JPS6318767Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an idle speed control device for an internal combustion engine, and is particularly suitable for use in an automobile engine equipped with an electronically controlled fuel injection device, and is introduced by bypassing a throttle valve. The present invention relates to an improvement in an idle speed control device for an internal combustion engine that controls the idle speed of the engine by controlling the flow rate of intake air.

One of the devices for controlling the air-fuel ratio of the air-fuel mixture in an internal combustion engine such as an automobile engine uses an electronically controlled fuel injection device. In an internal combustion engine equipped with this electronically controlled fuel injection device, for example, the fuel injection time is determined according to the intake air amount of the engine, the engine rotation speed, etc., and the fuel injection time is set in the intake manifold. In addition, the air-fuel ratio of the engine is controlled by opening the main injector that injects fuel toward the engine's intake port, which requires precise control of the air-fuel ratio. It is becoming widely used in automobile engines equipped with exhaust gas purification measures.

In internal combustion engines equipped with this electronically controlled fuel injection system, the idle speed of the engine is generally controlled by controlling the flow rate of intake air that is introduced by bypassing the throttle valve. A two-way air flow control valve is installed in the idle air flow path that communicates the intake pipe upstream of the throttle valve with the intake pipe downstream of the throttle valve (e.g. surge tank), and controls engine cooling water temperature, etc. The opening degree of the air flow rate control valve is controlled according to the operating state to control the flow rate of idle air (hereinafter referred to as idle flow rate).

On the other hand, in recent years, attempts have been made to improve the atomization of the fuel injected from the main injector by sending a portion of the intake air near the nozzle of the main injector using the air flow speed, and a certain level of effect has been achieved. However, in the past, the intake pipe upstream of the throttle valve and the vicinity of the nozzle of the main injector were directly connected by a small pipe, so the flow rate of assist air supplied near the nozzle of the main injector (hereinafter referred to as the assist flow rate) was determined according to the difference between the pressure of the intake manifold in which the main injector is located and the pressure of the intake pipe upstream of the throttle valve, and the assist flow rate could not be adjusted according to the engine operating state, and therefore sufficient effect was not necessarily achieved.

By connecting the downstream side of the two-way air flow control valve to the vicinity of the nozzle of the main injector, all of the idle air is supplied into the engine from the vicinity of the nozzle of the main injector. It is also possible to provide an assist function. However, there is a limit to the maximum value of the assist flow rate due to the need to maintain the maximum flow velocity near the main injector nozzle and from the viewpoint of vehicle installation.Especially in fast idle at low temperatures, the assist air flow path The idle flow rate will be insufficient if only the flow rate that can be flowed from the engine is sufficient. On the other hand, during normal idling after warm-up, it is necessary to reduce the idle flow rate to keep the idle rotation speed constant, and a flow rate suitable for assist would be too high as an idle flow rate. Therefore, in addition to the air flow control valve to control the idle flow rate, we added an air flow control valve to control the assist flow rate, and when idling,
It is possible to secure a fast idle flow rate by flowing idle air to the assist side, while during fast idle, flowing idle air to the assist side and bypass side, but this requires a large number of piping and installation and passageway problems. Not only is there a problem due to resistance, but the control system is complicated, and the air flow control valve has to be replaced by two.
There was a problem in that the cost increased because multiple units were used.

The present invention was developed to eliminate the above-mentioned drawbacks of the conventional technology, and by using a single air flow control valve, the present invention has a simple configuration, and the assist air that is supplied to the vicinity of the main injector nozzle can be adjusted. It is an object of the present invention to provide an idle speed control device for an internal combustion engine that can control the flow rate of bypass air fed to the downstream side of a throttle valve and is easy to control.

The present invention is an internal combustion engine idle speed control device that controls the idle speed of the engine by controlling the flow rate of intake air that is introduced by bypassing the throttle valve. an air flow control valve that controls the flow rate of idle air introduced according to the engine operating state, and at least a portion of the idle air whose flow rate is controlled by the air flow control valve, into the vicinity of the nozzle of the main injector. an assist air flow path for feeding the idle air as assist air; a bypass air flow path for feeding the remainder of the idle air to the downstream side of the throttle valve of the intake pipe as bypass air;
A differential pressure-responsive on-off valve that opens the bypass air passage when the differential pressure is higher than a preset value in accordance with the differential pressure between the idle air pressure and the intake pipe pressure downstream of the throttle valve. Therefore, the above objective has been achieved.

