JPS58178837A - Electronically controlled fuel injection apparatus for internal-combustion engine - Google Patents

Abstract

PURPOSE:To enable to correct the fuel injection rate correctly even at the time of acceleration and deceleration, by correcting the fuel injection pulses according to the rate of change of an engine-speed signal and a signal representing the flow rate of intake air. CONSTITUTION:Acceleration and deceleration of an engine are detected from the rate of change of an engine-speed signal that is calculated by a circuit 11 for calculating the rate of change and from the rate of change of a signal representing the flow rate of intake air that is calculated by a circuit 14 for calculating the rate of change. An arithmetic circuit 5, to which the signal representing the flow rate of intake air and the engine-speed signal corrected respectively at correction circuit 21, 20 are applied, produces injection pulses capable of supplying fuel at a most appropriate rate.

Description

[Detailed description of the invention] The present invention relates to an electronically controlled fuel injection system for an internal combustion engine.

An electronically controlled fuel injection system for an internal combustion engine calculates a fuel injection pulse with a pulse width based on various engine parameters (mainly engine speed and intake air amount) so that the engine always performs proper combustion. The pulse drives an electromagnetic fuel injection valve to intermittently supply fuel to the engine.

Conventional examples of such electronically controlled fuel injection devices are shown in FIGS. 1 and 2.
This will be explained with reference to the figures.

The ignition signal obtained from the primary side of the ignition coil 10 of the engine is input to the frequency divider circuit 2, where it is waveform-shaped and frequency-divided to become a frequency-divided signal, which is input to the arithmetic circuit 5. The intake air amount signal from the intake air amount measuring device (air flow meter) 3 provided in the A/D converter 4
The signal is input to the arithmetic circuit 5 via.

The arithmetic circuit 5 calculates the engine speed signal T El'('l'Ex', T Es') corresponding to the low level section of the frequency division signal.
,...) and the intake air amount signal Q l' (Q 2
' HQ 3'+...>, and from these, the optimal pulse width T Il'
,...) are calculated and output to the drive circuit 6. The drive circuit 6 drives the electromagnetic fuel injection valve I based on the fuel injection pulse at nr constant timing TI (T2*Ts...) synchronized with the branch signal.

However, in such a conventional electronically controlled fuel injection system, for example, for injection at TI timing, the reading of the engine speed signal and the intake air signal takes into account the delay time of reading and calculation. Timing TE,
, Ql before Th l' + Q 1 ', a response delay occurred particularly during acceleration and deceleration, and an appropriate fuel injection pulse could not be output.

That is, the originally required rotational speed signals are TE, TE,.

TE3. ..., and the intake air amount signal is Qt+Q
2HQ31..., and the pulse width t of the fuel injection pulse calculated from these signals; tTI+, TIi
.

'1"Is,... is the theoretical value, whereas
In reality, there is a delay in the input reading time and the calculation processing time from the input, so the engine speed signal is rp E , / ,
TE 2/ , Is E , /,..., the intake air amount signals are Q , / , Q2/.

Using Qs/, , , the calculation result is /11 Il/
, TI2/.

It has become TI3'...

For this reason, when there are few fluctuations in engine speed or intake air cover, using such past input signals will not have much of a negative effect on fuel efficiency, output, or emissions, but when the input signals are input during acceleration or deceleration, Good results were not obtained when the signal changed rapidly, and the addition was affected.

In view of the above-mentioned circumstances, the present invention was made with the aim of making it possible to obtain an appropriate fuel #+injection pulse even during acceleration and deceleration. A rate-of-change calculation circuit that calculates the rate of change from the rotational speed signal and a correction circuit that calculates the product of the input engine rotational speed signal and the rate of change and outputs this as a correction value are provided. A change rate calculation circuit that calculates the rate of change from the intake air amount signal and the previous intake air amount signal, and a correction that calculates the relationship between the input intake air amount signal and the change rate and outputs it as a correction value. By providing a circuit, a fuel injection pulse is calculated based on the corrected engine speed signal and intake air amount signal, so that a more appropriate fuel injection pulse can be obtained.

An embodiment of the present invention will be described below with reference to FIGS. 3 and 2. In FIG. 3, the same parts as in FIG. 1 are given the same reference numerals.

