JPH0430358Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] This 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 fuel injection engines are equipped with fuel injection valves in the cylinders and intake passages of the engine, and one or both of the injection valves are driven depending on the operating state of the engine. Conventionally, there is a method disclosed in Japanese Patent Application Laid-Open No. 54-69607. 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, collects the air-fuel mixture near the spark plug, improves ignition performance, and makes combustion unstable. This improves stability of drivability and fuel efficiency when the engine is under low load, while at the same time, when the engine is under high load, fuel is injected in an amount commensurate with the load from each of the fuel injection valves installed in the cylinders and intake passages, ensuring uniformity within the combustion chamber. This system is designed to generate a mixture with a high temperature, thereby improving output under high loads.

However, in conventional fuel injection engines of this type, the fuel injection valves installed in the cylinders are installed facing the combustion chamber and are exposed to a high temperature atmosphere, so the fuel evaporates and damages the fuel injection valves and fuel supply. There was a problem in that air bubbles were generated in the passage, and the air bubbles caused percolation, leading to concerns about a decrease in the control accuracy of the fuel flow rate.

[Purpose of invention]

In view of these problems, this invention aims to provide a fuel injection type engine that can guarantee the control accuracy of the fuel flow rate.

[Structure of the invention] Therefore, this invention provides a fuel injection type engine in which fuel injection valves are provided in the cylinders and intake passages, and fuel is injected from either or both of the injection valves depending on the operating condition of the engine. When the temperature of the internal injection valve or the temperature of a factor correlated thereto reaches an abnormal temperature, the cylinder injection valve is stopped and fuel is injected from the intake passage injection valve.

That is, this invention, as shown in the functional block diagram of FIG.
4, and an injector driving means 25 controls the first and second fuel injectors 22 and 24 according to the operating state of the engine.
At that time, the temperature detection means 26 detects the temperature of the first fuel injection valve 22 or the temperature of a factor correlated thereto, and the abnormality control means 27 detects the output of the temperature detection means 26. In response to this, when the temperature of the first fuel injection valve 22 or the temperature of a factor correlated thereto becomes abnormal when the first fuel injection valve 22 is driven, the injection valve driving means 25 is controlled and the first fuel injection valve 22 is The second fuel injection is stopped and the second fuel injection is stopped.
The fuel is injected from the fuel injection valve 24.

〔Example〕

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

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

On the other hand, one end of a fuel supply passage 10 is connected to the fuel tank 9, and first and second fuel injection valves 7 and 8 are connected to the fuel tank 9 in the first and second order. and is connected in communication with the fuel supply passage 1.
A fuel pump 11 and a fuel filter 12 are interposed between the No. 0 fuel tank 9 and the first fuel injection valve 7. Further, one end of a fuel return passage 13 is connected to the other end of the fuel supply passage 10, and a fuel pressure regulator 14 for controlling fuel pressure according to intake negative pressure is interposed at the connection between the two.
The other end of 3 is connected to a fuel tank 9.

Further, in the figure, 15 is a crank angle sensor that detects the rotation angle of the engine, 16 is a throttle opening sensor that detects the opening of the throttle valve 3, 17 is an O ₂ sensor provided in the exhaust passage 18 of the engine, and 19 is a throttle opening sensor that detects the opening of the throttle valve 3.
21 is a water temperature sensor that detects the temperature of the cooling water of the engine 1 near the first fuel injection valve 7; 21 is a temperature sensor that detects the ambient temperature of the first fuel injection valve 7; 20
is a control unit, and the control unit 20 drives the second fuel injection valve 8 provided in the intake passage 2 when the engine is under high load, and drives the first fuel injection valve 7 provided in the cylinder when the engine is under low load. If the ambient temperature of the injection valve 7 or the cooling water temperature near the injection valve 7 becomes abnormal while the first fuel injection valve 7 is being driven, the operation of the first fuel injection valve 7 is stopped. Control is performed such that the fuel injection valve 8 is stopped and the second fuel injection valve 8 is driven instead.