Further, the air flow rate control valve is a three-way valve, and the differential pressure responsive on-off valve is disposed in the bypass air flow path.

Alternatively, the configuration is further simplified by integrating the air flow rate control valve and the differential pressure responsive on-off valve.

In addition, by connecting the bypass air flow path near the nozzle of the start injector installed in the surge tank, the bypass air promotes atomization of the starting auxiliary fuel injected from the start injector. It was designed to be used as assist air for

Embodiments of the present invention will be described in detail below with reference to the drawings.

The first embodiment of the present invention is as shown in FIG.
An air cleaner 12 for taking in outside air, and an air flow meter 14 for detecting the flow rate of the intake air taken in by the air cleaner 12.
and an intake air temperature sensor 16 built into the air flow meter 14 for detecting the temperature of intake air.
, a throttle valve 22 for controlling the flow rate of intake air, which is disposed in the intake pipe 18 and rotates in conjunction with an accelerator pedal 20 disposed in the driver's seat; a throttle sensor 24 for detecting the opening degree of the engine 10, a surge tank 26, a main injector 30 for injecting main fuel toward the intake port of the engine 10 disposed in the intake manifold 28; A start injector 32 disposed in the surge tank 26 for injecting starting auxiliary fuel into the surge tank 26 when starting the engine; and an injector 3
A fuel tank 34 and a fuel pump 36 for supplying fuel at a predetermined pressure to the exhaust gases 0 and 32, and an oxygen concentration sensor disposed in the exhaust manifold 38 for detecting the air-fuel ratio from the residual oxygen concentration in the exhaust gas. 4
0, a distributor 42 having a distributor shaft 42a that rotates in conjunction with the rotation of the crankshaft of the engine 10, and a distributor 42 having a distributor shaft 42a that rotates in conjunction with the rotation of the crankshaft of the engine 10; A crank angle sensor 44 that outputs a crank angle signal, a cooling water temperature sensor 46 disposed on the engine block for detecting the engine cooling water temperature, a battery 48, and an intake air amount determined from the output of the air flow meter 14. The basic fuel injection time is determined according to the engine rotational speed obtained from the crank angle signal output from the crank angle sensor 44, and is determined based on the throttle valve opening output from the throttle sensor 24 and the idle time from the output from the oxygen concentration sensor 40. Fuel ratio, the cooling water temperature sensor 4
A valve opening time signal is output to the main injector 30 by correcting it according to the engine cooling water temperature of the 6 outputs, the voltage of the battery 48, etc., and the starting auxiliary fuel is injected when the engine is started. In an electronically controlled fuel injection system for an automobile engine 10, which is equipped with a digital control circuit 50 that outputs a valve opening time signal to the start injector 32, from an idle air port 52 formed in the intake pipe 18 upstream of the throttle valve 22. An idle air line 54 for introducing idle air by bypassing the throttle valve 22; and an idle air line 54 for controlling the idle speed of the engine.
A three-way air flow control valve 56 that controls the flow rate of idle air introduced through the engine according to the engine operating state, and at least a portion of the idle air whose flow rate is controlled by the air flow control valve 56. An assist air conduit 58 for feeding assist air to the vicinity of the nozzle of the main injector 30 and the remainder of the idle air to the vicinity of the nozzle of the start injector 32 disposed in the surge tank 26.
There is a bypass air pipe line 60 for supplying bypass air that also serves as assist air for the start injector, and a bypass air pipe line 60 arranged in the middle of the bypass air line 60 that controls the pressure of the idle air and the downstream side of the throttle valve. Depending on the pressure difference between the intake pipe pressure and the intake pipe pressure, when the pressure difference is equal to or higher than a set value, the bypass air pipe line 6
A differential pressure responsive on-off valve 62 that opens at 0 is provided, and the air flow rate control valve 56 is controlled by the digital control circuit 50.

