JPH09324689A - Electronically controlled fuel injection device - Google Patents

Abstract

(57) Abstract: In an electronically controlled fuel injection device, the number of timer means for generating a fuel injection pulse is reduced, the circuit configuration is simplified, and the cost is reduced. A fuel injection start timer 80 that controls only the start side of fuel injection pulses of a plurality of cylinders, and a fuel injection end timer 81 that controls only the end side of fuel injection pulses of a plurality of cylinders. The fuel injection start timer 80 is provided only for the cylinder designated at the timing when the fuel injection start timer 80 is set with the fuel injection start offset time width.
Starts fuel output at the moment when the time is up. The fuel injection end timer output is directly output as the fuel injection output only to the cylinder designated at the timing when the fuel time width is set in the fuel injection end timer 81. The output from the fuel injection start timer 80 and the fuel injection end timer 8
Fuel injection pulses for a plurality of cylinders are generated by the logical sum signal of the outputs from 1.

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. 7 shows a conventional electronically controlled fuel injection device.

Here, a case of a 4-cylinder engine will be described as an example. In FIG. 7, reference numeral 1 is a microcomputer (calculation means), and this microcomputer 1 calculates the basic fuel injection amount from the intake air pressure information from the intake pressure sensor and the engine speed sensor and the rotation speed information, and the throttle opening sensor. The fuel injection correction value is calculated based on the information from the engine temperature sensor, the intake air temperature sensor, etc., and the fuel injection timing is calculated. Reference numerals 52 to 55 are fuel injection start delay timers, and the fuel injection start delay timers 52 to 55 are the microcomputer 1
A signal having a time width corresponding to the fuel injection start delay time is output at the injection timing calculated in (4). When the fuel injection start delay time set in the fuel injection start delay timers 52 to 55 elapses and the time is up, fuel injection output is started. At the same time, the fuel injection start delay timer 52-
The fuel injection output timers 2 to 5 start counting with the time-up signal of 55 as a trigger. When the time corresponding to the value corresponding to the fuel injection amount calculated by the microcomputer 1 set in the fuel injection output timers 2 to 5 elapses and the time is up, the fuel injection output is ended.

FIG. 8 shows the configuration of the fuel injection output timers 2-5. In FIG. 8, 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 the compare counter 14
Is a comparator for comparing the count values of the free-run counter 15 and the free-run counter 15. The comparator 16 outputs a match signal when the count value of the free-run counter 15 matches the fuel timer value set in the compare counter 14. Reference numeral 17 denotes an inverting circuit, and the inverting circuit 17 generates a fuel pulse which rises at the injection timing and falls at the coincidence signal.

In FIG. 7, 6 to 9 are solenoid drivers, and 10 to 13 are injectors provided for each cylinder. The solenoid drivers 6 to 9 are the output timers 2 to 2 described above.
The injectors 10 to 13 are controlled according to the output of the fuel injector 5, the output of the output timers 2 to 5 is “H”, the fuel pulse is output, and the injectors 10 to 13 are opened.
Inject fuel.

FIG. 9 shows a fuel pulse waveform of the conventional example shown in FIG. In FIG. 9, 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.

In the above conventional electronically controlled fuel injection device, fuel pulses are supplied to the injectors 10 to 13 provided for each cylinder to control the fuel injection amount for each cylinder. Fuel injection device of simultaneous cylinder injection type, or dividing all cylinders into multiple groups and injecting fuel into each cylinder group at the same time compared with group simultaneous injection method, fuel value calculated by latest information is supplied to each cylinder In addition to that, there is an advantage that variation in the fuel supply amount can be avoided.

In the above-mentioned conventional example, the timer 52 to 55 sets the time width from the present time to the start of fuel injection, and the timer 2 to 5 sets the fuel injection output width. As an example, as shown in FIG.
In some cases, the time width from the current time to the start of fuel injection is set with 2 to 35, and the time width from the current time to the end of fuel injection is set with timers 42 to 45.