In FIG. 3, reference numeral 11 denotes a change rate calculation circuit for the engine speed signal, in which the input engine speed signal TEn' (for example, TE2') and the previously input and stored engine speed signal TEn-1' are used. (For example, TEt') TEn' and its rate of change 111τ7 is calculated. However, the engine speed signal T En' becomes smaller as the engine speed increases.

Reference numeral 12 and 13 are comparison circuits which generate signals for one of the comparison circuits. The other comparison circuit 13
When , a high level signal is emitted.

TEn-1' 1, 14 is a circuit for calculating the rate of change of the intake air amount signal,
Input intake air amount signal Qn' (for example, Q2')
and the intake air amount signal Qn- inputted last time and stored.
1' (for example, Qt'), the rate of change is calculated from 1' (for example, Qt').

Q n l/15.16 is a comparator circuit that emits one comparator signal. The other comparison circuit 16 generates a high level signal when the rate of change is <D.

Here, both output terminals of the comparison circuits 12 and 15 are connected to the AND circuit 1.
7 is connected. Then, when the output of the AND circuit 17 becomes high level, it is determined that acceleration is occurring. Further, both output ends of the comparison circuits 13 and 16 are connected to an AND circuit 18. Then, when the output of the AND circuit 18 becomes high level, it is determined that the vehicle is decelerating. j! , AND circuit 17
．． A sub-output terminal of 18 is connected to an OR circuit 19.

Reference numeral 20 denotes a correction circuit for the engine speed signal, to which the output terminal of the OR circuit 19 is connected, and when a high level signal is received from the OR circuit 19, the input signal (TEn'
) e correction and output, and when a low level signal is received, the input signal (TEn') is output as is without correction. When correcting, the TE of the input signal
n' and outputs the above change.

21 is a correction circuit for the intake air amount signal, to which the output terminal of the OR circuit 19 is connected, and when a high level signal is received from the OR circuit 19, the input signal (Qn') is
When a low level signal is received, the input signal (Qn') is output as is without being corrected. Then, the correction ridge is exposed from the chest and the value thereof is output as the correction value.

Next, for example, when the number of engine revolutions calculated by the 3° change rate calculating circuit 11, which will explain the operation during acceleration, satisfies the following condition, it is determined that the engine is accelerating.

At this time, the outputs of the comparison circuits 12 and 15 both become high level, and the output of the AND circuit 17 becomes high level. Therefore, the output of the OR circuit 19 is at a high level, and correction commands are issued to the two correction circuits 21 and 22.

is calculated and output as an engine speed signal.

This is output as an intake air amount signal.

Therefore, the arithmetic circuit 5 which receives the engine speed signal and the intake air amount signal corrected by these correction circuits 20 and 21,
It becomes possible to calculate and output a fuel injection pulse that is extremely similar to the fuel injection pulse having the optimal pulse width T I n in the case of Than, Qn.

As explained above, the present invention makes it possible to calculate fuel injection pulses with appropriate pulse widths even during acceleration and deceleration, which not only improves drivability by improving responsiveness but also improves fuel efficiency and output. , the effect that it is possible to improve emissions, etc. can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an electronically controlled fuel injection device showing a conventional example, FIG. 2 is a signal waveform diagram of the same as above, and FIG. 3 is a block diagram of an electronically controlled fuel injection device showing an embodiment of the present invention. 1... Ignition coil 3... Intake air amount measuring device 5.
...Arithmetic circuit 7...Fuel injection valve 11.14.
... Rate of change calculation circuit 20.21 ... Correction circuit
Applicant Japan Electronics Co., Ltd. Agent Patent Attorney Fujio Sasashima (9) = 19 [

Claims (1)

[Claims] The engine speed signal based on the time between ignition signals in the ignition coil and the intake air amount signal from the intake air amount measuring device are read, and an optimal fuel injection pulse is calculated from these.
In an electronically controlled fuel injection device for an internal combustion engine that drives a fuel injection valve by the fuel injection pulse, a change rate calculation circuit that calculates a rate of change from the engine speed signal and a previous engine speed signal; , a correction circuit that calculates the product of the engine speed signal and the rate of change and outputs this as a correction value, and calculates the rate of change from the intake air amount signal and the previous intake air amount signal. It is equipped with a change rate calculation circuit and a correction circuit that calculates the product of the intake air amount signal and the change rate and outputs this as a correction value, and calculates the fuel amount from the corrected engine speed signal, intake air amount signal, and K. An electronically controlled twist'4+ injection device for an internal combustion engine, characterized in that it calculates injection pulses.