JPS5879649A - Choke valve and throttle valve control device in carburetor - Google Patents

Abstract

PURPOSE:To always hold an operational condition of an engine to an adequate state, by controlling openings of a choke valve and throttle valve in accordance with an operating condition of the internal combustion engine. CONSTITUTION:A controller is constituted in such a manner that openings of a choke valve 4 and throttle valve 5 are steplessly controlled in accordance with operating conditions of engine temerature and the like by a signal of pulse motor M and the first and second rotary cam means C1, C2 driven by the motor M. For instance, in case of the enine temperature decreasing to a prescribed value or less, a signal form an engine temperature detector 23 is fed to a control circuit 22, and the control circuit 22 applies a pulse, in accordance with an input signal to said circuit, to the motor M to rotate all cam plates 16, 17, 18 to a direction B. As a result, a flank part 16a of the leading cam plate 16 is engaged firstly to a driven element 6a' to move turning the first arm 6a of a choke lever 6 against tension of a return spring 7, and the choke valve 4 is caused closing.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a carburetor in which a choke valve is installed on the upstream side of an intake passage and a throttle valve is installed on the downstream side of the intake path, with the venturi portion where the main fuel nozzle opens as a boundary, and the choke valve and the throttle valve are installed in the carburetor. The present invention relates to a choke valve and throttle valve control device that controls the opening degree of the internal combustion engine according to the operating conditions of the internal combustion engine so as to always maintain an appropriate operating state of the engine.

Conventionally, an auto choke device has been known as this type of device, and this device connects a temperature sensing member such as a bimetal to a choke valve, and controls the opening degree of the choke valve by operating the temperature sensing member in response to changes in engine temperature. At the same time, the idle opening of the throttle valve is also controlled in accordance with the engine temperature by interlocking the choke valve and the throttle valve through links and cams, etc., but the structure is complicated and the carburetor In addition to bulking up the
Since the closing force of the return spring is always acting on the throttle valve, there is a drawback that it is difficult to always properly control the idle opening of the throttle valve using only the output of the temperature sensing member. Since such an auto choke device uses the engine temperature as a control signal, for example, in an automobile, auxiliary equipment such as a congressor for a cooler, a hydraulic pump for power steering, a generator for charging, etc. are connected to the engine as a load. In this case, the engine does not have a function of increasing the idle opening of the throttle valve to maintain the idle link speed of the engine at a predetermined value. Therefore, in the past, in addition to the auto choke device, a negative pressure operated throttle lever was connected to the throttle valve, and when the auxiliary equipment was connected, the throttle lever was operated to open the throttle valve to an opening slightly larger than the normal idling opening. It is also known to include a load-responsive throttle valve control device that opens the throttle valve automatically. However, since such a device can only adjust the idle opening of the throttle valve in steps, it is difficult to accurately control the idle rotation of the engine to a constant level regardless of the weight of the load on the auxiliary engine. Needless to say, it is extremely difficult to do so, and needless to say, there is the disadvantage that the carburetor becomes even bulkier when it is installed in conjunction with an auto-choke device.

The present invention has been proposed in view of the above, and uses one pulse motor and rotating cam means driven by the pulse motor to control the opening degree of the choke valve and the throttle valve according to the engine temperature, the load applied to the auxiliary engine, and the like. Another object of the present invention is to provide a simple and compact choke valve and throttle valve control device capable of continuously maintaining an appropriate operating state of an engine by performing stepless control according to the operating conditions of the engine. It is something.

Hereinafter, one embodiment of the present invention will be explained with reference to the drawings. In FIG. 1, a carburetor main body 1 has an intake passage 2 in the vertical direction. A venturi part 2 is connected to an intake pipe (none of which is shown) of an internal combustion engine, and a main fuel nozzle 3 opens in the middle part of the venturi part 2.
α becomes L).

Upstream 1i of the intake passage 2 with this venturi part 2α as a boundary
111 (air cleaner side) choke valve 4, downstream side (
A throttle valve 5 is installed in the engine 1I4Il). These valves 4
゜5 are all butterfly type, each with 1 carburetor body.
The valve shafts 4α and 5α are rotatably supported by the valve shafts 4α and 5α.

A choke lever 6 is connected to the valve shaft 4α of the choke valve 4, and has two arms spaced apart from each other, that is, first and second arms 6a and 6b. A return spring T is connected to bias the choke valve 4 in the opening direction.

