JPH08312439A - Electronic control fuel injection device - Google Patents

Abstract

PURPOSE: To reduce the cost by reducing an outer circuit scale without complicating the structure of the outer circuits such as an MPU to operate the fuel injection amount. CONSTITUTION: The fuel injection pulse is produced by taking the logical OR of the outputs of fuel injection starters (the port output) 22a to 22d corresponding to the cylinders, and a timer 31 for injection finishing (the timer output) common to plural cylinders. The output of the timer 31 for injection finishing common to plural cylinders is distributed to the concerned cylinders by using the outputs of the fuel injection starters 22a to 22d indenpendent to each cylinder. When a cylinder B which finishes the fuel injection earler is generated by the variation of the operating condition and the like, after the output of the timer 31 is distributed to cylinders A, the output of the timer 31 for injection finishing to the cylinders A is converted to the outputs of the fuel injection starters 22a to 22d, and the output is distributed to the cylinder (or cylinders) B.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronically controlled fuel injection device for electronically controlling fuel injection of an engine such as an automobile.

[0002]

2. Description of the Related Art FIG. 8 is a block diagram showing the structure of a conventional electronically controlled fuel injection device. In FIG. 8, this example is
A microcomputer (MPU) 1 calculates a basic fuel injection amount from intake air pressure information and engine speed information output by an intake pressure sensor and an engine speed sensor. Also, M
PU1 calculates a fuel injection correction value and a fuel injection timing based on information output from a throttle opening sensor, an engine temperature sensor, and an intake air temperature sensor. Further, the output timer 2 whose detailed configuration is shown in FIG.
a, 2b, 2c, 2d output a fuel timer value signal having a time width corresponding to the fuel injection amount at the injection timing calculated by the MPU 1. This fuel timer value signal is input to the solenoid (SOL) drivers 6a, 6b, 6c, 6d, and is a signal corresponding to the output of the output timers 2a to 2d, and the injector 1 provided for each cylinder of the engine.
0a, 10b, 10c and 10d are controlled. The SOL drivers 6a to 6d send high (H) level fuel injection pulses corresponding to the outputs of the output timers 2a to 2d to the injectors 10a to 10d, and inject fuel by opening the valves into an engine (not shown).

FIG. 9 is a block diagram showing the configuration of the output timers 2a to 2d. In FIG. 9, the fuel timer value signal obtained by the MPU 1 is input to the compare counter 14. Further, the free-run counter 15 counts clock pulses in response to the injection timing obtained by the MPU 1. Then, the comparator 16 compares the count values from the compare counter 14 and the free-run counter 15, and if they match in this comparison, it outputs the match signal. This coincidence signal is input to the inversion circuit 17, and a fuel injection pulse that rises at the injection timing is output.

FIG. 10 is a timing chart showing processing signals and their timings in the operation of the electronically controlled fuel injection device shown in FIG. As shown in FIG. 10 (a), the engine repeats cycles of exhaust, intake, compression, and explosion,
As shown in FIG. 10B, the injector 10a starts fuel injection into the intake manifold communicating with the cylinder 1 (not shown) at the rising edge (1) of the fuel injection pulse, and at the falling edge (2) of the fuel injection pulse. Stop fuel injection. The fuel injected into the intake manifold is taken in by the intake cycle, and the compression cycle and the explosion cycle are processed. The other injectors 10b to 10d also operate in the same manner as the injector 10a shown in FIG. 10B, as shown in FIGS. 10C, 10D, and 10E.

As described above, in the above-described electronically controlled fuel injection device of the prior art, the injectors 10a to
The fuel injection pulse is supplied to 10d to control the fuel injection amount for each cylinder, and the all-cylinder simultaneous injection type fuel injection device or all cylinders that simultaneously inject fuel into all cylinders are divided into a plurality of groups. Compared to the group simultaneous injection method that simultaneously injects fuel into each cylinder of multiple groups, it is possible to supply the fuel value calculated by the latest information in engine operation to each cylinder,
Variations in fuel injection amount are avoided.

[0006]

However, the conventional electronically controlled fuel injection device requires the output timers 2a to 2d corresponding to each cylinder of the engine, which complicates the configuration of the external circuit for the MPU 1. That is, there is a drawback that the circuit scale increases and the cost increases.

The present invention solves such a conventional problem and reduces the circuit scale without complicating the structure of the external circuit such as the MPU for calculating the fuel injection amount, thereby reducing the cost. It is an object of the present invention to provide an excellent electronically controlled fuel injection device that enables

[0008]

In order to achieve the above object, an electronically controlled fuel injection device according to claim 1 is provided corresponding to each of a plurality of cylinders, and fuel injection is performed by an input fuel injection pulse. A plurality of fuel injection means for performing the fuel injection timing determination means for determining the fuel injection timing of the plurality of fuel injection means, and the fuel injection pulse from the injection timing determination means. A selecting means for selecting one of a plurality of fuel injection means to be supplied, and for the selecting means to terminate the fuel injection from the injection timing determining means to the fuel injection means of the cylinder in which the fuel injection finishes earliest. The fuel injection end pulse is selected and supplied.