[0009]

However, in any of the above-mentioned conventional devices, the number of timers that is twice as many as the fuel injection output signal is required, and the external circuit configuration connected to the microcomputer 1 becomes complicated. At the same time, there is a problem that it becomes expensive.

The present invention solves the above-mentioned conventional problems, and the number of timers can be reduced, and therefore the external circuit configuration connected to the microcomputer can be simplified and the cost can be reduced. It is an object of the present invention to provide an electronically controlled fuel injection device that can be realized.

[0011]

In order to achieve the above object, the present invention comprises a fuel injection start pulse generating means common to a plurality of fuel injection means, and the fuel of each of the plurality of fuel injection means is provided. The fuel injection start timing is determined by the fuel injection start pulse generation means, and a fuel injection end pulse generation means common to the plurality of fuel injection means is provided, and the fuel injection end timing of each of the plurality of fuel injection means is set. It is characterized in that it is configured to be determined by the fuel injection end pulse generating means.

As a result, it is possible to obtain an electronically controlled fuel injection device in which the number of timers is reduced and the external circuit structure connected to the microcomputer is simplified to reduce the cost.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION According to the first aspect of the present invention, a reference position is calculated from a rotation signal, and a timing when a predetermined time has elapsed from the reference position is set as a fuel injection start timing, and a fuel having a predetermined time width In an electronically controlled fuel injection device that generates an injection pulse signal, a fuel injection start timer that controls only the start side of the fuel injection pulses of a plurality of cylinders, and a fuel injection end that controls only the end side of the fuel injection pulses of a plurality of cylinders A timer, a fuel injection start cylinder distribution signal output means for designating a cylinder to start fuel injection, and a fuel injection start timer common to a plurality of cylinders. Latch the start cylinder distribution signal and only for the specified cylinder,
A means for starting the output of the fuel injection output signal at the moment when the fuel injection start timer times out, a fuel injection end cylinder distribution signal output means for designating the cylinder to end the fuel injection, and a fuel injection end timer common to a plurality of cylinders. Means for latching the fuel injection end cylinder distribution signal at the moment when the data for a predetermined time until the end of fuel injection is written, and outputting the output of the fuel injection end timer as the fuel injection output signal only to the designated cylinder And a logical sum of the output from the fuel injection start timer and the output from the fuel injection end timer to generate a distribution signal corresponding to each of the plurality of cylinders and output a fuel injection pulse signal. It is configured and has an effect that the number of timer means can be reduced.

According to a second aspect of the present invention, the fuel injection start cylinder distribution signal output means and the fuel injection end cylinder distribution signal output means are the same fuel injection cylinder distribution signal output means, and the signals are shared. It has the effect that

According to a third aspect of the present invention, a fuel injection start timer that controls only the start side of the fuel injection pulses of a plurality of cylinders and a fuel injection end timer that controls only the end side of the fuel injection pulses of a plurality of cylinders. Is a timer means composed of a free-run counter for counting clock pulses, 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. I have.

According to a fourth aspect of the present invention, each fuel injection means comprises a fuel pulse generation circuit, a solenoid driver, and an injector.

Embodiments of the present invention will be described below with reference to the drawings. (Embodiment 1) In this embodiment as well, a four-cylinder engine will be described as an example, as in the above-mentioned conventional example.

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

In FIG. 1, reference numeral 80 is a fuel injection start timer, 81 is a fuel injection end timer, and a basic fuel is supplied from an intake pressure sensor, an intake air pressure information from an engine speed sensor, and a rotation speed information by a microcomputer (not shown). The set value is calculated by calculating the injection amount and calculating the fuel injection correction value based on the information of the throttle opening sensor, the engine temperature sensor, the intake air temperature sensor, and the like.

