JPS6258043A - Suction quantity detector for engine - Google Patents

Abstract

PURPOSE:To make the highly accurate detection of a suction quantity performable, by setting start timing of the specified period for sampling to the time that output value of a suction quantity sensor comes near to the means value, at the time of detecting the suction quantity in equalizing the said output value of the suction quantity sensor subjected to sampling for the specified period. CONSTITUTION:Detection output of a suction quantity sensor 5 by the hot wire installed side by side at the upstream of a throttle valve 4 in a suction passage 3 is inputted into a control unit 9 together with each detection output out of a throttle opening sensor 6 and a crank angle sensor 8. From a time when a TDC signal is inputted out of the crank angle sensor 8 at the control unit 9, it is delayed as long as the specified time T presearched in conformity with an engine speed at that time and sampling is started at a time when the output value comes near to the mean value ES. Then, the output value subjected to the sampling as to the specified sampling period (t) is equalized whereby an average suction quantity should be found. According to this method, equalized handling excellent in accuracy is performable.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an intake port detection device for detecting the amount of intake air supplied to an engine.

(Conventional technique 1) Conventionally, when the amount of intake air supplied to the engine is detected by an intake ω sensor such as a hot wire installed upstream of the throttle valve or a negative pressure sensor installed downstream of the throttle valve, the detection signal is In order to remove pulsating components, etc., a technique was developed in which the output of the intake air amount sensor was sampled for a predetermined period of time, the sampled output values were averaged, and the intake amount was determined from the average value. 58-
It is known as seen in No. 160518.

However, in the sampling for averaging the output values, for example, sampling is started at every top dead center and the average value is determined, but the detection accuracy may be lower due to the relationship with pulsation. .

In other words, the above-mentioned pulsation period may deviate from the engine rotation period due to fluctuations in engine speed, and the sampling start or end time coincides with the peak or trough of the pulsation fluctuation. In this case, the first value or the final value sampled is large. Furthermore, due to the relationship between the sampling unit time and the pulsation period, sampling cannot be detected for a period completely corresponding to one period of pulsation, and there is a possibility that extra sampling or insufficient sampling is performed at the time when the above-mentioned sampling ends. Since the sampling values are large, the average value deviates from the true average value and the detection accuracy decreases.

(Objective of the Invention) In view of the above circumstances, the present invention aims to improve the detection accuracy of the intake port by performing highly accurate averaging processing to detect the intake air amount by averaging the sampling of the output value of the intake air amount sensor. The object of the present invention is to provide an intake seedling detection device for an engine.

(Structure of the Invention) The intake port detection device of the present invention samples the output of the intake air amount sensor for a predetermined period, and detects the intake amount by averaging the numbered output values. The invention is characterized in that the start time of the intake air amount sensor is set to a time when the output value of the intake air amount sensor approaches the average value (=J).

(Effects of the Invention) According to the present invention, the timing at which sampling of the intake air amount sensor output starts is set to the timing at which the output of the intake air (6) sensor becomes close to the average value. Even if there is excess or deficiency sampling at +1 at the end, this will have little effect on the average value, allowing highly accurate averaging processing, and detecting the intake air amount with high precision to improve various engine controls. It is something that can be implemented.

<Example) Hereinafter, the present invention will be explained in detail with reference to the drawings.

FIG. 1 shows the overall configuration of an engine equipped with an intake ω detection device according to the present invention.

The intake air amount detection device 1 includes an intake air amount sensor 5 using a hot wire, which is installed upstream of a throttle valve 4 in an intake passage 3 that supplies intake air to an engine main body 2 .

The detection output of the intake air amount sensor 5 is input to the control unit 9 together with the output of the throttle (i1 degree sensor 6) that detects the throttle opening degree and the detection output of the crank angle sensor 8 that detects the rotation of the crankshaft 7. The intake port is calculated in the unit 9, and a fuel injection pulse is outputted to the injector 10 based on the intake air amount to control fuel supply.

The above control unit l-0 starts sampling the output of the intake air amount sensor 5 from near the average value of the output, and after sampling for a predetermined period, averages the sampled output values to determine the intake air amount. . In addition, since the intake pulsation varies depending on the engine rotation speed, the sampling start timing is adjusted according to the engine rotation speed, and when the throttle opening is small, the sampling start timing is adjusted depending on the engine rotation speed. Therefore, the sampling start timing is fixed at throttle openings below a predetermined opening.

In other words, as shown in FIG. 2, the output of the intake air amount sensor 5 fluctuates in a waveform under the influence of pulsation, and the phase of the average value position varies from TDC to TDC for a predetermined time T in response to the engine rotation speed. The control unit 9 delays the sampling start timing from the time when the TDC signal is input from the crank angle sensor 8 by a predetermined delay time 1 determined experimentally in advance according to the engine speed at that time. Sampling is started when the output value becomes close to the average value ES, sampling is performed for a predetermined sampling period t, and the sampled output values are averaged to obtain the average intake air amount.

