requirements will vary with each installation, but its resilience is not critical and it is only desirable that its range of movement between closed and open positions in passage 60 should approximately correspond to the range of air flow through the passage so that the valve will be fully open in response to maximum air requirements and will be barely open in response to minimum air requirements.

The fuel reservoir is so designed as to have a large area in proportion to the amount of depth of fuel therein. Therefore the head against which the fuel must be drawn to the jet orifice 50 will not vary as greatly as would be the case if a high narrow tank were used. The design is preferably such that at normal operating speeds there will be ample depression at the jet orifice to draw the fuel from the bottom of the tank (at maximum head).

At the same time the depression available for lifting the fuel to the jet should not exceed the actual requirements of the motor, since otherwise the motor will operate at low volumetric efficiency. Accordingly I have provided means by which the volumetric efficiency may be at a maximum during normal operating speeds and means is provided to increase the depression in the mixing passage at low engine speeds sufficiently to compensate for the decrease of vacuum in the crankcase at such speeds.

In this, as in many other two cycle engines, speed is controlled by the timer, the plate l2 being mounted for angular adjustment about the axis of the crank shaft under control of the handle 68. Since the position of handle 68 and plate 12 is directly related to engine speeds, I am able to provide on plate 12 a cam at 69 having a surface of the generally helical form shown in Fig. 4. This cam acts upon a cam follower 10 which is in the form of a plunger and is efiective to choke the air inlet port 53.

The choke comprises a slide valve 12 removable across the top of port 53 to restrict the opening thereof. A yoke 13 carried by the slide valve engages a spool-shaped nut 14 which is screw threaded to the cam follower plunger 10, the nut being restrained by the yoke from rotation. A compression spring at 15 acts on nut 14 to maintain the slide valve 12 in its normally retracted wide open position and to maintain the cam follower 10 in abutment with the operating surface of cam 69.

As the lever 68 is actuated toward the retarded position shown in Fig. 4 it pushes the cam follower "rod 10 to the right as viewed in Fig. 1, until the slide valve 12 partially covers the aperture 53. The exact degree of coverage may be controlled and adjusted by the rotation of the cam fo ower rod 10 in nut 14, and by the end of the rod being exposed and provided with a screw driver slot for this purpose.

At normal operating speeds the parts are as shown in Fig. 1, port 53 being wide open.

It is also desirable to choke the air intake for starting. For this purpose a separate choke may conveniently be provided comprising a piston type slide valve in the bore beneath the inlet port 53 at 16. This choke valve is mounted on a valve stem 11 having an exposed button at 18 normally held in the retracted position by a compression spring at 19. By pressing the button the operator may substantially close off the air below port 53, as will be obvious from inspection of Fig. 1.

I claim:

1. In a device of the character described, the combination with a. two cycle engine having crank case compression, and a fly-wheel magneto including an angularly adjustable timer plate, of a fuel reservoir disposed adjacent the engine crank case and below the magneto and providing intersecting passages for fuel and air leading to the engine crank case, of interacting means carried by said fuel reservoir and timer plate for progressively obstructing the passage for air in the movement of the timer plate toward an engine retarding position.

2. In a device of the character described, the combination with an engine having crank case compression and a timer speed control member, of a fuel reservoir provided unitarily with a charge forming device communicating with the engine crank case, an air throttle associated with said charge forming device, and a connection from said speed control member to said throttle for the closing of said throttle progressively in accordance with the movement of said member in an engine retarding direction.

3. In a device of the character described, the combination with an upright crank shaft, of an internal combustion engine cylinder and crank case operatively associated with the crank shaft, 8. fly-wheel magneto above said cylinder on the crank shaft and provided with an angularly adjustable timer plate, a fuel reservoir adjacent the crank case and provided unitarlly with a charge forming device including an air passage underlying said fly-wheel and plate, a valve controlling air flow through said passage, a cam follower connected with said valve, and a cam connected with said plate for the movement of said valve to regulate air flow through the passage in accordance with the timing movement of said plate.

4. In a device of the character described, the combination with an engine having a speed control, of a fuel reservoir for said engine, a charge forming device including an air passage unitarily incorporated with said fuel reservoir, a valve controlling air flow through said passage operatively connected to'be operated in accordance with the movement of said speed control, and a second valve manually operable for control of air flow through said passage.

' 5. In an internal combustion engine, the combination with an upright crank shaft, of a crank case enclosing a portion of said shaft, a cylinder projecting rearwardly therefrom, means supporting said crank case, an engine piston and connecting rod operatively assembled with said cylinder and shaft, a charge forming device operatively connected with said crank case and dependent thereon for support and projecting forwardly therefrom, and a fuel reservoir suspended from said crank case on said charge forming device and of which said charge forming device constitutes the cover.

6. In an internal combustion engine, the combination with a crank case provided with upright crank shaft bearings and a cylinder projecting.

said crank shaft, and a cam on said timer plate engagingsaid stem for the adjustment of said valve in the angular movement of said plate.

7. In an internal combustion engine, the combination with a crank case, of a charge forming device projecting laterally from said crank case,

said crank case and charge forming device having registering passages in communication for the admission of air to said crank case, a fuel duct intersecting one of said passages for the carburetion of such air, a pipe comprising a downward extension of said duct, and a fuel reservoir supported by said charge forming device from said crank case and toward the bottom of which said pipe extends, said charge forming device constituting a closure for the top of said reservoir.

8. In an internal combustion engine, the combination with a crank case, of a charge forming device projecting laterally from said crank case, said crank case and charge forming device having registering passages in communication for the admission of air to said crank case, a fuel duct intersecting one of said passages for the carburetion of such air, a pipe comprising a downward extension of said duct, and a fuel reservoir supported by said charge forming device from said crank case and toward the bottom of which said pipe extends, said charge forming device constituting a closure for the top of said reservoir and being provided with a filler opening and a cap for replenishing the contents of said res- .ervoir.

9. In an internal combustion engine, the combination with a crank case and an upright crank shaft provided with bearings therein, of a magneto fly wheel carried by said crank shaft above said crank case and provided with an adjustable timer plate,a charge forming device projecting laterally from said crank case beneath said fly wheel and plate and provided with internal air and fuel passages leading to sand crank case, a fuel reservoir for which said charge forming device constitutes a cover, a plurality of valves controllingsaid air passage, one of which has a manual control element located adjacent the front of said charge forming device and another of which has a rearwardly projecting stem extending toward said crank shaft, cam means on said plate engaging said stem for the movement of the last mentioned valve in accordance with timing adjustments of said plate, and a handle projecting forwardly from said plate for the manual control thereof, whereby the several controls of said engine are centralized adjacent the front of said charge forming device.

FINN T. IRGENS.

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