Reference numeral 83 is an output level selection signal for selecting an output level at the moment when the fuel injection start timer 80 times out, and reference numeral 84 is a fuel injection start cylinder switching signal indicating to which cylinder the fuel injection start timer 80 is a signal. Reference numeral 85 is a fuel injection end cylinder switching signal indicating to which cylinder the fuel injection end timer 81 is a signal, and reference numeral 86 is an output fuel injection pulse.

The fuel injection start timer 80 and the fuel injection end timer 81 can be provided with a free-run counter, a compare counter, and a comparator as in the conventional example shown in FIG. Similarly to the above, it can be composed of a fuel pulse generation circuit, a solenoid driver, and an injector.

The fuel injection start timer 80 determines the offset time from the timing signal synchronized with the engine rotation until the start of fuel injection. The cylinders latched at the moment when the fuel injection start timer 80 starts counting. According to the information of the distribution signal and the output level signal, the fuel injection start timer 80 starts the output with the logic of the latched output level only for the latched cylinder from the time when the time is up.

The fuel injection end timer 81 is only for the cylinders selected by the cylinder distribution signal at the moment when the fuel injection end timer starts counting.
The pulse signal having the time width set in 1 is output.

A fuel injection pulse is generated by taking the logical sum of the output from the fuel injection start timer 80 and the output from the fuel injection end timer 81.

The above process will be described with reference to FIG. FIG.
FIG. 2 is a detailed block diagram showing the inside of a fuel injection pulse generation block for one cylinder in FIG. 1.

A fuel injection start cylinder distribution signal is set for the cylinder that starts fuel injection this time. First, set only the D terminal input of the D latch "A" of the cylinder that starts fuel injection to "H".
D latch “A” for a cylinder that is set to i ′ and does not start fuel injection
All the D terminal inputs of are set to'Lo '.

At the same time, the output level of the D latch "C" at the timing when the fuel injection start timer 80 is up is set by the output level selection signal 83. In the case of the present embodiment, the D terminal input of the D latch “B” is set to “Hi”. Here, the time width from the current time to the timing of starting fuel injection is set in the fuel injection start timer 80. In the fuel injection start timer 80, the output signal rises at the moment when the value is written, and the output signal falls at the moment when the set time elapses.

The output signal of the fuel injection start timer 80 is connected to the clock input of the D latch "A", and the output Q of the D latch "A" and the output signal of the fuel injection start timer 80 are AND gate ". Has been entered in "D". Therefore,
The output signal of the fuel injection start timer 80 is input to all the cylinders, but it is'H 'at the D input terminal of the D latch "A".
Only for the cylinder selected as i ', the Q output of the D latch "A" becomes "Hi", and the cylinders not selected remain "Lo". Therefore, the output signal of the AND gate "D" is the same signal as the fuel injection start timer output for the selected cylinder, and remains "Lo" fixed for the non-selected cylinders.

The output of the AND gate "D" is inverted by the NOT gate "E" and input to the clock terminal of the D latch "C". Therefore, set the fuel injection start timer 80,
At the timing when a predetermined time has elapsed, only the click terminal input of the D latch “C” for the selected cylinder is activated.

At the same time, the output of the AND gate "D" is also input to the clock terminal of the D latch "B". Therefore, if the output level selection signal is set to “Hi”, this signal is input to the D terminal of the D latch “B”.
When the clock input rises, that is, at the moment when the fuel injection start timer 80 is set, D for the selected cylinder
Only the Q output of the latch “B” rises to “Hi” and the information is latched. This Q output remains in the state unless the same cylinder is selected and the fuel injection start timer 80 is started.

Since the Q output of the D latch "B" is input to the D terminal of the D latch "C", the D latch "C" is output.
When the clock terminal rises, that is, when the fuel injection start timer 80 has passed a predetermined time and the clock terminal input of the D latch “C” for the selected cylinder rises,
The state of the D terminal is output to the Q output.

That is, the cylinder is selected, the output level selection signal is set to "Hi", and the offset time from the current time to the time at which the fuel injection is to be started is set in the fuel injection start timer 80 common to a plurality of cylinders. If set, the output becomes “Hi” only for the selected cylinder after the set time has elapsed, and the fuel injection signal starts at a predetermined offset time.