The electronically controlled fuel injection device according to claim 2 is
One injection timing determination means is provided for a plurality of fuel injection means.

The electronically controlled fuel injection device according to claim 3 is
A plurality of fuel injection means is divided into a plurality of groups, and one injection timing determination means is provided for each of the divided fuel injection means groups.

The electronically controlled fuel injection device according to claim 4 is
Each of the plurality of fuel injection means includes a fuel pulse generation circuit, a solenoid driver, and an injector.

[0012]

With the above-mentioned structure, the first, second, third, and fourth aspects are provided.
The electronically controlled fuel injection device described is provided with a common injection timing determination means for a plurality of fuel injection means provided corresponding to each of a plurality of cylinders, and the fuel of the cylinder in which fuel injection ends the earliest A fuel injection end pulse for ending the fuel injection is selected and supplied to the injection means. In this case, one injection timing determination means is provided for a plurality of fuel injection means, or one injection timing determination means is provided for each of the fuel injection means groups divided into a plurality of groups. Therefore, it is not necessary to provide the injection timing determination means for each of the plurality of fuel injection means as conventionally done, and the configuration of the external circuit such as MPU for calculating the fuel injection amount becomes complicated. However, the circuit scale is reduced.

[0013]

Embodiments of the electronically controlled fuel injection device of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of an electronically controlled fuel injection device according to an embodiment of the present invention. In FIG. 1, in this example, a basic fuel injection amount is calculated from intake air pressure information and engine speed information output from an intake pressure sensor and an engine speed sensor, and a throttle opening sensor, an engine temperature sensor, and an intake air temperature are also calculated. An MPU 20 is provided that calculates a fuel injection correction value based on the information output from the sensor and calculates the fuel injection timing. The MPU 20 includes a calculation unit 21, fuel injection start units (port outputs) 22a, 22b, 22c, 22d that determine the start of fuel injection in synchronization with engine rotation, and injection for determining the end of fuel injection. Termination timer (timer output) 3
1 and are provided. The injection end timer 31 has a time width set from the present time to the time when it is desired to turn off (OFF) in the arithmetic unit 21, and is turned on (ON) at this time.
It turns off after this set time.

Further, in this example, the injection end timer 31 is used.
The set time information from the fuel injection start unit 2 is supplied.
2a to 22d are input to select injectors to select injectors, and fuel injection start units 22a to 22d output and injector selection and distribution unit 3
Fuel pulse generation circuit 34 for generating a logical sum with the output of 2
a, 34b, 34c, 34d are provided. Further, solenoid (SOL) drivers 36a, 36b, 36c, 36 for sending out high (H) level fuel injection pulses corresponding to the outputs of the fuel pulse generating circuits 34a to 34d.
d and injectors 40a, 40b, 40c, 40d for injecting fuel to the engine (not shown) by opening a signal corresponding to the outputs of the SOL drivers 36a to 36d.

FIG. 2 is a block diagram showing a detailed structure of the injector selection / distribution unit 32. In FIG. 2, the injector selecting / distributing section 32 includes a fuel injection starting section 22a.
A flip-flop in which the output signal from 22d is input to the data (D) terminal, the set time information from the injection end timer 31 is input to the clock terminal, and a signal at that timing is output from the output (Q) terminal (F /
F) AND circuit 33a, 33b, 33c, 33d, AND which outputs a signal by AND logic between the output signals from the output (Q) terminals of the F / F circuits 33a to 33d and the set time information from the injection end timer 31. Circuits 35a, 35b, 35
c, 35d.

FIG. 3 shows fuel pulse generation circuits 34a to 34d.
3 is a block diagram showing a detailed configuration of FIG. In FIG.
The fuel pulse generation circuits 34a to 34 are OR circuits 3 that take the logical sum of the output signals of the fuel injection start units 22a to 22d and the set time information from the injection end timer 31.
7a (37b, 37c, 37d).

