JPS61279737A - Fuel-injection type engine - Google Patents

Abstract

PURPOSE:To perform fuel control in a highly accurate manner, by controlling a fuel injection valve in a cylinder according to the specified load, while having another fuel injection valve in a suction passage operated at a driving range of more than the specified load, in case of an engine installing the fuel injection valve in the cylinder and the suction passage each. CONSTITUTION:A first fuel injection valve 21 is installed in a cylinder of an engine, while a second fuel injection valve 23 is installed in a suction passage, respectively. And, there is provided with a load detecting device 24 detecting engine load, output of which is inputted into both first and second injection valve driving devices 25 and 26. The first fuel injection valve driving device 25 makes out a fuel injection pulse in pulse width corresponding to load when engine load is less than the setting load, but when it is more than the setting load, it makes out the fuel injection pulse of constant pulse width each, and it is made so as to be added to the first injection valve 21. Likewise, the second injection valve driving device 26 adds the fuel injection pulse to the second injection valve 23 at the time of driving the engine load is more than the specified load, whereby a portion of shortage in a fuel injection quantity is made so as to be sprayed.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a fuel injection engine.

[Prior art]

In vehicle engines, a fuel injection device is used as a fuel supply means in place of a conventional carburetor from the viewpoint of improving fuel control accuracy. Some of these fuel injection engines are equipped with fuel injection valves in the cylinders and intake passages of the engine, and both injection valves are controlled according to the operating state of the engine. Kaisho 5
There is one shown in Publication No. 4-69607. In other words, when the engine is under low load, the fuel injector installed in the cylinder injects an amount of fuel according to the load from 0'1.
1) `` Gather the air-fuel mixture nearby to improve ignitability and
) Improving stability of drivability and fuel efficiency at low loads where combustion becomes unstable, while at high engine loads 1, sometimes each of the fuel injection valves installed in the cylinders and intake passages 11! - The fuel is injected in an amount according to the load from each engine to generate a uniform air-fuel mixture in the combustion chamber, thereby improving output under high loads.

However, if the fuel injection valves installed in the cylinders and intake passages are configured to inject fuel in an amount that corresponds to the load condition over the entire operating range, the large fuel injection pulse width at high loads will cause in-cylinder fuel injection. Since the pressure is applied to the valve and the pressure within the cylinder at this time fluctuates greatly, there is a problem in that highly accurate fuel injection control becomes difficult.

By the way, considering the vaporization and atomization of fuel injected from an in-cylinder injection valve, when fuel is injected from an in-cylinder injection valve, the advantage is that the air-fuel mixture can be collected around the spark plug to improve ignition performance, as mentioned above. However, in this case, if fuel is simply injected at the same rate from both injectors at high loads as in the above-mentioned Japanese Patent Application Laid-open No. 54-69607, the fuel injection amount will be reduced at high loads. If the amount of fuel injected from the in-cylinder injection valve increases, there is no room for some of the fuel injected from the in-cylinder injection valve to vaporize and atomize, which may reduce combustibility. From the viewpoint of optimization, it is desirable to set a certain limit rather than simply controlling according to the load.

[Purpose of the invention]

In view of these problems, the present invention aims to provide a fuel injection engine that can control fuel injection with high precision.

[Structure of the invention]

Therefore, this invention provides an engine in which fuel injection valves are provided in a cylinder and an intake passage, and both injection valves are controlled according to the operating state of the engine.
When the load is below the set load, an amount of fuel is injected according to the load, and when the load is above the set load, a fixed amount of fuel is injected at a predetermined timing synchronized with the rotation of the engine.On the other hand, for the intake road injection valve, when the load is at least above the predetermined load The fuel is designed to be injected in the operating range.

That is, as shown in the functional block diagram of FIG. The first injection valve drive means 25 receives the output of the load detection means 24 and injects a fuel injection pulse with a pulse width corresponding to the load when the load is below the set load, and with a partial pulse width when the load is above the set load. A fuel injection pulse is created and applied to the first fuel injection valve 21 at a predetermined timing synchronized with the rotation of the engine, and the second injection valve driving means 26
receives the output of the load detection means 24 and applies a fuel injection pulse to the second fuel injection valve 23 when the operation is at least at a predetermined load or higher to inject the shortfall in the amount of fuel injected by the first fuel injection valve. It is.