The fuel injection is started by the above algorithm, and the fuel injection end timer 81 is set before the fuel injection end timing comes. The time width from the current time to the timing of ending the fuel injection is set in the fuel injection end timer 81. Also in the fuel injection end timer 81, the output signal rises at the moment when the value is written, and the output signal falls at the moment when the set time elapses.

First, only the D terminal input of the D latch "F" of the cylinder whose fuel injection is to be terminated is set to "Hi", and all the D terminal inputs of the D latch "F" of the cylinder whose fuel injection is not terminated are set to "Lo". To do.

The output signal of the fuel injection end timer 81 is connected to the clock input of the D latch "F", and the output Q of the D latch "F" and the output signal of the fuel injection end timer 81 are AND gate ". It has been entered in "G". Therefore,
The output signal of the fuel injection end timer 81 is input to all the cylinders, but it is'H 'at the D input terminal of the D latch “F”.
The output'Q 'of only the D latch "F" for the cylinder selected as i'becomes'Hi', and the cylinder not selected is
It remains'Lo '. Therefore, the output signal of the AND gate "G" is the same signal as the fuel injection end timer output for the selected cylinder, and remains "Lo" fixed for the non-selected cylinders.

The Q output of the D latch "C" and the output of the AND gate "G", which have been described above, are connected to the OR gate "H".
The logical sum is taken to generate a fuel injection signal.

It should be noted here that the timing at which the fuel injection end timer 81 times out and the output of the AND gate "G" falls to the "Lo" level, that is, the timing earlier than the fuel injection end timing. so,
It is necessary to drop the Q output of the D latch "C"to'Lo'.

Therefore, the Q output of the D latch "C" is set to "L" at the same time when the fuel injection start timing is set.
Only the D terminal input of the D latch "A" of the cylinder to be set to "o" is set to "Hi", and all the D terminal inputs of the D latch "A" of the cylinders whose Q output is not set to "Lo" are set to "Lo". at the same time,
The output level of the D latch "C" at the timing when the fuel injection start timer 80 has timed out is set by the output level selection signal.

In the case of this embodiment, D of the D latch "B" is
Leave the terminal input at'Lo '. Where D from the current time
The time width until the Q output of the latch "C" is dropped to "Lo", in this example, the minimum time that the fuel injection start timer 80 can set is set in the fuel injection start timer 80. The output signal of the fuel injection start timer 80 rises at the moment when the value is written and falls at the moment when the set time elapses, so that a whisker-like impulse signal having a settable minimum time width is output. .

The output signal of the fuel injection start timer 80 is connected to the clock input of the D latch "A", and the output Q of the D latch "A" and the output signal of the fuel injection start timer 80 are AND gate ". The output signal of the fuel injection start timer 80 is input to all cylinders because it is input to D ", but the D signal of the cylinder selected as" Hi "at the D input / output terminal of the D latch" A "is input. Only the output "Q" of the latch "A" becomes "Hi", and the cylinders not selected remain "Lo". Therefore, the output signal of the AND gate "D" is
The same signal as the fuel injection start timer output is output for the selected cylinders, and for the unselected cylinders,
It remains'Lo '.

The output of the AND gate "D" is inverted by the NOT gate "E" and input to the clock terminal of the D latch "C". Therefore, set the fuel injection start timer 80,
The clock terminal input of the D latch "C" rises at the timing when the impulse-like time width has elapsed. At the same time, AN
The output of the D gate "D" is also input to the clock terminal of the D latch "B". Therefore, by setting the output level selection signal to “Lo”, this signal is input to the D terminal of the D latch “B”. Therefore, when the clock input rises, that is, the fuel injection start timer 80 is set. At that moment, only the Q output of the D latch "B" for the selected cylinder rises to "Hi", and the information is latched.

