JPS5827016A - Device for controlling engine - Google Patents

Abstract

PURPOSE:To make it possible to perform highly accurate control characterized by a high speed response, by simultaneously inputting a frequency output signal which is proportional to a vortex frequency and an analog signal corresponding to a mean flow speed, and performing the like. CONSTITUTION:When the analog signal V5 corresponding to an airflow rate is differentiated, an acceleration signal in the case of rapid increase in intake airflow rate and the like is obtained. When the averaged time with respect to an output V4 corresponding to the vortex frequency is changed in response to the acceleration signal, the averaged time can be shortened only at the time of accleration and the response delay can be made small. Meanwhile, in the case the change in the analog signal is small in the normal operation, the averaged time for long period of time can be secured. In the case the airflow rate is rapidly decreased, the engine can be likewise controlled highly accurately and highly responsively.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvements in the transient characteristics of automotive air flow measurement devices, particularly vortex flowmeters.

Among the vortex flowmeters, the μ-Man vortex type and the swirl type are in practical use as air flowmeters for automobiles, and both output frequency signals that are approximately proportional to the intake air amount or flow velocity.

This frequency signal is highly accurate over a wide flow range.

Although it has the feature of being very fast in following transient changes in flow velocity, since it is a frequency output, it is impossible to respond at a high speed of more than one cycle of the vortex, especially when the flow velocity changes from low flow rates or from high flow rates. The disadvantage is that the output response is poor during sudden deceleration. Furthermore, even if you measure the period of the frequency signal and try to measure the air flow rate at a higher speed, there will be fluctuations in the period caused by fluctuations in the vortex, so it will not be stable unless averaging such as a moving average is performed. There were disadvantages in that the output could not be expected and the response was further impaired. This drawback is.

This is critical to the welfare of systems that control automobile fuel and exhaust gas based on the amount of intake air.

Figure 1 shows the delay when averaging the frequency output proportional to the air flow rate.Compared to the analog air flow rate indication value shown in Figure 1, the frequency information converted into digital μ indicates that the next pulse will be input. It will continue to output old information until it is done. This delay time always exists for one period of the pulse even when it is the minimum, and if n times are averaged, n times are required.

If this averaged frequency signal is used to control the amount of fuel in a car, it will be uniform during acceleration, but rich during deceleration, which is undesirable.On the other hand, if the frequency output is always processed using the minimum averaging time, it will be in a steady state. This is a p problem in which the frequency fluctuation at is large.

This invention is intended to eliminate the above-mentioned drawbacks, and aims to eliminate the drawbacks of the frequency signal by outputting an electrical signal corresponding to the flow velocity at the same time as the frequency signal caused by the vortex. FIG. 2 is a basic configuration diagram of an embodiment of the present invention.

In Figure 2, (1) is the intake air passage, Q) is the vortex generator, (+) is a pair of hot wires installed in the wake of the vortex generator (no. Hot wire 0) is the resistance. vessel (sl, fa
The heating wire (4) is controlled to a constant temperature by resistors (81, +91, 1101 and the operational amplifier rJ) by t, fyl and the operational amplifier (11).

The control voltages of these hot wires (3) and +41 are respectively (V
, ) (Vm ), this control voltage (V, ) (V
, Gokukondey-Ha, +141, 122. Resistance 0
29, (11, (1?), 081, H, @
1) A difference signal amplification circuit consisting of an operational amplifier generates a signal (Vs) which becomes a difference amplification signal (V, ).
2) becomes the frequency output (V,), that is, the output (1), and the signal (Vl) (Vm' is the addition resistor (24
16! Added by fQ fi, voltage output (V, )
In other words, the output is ■.

FIG. 3 shows voltage waveform diagrams at various parts in FIG. 2. With the configuration shown in FIG. 2, Karman vortex streets are generated regularly and symmetrically to the left and right in the wake of the vortex generator Q). The hot wires (3), +41 are cooled by the average flow velocity and at the same time are cooled regularly and alternately at high frequency by the Karman vortex street. For this reason, the control voltage (V
l) (Vm) is the component m corresponding to the average flow velocity.

■, and the component Δv, which corresponds to the flow velocity change due to the force μ Mann vortex.

Δv1.

The polarity of Δv1 and Δvyuzumi is opposite, and (Δv1−Δ
A signal v1 is obtained from V, ) and a 5-frequency output v4 is obtained. The ratio between this frequency and the amount of intake air is approximately constant.

