JPS58200062A - Differential calculation circuit for suction air volume control device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a differential calculation circuit for an intake air amount control device for an internal combustion engine.

In internal combustion engines, particularly in-vehicle internal combustion engines, it is necessary to control the engine speed during idling in order to suppress harmful components in exhaust gas or improve fuel efficiency. For this reason,
There is an intake air amount control device that supplementally controls the amount of intake air so that the engine speed becomes a predetermined target rotation speed depending on the operating state of the engine.

The intake air amount control device detects the actual rotational speed of the engine, and controls the amount of intake air flowing through the auxiliary intake air passage that bypasses the throttle valve according to the actual rotational speed. Tsuk control is being performed. Generally, in foot knock control, there is a proportional operation (P operation) in which the control amount changes linearly according to the deviation between the target rotation speed and the actual rotation speed, and an integral operation (■ (operation) and a differential operation (D operation) that is proportional to the rate of change (differential) of the deviation.Each operation is used alone or in a composite operation such as a PI operation.

By the way, in the D operation, the control amount is large relative to the target rotation speed.
This is an operation that corrects this when it is about to occur, and by performing a combined operation with other operations, the responsiveness and stability of control are improved. Therefore, the intake air amount control device is provided with a differential calculation circuit for the D operation.

FIG. 1 shows a conventional digital differential calculation circuit. In FIG. 1, an output signal (8) of a crank angle sensor (not shown) is supplied to an input terminal IN, and the output signal (8) of a crank angle sensor (not shown) is supplied to a counter 1 and a timing signal (8). A pulse generator 2 is connected. A divider 3 is connected to the output end of the counter 1, and a subtracter 4 and a latch 5 are connected to the output end of the divider 3. The output terminal of the latch 5 is connected to the other input terminal of the subtracter 4. A divider 6 is connected to the output end of the subtracter 4, and the divider 6 is connected to the output end of the counter 1. The divider 3 has a timing difference (to), the subtracter 4 has a timing difference of 0, and the latch 5 has a timing difference of 0.
The timing pulse generator 2 supplies the timing pulse sum to the divider 6, and the timing pulse sum to the divider 6.

Figure 2 (5) to ■ indicate each pin in the circuit of Figure 1.
Crank angle sensor output (5)
In accordance with
Generates bacteria.

When the output iR pulse) is supplied to the divider 3, the generation period Tt of the output pulse is counted by a counter l.

The crank angle sensor generates an output pulse every time the engine's crankshaft (hereinafter referred to as crankshaft is omitted) rotates once, so the output signal of the counter l is
The period per rotation is Tt. From this period Tt, divider 3
The engine rotation speed Nt is calculated. The engine speed Nt is Nt = /Tt (1)
(K is a constant). Then, from the rotation speed Nt and the rotation speed Nt -1 of the engine one revolution before, which is stored in the latch 5, the subtracter 4 calculates the rotation speed change ΔN during one rotation of the engine.

The rotational speed change ΔN is obtained from ΔN=Nt −Nt −1 (2)K. Next, a speed change Dt per engine rotation is calculated by a divider 6 from the rotational speed change ΔN and the period Tt. The speed change Dt is obtained from Dt=ΔN/Tt (3). A digital signal representing this speed change Dt is output from the divider 6.

For example, when the output/base pulse of the rank angle sensor is supplied as shown in FIG. 3(a), the engine rotation speed Nt calculated by the divider 3 and output as a digital signal is
”). Then, the speed change 1) t output as a digital signal from the divider 6 is as shown in Fig. 3 (C).
The characteristics are as follows. Note that NS in FIG. 3(h) is the target rotational speed, and the broken line A is an analog change in the engine rotational speed.

However, in such a conventional differential calculation circuit, due to dinotal processing that calculates the speed change Dt every time the engine rotates, the output change of the speed change Dt becomes rough as shown in FIG. The drawback was that the feedback control of the intake air amount was not good.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a digital differential calculation circuit that can improve the control of the amount of intake air through the D operation.

Embodiments of the present invention will be described below with reference to FIGS. 4 to 6.

In FIG. 4, parts equivalent to those in FIG.
are connected, and an adder IO is connected to each output terminal of the latch 7.8.9. Further, the latch 7 is supplied with a timing pulse [F], the latch 8 is supplied with a timing pulse 0, and the latch 9 is supplied with a timing pulse 0 from the timing pulse generator 2. . The output signal of the adder 10 becomes the control amount for the D operation. The rest of the configuration of the differential calculation circuit according to the present invention is the same as that of the conventional example shown in FIG. 1, so a description thereof will be omitted here.

5(8) to 0 indicate the respective signals (5) to 0 in the circuit of FIG. 4, respectively. timing·
The pulse generator 2 first generates timing pulses (T), (C), (Di, @(each in the order of D)) according to the output of the crank angle sensor supplied to the input terminal IN. pulse and timing pulse [F]
, (Gl, (-)) as a timing pulse (
Timing pulse ■ in the order of 1'l, (G), H
Occurs after the occurrence of. The output terminal of the divider 6 outputs a digital signal representing a speed change Dt per engine revolution. For example, the output of the crank angle sensor is 6th.
When the occurrence occurs as shown in Figure 6(a), the engine speed Nt output as a digital signal from the divider 3 is as shown in Figure 6(b).
become that way. The speed change Dt output from the divider 6 as a digital signal is determined by a timing pulse (t).
, (Ql, 1) Latch 7.8,9,7 according to 1)
．． 8... are stored in the order. The latches 7.8.9 hold and output digital signals representing the same speed change Dt until a timing pulse is applied to each again. Because of this, the latch? . It will look like (a). The output signal of this adder 10 becomes the control amount for the D operation.

As described above, according to the differential calculation circuit according to the present invention, the calculated speed change (differential) per engine rotation is added to at least the previously calculated speed change, and the value is output as the control amount for the D operation. Therefore, the feed puncture control of the intake air amount by the D operation becomes good.

Note that the differential calculation circuit of the present invention is not limited to the above-mentioned embodiments, and a microcombinator may be used to process the same arithmetic operation as the circuit of the above-described embodiments by a program.

[Brief explanation of the drawing]

Figure 1 is a block diagram showing a conventional example of a differential calculation circuit, Figures 2 and 3 are operational waveform diagrams of the circuit in Figure 1, and Figure 4 shows an embodiment of the differential calculation circuit of the present invention. The block diagrams of FIGS. 5 and 6 are operational waveform diagrams of the circuit of FIG. 4. Explanation/clarification of symbols of main parts l... Counter 2... Timing pulse generator

Claims (1)

[Claims] Differentiation of the deviation between the actual rotation speed and the target rotation speed to be used as a control signal in an intake air amount control device that supplementarily controls the intake air amount according to the actual rotation speed so that the engine rotation speed becomes the target rotation speed. A differential calculating circuit that generates a differential signal having a level representing the magnitude of the differential signal every predetermined rotation of a crankshaft of an engine, the circuit comprising: a plurality of holding means; One of the plurality of holding means
1. A differential calculating circuit comprising: a switching means for holding output levels at a constant value; and an addition means for adding the holding output levels of the plurality of holding means.