The Q output remains in the state unless the same cylinder is selected and the fuel injection start timer 80 is started. That is, the cylinder is selected, the output level selection signal is set to'Lo ', the minimum time width that can be set in the fuel injection start timer 80 common to a plurality of cylinders is set, and after the corresponding time has elapsed, The output for the selected cylinder becomes "Lo", and the Q output of the D latch "C" can be lowered to the "Lo" level after the lapse of the minimum settable time.

An example of the output waveform for a specific one cylinder is shown in FIG. First, in order to set the start of fuel injection output, the start timer side output level selection signal is set to “Hi” (a), and at the same time, the cylinder distribution signal specifies the cylinder to which the start timer side output is distributed (b). ). A delay time from the current time until the fuel injection output is started is set in the fuel injection start timer 80 (c). By the rising edge of the fuel injection start timer 80, the state of the output level selection signal on the start timer side and the state of the cylinder switching signal for fuel injection start timing are latched, and fuel injection is started only for the cylinder designated by the latch information. At the moment when the timer 80 times up, the output of the start timer side is latched, that is, the state of the output level selection signal of the start timer side that is'H
Set to the i'level (d).

Next, at the timing of setting the end of the fuel injection output, the cylinders for which the end timer side output is distributed and output are designated by the fuel injection end timing cylinder switching signal (e). The time from the current time until the fuel injection output is ended is set in the fuel injection end timer 81 (f). The state of the cylinder switching signal for fuel injection end timing is latched by the rising edge of the fuel injection end timer 81, and the fuel injection end timer 81 is output and output to the end timer side only for the cylinder specified by the latch information ( g).

A fuel injection output pulse is generated by a logical sum signal of the start timer side output and the end timer side output (h).

Here, it is necessary to drop the output on the start timer side to the level of'Lo 'while the output on the end timer side holds the'Hi' level. Therefore, the start timer side output level selection signal is set to'Lo '(j), and at the same time, the cylinder distribution signal specifies the cylinder forcibly ending the start timer side output (k). The minimum time that can be set from the current time is set in the fuel injection start timer 80 (m). By the rising edge of the fuel injection start timer 80, the state of the start timer side output level selection signal'Lo 'and the state of the fuel injection start timing cylinder switching signal are latched, and at the moment when the fuel injection start timer 80 times out, The start timer-side output for the cylinder designated by the latch information is set to "L" of the latched start timer-side output level selection signal.
The o'state is set (n).

The fuel injection output pulse is generated by the above algorithm. FIG. 4 is a timing chart of fuel injection output pulses in the case of a 4-cylinder engine. Each cylinder is generated by the same algorithm as described in FIG. In FIG. 4, each of the fuel injection start timer 80 and the fuel injection end timer 81 generates fuel injection output pulses for four cylinders. As is clear from FIG. 4, unless the fuel injection start timings of different cylinders and the fuel injection end timings of different cylinders are very close to each other, one fuel injection start timer 80 and one fuel injection end timer 81 are used. It can be seen that a fuel injection device for a multi-cylinder engine having four or more cylinders, for example, a six-cylinder engine or an eight-cylinder engine can be realized.

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

In the present embodiment, the fuel injection start timing cylinder switching signal and the fuel injection end timing cylinder switching signal are realized by the same signal.

As described above, the cylinder switching signal latches the state in the D latch at the moment when the values are set in the fuel injection start timer 80 and the fuel injection end timer 81. The state of the cylinder switching signal is indefinite and there is no problem except the moment when the value is set in the end timer 81. Therefore, even if the cylinder switching signal for the fuel injection start timing and the cylinder switching signal for the fuel injection end timing are shared, the fuel injection start timer 80 and the fuel injection end timer 81 are set to predetermined levels at the moment they are set. If confirmed, the fuel injection output signal can be generated without any problem as in the case of the first embodiment.

(Third Embodiment) FIG. 6 is a block diagram showing an electronically controlled fuel injection device according to a third embodiment of the present invention.

