JPH06129295A - Electronic control fuel injection device - Google Patents

Abstract

PURPOSE:To provide a less expensive device by reducing the number of timer means to generate a fuel injection pulse less than the number of cylinders in an electronic control fuel injection device. CONSTITUTION:Fuel injection starting means 22-25 are provided for each of a plural number of cylinders, and by a logical sum of a fuel injection starting signal synchronized with a rotational signal and a fuel injection finish signal which is an output signal of a timer 31 for fuel injection finish common to a plural number of the cylinders, a fuel injection oulse is generated. The output signal of the timer 31 for fuel injection finish common to a plural number of the cylinders is distributed to a plural number of the cylinders by using output signals of the fuel injection starting means 22-25 for each of a plural number of the cylinders. Consequently, it is possible to reduce the number of timer means to generate the fuel injection pulse less than the number of the cylinders.

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 controlling fuel injection of an engine.

[0002]

2. Description of the Related Art FIG. 9 shows a conventional electronically controlled fuel injection device. In FIG. 9, 1 is a microcomputer, and this microcomputer 1 is an intake pressure sensor,
The basic fuel injection amount is calculated from the intake air pressure information and the rotation speed information from the engine speed sensor, and the fuel injection correction value is calculated based on the information from the throttle opening sensor, engine temperature sensor, intake air temperature sensor, etc. The injection timing is calculated. 2 to 5 are output timers, and the output timers 2 to 5 output signals of a time width corresponding to the fuel injection amount at the injection timing calculated by the microcomputer 1. 6-9 are solenoid drivers, 10-13
Is an injector provided for each cylinder, and the solenoid drivers 6-9 control the injectors 10-13 in accordance with the outputs of the output timers 2-5.
The output timers 2 to 5 output fuel pulses while the output is "H", and the injectors 10 to 13 are opened to inject fuel.

FIG. 10 shows output timers 2 to 2 in FIG.
5 shows the configuration of No. 5. In FIG. 10, 14 is a compare counter in which the fuel timer value obtained by the calculation of the microcomputer 1 is set, 15 is a free-run counter which counts clock pulses in response to the injection timing obtained by the microcomputer 1, 16 Is a comparator that compares the count values of the compare counter 14 and the free-run counter 15, and this comparator 16 will match if the count value of the free-run counter 15 matches the fuel timer value set in the compare counter 14. Output a signal. 1
Reference numeral 7 denotes an inversion circuit, and this inversion circuit 17 generates a fuel pulse which rises at the injection timing and falls by the coincidence signal.

FIG. 11 shows the fuel pulse waveform of the conventional example shown in FIG. In FIG. 11, injector # 1
Starts fuel injection into the intake manifold communicating with the # 1 cylinder at time (a), and ends fuel injection at time (a). The fuel injected into the intake manifold is sucked into the # 1 cylinder in the intake cycle of the # 1 cylinder. The same operation is performed for the other cylinders.

As described above, in the above-mentioned conventional electronically controlled fuel injection device, each injector 1 provided for each cylinder.
Fuel pulses are supplied to 0 to 13 to control the fuel injection amount for each cylinder. For this reason, the latest information is available in comparison with the all-cylinder simultaneous injection type fuel injection device that injects fuel to all cylinders simultaneously, or the group simultaneous injection method that divides all cylinders into multiple groups and injects fuel simultaneously for each cylinder group. It is possible to supply the fuel value calculated in step 1 to each cylinder and to avoid variations in the fuel supply amount.

[0006]

However, the above-mentioned conventional device requires the output timers 2 to 5 corresponding to the number of cylinders, the external circuit configuration connected to the microcomputer 1 becomes complicated, and the device is There was a problem that it became expensive.

The present invention solves the above-mentioned conventional problems, and provides an excellent electronically controlled fuel injection device in which the number of timers can be made smaller than the number of cylinders.

[0008]

In order to achieve the above object, the present invention provides a fuel injection end pulse generating means common to a plurality of fuel injection means, and the fuel to any one of the plurality of fuel injection means. Selection means for selecting a fuel injection means for supplying the output of the injection end pulse generation means, and defining the fuel injection end timing of each of the plurality of fuel injection means by the fuel injection end pulse generation means. To do.

[0009]

The present invention is configured as described above, and supplies the output of the timer means to the fuel injection means selected by the selection means to define the end of fuel injection of this fuel injection means. Since the common timer means is used for the injection means, the number of timer means is reduced.

