JPS60108544A - Fuel injection device of engine - Google Patents

Abstract

PURPOSE:To ensure good ignitionability and combustibility, by injecting fuel by the first injection valve in a low region of intake air quantity while additionally from the second injection valve in a high region of intake air quantity and controlling the second injection valve so as to stop its injection of fuel under a specific condition. CONSTITUTION:An engine provides the first injection valves 12 in the first intake passage 7a while the second injection valves 13 in the second intake passage 7b. Then an injection valve actuating means 20 drives the first injection valve 12 when an arithmetic injection quantity by a fuel injection quantity- arithmetic means 19 is below the preset value while drives both the first and the second injection valves 12, 13 when the arithmetic injection quantity exceeds the preset value. Further a stopping means 21 of the second injection valve causes the second injection valve 13 to stop its action in a region where the second throttle valve 11 is closed. In this way, good ignitionability and combustibility can be ensured by performing accurate injection of fuel corresponding to an operating condition of the engine.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an improvement in a fuel injection device for an engine.

(Conventional technology v#) Two intake passages are provided for each cylinder of the engine, and a fuel injection valve is arranged in each intake passage, and the fuel injection valve is arranged in each intake passage according to the operating condition such as engine load. The throttle valve is opened and closed to control the intake air amount, and the fuel r1 injection QJ amount from each fuel injection valve is controlled, and fuel is injected from the first injection valve in the entire operating range including the lowest intake air range, For example, the fuel injection port 4 device injects fuel in a high intake air amount range from the second injection valve to achieve highly accurate fuel supply control from a low load range to a high load range. 1977
It is known as seen in No.-12025.

In the above-mentioned fuel injection system, if a single fuel injection valve performs multiple fuel injections during high loads, the accuracy will decrease when performing mid-range fuel injections during low loads. While the first injector, which has a good supply N degree in the low-flow region, injects fuel in the low-load region, the second injector also injects fuel in the high-flow region that cannot be supplied by the first injector. This is what I decided to do.

Therefore, as in the preceding example, the start timing of fuel injection from the second injector corresponds to the magnitude of the fuel injection amount (fuel injection pulse width) calculated according to the engine σ operating state, and the calculated injection In the case where fuel is also injected from the second injection valve when the amount exceeds a set value, the second injection valve is injected before the second intake passage for the high flow area is opened by the second throttle valve. This has the problem that fuel injection is performed from the beginning.

That is, for example, when the engine is cold, in order to increase the fuel injection amount relative to the intake air amount and obtain good warm-up performance, a cold-time correction is performed to increase the calculated injection amount. The amount of intake air is increased to increase the rotational speed. In the above correction, although the actual operating state of the engine is the amount of fuel injected only by the first injector, the calculated injection amount based on the detection of the engine temperature and intake air amount exceeds the set value, and the amount of fuel injected from the second injector also exceeds the set value. This may be the area where fuel injection is performed.

Therefore, in this case, fuel is injected from the second injection valve even though the second throttle valve is not opened, and this fuel does not flow into the combustion chamber but accumulates in the intake passage, and does not flow into the combustion chamber. The fuel is not supplied to the combustion chamber and there is a risk of misfire, and the fuel also has problems such as atomization of the fuel and worsening of mixing.

(Object of the Invention) In view of the above circumstances, the present invention provides that even if the calculated injection port increases due to cold time correction etc., when the second intake passage is not opened by the second throttle valve, the calculated injection amount increases. Regardless, the object of the present invention is to provide a fuel injection device for an engine in which fuel is injected into a first intake passage only by a first injector without injecting fuel by a second injector. .

(Structure of the Invention) The fuel injection device for an engine of the present invention includes a first intake passage that supplies intake air to each cylinder in all operating ranges including a low intake air amount range, and a first intake passage that supplies intake air in a high intake air amount range to each cylinder. The first intake passage is provided with a first injection valve and a first throttle valve, and the second intake passage is provided with a second VS valve and a second throttle valve. The fuel injection amount calculation means calculates the fuel injection amount according to the intake air amount detected by the air amount detection means, and the injection valve operating means operates the first injection valve when the injection amount calculated by the fuel injection amount calculation means is less than a set value. When the calculated injection amount exceeds a set value, the first and second injection valves are driven. The present invention is characterized by comprising a second injection valve stopping means for stopping the operation of the valve.

The above-mentioned second injection valve stopping means may be one that increases the setting value for starting fuel injection from the second injection valve when the second injection valve is cold, or one that detects the opening degree of the second injection valve and starts the second injection when the valve is closed. A type with a non-operating valve is adopted.