FIG. 3 shows the internal configuration of the control unit 9, which includes a CPU 12, a ROM 1,
3. Equipped with a RAM 14, the detection outputs of the intake value sensor 5 and the throttle opening sensor 6 are inputted via the input circuit 15, multiplexer 16 and A/[] converter]7, and the CPU 12 receives the detected outputs. The crank angle sensor 4/8 signal is transmitted through the input circuit 18 to TDC,!
11 inclusive signal, an interrupt signal every 1 m5ec from the free running counter 19, and a signal from the bell reduction counter 20 are also input. Timer 21, drive circuit 2 as output of control results
The fuel injection control signal is configured to output a fuel injection control signal to the injector 10 via the injector 2.

The operation of the control unit 9 will be explained based on the flowchart shown in FIG. FIG. 4A shows the main routine. After the start, in step S1, the initial value is set by initializing X7, and in step S2, the average intake flow speed v is
The fuel injection amount P is calculated from S and the rotation speed.

FIG. 4B shows a TDC interrupt processing routine, in which the engine rotational speed is calculated from the interrupt cycle in step S3, and the throttle opening is read from the throttle opening sensor 6 in step S4. Next, in step S5, a sampling delay time T in the average calculation of the intake air amount is calculated from the throttle opening degree and engine speed. Is the calculation under this delay time higher than the engine speed? Since the period of pulsation is R as shown in FIG. is set so that it becomes large. In addition, since the influence of pulsation on the output of the intake air amount sensor 5 does not become a problem unless the throttle opening is more than a certain level, the delay coefficient K is set at a predetermined throttle opening or more as shown in FIG. 5B. Standard delay time T obtained from the rotation speed according to Figure 5A above
The delay time T is obtained by multiplying o by the delay coefficient K obtained from this throttle opening.

The delay time obtained in step S5 as described above is
After setting the subtraction counter 20 in step S6, a subtraction counter set flag F is set in step S7, and in step S8, fuel injection is set based on the fuel injection 1) 1ωP calculated in step S2. The subtraction counter 20 subtracts the set value to 0 at regular intervals, and stops when it reaches 0.

FIG. 4C shows a 1 m5ec interrupt processing routine. In step S9, the output value of the intake air amount sensor 5 is read, and in step S10, the output value of the intake air flow sensor 5 is combined with the previously determined intake air flow sensor output and flow rate characteristic. It is converted to the intake flow rate VO from the relationship with . In step S11, the total SUM of this stream IVo is calculated, and in step S12, the number N of sampling data is updated. In step 813, it is determined whether or not the subtraction counter set flag ``is set, and if the flag F is set during subtraction, Y
At the time of ES, the subtraction count value is read in step 314, and it is determined in step S15 whether or not this nose reduction count value has reached O. When the decrement counter value reaches O, in step 816 the flow meter total SUM and the sampling data r
! After calculating the average airflow ff1Vs from IN, in step S17, the registers for the total flow rate SUM and the number of data N are cleared for the next flow rate calculation, and in step 318, the subtraction counter set flag F is reset. be.

If it is 1J, sampling is started when the subtraction counter reaches O, and the intake sensor output is accumulated every 1 m5ec.No judgment in step 813 is made until the TDC signal is input and flag F is set. The above sampling is repeated based on. After subtracting a predetermined delay time T from the counter 20 in response to the input of the TDC signal and setting the flag F, the subtraction counter 20
Until it becomes Of, :, the sampling data is accumulated in the same way as above based on the No determination in step S15. Then, when the value of the subtraction counter 20 becomes O and a predetermined delay time T has elapsed, the sampling accumulation is finished and the average value VS is determined.

With the above configuration, the time point at which the sampling of the intake ω sensor 5 is averaged can be set near the average value, and the error in the average value due to fluctuations in the number of samplings near the point IUJ for which this average value is calculated can be reduced. can do.

In addition, in the above embodiment 43, an example of a sensor using a hot wire is shown as the intake air amount sensor, but a negative pressure sensor or the like may be used as the intake air amount sensor. The present invention can be applied when sensor output is affected by intake pulsation and requires averaging processing, and improves the accuracy of the averaging process.

[Brief explanation of drawings]

Fig. 1 is an overall configuration diagram of an engine equipped with an intake air pressure detection device according to an embodiment of the present invention, Fig. 2 is an explanatory diagram showing an example of sampling and averaging of intake air amount sensor output, and Fig. 3 is a control unit. 4, B and G are flowcharts to explain the operation of the control unit, and FIGS. 5A and B show the engine speed and throttle opening for determining the delay time. FIG. 1... Intake temperature detection device 2... Engine body 3... Intake passage 4...
...Throttle valve 5...Intake air flow sensor 9...Control unit Fig. 3 ~ 414 (A) (B) (C)
) - Figure 5 (B)

Claims (1)

[Claims] (1) The output of an intake air amount sensor such as a hot wire installed upstream of the engine throttle valve or a negative pressure sensor installed downstream of the throttle valve is sampled for a predetermined period, and the sampled output values are averaged to determine the intake air amount. An intake air amount detection device for an engine, characterized in that the start time of the predetermined period of sampling is set at a time when the output value of the intake air amount sensor is close to an average value.