A throttle lever 8 is fixed to the valve shaft 5α of the throttle valve 5, and a return spring 9 is connected to the lever 8 to bias it in the closing direction of the throttle valve 5. The throttle lever 8 is fan-shaped and has a guide groove 10 on its outer periphery, and an operating wire 11 connected to an accelerator pedal (not shown) is engaged with the guide groove 1o and connected to the throttle lever 8.

Further, an interlocking lever 12 extending to a portion near the choke lever 6 is rotatably attached to the valve shaft 5α. The interlocking lever 12 and the throttle lever 8 are each integrally equipped with a stopper piece 13 and a contact piece 14 facing each other, and a stopper screw 15 screwed onto the stopper piece 13
is blanked out on the contact piece 14 so that it can be separated.

*i of the choke lever 6, the second arms 6α and 6b, and the side surface of each tip of the interlocking lever 12 are provided with followers 6at.

6b/ and 11 are provided, and followers 6d, fi
bIk is engaged with the first rotary cam means C3 capable of rotating the choke lever 6, and is engaged with the follower 12' and rotates the interlocking lever 1.
A second rotary cam means C3 capable of rotating the second rotary cam 2 is disposed coaxially as follows.

That is, as shown in FIG. 1.2, the first rotating cam means C1
is composed of two cam plates that are overlapped and bonded to each other, that is, a leading cam plate 16 and a trailing cam plate IT, and a second cam plate IT.
The rotating cam means C1 is composed of one cam plate 18.

The cam plates 16 and 17 each have one flank portion 16α and one ITα, but the cam plate 18 has two flank portions tab and t8cll on both sides with the base portion 18α in between, and the cam plate 18 has a follower. A spring 19 is connected to the interlock lever 12 to keep 72' engaged at all times.

The three cam boards mentioned above? 6, 17, and 18 are each fixed at its rotational center to the rotor shaft 21 of one pulse motor M mounted on a fixed support base 20 on the carburetor main body 1. Consequently, all cam plates 16, 17, 18 are driven by one common pulse motor M.

The pulse motor M includes an electronic control circuit 2 that applies pulses for forward rotation or reverse rotation of the motor MK according to an input signal.
2 is connected, and the input of this circuit 220 has a
an engine temperature detector 23 that emits a signal depending on the engine temperature;
Engine speed detector 2j that emits a signal according to the engine speed
, an intake air temperature detector 25, etc., which generates a signal according to the temperature of intake air of the engine, are connected.

Next, the operation of this embodiment will be explained.

Figure 1 shows the state of the carburetor when the engine is idling after warming up, and the choke lever 6 is completely released from both the leading and trailing cam plates 16, 17 and returned to its original position. Choke valve 4Ik due to biasing force of spring 7
It is fully open. On the other hand, the interlocking lever 12 has a spring 19
Due to the biasing force of
1z to hold the stopper screw 15 in the most retracted position with respect to the contact piece 14 of the throttle lever 8, and the screw 15 contacts the stopper piece 13 and therefore the throttle lever 8.
The throttle valve 5 is closed at the normal idle opening position by supporting the throttle valve 5. The idle opening degree can be arbitrarily adjusted by advancing and retracting the stopper screw 15 by screwing it.

Now, when an auxiliary machine such as a tala compressor is connected to the engine as a load, and the engine speed drops below the specified idling speed, the engine speed detector 24 sends a signal indicating the situation to the control circuit. 2.2, the control circuit 22 applies a pulse according to the input signal to the pulse motor M, and thereby the pulse motor M moves all the cam plates 16, 17, 18 in the direction of arrow A by its rotor shaft 21. Rotate. Then, the cam plate 18 is moved to the first flange portion 18
b engages with the follower 12' and rotates the interlocking lever 72 in the opening direction of the throttle valve 5, so that the throttle lever 8 is also returned to the position of the return spring 9 via the stopper screw 15 and the abutting piece 14 that are in contact with each other. They simultaneously rotate against the force to increase the idle opening degree of the throttle valve 5. That is, an appropriate fast idle opening degree is provided.

When the engine speed returns to the specified idling speed due to the fast idle opening of the throttle valve 5, the engine speed detector 24 stops generating a signal, and the pulse motor M stops.