(Effects of the Invention) According to the present invention, the first injector performs accurate fuel injection in the low intake air amount range, and the second injector injects the fuel in the high intake air amount area.
While fuel atomization is promoted by injecting fuel from the injector as well, when the calculated injection amount exceeds a predetermined value due to cold time correction etc., fuel is injected from both the first and second injectors. Even if the size is large, fuel injection from the second to lower valves is not performed in the region where the second throttle valve of the second intake and air passage where the second injection valve is installed is closed. In addition, it is possible to ensure good ignition and combustibility by specifying fuel injection into an intake passage where there is no intake air, performing accurate fuel injection corresponding to the operating condition.

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

Embodiment 1 This embodiment is shown in FIGS. 1 to 5, and FIG. 1 is an overall configuration diagram, in which two first and second intake boats 3 and 4 are provided for the combustion chamber 2 of each cylinder of the engine 1. is opened, and the two first and second exhaust boats 5 and 6 are opened, respectively.

An intake passage 7 for supplying intake air is connected to the intake boats 3 and 4. This intake passage 7 has an air cleaner 8 at its flow end, and an intake air amount detection means 9 (air flow meter) for detecting the amount of intake air is installed downstream of this air cleaner 8. The intake passage 7 on the more downstream side is branched into a first intake passage 7a and a second intake passage 7b. The first intake passage 7a is an expansion chamber 7C.
The second intake passage 7b is connected to the second intake port 4 of each combustion chamber 2 via an expansion chamber 7d.

A first throttle valve 10 for controlling the amount of intake air flowing through the first intake passage 7a is provided at the entrance of the first intake passage 7a, and a first throttle valve 10 is provided at the entrance of the second intake passage 7b. A second
A throttle valve 11 is provided, and both throttle valves io and 1i are opened and closed in conjunction with throttle operation. The first throttle valve 10 opens when the load is low and becomes fully open as the load increases,
The second throttle valve 11 begins to open when the opening degree of the first throttle valve 10 reaches a set opening or more, and becomes fully open as the load increases.

In the first intake passage 7a, a first injection valve 12 for injecting fuel in all operating ranges including the low intake air amount range is arranged for each cylinder, and in the second intake passage 7b indicated by -F. A second injection valve 13 that injects fuel in the high intake ω range is provided for each cylinder. The first and second injection valves 12 and 13 receive a fuel control signal from a control unit 14 (microcomputer).
An injection pulse is output, and a predetermined amount of fuel is injected according to the injection pulse width.

Further, the intake passage 7 is provided with a bypass passage 15 that bypasses the first throttle valve 10.
Bypass control valve 16 for controlling bypass air flow during the
The opening of this bypass control valve 16 is adjusted by the operation of the near solenoid 16a based on the control signals from the control units 1 to 14, and the lower the engine temperature (cold U1 water temperature), the more bypass air is provided. The amount is controlled to increase.

The control unit 14 receives an intake signal from the intake air amount detecting means 9, and receives an engine rotational speed signal from the rotational speed sensor 77 and an engine cooling water temperature signal from the water temperature sensor 18.

This control unit 14 calculates the fuel injection port and timing (number of injections) corresponding to the operating state including cold time correction according to the outputs of the intake air amount detection means 9, the rotation speed sensor 17, and the water temperature sensor 18. Based on the fuel injection amount calculating means 19 and the calculated injection rJJm (injection pulse width) by this fuel injection amount calculating means 19, an injection pulse is output to the first injection valve 12 when the calculated injection amount is less than a set value. and an injection valve actuating means 20 which outputs an injection pulse to the first and second injection valves 12 and 13 when the set value is exceeded, and which receives a signal from the water temperature sensor 18. At times, the setting value of the injection valve operating means 20 is increased in accordance with the cold increase, and the injection start timing of the second injection valve 13 is delayed, so that at least in the region where the second throttle valve 11 is closed, the 21114th injection valve is 13 and the output of the water temperature sensor 18], the lower the engine temperature, the lower the bypass passage 1.
The bypass control valve driving means 22 outputs a control signal to the linear solenoid 16a to open the bypass control valve 16 of No. 5 and increase the amount of bypass air.

The fuel injection control by the control unit 14 is as follows:
As shown in FIG. 2, in the relationship between the engine speed N and the intake air amount Qa, when the engine is warm, the region (■) below the setting curve A is the injection region by the first injection control valve 12, and the region (■) is the injection area by the first and second injection valves 12.13. This setting curve A approximately corresponds to the valve opening curve of the second throttle valve 11, and in the low intake m region, the first injection valve 12
When the fuel injection port reaches the set value (the set value of the injection pulse width),
This is to start fuel 1174 hj from the second injection valve 13, and when it is cold, this setting curve B is shown as a broken line.
is set to a high value, and by delaying the start of injection by the second injection valve 13 even if the fuel injection amount increases, the second throttle valve 11 is increased due to the increase in fuel during cold conditions and the increase in the bypass air gate.
This prevents the second injection valve 13 from injecting fuel before the opening operation.