The tip of the main injector 30 is connected to a second
The structure is as shown in the figure, and includes a needle 30a whose tip constitutes a valve body 30b, a holder 30c that slidably supports the needle 30a, and a needle 30c that is press-fitted to cover the tip of the holder 30c. The holder 30c has an adapter 30d for introducing assist air, and a fuel collision plate 30e disposed at the tip of the needle 30a.
Valve seat portion 3 on which the valve body 30b of the needle 30a is seated
It constitutes 0f. Therefore, the pressurized fuel reaches the valve seat portion 30f through the gap between the inner hole of the holder 30c and the needle 30a, and when the needle 30a is pulled upward in the drawing by electromagnetic force, the pressurized fuel reaches the valve seat portion 30f. It is discharged from the injector nozzle 30g formed between the portion 30f and the valve body 30b. The fuel discharged from the injector nozzle 30g is transferred to the fuel collision plate 30e.
and forms a thin liquid film that spreads in the direction away from the axis of the needle 30a, resulting in primary atomization. adapter 3
0d is provided with a plurality of assist air intake ports 30h, and the assist air sent from the assist air intake ports 30h is delivered to the fuel collision plate 30.
It collides with the fuel that has become a liquid film at e, and secondary atomization of the fuel is performed. Therefore, the fuel whose atomization has been promoted by the assist air is sucked into the combustion chamber of the engine 10 through the adapter nozzle 30i.
As is clear from the structure shown in FIG. 2, there is a limit to the assist flow rate in order to achieve the maximum flow velocity near the adapter nozzle 30i of the main injector 30, or for reasons of mounting.

As shown in detail in FIG. 3, the digital control circuit 50 is a central processing unit (hereinafter referred to as CPU) consisting of a microprocessor that performs various arithmetic operations.
50a, and an analog multiplexer for converting analog signals inputted from the air flow meter 14, intake temperature sensor 16, oxygen concentration sensor 40, cooling water temperature sensor 46, battery 48, etc. into digital signals and sequentially inputting them into the CPU 50a. a digital converter 50b and the throttle sensor 2
4. The digital signal input from the crank angle sensor 44 etc. is taken into the CPU 50a at a predetermined timing, and the calculation result in the CPU 50a is sent to the main injector 30, start injector 32, and air flow control valve 56 at a predetermined timing. Input/output port 5 with buffer to output to etc.
0c, a read-only memory 50d for storing programs or various constants, and a CPU.
Random access memory 50e for temporarily storing calculation data, etc. in 50a, and random access memory 50f for backup, which can be supplied with power from an auxiliary power source and retain memory even when the engine is stopped.
and a common bus 50 that connects each component device.
It is composed of g.

As shown in detail in FIG. 4, the air flow control valve 56 includes an intake port 56a to which the idle air line 54 is connected, an assist air supply port 56b to which the assist air line 58 is connected, and an assist air supply port 56b to which the assist air line 58 is connected. A cylindrical case 56d has a bypass air supply port 56c connected to the bypass air conduit 60 connected to the circumferential surface thereof, and rotates within the case 56d to linearly open and close the intake port 56a. It has an arc-shaped valve body 56e and a rotation drive device 56f, which is made of, for example, a linear motor or a step motor, for rotating the valve body 56e. When rotated, the intake port 56a begins to open.

As shown in detail in FIG. 4, the differential pressure responsive on-off valve 62 includes a case 62b in which a valve body seating portion 62a is formed, and a pressure and surge tank of the bypass air supply port 56c of the air flow rate control valve 56. 2
and a reed valve 62c that opens the valve element seating portion 62a when the differential pressure is equal to or higher than a set value in accordance with the differential pressure between the intake pipe pressure and the intake pipe pressure in the reed valve 62a.

The action will be explained below.

First, during idling operation after warm-up, where a high idle flow rate is not required, the air flow control valve 56 valve body 56e is slightly opened. Therefore, the intake port 56a is considerably narrowed, and the assist air intake port 30h of the main injector 30 is narrowed.
The opening diameter of the bypass air supply port 56c is reduced, and the bypass air supply port 56c is under negative pressure. The differential pressure responsive on-off valve 62 is formed to open due to the differential pressure between the intake pipe negative pressure and the bypass air supply port 56c, but since this differential pressure does not become that large, the differential pressure responsive on-off valve 62 opens. 62 is closed. Therefore,
All idle air taken in from the intake port 56a according to the opening degree of the valve body 56e of the air flow control valve 56 is sent to the assist air intake port 30h of the main injector 30 via the assist air supply port 56b. It is used as assist air.