[0010]

FIG. 1 shows a first embodiment of the present invention.
In FIG. 1, the same components as those of the conventional example shown in FIG. 9 are designated by the same reference numerals and the description thereof will be omitted. Reference numeral 21 denotes a calculation means, which calculates the basic fuel injection amount from the intake air pressure information and the rotation speed information from the intake pressure sensor and the engine rotation speed sensor, and based on the information of the throttle opening sensor, the engine temperature sensor, the intake air temperature sensor and the like. In addition to calculating the fuel injection correction value, the fuel injection timing is calculated. 22 to 25 are fuel injection starting means for defining the start of fuel injection in synchronization with the engine rotation.
Reference numeral 31 denotes a fuel injection end timer provided in the microcomputer 20, which is a timer for defining the end of fuel injection. Reference numeral 26 is an injector selecting means, which outputs a designation signal for designating an injector that terminates fuel injection. Reference numeral 27 denotes a distributor including a decoder and the like, which supplies the output of the fuel injection end timer 31 to an output terminal selected from the plurality of output terminals. Numerals 34 to 37 are fuel pulse generation circuits, which rise with a fuel injection start signal output from the fuel injection start means 22 to 25, and fall with the output of the fuel injection end timer 31 supplied via the distributor 27. Generate a pulse. Reference numeral 20 denotes a microcomputer, which is a calculation means 21 and fuel injection start means 22-2.
5, injector selection means 26 and fuel injection end timer 31.

2 (A) and 2 (B) show an injection start pulse output routine and an injection end pulse routine in the arithmetic means 21 constituting the microcomputer 20. The injection start pulse output routine is shown in FIG.
As shown in, it starts by the interrupt by the crank signal,
In step a, it is determined whether or not the crank signal of this time is the stage at which injection should be started, and if YES (Y), the fuel injection starting means 22 to 25 corresponding to the injectors at which fuel injection should be started in step b are performed. , Start the fuel pulse. In FIG. 2 (A), in step a, know (N)
If it is determined that the fuel injection start means 22-2
5, the fuel injection start signal is not generated. As shown in FIG. 2 (B), the injection end pulse output routine is started by interruption by a crank signal, and in step c, it is determined whether or not the current crank signal is the timing at which the fuel injection end pulse should be output. If it is determined to be Y), the injector designation signal is set in the distributor 27 in step d,
In step e, the timer value (Toff) calculated is set in the fuel injection end timer 31. After that, before the timer for fuel injection end times out in step f and the fuel end pulse is made to fall, the output of the fuel injection start means is made to fall. When the timer value (Toff) set in the injection end timer 31 has elapsed, an injection end pulse is output by the injection end timer 31, and this injection end pulse is supplied to the injector designated by the distributor 27. In FIG. 2 (B), if it is determined to be No (N) in step c, the distributor 27, the injection end timer 31 and the output of the fuel injection starting means are not reset.

Next, the operation of the above embodiment will be described with reference to FIG. FIG. 4A shows a cylinder discrimination signal output at every crank angle of 760 °, and FIG. 4B shows a crank signal output at every crank angle of 30 °.
Based on various information input to the microcomputer 20, the calculation means 21 calculates the timing at which the injection should start and the timing at which the injection should end. Here, the timing at which the injection should be started indicates which crank signal the fuel injection is started in synchronization with, and is referred to as an ON stage. Further, the timing at which the injection should end means the time (Toff) from the beginning of the OFF stage which indicates the crank signal immediately before the end of injection and the OFF stage which is set in the injection end timer 31. For each crank signal, it is determined whether or not this crank is in the ON stage at which injection should be started, and if it is the ON stage, the fuel injection start means 22 to 25 of the corresponding cylinder outputs a fuel injection start signal. The fuel injection starting means is applied to one input terminal of the fuel pulse generating circuits 34 to 37 corresponding to the injector. In FIG. 4C, injectors # 1, # 2, #
It is shown that the fuel is applied to the corresponding fuel generation circuits 34 to 37 in the order of No. 3 and # 4. On the other hand, for each crank signal, it is determined whether the main crank is in the OFF stage at which injection should be ended. , And outputs a fuel injection end pulse that falls after Toff time.

FIG. 4 (D) shows the output of the fuel injection end timer. This fuel injection end pulse is applied to the other input terminal of the fuel pulse generation circuits 34 to 37 corresponding to the injector (for example, injector # 1) designated by the injector selection means 26 via the distributor 27. In FIG. 4 (E), the injector 27 outputs injector end pulses that are sequentially output by the distributor 27.
4 is applied to the corresponding fuel pulse generation circuits 34 to 37 in the order of 4. The output of each fuel pulse generation circuit is generated by the logical sum of the fuel injection start signal and the fuel injection end signal, as shown in FIG. That is, O
A fuel pulse is generated by the fuel injection start signal from the N stage to the beginning of the OFF stage, and a fuel pulse is generated by the fuel injection end timer from the beginning of the OFF stage to the end of fuel injection. Therefore, as shown in FIG. 4 (C), the fuel injection start signal must be lowered before the time when the fuel injection end signal of the corresponding cylinder rises and is set and then falls. This fuel pulse is applied to the solenoid drivers 6 to 9, and the injectors # 1, # 2, # 3, and # 4 are opened to inject fuel as shown in FIG. 4 (F).

In the above embodiment, it is also possible to calculate the injection correction value by interrupting the crank signal immediately after the start of fuel injection and correct the timer value of the fuel injection end timer 31 based on this correction value.

In the above embodiment, the fuel injection start timing is synchronized with the crank signal, and only the fuel injection end timing is defined by the injection end timer, but conversely, the fuel injection end is determined with the crank signal synchronization. The start timing may be defined by the injection start timer.