In the above configuration, the water temperature sensor 19 and the temperature sensor 21 serve as the temperature detection means 26 shown in FIG. 1, and the control unit 2
0 realizes the functions of the injection valve driving means 25 and the abnormality control means 27 shown in FIG.

Next, the operation will be explained using FIGS. 3 to 6. Here, FIG. 3 shows a flowchart of the processing of the control unit 20, FIG. 4 shows the intake pipe injection region, direct injection region, and fuel cut region with the engine speed and throttle opening as parameters, and FIG. 6 shows the function f2 of the acceleration increase correction rate Cacc with respect to the throttle opening change rate dθ/dt and the acceleration elapsed time Δt, respectively.

When the engine starts operating, the control unit 20 executes the process shown in the flowchart in FIG.
9 and 21 are read (step 30), and the engine operating range determined by the engine speed rpm determined from the output of the crank angle sensor 15 and the throttle opening θ is determined by the fuel cut range boundary line a (Fig. 4). (see step 31).
If it is below the fuel cut region boundary line a, the process returns to step 30, and if the engine operating region is in the fuel cut region, the first and second fuel injection valves 7 and 8 are not driven and the fuel supply is stopped. Make a cut.

On the other hand, when the operating range of the engine is equal to or higher than the fuel cut range boundary line a, the control unit 20 calculates the basic pulse width τe of the fuel injection pulse according to the intake air amount and the engine speed rpm (step 32), it is determined from the change in the throttle opening θ whether or not acceleration is to be started (steps 33, 34), and whether the cooling water temperature TW near the first fuel injection valve 7 is within the set range (TWC≦TW≦TWH). or the injection valve 7
The ambient temperature TA is within the setting range (TAC≦TA≦
TAH) (steps 35 and 36),
Determine whether or not the operating region of the engine is below the direct injection region boundary line b (see FIG. 4) where fuel is injected by the first fuel injection valve 7 (step 37);
When the engine is in a light load state below boundary line b, the switching weight loss rate CCH1 is set to a predetermined value CCHG1 or After setting it to zero (steps 38, 39, 40), the first fuel is The pulse width of the fuel injection pulse to be applied to the injection valve 7, that is, the direct injection pulse width TD [=k×
τe×(1-CCH1)+τBATD] is added to the first fuel injection valve 7 to drive the injection valve 7 (steps 41 and 42), and in this way, when the engine is under light load, the first fuel injection is performed. The valve 7 is driven and fuel is directly injected and supplied to the combustion chamber 6.

Further, when the engine operating region is in a high load state equal to or higher than the direct injection region boundary line b, the control unit 20 determines whether the engine is in an acceleration/deceleration state (step 43) and then determines whether or not it is immediately after the start of intake pipe injection. According to
The switching increase rate CCH2 is set to a set value CCHG2 or zero considering the shortage of fuel adhering to the intake pipe wall (steps 44, 45, 46), and the above-mentioned basic pulse width τe, switching increase rate CCH2 and injection valve 8 are set. The pulse width of the fuel injection pulse to be applied to the second fuel injector 8, that is, the intake pipe injection pulse width TM [=τe×(1+CCH2)+τBATM] is calculated using the invalid injection period τBATM of In addition to the fuel injection valve 8, the fuel injection valve 8 is also driven (steps 47 and 48), and when the engine is under high load, the second fuel injection valve 8 is driven and fuel is injected into the intake passage 2, from where it is combusted. It will be supplied into the chamber 6.

When the first fuel valve 7 is being driven as described above, the temperature of the cooling water near the first fuel injection valve 7 is
TW or ambient temperature TA is within the setting range (TWC≦TW
≦TWH, TAC≦TA≦TAH), the control unit 20 proceeds from step 35 or 36 to step 44, executes steps 44 to 48, and drives the second fuel injection valve 8. Thus the first
cooling water temperature near the fuel injection valve 7 or the injection valve 7
When the ambient temperature reaches an abnormal temperature, the driving of the first fuel injection valve 7 is stopped and fuel is injected and supplied from the second fuel injection valve 8.