In each of the above-mentioned embodiments, the description has been given of the case where the timer output has one fuel injection start end and two fuel injection end ends, that is, a total of two timer outputs. However, as in the embodiment shown in FIG. In this case, it is also possible to have a structure in which one bank for fuel injection and one for fuel injection are provided for each bank, that is, a total of four, and how many timers are judged from the number of timer means incorporated in the microcomputer and the processing capacity of software. You can decide whether to use.

[0053]

As described above, according to the present invention, the common timer means for defining the fuel injection start timing is provided for the plurality of fuel injection means, and the fuel injection is completed for the plurality of fuel injection means. Since the common timer means for defining the timing is provided and the fuel injection signal is generated by the OR signal thereof, the number of timer means can be reduced, and the circuit configuration can be simplified and the cost can be reduced. .

[Brief description of drawings]

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

FIG. 2 is a detailed block diagram showing the electronically controlled fuel injection device.

FIG. 3 is a timing chart of fuel injection output pulses for one cylinder of the electronically controlled fuel injection device.

FIG. 4 is a timing chart of fuel injection output pulses for four cylinders of the electronically controlled fuel injection device.

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

FIG. 6 is a block diagram showing an electronically controlled fuel injection device according to a third embodiment of the present invention.

FIG. 7 is a block diagram showing a conventional electronically controlled fuel injection device.

FIG. 8 is a block diagram of an output timer of the electronically controlled fuel injection device.

FIG. 9 is a timing diagram of fuel pulses in the electronically controlled fuel injection device.

FIG. 10 is a block diagram showing another conventional electronically controlled fuel injection device.

[Explanation of symbols]

 80 Fuel injection start timer 81 Fuel injection end timer 83 Output level selection signal 84 Fuel injection start cylinder selection signal 85 Fuel injection end cylinder selection signal 86 Fuel injection pulse

Claims (4)

[Claims] 1. An electronically controlled fuel injection device for generating a fuel injection pulse signal having a predetermined time width by calculating a reference position from a rotation signal, and using a timing when a predetermined time has elapsed from the reference position as a fuel injection start timing. Fuel injection start timer that controls only the start side of the fuel injection pulse of each cylinder, a fuel injection end timer that controls only the end side of the fuel injection pulses of a plurality of cylinders, and a fuel injection that specifies the cylinder to start fuel injection Start cylinder distribution signal output means,
A fuel injection start cylinder distribution signal is latched at the moment when data is written for a predetermined time until fuel injection is started in the fuel injection start timer common to a plurality of cylinders, and the fuel injection start timer is set only for the designated cylinder. A means for starting the output of the fuel injection output signal at the moment when the time is up, a fuel injection end cylinder distribution signal output means for designating the cylinder to end the fuel injection, and a fuel injection end timer common to a plurality of cylinders for ending the fuel injection. And a means for latching the fuel injection end cylinder distribution signal at the moment when the data is written for a predetermined time, and outputting the output of the fuel injection end timer as a fuel injection output signal only to the designated cylinder. A distribution signal corresponding to each of a plurality of cylinders is generated by a logical sum of the output from the fuel injection start timer and the output from the fuel injection end timer. Configuration the electronic control fuel injection device so as to output a fuel injection pulse signal. 2. A fuel injection start cylinder distribution signal output means,
The electronically controlled fuel injection device according to claim 1, wherein the fuel injection end cylinder distribution signal output means is the same fuel injection cylinder distribution signal output means. 3. A fuel injection start timer that controls only the start side of fuel injection pulses of a plurality of cylinders, and a fuel injection end timer that controls only the end side of fuel injection pulses of a plurality of cylinders count clock pulses. A free-run counter,
2. The electronically controlled fuel injection device according to claim 1, further comprising timer means comprising 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 the two coincide. 4. The electronically controlled fuel injection device according to claim 1, wherein each fuel injection means comprises a fuel pulse generation circuit, a solenoid driver, and an injector.