It is a function of 9 average flow velocity - 0. By adding the signal (vl) and the signal (V, ), Δv8 and ΔV of opposite polarity are canceled and v, = v, + VB = kVx = k
V* Tona! l, which is a function of the flow velocity (Vi
) is obtained. Since this signal (V,) is an analog voltage signal, it has good responsiveness and always outputs information corresponding to the flow rate O.

By effectively using the signals v1 and vI in parallel, a highly accurate and fast-response automobile air flow meter can be realized.

In FIG. 2, H is various parameter information representing the operating state of the engine, such as engine rotational speed information, negative pressure, intake air temperature, atmospheric pressure, and water temperature. If necessary, this information can be input into the air flow rate signal processing circuit.

Consider a case where the amount of intake air increases rapidly in the air flow meter configured as described above. Since the analog signal (V,) corresponds to the intake air amount, by differentiating % (■,), an acceleration signal corresponding to the increase in the intake air amount can be obtained. By changing the averaging time of the frequency signal (v4) according to this acceleration signal, the averaging time can be shortened and the response delay can be reduced only during acceleration. V in steady operation,
When the change in the analog signal is small, a long averaging time can be secured. The same applies when there is a sudden decrease.

In this case, information on the intake air temperature is sufficient as the necessary engine operating parameter.

In the above embodiment, (V, ) is determined by the differential signal of (Vl).
We have explained the case where the averaging time (or the number of moving averages) of the frequency signal of (Vl) is changed. It goes without saying that a similar effect can be expected even if an increase coefficient is determined and multiplied accordingly.

Also, depending on the operating state of one engine, only the frequency output (v4) may be disturbed due to intake pulsation, especially during full throttle operation at low speed rotation, and the proportional relationship with the intake air amount may no longer hold. Even in this case, the value of the analog output (V, ) is (v
4) Since it is not as disturbed as the signal, (ff, ) signal is used instead of (ff,) signal.
It is also possible to output the air amount signal obtained by the signal vs).

In the above embodiment, a case was described in which both rows of Power Man were detected using a pair of hot wires, but the same effect can be expected in the case of both rows of Sufu-2 type or with one or more hot wires. Needless to say, although the vortex detection means has been described as a heat wire, it goes without saying that the same effect can be achieved using a thermistor or other heat-sensitive element.

Furthermore, even if the vortex frequency signal is no longer usable due to a break in one of the pair of hot wires, the average flow velocity signal can be used as a backup signal.

As explained above, according to the present invention, the frequency output signal proportional to the vortex frequency and the analog signal corresponding to the average flow velocity are simultaneously input, and the optimal intake air flow rate output is determined by referring to the input of engine operating parameters, etc. A simple configuration of processing has the effect of eliminating the drawbacks of frequency output signals.

[Brief explanation of the drawing]

Figure 1 is a graph showing the drawbacks when frequency output signals are averaged, Figure 2 is a basic configuration diagram of an embodiment of the present invention, and Figure 3 is a graph showing the drawbacks when frequency output signals are averaged.
The figure is a voltage signal waveform diagram of the second figure part. In the figure, (1) is the intake air passage, (2) is the vortex generator, and (3) is the vortex generator.
), +41 is a hot wire. (V,) is a frequency output signal approximately proportional to the amount of intake air, (V,) is an analog output signal corresponding to the amount of intake air, H is an engine operation buff meter input, and (22 is an air flow rate signal processing circuit). Agent Makoto Kuzuno

Claims (3)

[Claims] (1) A means provided in an intake air passage of an internal combustion engine, which captures the air flow rate as a change in a fluid vortex, and captures the change in the fluid vortex as a frequency signal using at least one heat-sensitive element; It is equipped with an air flow meter having means for outputting an analog signal corresponding to the average flow velocity from among the electric signals of the element. An engine control device comprising an air flow signal processing circuit that receives the frequency signal and the analog signal as input and outputs a desired air flow signal. (2) The air flow rate is measured by the average value of the period of the frequency signal, and the number of cycles or the averaging time for calculating the average value is controlled by the value of the analog signal. An engine control device according to claim 1. (3) The air flow rate is measured based on the average value of the period of the frequency signal, and the value of the average value is corrected in accordance with the change value of the analog signal.
Control equipment for the engine described in Section 1.