〔Example〕

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

2 to 4 show a fuel injection engine according to an embodiment of the present invention. In the figure, ■ is an engine, a throttle valve 3 is disposed in the middle of an intake passage 2 of the engine 1, an air flow meter 4 is provided upstream of the throttle valve 3 in the intake passage 2, and The upstream end of 2 reaches an air cleaner 5. Further, a first fuel injection valve 7 is provided in the cylinder of the engine 1 facing the combustion chamber 6, and a second fuel injection valve 8 is provided in the intake passage 2 of the engine 1 downstream of the throttle valve 3. There is.

On the other hand, one end of a fuel supply passage 10 is connected to the fuel tank 9, and a first end of the fuel supply passage 10 is connected to the fuel tank 9. A second fuel injection valve 7.8 is communicatively connected to the fuel tank 9 in the order of -1st and second. Also, fuel supply passage 1
[:□ Between the 0 fuel tank 9 and the first fuel injection valve 7
5 has a fuel pump 11 and a fuel filter 2 interposed therein.The other end of the fuel supply passage 10 is connected to one end of a fuel return passage 13, and the connection between the two is connected to an intake negative pressure. A fuel pressure regulator □i4 erator 14 is interposed to control the fuel pressure according to the fuel pressure, and the other end of the fuel return passage 13 reaches the fuel tank 9. ,
.

In addition, in the figure, I5 detects the rotation angle of the engine.
Kakuya 7+, 16 is Yuwa 787. Valve 3° opening
) (throttle opening sensor that detects the inside, 17 is the engine
:71 (D Engineering, A1BCfQ&+6ゎE.2 Yatsuke, 1 :□゛'・'j;・ 9 is the water temperature sensor that detects the cooling water temperature of engine 1, 2
0 is a control unit that calculates the first fuel injection pulse to be applied to the fuel injection valve 7 of the control unit 20, and when this first fuel injection pulse exceeds a predetermined pulse width, the pulse of this predetermined width is The second fuel to be applied to the first fuel injector 8
The first fuel injection pulse is applied to the first fuel injection valve 7 and the second fuel injection pulse is applied to the second fuel injection valve 8 at a predetermined timing synchronized with the rotation of the engine. This control is performed.

In addition, in the above configuration, the air flow meter 4
is the load detecting means 24 shown in FIG. 1, and the control unit 20 realizes the functions of the first and second injection valve driving means 25, 26 shown in FIG.

Next, the operation will be explained using FIGS. 3 and 4.

Here, FIG. 3 is a flowchart of the processing of the control unit 20, FIG. The upper limit of the direct injection pulse width (the above-mentioned first fuel injection pulse width) with respect to the engine speed,
The figure (C) shows the 1. The fuel flow rates of the second fuel injection valves 7 and 8 are shown.

When the engine starts, the control unit 20 first outputs each output Qa of the air flow meter 4°, the crank angle sensor 15, and the throttle opening sensor 16, which indicate the operating state of the engine.
θC2θTVO is read (step 30), and it is determined whether the engine is in the fuel injection region (see Fig. 4 (al)) from the engine speed and throttle opening (step 31), and if it is in the injection stop region, Injection valve 7, 8
This is not performed when driving the fuel injection valve 7, but when the fuel injection valve is in the fuel injection region, the basic fuel pulse width to be applied to the first fuel injection valve 7, that is, the direct basic pulse width τD, is calculated from the engine rotation speed and intake air amount. On the other hand, the upper limit τDO of the direct pulse width (see Fig. 4 (bl)) is determined according to the engine speed, and the direct basic pulse width τD is the upper limit τ
It is determined whether it is less than or equal to DO (steps 32 and 33), and if the direct basic pulse width τD is greater than the upper limit τDo, this upper limit value τDO is set as the direct basic pulse width τD (step 34).

When the direct basic pulse width τD is determined in this way, the control unit 20 then calculates the required total fuel injection 1r (, cta
, Ne), and combine this with the direct fundamental pulse width τD
The second actual fuel injection pulse width TM to be applied to the second fuel injection valve 8 from [=f (Qa, Ne)−Cxr
D+rBATM] (step 35)
, from the direct basic pulse width τD to the first fuel injector 7
The first actual fuel injection pulse TD (=τD
+τBATD) in step 36), and the thus obtained 1st. The second actual fuel injection pulse TD, TM is the first
．． In addition to the second fuel injection valve 7.8, fuel is injected (step 37.38), so that the intake air amount Qa becomes less than the set value Qa'' as shown in FIG. At low load, an amount of fuel corresponding to the intake air amount Qa is injected from the first fuel injection valve 7 into the combustion chamber 6, and at the same time, the second fuel injection valve 8 is injected into the intake passage 2. , injection foam, air 1 liter of fuel is supplied with the required flow rate according to the operating condition;
□When the intake air amount Qa is higher than the set value Qa' and the load is high, a certain amount of fuel is injected into the combustion chamber 6 from the first fuel injection valve 7 and at the same time from the second fuel injection valve 8. Also, fuel is injected into the intake passage 2, and the engine is supplied with a required flow rate of fuel depending on the operating condition. Here, in the above equation, the constant C is a constant for converting the direct basic injection pulse to the intake pipe injection pulse, and τBATD and τBATM are the invalid injection times taking into account the time delay of the fuel injection valve 7.8. be. Regarding the application timing of the first and second fuel injection pulses, for example, the first fuel injection pulse may be applied in the latter half of the intake stroke in synchronization with the rotation of the engine.
1. Good, the fuel injection pulse in Collection 2 is strict. 1'4 engineering 14iy9"□,
4, 10.1, 1j, it may be applied just before the intake valve opens.