FIG. 3 is a flowchart for explaining the operation of the control unit 14. After starting, a water temperature signal from the water temperature sensor 18 is input in step S1, and a fuel injection amount corresponding to the operating state is calculated in step S2. The intake air I detected by the intake air amount detection means 9
Qa, engine rotation speed N1 determined by rotation speed sensor 17
Calculate the fuel injection pulse width τ (injection time) from the constant K, correction coefficient α, etc. Note that the correction coefficient α is for correcting and increasing fuel consumption during cold periods, etc., and the additional correction value τ0 is used even if the fuel injection pulse is output to the first or second injection valve 12.13.
Since it takes a certain amount of time to actually start fuel injection, this is to correct the rise time. Further, τa is a basic injection time that takes into account cold correction, etc., and τb is an acceleration increase time.

Subsequently, the control amount of the bypass control valve 16 is read out in accordance with the cooling water temperature t (S3), and the linear solenoid 16a of the bypass control valve 16 is driven in accordance with this control port (S4). Also, the set pulse width τV for starting the injection of the second injection valve 13
The injection pulse width τa + τb as the calculated injection amount in step S2 is the set pulse width τ.
If this judgment is No (low injection m range), it is necessary to judge whether the asynchronous acceleration switch is on or not (S7), and the asynchronous acceleration switch is on (YE
Step S) when there is a large acceleration state such as S).
8, asynchronous injection is performed at 8, while when this asynchronous acceleration switch is off (No), asynchronous injection is not performed and the injection pulse τp for the first injection valve 12 and the injection pulse τp for the second injection valve 1 are
@Q-J pulse τS for 3 is calculated (S9). In the low injection m range, the injection pulse τS for the second injection valve 13 is set to Fir, and the fuel injection from the second injection valve 13 is not performed, and step S2 is performed only by the first injection valve 12. The first injection pulse width τp is determined by the control signal of the injection pulse width τp.
The injection valve 12 is driven to perform fuel injection (813).

On the other hand, if the determination in step S6 is YES and the injection amount is in the high injection amount region, it is similarly determined whether the asynchronous acceleration switch is on (510) and the asynchronous acceleration switch is on (YES).
), when the acceleration state is large, step S1
1, while performing asynchronous injection when the asynchronous acceleration switch is off (NO), calculate the injection pulse τp for the first injection valve 12 and the injection pulse τS for the second injection valve 13 without performing asynchronous injection. 512) This control signal drives the first and second injection valves 12.13 to perform fuel injection (313). Note that in this example, the first injection valve 12
and the second injection valve 13 are set to inject the same amount of fuel (half each).

The value of the set value τV read out in step $5 above is now:
The characteristics are set as shown in FIG.

That is, the cooling water temperature t detected by the water temperature sensor 18
is a large set value τV when the temperature is lower than @machine completion temperature to.
It is set so that when the value exceeds τV, a small set value τV is read out.

In the above fuel injection, the outputs of the injection pulses τp and τS when performing asynchronous injection in a high injection amount range are as shown in FIG.

Embodiment 2 In this embodiment, the overall configuration is shown in FIG. 6, and the flowchart is shown in FIG. In this example, instead of detecting the cooling water temperature, the opening degree of the second throttle valve 11 is directly detected by the thrower 1 to the sensor 23, and this detection signal is sent to the second injection valve stop means 21 of the control unit 1 to the roll unit 1 to 14. Even when the fuel F4 injection range calculated by the fuel injection amount calculation means 19 according to the engine operating state exceeds the set value in the injection valve actuation means 20, the second throttle valve 11 closes. When the signal is output to the second injection valve stop means 21,
The operation of the second injection valve 13 is stopped, and each calculated injection is
It outputs a control signal for injection by the injection valve 12. The rack is installed in the same manner as in the previous example, and the same 1'4 structures as in Figure 1 are given the same reference numerals and explanations are omitted.

FIG. 7 shows the control unit of this example for obtaining the above characteristics.The operation of ~14 is not shown at flow t-1~, and after moving to star 1, the fuel injection ω corresponding to the operating state is calculated in step S1. The fuel injection pulse width τ is calculated from the intake air IQa determined by the intake air value detection means 9, the engine rotational speed N1 constant determined by the rotational speed sensor 17, and the 1 correction coefficient α.

Next, the set pulse width τV for starting fuel injection of the second injection valve 13 is read out (82), and the injection pulse width τδ+τb calculated in step S1 is the set pulse width τv 1
If the determination is NO (low injection amount area), it is determined whether the asynchronous acceleration switch is on (S4), and the asynchronous acceleration switch is on (YES).
) in a large acceleration state, step S5
On the other hand, when this asynchronous acceleration switch is off (No>), asynchronous injection is not performed and the first
The injection pulse τp for the injection valve 12 and the injection pulse τS for the second injection valve 13 are calculated (S6).