FIG. 5 shows a second embodiment of the present invention. In this embodiment, the injector selecting means of the first embodiment is constructed by using the output signals of the fuel injection starting means 22-25. FIG. 6 shows injector selection and distribution means. The fuel injection end signal is distributed only to the cylinder for which the fuel injection start signal is output at the moment when the output of the fuel injection end timer rises. According to this embodiment, the fuel injection end signal is output not only to the fuel pulse generation circuit corresponding to the injector that really wants to output the end signal but also to the cylinder to which the fuel injection start pulse is output. However, since the fuel pulse generation circuit is generated by the logical sum signal of the fuel injection start pulse and the fuel injection end pulse, even if the fuel injection end pulse is output while the fuel injection start pulse is output, the fuel pulse generation The output of the circuit is unaffected. Further, when it is desired to output the fuel injection pulse to a plurality of injectors simultaneously, it is not necessary to newly add a timer means, and an injection start pulse is output from the fuel injection start means corresponding to the injector to inject fuel, and then When the fuel injection end pulse is output,
Fuel pulses are output to all the corresponding cylinders. After that, if the fuel start pulse is made to fall before the fuel injection end pulse falls, the fuel injection end will be performed at the required timing for all the relevant cylinders after the time set in the fuel injection end timer. A pulse is delivered.

FIG. 7 shows a third embodiment of the present invention, in which two fuel injection end timers are used in the embodiment shown in FIG. 4, and the fuel injection end timing of the injectors # 1 and # 3. Is defined by the first timer 32 for ending fuel injection,
The fuel injection end timing of the injectors # 2 and # 4 is defined by the second fuel injection end timer 33.
The present embodiment is particularly effective for a fuel injection control device having two feedback systems for feeding back the oxygen concentration sensor output to perform fuel injection control. As shown in FIG. 8, a rich feedback system and a lean feedback system are provided. The system and the system can be controlled independently.

[0018]

As is apparent from the above embodiment, the present invention provides a common timer means for a plurality of fuel injection means and selects the fuel injection means for supplying the output of the timer means. Since the fuel injection end timing of the plurality of fuel injection means is defined by the common timer means, the number of timer means can be reduced.

[Brief description of drawings]

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

FIG. 2 is a flowchart for explaining the operation of the embodiment.

FIG. 3 is a block diagram of a fuel pulse generation circuit of the same embodiment.

FIG. 4 is a timing chart illustrating the operation of the same embodiment.

FIG. 5 is a block diagram of an electronically controlled fuel injection device according to a second embodiment of the present invention.

FIG. 6 is a block diagram of injector selection and distribution means in the embodiment.

FIG. 7 is a block diagram of an electronically controlled fuel injection device according to a third embodiment of the present invention.

FIG. 8 is a timing chart illustrating the operation of the embodiment.

FIG. 9 is a block diagram of a conventional electronically controlled fuel injection device.

FIG. 10 is a block diagram of an output timer of the device.

FIG. 11 is a timing chart of the device.

[Explanation of symbols]

 20 Microcomputer 21 Calculation means 22-25 Fuel injection start means 26 Injector selection 27 Distributor 28 Injector selection, distribution means 29 FB system 1 injector selection, distribution means 30 FB system 2 injector selection, distribution means 31 Fuel injection Termination timer 32 Fuel injection termination timer for FB system 1 33 Fuel injection termination timer for FB system 2 34 to 37 Fuel pulse generation circuit

Claims (5)

[Claims] 1. A plurality of fuel injection means corresponding to each of a plurality of cylinders, and a fuel injection start pulse generation means independently provided for each cylinder for defining a fuel injection start timing of each of these fuel injection means. A common fuel injection end pulse generation means for defining the fuel injection end timing of each of the fuel injection means, and a selection means for selecting the fuel injection means for supplying the output of the fuel injection end pulse generation means. An electronically controlled fuel injection device, wherein the fuel injection end timing of each of the fuel injection means is defined by the fuel injection end pulse generation means. 2. A fuel pulse signal corresponding to each of a plurality of cylinders, an output signal of a fuel injection start pulse generating means independently having each cylinder, and a fuel injection end pulse generating means common to the plurality of cylinders. 2. The electronically controlled fuel injection device according to claim 1, wherein the output signal is defined by a logical sum of the signals selected by the selection means. 3. The fuel injection start pulse generating means independently provided for each cylinder is a signal generating means synchronized with the engine, and the fuel injection end pulse generating means common to a plurality of cylinders counts clock pulses. A timer means comprising a free-run counter for setting, a compare counter for setting a timer value, and a comparator for comparing the compare counter and the free-run counter and outputting a coincidence signal when they match each other. Item 2. The electronically controlled fuel injection device according to item 2. 4. The electronically controlled fuel injection device according to claim 2, wherein the selection means is defined by an output signal of a fuel injection start pulse generation means independently provided for each cylinder. 5. The electronically controlled fuel injection device according to claim 2, wherein each fuel injection means includes a fuel pulse generation circuit, a solenoid driver, and an injector.