JP3780546B2 - Fuel control device for vehicle engine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a fuel control apparatus for a vehicle engine having a variable Benchery type carburetor.
[0002]
[Prior art]
In general, the variable Benchery type carburetor has an upper power generated by guiding the negative pressure generated in the intake passage to the negative pressure chamber (suction chamber), a spring force opposed to the upper power, a lower power due to gravity, etc. There is a negative pressure servo type carburetor that controls the opening of the negative pressure responsive valve (suction piston).
[0003]
[Problems to be solved by the invention]
However, in the general type variable Benchery type carburetor, since the opening degree of the suction piston is determined in proportion to the pressure, the degree of freedom of adaptation is limited.
Further, if the spring is weakened so as to improve the throttle response, the opening degree of the suction piston becomes larger than necessary at a specific rotational speed, and an appropriate air-fuel ratio cannot be obtained and the combustion state may be deteriorated.
Furthermore, in the above general carburetor, the lift characteristics of the suction piston cannot be changed according to the demands of the engine, which is not sufficient for further improving the ride feeling.
[0004]
Various proposals have been made for the above. That is, Japanese Patent Laid-Open No. 58-155260 discloses a fuel control device that controls the amount of fuel supplied to an engine by operating a fuel system of a carburetor according to information related to the operating state of the engine. . Japanese Patent Publication No. 61-12104 discloses a vaporizer in which a pressure receiving chamber is formed at a position facing the suction chamber, and a constant negative pressure is introduced into the pressure receiving chamber by a regulator having a nozzle flapper mechanism. Japanese Patent Application Laid-Open No. 6-235351 discloses a carburetor that provides a control valve between the negative pressure chamber and the atmosphere to control the opening of the suction piston by controlling the pressure in the suction chamber (negative pressure chamber). ing.
[0005]
However, in the proposed carburetor, when a plurality of carburetors are provided in a multi-cylinder engine, the number of installation locations of the control unit of the suction chamber is increased and the cost for mass production is increased. Therefore, it is required to reduce the size and cost.
[0006]
The present invention has been made to solve the above-mentioned conventional problems, and provides a fuel control device for a vehicle engine capable of reducing the size of a negative pressure control unit of a suction chamber and reducing the cost during mass production. Let it be an issue.
[0007]
[Means for Solving the Problems]
The present invention has the following configuration in order to solve the above problems.
The present invention opens a part of a suction piston and connects a negative pressure introduction hole for introducing negative intake pressure into the suction chamber, and the lift control valve and the suction chamber, thereby reducing the negative pressure in the suction chamber. A negative pressure pipe to be introduced into the suction chamber, the cross-sectional area of the negative pressure pipe is determined from the opening area of the negative pressure introduction hole, and is driven by the intake negative pressure upstream of the throttle valve, which is introduced into the suction chamber. In a fuel control device for a vehicle engine having a variable Benchery-type carburetor whose ventilator opening is changed by a suction piston, the lift amount of the suction piston is changed by changing the negative pressure in the suction chamber. The lift control valve that controls the air flow is integrated with the float chamber of the vaporizer. A plurality of carburetors are provided for the engine, an operation valve for operating the lift control valves of each carburetor at once is provided, and the control line connecting the lift control valves of each carburetor to each other is lift controlled. Provided along the direction in which the valves are arranged, the actuating valve is arranged close to the control pipe line and generally between the intake passage inlet end and the intake passage outlet end of the carburetor when viewed in the arrangement direction of the plurality of carburetors The lift control valve is fixed to the carburetor at the position where it fits , and the lift control valve is controlled to lift when the engine speed is low and the vehicle speed is low , and the engine output fluctuation is alleviated when the lift control is released. Thus, the fuel control device for a vehicle engine is characterized in that ignition timing control is performed as described above.
[0010]
In the present invention, since the lift control valve is formed integrally with the float chamber of the vaporizer, the space utilization is increased and the mounting work load can be reduced. In addition, since the lift control valves of a plurality of vaporizers are collectively operated by the operation valves, the mounting load can be further reduced.
[0011]
Further, the cross-sectional area of the negative pressure line so as to determine the opening area of the negative pressure introduction hole. For example, the cross-sectional area of the negative pressure line of the suction piston exceeds twice the opening area of the negative pressure introduction hole, so that the suction piston can be sufficiently smoothly and appropriately lift controlled.