Next, the operation of this embodiment will be described. FIG. 4 shows the fuel injection start parts 22a to 22 in the calculation part 21.
9 is a flowchart showing a processing procedure of an operation of setting d. In FIG. 4, it is started by interruption by a crank signal, and in step S10, it is determined whether or not the current crank signal is the timing at which fuel injection of the cylinder in any engine should be started. When starting fuel injection (Y
es), the fuel injection starting unit (port output) 22a corresponding to the cylinder from which fuel injection should be started in step S11.
22d is set to ON (ON), and the high (H) level fuel injection pulse corresponding to the output of the fuel pulse generation circuits 34a to 34d is output to the SOL drivers 36a to 36d.
Output from When fuel injection is not started in step S10 (No), the process ends. Next, in step S12, the fuel injection start parts (port outputs) 22a to 22d corresponding to the cylinders in which fuel injection ends the earliest are determined, and in subsequent step S13, they are set to ON (ON). Next, in step S14, the output of the injection end timer 31 is set to zero and forcibly set to OFF.
In this case, fuel injection pulses are being supplied to the cylinders corresponding to the fuel injection start parts (port outputs) 22a to 22d that are turned on. Next, in step S15, the remaining injection time of the cylinder where the fuel injection ends (in the case of Yes) is calculated, and the time is set in the injection end timer 31. When the set time is reached here, the output of the fuel injection start units (port outputs) 22a to 22d corresponding to the corresponding cylinders is ended in order to stop the delivery of the fuel injection pulse in step S16.

FIG. 5 is a flow chart showing the procedure of interrupt processing that occurs when the injection end timer 31 times out. In FIG. 5, in step S20,
It is determined whether there is another cylinder that is injecting fuel. When no other cylinder is injecting fuel (step S20: No)
Ends the process. Further, when there is another cylinder that is injecting fuel (step S20: Yes), that is, when any of the fuel injection start units (port outputs) 22a to 22d is on (ON), an injection end timer (timer). Output) 3
In order to output 1 to the cylinder in which fuel injection is completed earliest, the time width of the remaining fuel injection of the corresponding cylinder is calculated, and the time width is set in step S21. When the set timer value is reached, the outputs of the fuel injection start parts (port outputs) 22a to 22d corresponding to the corresponding cylinders are turned off in order to end the fuel injection pulse.

FIG. 6 is a timing chart showing the processed signals in the entire operation and their timings. Figure 6
6A shows a cylinder discrimination signal output for each crank angle of 360 °, and FIG.
It is a crank signal output every 0 °. MPU20
Information is input to the calculation unit 21 to calculate the timing at which injection should be started and the injection output time width. Here, the timing at which the injection should be started indicates which crank signal the fuel injection is started in synchronization with, and hereinafter, is turned on.
Described as a stage. For each crank signal, it is determined whether this crank is the ON stage at which injection should start.
When in the ON stage, the fuel injection start signal (port output) 22a to 22d of the corresponding cylinder sends a fuel injection start signal. Fuel injection starting portion (port output) 22a-
The output of 22d is input to one of the input terminals of the fuel pulse generation circuits 34a to 34d corresponding to the injectors 40a to 40d. Here, it is shown that the fuel is input to the corresponding fuel pulse generation circuits 34a to 34d in the order of the injectors 40a to 40d. On the other hand, in the interrupt process that occurs when the injection end timer (timer output) 31 times out, the injectors 40a to 40d that finish the fuel injection earliest are determined, and the corresponding cylinder is selected by the injector selection distribution unit 32. The fuel injection pulse that rises by the output of the injection end timer (timer output) 31 and falls after the remaining time of the injectors 40a to 40d is output. FIG. 6D shows the output of the injection end timer (timer output) 31, and the injector selection / distribution unit 3
2 is input to the other input terminal of the fuel pulse generation circuits 34a to 34d corresponding to the selected injectors 40a to 40d. In FIG. 6E, the output of the injection end timer (timer output) 31 that is sequentially output is output by the injector selection / distribution unit 32 to the injectors 40a to 40d.
In order of the corresponding fuel pulse generation circuits 34a-34d
Has been entered in. The outputs of the fuel pulse generation circuits 34a to 34d are the OR circuits 37a shown in FIG.
.About.37d are generated by the logical sum of the output signals of the fuel injection start units 22a to 22d and the set time information from the injection end timer 31. As a result, as shown in FIG. 6 (c), the fuel injection start portions (port outputs) 22a to 22d are set after the output of the injection end timer (timer output) 31 of the corresponding cylinder is set to ON (ON). Is turned off before is passed. This fuel injection pulse is SO
It is input to the L drivers 36a to 36d, and as shown in FIG. 6 (f), the injectors 40a to 40d are opened to inject fuel.

In this embodiment, the injection correction value may be calculated by interrupting the crank signal after the start of fuel injection, and the time value of the injection end timer 31 may be corrected based on this correction value. .