On the other hand, the leading cam plate 16 of the first rotary cam means C1 also moves away from the choke lever 6 as the pulse motor M rotates in the direction of arrow A, and therefore, during this period, the choke valve 4 is not fully open. is total (no change).

Switch the engine from idle link operation to output operation (,
When the accelerator pedal is operated to pull the operating wire 11, the throttle lever 8 can be rotated against the force of the return spring S to open the throttle valve 5 to an arbitrary opening degree. In this case, the contact piece 14 moves away from the stopper screw 15, and the interlocking lever 12 does not change its engagement position with the cam plate 18.

Next, if the engine temperature falls below a predetermined value (to explain the case, in this case, the engine temperature detector 23 sends a signal indicating this situation to the control circuit 22, and the control circuit 22 responds to the input signal). Apply a pulse to the Hals motor M,
This causes the pulse motor M to move all the cam plates t6. t7. t
8 in the direction of arrow B (opposite to the previous rotation), first, the flank portion 16α of the cam plate 16 engages with the follower 61 to return the first arm 6α of the choke lever 6 to the spring T. The choke valve 4 is closed (this state is shown in FIG. 3).

By the time the pulse motor M rotates in the direction of arrow B to a predetermined angle and the leading cam plate 16 separates from the follower 61 of the first arm 6α, the flank portion 17α of the trailing cam plate IT moves to the second arm 6b.
Therefore, the subsequent rotation of the choke lever 6 is caused by the following cam plate 17 and the second cam plate 17.
arm 6b (see FIG. 4), and choke valve 4 can be moved to the fully closed position. 2 like this
Leading and trailing cam plates ts*tr and two arms 6a*6
According to the use of b, the choke lever 6 is largely rotated within a limited rotation angle range of the pulse motor M to open the choke valve 4.
can be closed securely.

During this time, the cam plate 18 engages the second flank portion 18C with the follower 12', returns the throttle lever 8 via the interlocking lever C-12, and rotates against the force of the spring 9. Accordingly, the fast idle opening degree is given to the throttle valve 5 according to the degree of closing of the choke valve 4. (Thus, the engine can be easily cold started and warmed up properly.

As described above, according to the present invention, one pulse motor and
The opening degrees of the choke valve and the throttle valve are controlled steplessly according to the engine temperature, the load applied to the auxiliary engine, and other engine operating conditions by the first and second rotary cam means driven thereby. Therefore, the operating condition of the south gate can always be maintained properly, and since the structure is simple and compact, the carburetor does not need to be bulky.

[Brief explanation of the drawing]

FIG. 11 is a side view of a vaporizer equipped with the device of the present invention. FIG. 2 is a cross-sectional view taken along line 1l-UN, and FIGS. 3 and 4 are operational diagrams. C1, C, ... 1st. Second rotary cam means, M... Pulse motor, 2... Intake path, 2α... Venturi section, 3... Main fuel nozzle, 4... Choke valve, 4α...
...Valve stem, 5... Throttle valve, 5α... Valve stem, 6... Choke lever, 12... Interlocking lever, 13... Stopper piece, 14... ° Contact piece, 15...・Stopper screw,
16... Leading cam plate, 17... Following cam plate, 18...
...Cam plate, 22...Control circuit, 23...Engine temperature detector, 24...Engine speed detector, 25...Intake air temperature detector Patent applicant Honda Motor Co., Ltd.

Claims (2)

[Claims] (1) In a carburetor installed with a choke valve on the upstream side of the intake passage and a throttle valve downstream of the venturi part where the main fuel nozzle opens, the choke valve is connected from the fully open position to the fully closed position. A first rotary cam means capable of operating is interlocked, and a second rotary cam means capable of operating the throttle valve from a fully closed position to a predetermined fast idle opening is interlocked, and the first and second rotary cams are interlocked. 1 which operates in response to an input pulse indicating the operating conditions of the internal combustion engine;
A choke valve and throttle valve control device in a carburetor, which is connected to a pulse motor. (2) In the device described in claim (1), the throttle valve is configured in a butterfly type having a valve stem,
An interlocking lever operated by the second rotary cam means is rotatably supported on the valve shaft, and the interlocking lever is provided with a stopper means for regulating the closing/opening degree of the h-numbered valve. Valve and throttle control devices.