[0012]
Further, since the ignition timing control is performed in response to the control of the lift control valve to improve the ride feeling, it is possible to appropriately remove the adverse effect on the ride feeling. In other words, when lift control of the suction piston by the lift control valve is released and normal negative pressure is introduced to the suction piston, the suction piston rises rapidly, so the output fluctuation is particularly large in the high engine speed range. Adversely affect. In order to prevent this adverse effect, for example, the ignition timing is controlled in accordance with the release of the lift control to improve the ride feeling.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
1 to 5 are explanatory views of a fuel control apparatus for a vehicle engine according to an embodiment of the present invention. FIG. 1 is an overall view seen from the intake introduction side of the carburetor 10, and FIG. FIG. 3 is a view in the direction of III in FIG. 1, FIG. 4 is a view in the direction of IV in FIG. 3, FIGS. 5 and 6 are explanatory views in section of the vaporizer 10, and FIGS. FIG.
[0014]
As shown in the figure, the engine (not shown) is of four cylinders, and carburetors 10 ₁ to 10 ₄ for supplying fuel as an air-fuel mixture independently are connected to the intake side of each cylinder. The containers 10 ₁ to 10 ₄ are arranged in parallel in the direction in which the cylinders are arranged.
Each of the carburetors 10 ₁ to 10 ₄ has the same shape, and the Benchery opening degree is increased by the suction piston 16 that is introduced into the suction chamber 12 and driven by the intake negative pressure upstream of the throttle valve 14. It is a variable Benchery type vaporizer designed to change.
[0015]
The carburetors 10 ₁ to 10 ₄ are housed in a substantially cylindrical suction piston 16 so as to be slidable in a direction orthogonal to the intake flow direction, inside the opening 18a of the throttle bore 18 of the intake passage. .
[0016]
The suction piston 16 has a hollow cylindrical body, and a distal end portion facing the throttle bore 18 is closed and a proximal end portion facing the inside of the suction chamber 12 is opened. A communication hole (negative pressure introduction hole) 16a that connects the throttle bore 18 and the inside of the suction piston 16 is formed at the tip of the suction piston 16, and the amount of fuel sucked into the throttle bore 18 (amount of supply) is changed. A jet needle 20 is fixedly provided. A diaphragm 22 is fixed to the proximal end portion of the suction piston 16, and a space surrounded by the diaphragm 22 and the chamber lid 24 is a suction chamber 12.
Therefore, the throttle bore 18 and the suction chamber 12 are connected to each other via the negative pressure passage formed of the inside of the suction piston 16 and the communication hole 16a.
[0017]
A throttle valve 14, which is a butterfly valve, is disposed on the throttle bore 18 so as to be rotatable by a throttle shaft (fixed to the throttle valve 14). Throttle shaft 26 of the carburetor 10 ₁ to 10 ₄ are connected, at the same time rotated by the operation of the throttle wire (not shown), each throttle valve 1 4 is adapted to operate simultaneously. In FIG. 3, reference numeral 28 denotes a throttle lever that converts the forward / backward movement of the throttle wire into the rotational movement of the throttle shaft 26.
[0018]
The vaporizers 10 ₁ to 10 ₄ include a float chamber body (float chamber outer lid) that forms a float chamber that stores fuel supplied from the jet needle 20 on the opposite side of the chamber lid 24 across the throttle bore 18. 30 is provided.
[0019]
A lift control valve 32 for controlling the lift amount of the suction piston 16 by changing the negative pressure in the suction chamber 12 is formed by integral casting with the float chamber body 30 of the vaporizers 10 ₁ to 10 ₄ .
[0020]
Further, the lift control valve 32 of each carburetor 10 ₁ to 10 ₄ is for controlling the negative pressure of the suction tea down bar 12 by the control input of the negative pressure / atmospheric pressure actuated valve 34, actuating the output side negative The negative pressure in the suction chamber 12 is controlled by connecting to the suction chamber 12 via the pressure line 33. The vacuum duct 33 be made of a resilient material such as rubber hose for instance, one end connected to cover the nipple 24a that protrudes from the chamber lid 24, connected over the nipple 32a to the other end protrudes from the lift control valve 32 ing. Note that the atmosphere flows through the air release side (A / C: not shown) of the lift control valve 32 to the atmosphere opening side.
[0021]
A single operation valve 34, which is a three-way solenoid valve that collectively operates the valves 32, is connected to the control input side of each lift control valve 32 via a control line 36. The control line 36 includes a hose and a connection nipple, and the valves 32 are connected to each other so as to apply the same control pressure to the lift control valves 32. And the operation valve 34 is connected to the control pipe line 36 via the three-way pipe | tube and the hose, for example in the center part of the arrangement direction of vaporizer 10 ₁ -10 ₄ .
[0022]
Further, as shown in FIG. 1, the operation valve 34 is screwed to two ones of the vaporizers 10 ₁ to 10 ₄ (the lower two vaporizers 10 ₁ and 10 _{2 in} FIG. 1). It is fixed to the two vaporizers 10 on one side thereof via the bracket 38. The bracket 38 has a substantially trapezoidal shape that is long along the direction in which the vaporizers 10 are arranged, and a protruding piece 38a is formed perpendicular to the direction in which the vaporizers 10 are arranged. The projecting piece 38 a is inserted into the outer case of the operating valve 34 to fix the operating valve 34 to the bracket 38.