Also, during fast idle control at low temperatures,
Since the required idle flow rate is large, the digital control circuit 50 opens the valve body 56e of the air flow control valve 56 wide. Therefore, main injector 3
Inlet port 5 from assist air intake 30h of 0
The opening diameter of 6a becomes large, and the pressure of bypass air supply port 56c also approaches atmospheric pressure. On the other hand, the intake pipe pressure is low because the idle speed increases during the fast idle control, and the differential pressure responsive on-off valve 62 is opened. Therefore, during fast idle control at low temperatures, assist air is not only supplied to the vicinity of the nozzle of the main injector 30 via the assist air line 58 but also to the inside of the surge tank 26 via the bypass air line 60. Bypass air is supplied to the engine, and the required idle flow rate can be ensured.

In this embodiment, the bypass air pipe line 60
is connected to the vicinity of the nozzle of the start injector 32 disposed in the surge tank 26, so bypass air with a flow rate greater than the assist flow rate atomizes the starting auxiliary fuel injected from the start injector 32. It is used as assist air for this purpose, and is extremely efficient. Note that the connection destination of the bypass air pipe line 60 is not limited to this, and may be any other place as long as it is downstream of the throttle valve 22.

Further, in the embodiment, the differential pressure responsive on-off valve 6
2, a reed valve type differential pressure responsive on-off valve having a reed valve 62c was used, but the configuration of the differential pressure responsive on-off valve 62 is not limited to this, and for example, a valve as shown in FIG. A case 63b in which a body seating portion 63a is formed, a valve body 63c capable of closing the valve body seating portion 63a, and a diaphragm 63e for driving the valve body 63c via a rod 63d.
, a compression spring 63f for urging the diaphragm 63e downward in the figure, and the diaphragm 63
In the diaphragm chamber 63g formed in the upper part of e,
It is also possible to use a diaphragm-type differential pressure-responsive on-off valve 63 that includes a pressure conduit 63h for introducing pressure (intake pipe pressure) downstream from the valve body seating portion 63a.

Furthermore, in the embodiment, a three-way valve is used as the air flow rate control valve 56, and the differential pressure-responsive opening/closing valve is activated by the differential pressure between the pressure of the bypass air taken out from the bypass air supply port 56c of the three-way valve and the intake pipe pressure. However, the pipe line configuration is not limited to this. For example, a two-way valve in which the bypass air supply port 56c is omitted may be used as the air flow rate control valve 56, as shown in FIG. As shown by the two-dot chain line A, the assist air taken out from the middle of the assist air pipe 58 connecting the assist air supply port 56b of the air flow control valve 56 and the vicinity of the nozzle of the main injector 30 is opened and closed in response to the differential pressure. valve 62
It is also possible to feed it to the inlet side.

Next, a second embodiment of the present invention will be described in detail.

This embodiment is similar to the first embodiment and includes an air cleaner 12, an air flow meter 14, an intake air temperature sensor 16, and an intake pipe 1 as shown in FIG.
8, accelerator pedal 20, throttle valve 22, throttle sensor 24, surge tank 26, intake manifold 28, main injector 30, start injector 32, fuel tank 34, fuel pump 36, exhaust manifold 38, oxygen concentration sensor 4
0, electronics of an automobile engine 10 having a distributor 42, a crank angle sensor 44, a cooling water temperature sensor 46, a battery 48, a digital control circuit 50, an idle air line 54, an assist air line 58, and a bypass air line 60. In the controlled fuel injection device, there is an air flow control valve section 64a that controls the flow rate of idle air introduced by bypassing the throttle valve 22 according to the engine operating state, and the pressure of the idle air and the intake pipe pressure on the downstream side of the throttle valve. An air flow control valve 64 is provided which is integrated with a differential pressure responsive opening/closing valve part 64b that opens the bypass air pipe 60 when the differential pressure is equal to or higher than a set value.