Furthermore, when the engine is in an acceleration/deceleration state, the control unit 20 increases the acceleration based on a predetermined function f2 (see Figs. 5 and 6) according to the throttle opening change rate dθ/dt and the elapsed acceleration time Δt. Correction factor
Calculate Cacc [=f2(dθ/dt, Δt)] (step
49), when the speed of change in throttle opening dθ/dt is greater than the set value α0 during sudden acceleration, the first fuel injector 7
Acceleration increase [k=τe×(1+Cacc−CCH1)+
τBATD)] is injected, and during slow acceleration where the rate of change dθ/dt is smaller than the set value α0, the second fuel injector 8 injects the fuel that has undergone acceleration increase [=τe×(1+
Cacc+CCH2)+τBATM] is injected and supplied.

In the device of this embodiment as described above, when the first fuel injection valve installed in the cylinder becomes abnormally temperature, the second fuel injection valve installed in the intake passage is driven instead. Therefore, the second fuel injector is
Compared to other fuel injection valves, the temperature does not reach that high, and fuel can be supplied with relatively high accuracy.

Further, in the above-mentioned device, since the first fuel injection valve provided in the cylinder also increases the amount of acceleration during sudden acceleration, acceleration responsiveness can be guaranteed.

In the above embodiment, the cooling water temperature near the first fuel injection valve and the ambient temperature around the injection valve are detected, and when either one becomes abnormal temperature, the driving of the first fuel injection valve is stopped. However, this may be done by detecting only one of them, or by detecting the temperature of the first fuel injection valve or a factor correlated thereto other than the above-mentioned cooling water temperature or ambient temperature, such as engine oil temperature. Temperature may also be detected.

[Effect of idea]

As described above, according to the present invention, in a fuel injection type engine in which fuel injection valves are provided in cylinders and intake passages, and fuel is injected from either or both injection valves depending on the operating condition of the engine, When the temperature of the internal injection valve or the temperature of a factor related to this reaches an abnormal temperature, the cylinder injection valve is stopped and fuel is injected from the intake passage injection valve, ensuring the accuracy of fuel flow control. There is an effect that can be done.

[Brief explanation of the drawing]

Figure 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, FIG. 3 is a flowchart of the calculation processing of the control unit 20 in the engine, and FIG. 4 is a diagram showing the engine speed and throttle opening. Figures 5 and 6 are diagrams showing the intake pipe injection area, direct injection area, and fuel cut area where the degree and degree are parameters, respectively.
FIG. 7 is a diagram showing a function f2 for determining an acceleration increase correction rate Cacc with respect to dθ/dt and acceleration elapsed time Δt. 22...First fuel injection valve, 23...Intake passage, 24...Second fuel injection valve, 25...Injection valve driving means, 26...Temperature detection means, 27...Abnormality control means, 1 ...Engine, 2...Intake passage,
7...First fuel injection valve, 8...Second fuel injection valve, 19...Water temperature sensor, 20...Control unit, 21...Temperature sensor.

Claims (1)

[Scope of utility model registration request] A first fuel injection valve provided in a cylinder of the engine, a second fuel injection valve provided in an intake passage of the engine, and one of the first and second fuel injection valves depending on the operating state of the engine. an injector driving means for driving one or both of the above, a temperature detecting means for detecting the temperature of the first fuel injector or a temperature of a factor correlated thereto, and a temperature detecting means for detecting the temperature of the first fuel injector or the temperature of a factor correlated thereto; When the temperature of the fuel injection valve or the temperature of a factor correlated thereto reaches an abnormal temperature when the fuel injection valve is driven, the injection valve driving means is controlled to stop the fuel injection of the first fuel injection valve, and the fuel injection valve is controlled to stop the fuel injection of the first fuel injection valve. What is claimed is: 1. A fuel injection engine comprising: abnormality control means for injecting fuel from two fuel injection valves.