In the device of this embodiment as described above, when the intake air amount of the engine is high load and exceeds the set value, the injection amount from the in-cylinder injection valve (first fuel injection valve) is kept constant, and the shortage is compensated for by filling the air in the intake road. Since this is supplemented by fuel injection from the injector (second fuel injector), controlling the injection amount from the first and second fuel injectors is easier than when both are controlled according to the load. This is simple and can guarantee vaporization of the fuel injected from the in-cylinder injection valve.

In the above embodiment, the engine load is detected from the intake air amount and the engine speed, but it may also be detected from other parameters of the engine load, such as the throttle opening. Furthermore, in the above embodiment, the 1st.
Fuel is injected from both second fuel injectors, but when the load is extremely low such as when idling, only the first fuel injector injects fuel, and the second fuel injector is injected when the load is above a predetermined load. Fuel may also be injected.

〔Effect of the invention〕

As described above, according to the present invention, in an engine in which fuel injection valves are provided in a cylinder and an intake passage, and both injection valves are controlled according to the operating state of the engine, the settings for the injection valves in the cylinders are When the load is below, an amount of fuel is injected according to the load, and when the load is above the set load, a fixed amount of fuel is injected at a predetermined timing synchronized with the rotation of the engine.On the other hand, the intake road injection valve is injected at least in the operating range above the predetermined load. Since the fuel is injected at the same time, fuel can be controlled with high precision.
Moreover, since the in-cylinder fuel injection valve injects only a fixed amount when the load is above a predetermined load, there is an effect that vaporization and atomization of the fuel injected by the injection valve can be guaranteed.

[Brief explanation of drawings]

FIG. 1 is a functional block diagram showing the configuration of the present invention, FIG. 2 is a schematic configuration diagram of a fuel injection type engine according to an embodiment of the present invention, and FIG. 3 is a diagram showing a flowchart of processing of the control unit in the engine. , FIGS. 4(a) to (C) are diagrams showing the fuel injection region and injection stop region with the engine speed and intake air amount as parameters, respectively, and the diagram showing the upper limit of the direct injection pulse width with respect to the engine speed, and the first for the intake air amount. It is a figure which shows the fuel injection amount of the 2nd fuel injection valve 7.8. 21... First fuel injection valve, 22... Intake passage, 2
3... Second fuel injection valve, 24... Load detection means,
25.26...1st. Second injection valve driving means, 1...
- Engine, 2... Intake passage, 4... Air flow meter, 7.8... 1st. Second fuel injection valve, 15...
- Crank angle sensor, 20...control unit. Patent Applicant: Mazda Motor Corporation Agent, Patent Attorney Ken Hayase - Figure 1 i' Figure 2 Figure 3

Claims (1)

[Claims] (1) a first fuel injection valve that is provided in a cylinder of the engine and injects an amount of fuel according to the applied fuel injection pulse;
a second fuel injection valve that is provided in the intake passage of the engine and injects an amount of fuel according to the applied fuel injection pulse; a load detection means that detects the load of the engine; and a load detection means that receives and sets the output of the load detection means. When the load is below, a fuel injection pulse with a pulse width corresponding to the load is generated, and when the load is above a set load, a fuel injection pulse with a constant pulse width is generated, and the fuel injection pulse is injected at a predetermined timing synchronized with the rotation of the engine. a first injection valve driving means that applies a fuel injection pulse to the valve; and a fuel injection pulse that is applied to the second fuel injection valve when the load is at least equal to or higher than a predetermined load upon receiving the output of the load detection means; 1. A fuel injection type engine, comprising: a second injection valve driving means for injecting the insufficient amount of the injection amount.