As shown in detail in FIG. 6, the air flow control valve 64 includes a cylindrical case 64e with an open bottom surface and an open air intake port 64c and an assist air supply port 64d connected to the circumferential surface of the case 64e. An arc-shaped valve body 64f that rotates inside the valve body to linearly open and close the air intake port 64c, and a rotary drive device 64g consisting of, for example, a linear motor or a step motor, for rotating the valve body 64f. an adapter case 64 which is fixed to the bottom of the case 64e and has a bypass air supply port 64h connected and opened on the side surface;
i, a valve body 64j capable of closing the upper opening of the adapter case 64i, and a compression spring 64k that biases the valve body 64j upward in the figure.
4b, and controls the idle flow rate by the opening degree of the valve body 64f, and also controls the pressure of the bypass air supply port 64h and the case 64c.
The bypass air supplied to the bypass air supply port 64h is cut off and supplied by the action of the valve body 64j that operates in response to the pressure difference within the bypass air supply port 64h.

Other points and operations are the same as those of the first embodiment, so explanations will be omitted.

In this embodiment, since the air flow rate control valve and the differential pressure responsive on-off valve are integrated, the configuration is even simpler.

As explained above, according to the present invention, it is possible to control the assist flow rate and the bypass flow rate during idling with a simple configuration, and it is possible to reduce costs.
Furthermore, since the bypass flow rate is self-controlled, control is easy. Furthermore, it has excellent effects such as being able to easily match the assist flow rate to the optimum flow rate.

[Brief explanation of drawings]

FIG. 1 shows the configuration of an electronically controlled fuel injection device for an automobile engine in which a first embodiment of the idle speed control device for an internal combustion engine according to the present invention is installed.
FIG. 2 is a cross-sectional view including a partial block diagram; FIG. 2 is a cross-sectional view showing the configuration near the tip of the main injector used in the embodiment; FIG.
FIG. 4 is a block diagram showing the specific configuration of the digital control circuit. Similarly, FIG. 4 is a sectional view showing the configuration of the air flow control valve and the differential pressure responsive valve. FIG.
FIG. 6 is a sectional view showing a modification of the differential pressure responsive on-off valve used in the embodiment, and FIG. FIG. 2 is a cross-sectional view showing the configuration of an air flow control valve with an integrated responsive on-off valve. 10...Engine, 18...Intake pipe, 22...
Throttle valve, 26...Surge tank, 28...
Intake manifold, 30...main injector,
32...Start injector, 50...Digital control circuit, 52...Intake port, 54...Idle air pipe line, 56...Air flow rate control valve, 58...
...Assist air pipe line, 60...Bypass air pipe line, 62, 63...Differential pressure responsive on-off valve, 64...Air flow rate control valve, 64a...Air flow rate control valve section, 6
4b...Differential pressure responsive on-off valve section.

Claims (1)

[Claims for Utility Model Registration] (1) An idle speed control device for an internal combustion engine that controls the idle speed of the engine by controlling the flow rate of intake air that is introduced by bypassing the throttle valve. an air flow control valve that controls the flow rate of idle air introduced by bypassing the throttle valve according to the engine operating state; and at least a portion of the idle air whose flow rate is controlled by the air flow control valve. an assist air flow path for feeding assist air near the nozzle of the main injector; a bypass air flow path for feeding the remainder of the idle air to the downstream side of the throttle valve of the intake pipe as bypass air; A differential pressure-responsive on-off valve that opens the bypass air passage when the differential pressure is equal to or higher than a set value in accordance with the differential pressure between the idle air pressure and the intake pipe pressure downstream of the throttle valve. An idle speed control device for an internal combustion engine, characterized by: (2) The idler for an internal combustion engine according to claim 1, wherein the air flow rate control valve is a three-way valve, and the differential pressure responsive on-off valve is disposed in the bypass air flow path. Rotation speed control device. (3) The idle speed control device for an internal combustion engine according to claim 1, wherein the air flow rate control valve and the differential pressure responsive on-off valve are integrated. (4) The idle speed control device for an internal combustion engine according to claim 1, wherein the bypass air flow path is connected to the vicinity of the nozzle of a start injector disposed in a surge tank.