[0023]
A control system for the lift control valve 32 will be described.
In the control device of the embodiment, an electronic control unit (ECU) 40 has a throttle opening signal from an opening sensor of a throttle valve 14, an engine speed signal from an engine speed sensor, and a gear position signal from a gear position sensor. Thus, an on / off signal is output to the operating valve 34 in accordance with the stored software. The operating valve 34 is supplied with a suction pipe negative pressure downstream of the throttle valve 14, and the operating valve 34 receives an intake pipe negative pressure on the control input side of the lift control valve 32 by the on / off signal. / Supply atmospheric pressure. The ECU 40 also controls the ignition timing of the engine.
The control line 36 to the operating valve 34 has V.V. T. T. et al. V (vacuum, transmission, valve) is provided, thereby delaying the intake pipe negative pressure and preventing the lift control valve 32 from operating suddenly. V. T. T. et al. V is transmitted through the orifice in one direction and the check valve in the other direction. When the engine is stopped, the pressure in the operating valve 34 is released into the throttle bore 18 through the check valve, and the operating valve 34 is quickly returned.
[0024]
As shown in FIG. 5, the lift control valve 32 includes an operation output side pressure passage 32 b connected to the negative pressure line 33 and a control input side chamber 32 c connected to the operation valve 34 via the control line 36. It is partitioned by a valve body 32d and a diaphragm 32e. In this case, the valve body 32d switches between open and close to the negative pressure line 33 according to the on / off of the operation valve 34, and is biased by a spring in the direction of closing the pressure passage 32b. When the negative pressure of the control input to the chamber 32c becomes stronger than the urging force of the spring, the valve body 32d is operated to open the negative pressure line 33 to the atmosphere.
[0025]
Next, the operation of the embodiment will be described.
Initially, when the operation valve 34 is not open, the lift control valve 32 is not operated as shown in FIG. At this time, intake pipe negative pressure is supplied to the suction chamber 12 from the communication hole 16a at the tip of the suction piston 16, and the suction piston 16 rises and falls according to the intake pipe negative pressure, and the fuel supply amount also changes accordingly. Become.
[0026]
Each sensor detects the throttle opening, the engine speed, and the gear position. The ECU 40 controls the suction piston 16 according to a predetermined map based on these detected signals. open.
[0027]
When the operation valve 34 is opened, the intake pipe negative pressure is applied to the control input side of the lift control valve 32 via the control line 36, and the diaphragm 32e and the valve body 32d are opened as shown in FIG. Then, the air guided from the clean side of the air cleaner flows into the suction chamber 12 of the vaporizer 10 through the negative pressure line 33.
Then, the negative pressure in the suction chamber 12 decreases, and the lift amount of the suction piston 16 decreases.
[0028]
When the predetermined condition is exceeded, the operation valve 34 is closed as shown in FIG. 5, whereby the lift control valve 32 is closed, the suction piston 16 returns to the original position, and the Benchery opening degree according to the intake pipe negative pressure is reached. Become.
[0029]
Inner diameter d ₁ of the negative pressure line 33 is defined by the size of the communication hole 16a.
It may, for example according to the following equation (1), it is to determine the inner diameter d ₁ of the vacuum duct 33.
D ₁ > A × 2 (1)
However, D ₁ : Inner peripheral cross-sectional area of the negative pressure pipe 33
A: Area of the communication hole 16a.
The reason why it is defined as described above is that the suction piston 16 cannot be properly controlled unless the dimensions of the negative pressure pipe 33 satisfy the above-described conditions.
[0030]
Further, the ignition timing is controlled in correspondence with the control of the lift control valve 32 .
When the lift control of the suction piston 16 is released, the suction piston 16 is lifted rapidly, so that the fuel supply amount and the air-fuel ratio fluctuate and the output fluctuates. In particular, the output fluctuates greatly in the high engine speed range. It has an adverse effect on the feeling.
To prevent this, in the present embodiment, as shown in FIG. 7, those ignition timing control was OFF, the in accordance with the release of the lift control and ON the ignition timing control to mitigate output fluctuations The ride feeling is improved.
[0031]
Even in the same vehicle type, the range in which the suction piston 16 is lift-controlled differs depending on the engine specifications and specifications. One software will be able to meet the engine specifications here. FIG. 8 shows an operation range of lift control based on vehicle speed−engine speed−speed stage. In FIG. 8, the lift control is performed in the low speed range and the lift control is performed in the medium speed range even when the engine speed is low regardless of each gear position (1st to 4th speeds). However, the lift control is not performed in order to prevent the output fluctuation in the high speed range, and in particular, the lift control is performed only at the low speed in the fourth speed, and the rest is not performed to prevent the output fluctuation.