FIG. 7 is a timing chart showing processing signals and their timings in another example of the whole operation.
This is an example in which the timing of the fuel injection pulse to be output does not match the order of fuel injection start, as shown in FIG. 7A. At timing 5a in FIG. 7 (f), the injector 40a terminates fuel injection earliest, so the injection end timer (timer output) is set at time T1 by the processing of steps S10 to S12, S15, and S16 in FIG.
Set with 31. Next, timing 5b in FIG. 7 (f)
Is the injector 40b that selects the cylinder for which fuel injection is completed earliest, and steps S10 to S1 in FIG.
By the process of 6, the output of any of the fuel injection starting parts (port output) 22a to 22d corresponding to the timing 5a is turned on (ON), and the fuel injection starting part (port output) is turned on.
The outputs 22a to 22d are turned off once. Then, the fuel injection start parts (port outputs) 22a to 22d corresponding to the injectors 40b are turned on (ON), and the time T2 is set by the injection end timer (timer output) 31, and this fuel injection start part (port output) is set. 22a to 22d
Turn off. Next, in the interrupt occurring at the timing 5c when the time T2 ends, the cylinder that finishes the fuel injection earliest is selected. In this case the injector 4
0a, the remaining time T3 of the injector 40a is set by the injection end timer (timer output) 31, and the fuel injection start parts (port output) 22a to 22d corresponding to the injector 40a are turned off.

In this way, the injection end timer (timer output) 3 is applied to the cylinder in which the fuel injection is always completed earliest.
By outputting 1, the processing can be performed only by this injection end timer (timer output) 31. Also, here, the explanation was given with a 4-cylinder engine, but 3
In the case of four cylinders, five cylinders, fuel injection can be controlled by the same processing procedure. Furthermore, although one injection end timer (timer output) 31 has been described, for example, in the case of a V-type engine, an injection end timer may be provided for each bank to control the fuel injection.

[0024]

As is apparent from the above description, according to the electronically controlled fuel injection device of the first to fourth aspects, the common injection timing determination means is provided for the plurality of fuel injection means, The fuel injection end pulse for ending the fuel injection is selected and supplied to the fuel injection means of the cylinder in which the fuel injection ends the earliest. In this case, one injection timing determination means is provided for a plurality of fuel injection means, or one injection timing determination means is provided for each of the fuel injection means groups divided into a plurality of groups. It is not necessary to provide an injection timing determining unit for each fuel injection unit, the circuit scale can be reduced and the cost can be reduced without complicating the configuration of an external circuit such as an MPU for calculating the fuel injection amount. Have an effect.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an electronically controlled fuel injection device according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a detailed configuration of an injector selection / distribution unit in FIG.

FIG. 3 is a circuit diagram showing a detailed configuration of a fuel pulse generation circuit in FIG.

FIG. 4 is a flowchart showing a processing procedure of a setting operation of a fuel injection start portion in FIG.

5 is a flow chart showing a processing procedure of interrupt processing that occurs when the injection end timer in FIG. 1 times out.

FIG. 6 is a timing chart showing a processing signal and its timing in the entire operation in the embodiment.

FIG. 7 is a timing chart showing processing signals and their timings in another overall operation in the embodiment.

FIG. 8 is a block diagram showing a configuration of a conventional electronically controlled fuel injection device.

9 is a block diagram showing the configuration of an output timer in FIG.

10 is a timing chart showing processing signals and their timings in the operation of the electronically controlled fuel injection device shown in FIG.

[Explanation of symbols]

 20 MPU 21 operation part 22a-22d fuel injection start part 31 injection end timer 32 injector selection distribution part 34a-34d fuel pulse generation circuit 33a-33d F / F circuit 35a-35d AND circuit 36a-36d SOL driver 37a-37d OR Circuit 40a-40d injector

Claims (4)

[Claims] 1. A plurality of fuel injection means provided corresponding to each of a plurality of cylinders and performing fuel injection with an input fuel injection pulse; and a plurality of fuel injection means provided in common to the plurality of fuel injection means, An injection timing determining means for determining fuel injection timings of the plurality of fuel injection means, and a selecting means for selecting one of the plurality of fuel injection means for supplying the fuel injection pulse from the injection timing determining means, Electronic control, characterized in that the selecting means selects and supplies a fuel injection end pulse for ending the fuel injection from the injection timing determining means to the fuel injection means of the cylinder in which the fuel injection ends earliest. Fuel injection device. 2. The electronically controlled fuel injection device according to claim 1, wherein one injection timing determination means is provided for the plurality of fuel injection means. 3. The electronically controlled fuel according to claim 1, wherein the plurality of fuel injection means are divided into a plurality of groups, and each divided fuel injection means group is provided with one injection timing determination means. Injection device. 4. The electronically controlled fuel injection device according to claim 1, wherein each of the plurality of fuel injection means comprises a fuel pulse generation circuit, a solenoid driver and an injector.