In the above low injection DAω region, the injection pulse τ for the second injection valve 13
S'tfi is set to zero, and the first injection is performed only by the first injection valve 12 by the control signal of 1li4 injection pulse width τp obtained in step S1 without injecting fuel from the second injection valve '13. Fuel injection is performed by driving the valve 12 (S11).

On the other hand, when the determination in step S3 is YES in the high injection Q region, it is determined in step S7 whether or not the second throttle valve 11 is open based on the signal of the throttle sensor 23, and the second throttle valve 11 is closed. Proceeding from S4 to 86, the second injection valve 13 is not operated.If the judgment in step S7 is YES and the second throttle valve 11 is open, it is not necessary to judge whether the asynchronous acceleration switch is on. S8), when the asynchronous acceleration switch is on (YES), the asynchronous @ rule is performed in step S9 after a particularly large acceleration state, while when the asynchronous acceleration switch is off (no), the asynchronous injection is not performed and step In S10, the injection pulse τp for the first injection valve 12 and the injection pulse τS for the second injection valve 13 are calculated, and the injection pulse drives the first and second injection valves 12.13 to perform fuel injection. conduct(
S11).

In this example, the acceleration correction τb is such that the entire amount is injected into the first injection valve 12 at J:.

As explained above, the calculation injection port (injection pulse width ra
Even when +τb) exceeds the set value τV, fuel injection by the second injection valve 13 is not performed when the second throttle valve 11 is closed.

d3, in the above embodiment, the first
The injection valve 12 is arranged at a downstream portion of the first intake passage 7a relatively close to the combustion chamber 2, so that the fuel injected from the first injection valve 12h is quickly supplied to the combustion chamber 2. The second injector 13 is disposed in the second intake passage 7b upstream of the first injector 12 to improve the responsiveness of the fuel to increases and decreases in the amount of intake air. This improves mixing with intake air and atomization to promote atomization.

Also, a first
The throttle valve 10 can be installed at the inlet of the first intake passage 7a as shown in FIG. 1, or it can be installed at the intake passage 7 on the −L flow side from the second throttle valve 11 to achieve the same control effect. can get.

Furthermore, in the above embodiment, the two intake boats 1 to 1 connected to the intake passages are opened independently in the combustion chamber of each cylinder, and each is opened and closed by an intake valve, but a single intake boat is used. The intake passage which is opened and connected thereto may be divided into a plurality of intake passages.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram of the fuel injection system of a J5 engine according to the first embodiment of the present invention, and Fig. 2 is a schematic drawing of the fuel injection system of a J5G engine according to the first embodiment of the present invention. 3 is an explanatory diagram showing the control characteristics of the injection amount region of the IJJ valve in the first embodiment.
Figure 4 is an explanatory diagram showing an example of the fuel angle injection pulse output to the Ni-C injection valve in Figure 3. Figure 5 shows the characteristics of the set value with respect to the cooling water temperature in Figure 3. 6 is a schematic configuration diagram of the fuel injection neck of the engine in the second embodiment, and FIG. 7 is a diagram showing the control unit 1 to 1 in the second embodiment.
FIG. 1 is a flowchart 1 to FIG. 1...Engine 2...Combustion chamber 3.4
...Intake boat 7...Intake passage 7a.
...First intake passage 7b... Second intake passage 9... Intake air amount detection means 10... First throttle valve 11... Second throttle valve 12...First injection valve 13...Second injection valve 14...Control unit 18.
...Water temperature sensor 19...Fuel injection amount calculation means 20...Injection valve operating means 21...Second injection valve stopping means 23...・Throttle sensor

Claims (1)

[Claims] (1) A first M air passage that supplies intake air to each cylinder in all operating ranges including the low intake air range, a second intake passage that supplies intake air in the high intake ω range, and a first intake passage are provided. a first injection valve; a second injection valve provided in the second intake passage;
A first throttle valve that controls the amount of intake air in the intake passage, a second throttle valve that controls the amount of intake air in the second intake passage, a means for detecting intake air 5 that detects the amount of intake air, and an output of the intake air amount detection means. A fuel injection m calculation means calculates the fuel injection amount according to the fuel injection amount, and when the calculated injection amount by the fuel injection amount calculation means is less than or equal to the set value, the first injection valve is driven, and this calculated injection amount exceeds the set value. rpJ injection valve operating means that drives the first and second injection valves when the throttle valve is exceeded; 1. A fuel injection device for an engine, comprising: injection valve stopping means.