[0032]
In the carburetor fuel control apparatus according to the embodiment, as shown in FIGS. ₁ to ₄ , the float chamber 30 and the lift control valve 32 of the carburetors 10 ₁ to 10 ₄ are formed by integral casting. 1). Therefore, the cost is reduced, the mounting work load is reduced, and the mass productivity is excellent.
[0033]
The lift control valves 32 are individually provided in the vaporizers 10 ₁ to 10 ₄ , and are collectively operated by the operation valves 34. Therefore, the operation timing of each lift control valve 32 is not shifted. Since the lift control valve 32 is attached to the vaporizer 10, the piping of the control line 36 is short. Further, since the carburetor is fixed via a rubber (rubber mount), there is little vibration, so there is little vibration applied to the operating valve 34. Therefore, the durability of the actuation valve 34, which is a solenoid valve, is improved. Further, since the operation valve 34 is controlled by electrical control based on the output of the ECU 40, the lift control valve 32 is excellent in operability.
[0034]
【The invention's effect】
As described above, according to the present invention, since the lift control valve is integrally formed with the float chamber of the vaporizer, the space utilization is increased and the mounting work load can be reduced. In addition, since the lift control valves of a plurality of vaporizers are collectively operated by the operation valves, the mounting load can be further reduced. Therefore, the negative pressure control unit of the suction chamber can be downsized and the cost during mass production can be reduced.
Further, since the cross-sectional area of the negative pressure pipe is determined from the opening area of the negative pressure introducing hole, for example, the cross-sectional area of the negative pressure pipe of the suction piston is set to be at least twice the opening area of the negative pressure introducing hole. Sufficient lift control of the suction piston can be performed.
Moreover, the bad influence with respect to a boarding feeling can be removed appropriately. In other words, when lift control of the suction piston by the lift control valve is released and normal negative pressure is introduced to the suction piston, the suction piston rises rapidly, so the output fluctuation is particularly large in the high engine speed range. Adversely affect. In order to prevent this adverse effect, for example, the ignition timing can be controlled in accordance with the release of lift control to improve the ride feeling.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram of a fuel control device for a vehicle engine according to an embodiment of the present invention, and is an overall view seen from an intake introduction side of a carburetor.
FIG. 2 is a view in the II direction of FIG.
FIG. 3 is a view in the III direction of FIG. 1;
4 is a view in the IV direction of FIG. 3;
FIG. 5 is an explanatory view of a cross section of the vaporizer, and is an explanatory view of a lift control valve in an off state.
FIG. 6 is an explanatory diagram of a lift control valve in an on state.
FIG. 7 is an explanatory diagram of an example of a timing chart for performing ignition timing control in lift control of the lift control valve.
FIG. 8 is an explanatory diagram of lift control of a lift control valve.
[Explanation of symbols]
10, 10 ₁ to 10 ₄ Vaporizer 12 Suction chamber 14 Throttle valve 16 Suction piston 16a Communication hole (negative pressure introduction hole)
30 Float chamber 32 Lift control valve 33 Negative pressure line 34 Actuation valve 36 Control line 40 Electronic control unit

Claims (1)

A negative pressure introduction hole that opens to a part of the suction piston and introduces negative intake pressure into the suction chamber, and a negative pressure that introduces the negative pressure in the suction chamber to the lift control valve by connecting the lift control valve and the suction chamber. A suction pipe driven by the intake negative pressure upstream of the throttle valve, which is introduced into the suction chamber, the cross-sectional area of the negative pressure pipe is determined from the opening area of the negative pressure introduction hole In the fuel control device for a vehicle engine having a variable Benchery-type carburetor in which the Benchery opening is changed,
A lift control valve that controls the lift amount of the suction piston by changing the negative pressure in the suction chamber is configured integrally with the float chamber of the vaporizer,
A plurality of carburetors are provided for the engine, and an operation valve for operating the lift control valves of each carburetor at once is provided.
A control line that connects the lift control valves of each vaporizer to each other is provided along the direction in which the lift control valves are arranged,
The actuating valve is fixed to the carburetor at a position that is close to the control pipe line and that is generally located between the intake passage inlet end and the intake passage outlet end of the carburetor when viewed in the arrangement direction of the plurality of carburetors. ,
The lift control valve is controlled to lift when the engine speed is low and the vehicle speed is low, and ignition timing control is performed so as to reduce engine output fluctuations when the lift control is released. A fuel control device for a vehicle engine.

Images