JPH0718370B2 - Engine controller - Google Patents

Description

The present invention relates to an engine control device.

[Conventional technology]

Recently, various vehicle engines have been proposed in which the amount of intake air to be supplied to the engine is controlled to control the idle speed during idle operation. As one example thereof, conventionally, as shown in, for example, Japanese Patent Laid-Open No. 55-148939, a bypass passage for bypassing a throttle valve and a bypass valve for controlling the amount of air flowing through the bypass passage are provided, and idle rotation is performed. There is a system in which the opening of the bypass valve is feedback-controlled so that the engine speed reaches the target speed, and this type of engine controller does not operate even when various engine conditions such as aging change. There is an advantage that the rotation speed can be controlled to the target rotation speed.

However, in the conventional engine control device, the intake air amount is simply increased / decreased to control the idle speed. For example, if the intake air amount is increased due to changes in various conditions of the engine, the fuel supply amount is increased accordingly. However, there was a problem that the fuel efficiency during idling deteriorates.

[Object of the Invention]

In view of the above problems, the present invention is to provide an engine control device that can control the idle speed and can cope with changes in various conditions such as aging.

[Structure of Invention]

Therefore, in the present invention, in an engine having an idle speed control system, feedback control of the fuel supply amount and the idle speed is performed for a predetermined period to make the fuel supply amount constant, and in that state, the intake air amount is increased to increase the idle speed. Is controlled to the maximum, and thereafter, the fuel supply amount is reduced according to the difference between the actual guidel rotation speed and the target rotation speed.

That is, according to the present invention, as shown in the functional block diagram of FIG. 1, the fuel control unit 30 controls the fuel supply amount according to the intake air amount supplied to the engine, while the idle speed control unit 31 controls the fuel supply amount. After controlling the intake air amount to control the idle speed during idling to the target speed, the first idle time control means 33 receives the output of the speed sensor 32 and controls the fuel control means 30 and the idle speed control. The means 31 is controlled for a predetermined period to keep the fuel supply amount constant and the intake air amount is increased so that the idle speed becomes maximum, and the output of the speed sensor 32 is received by the second idle time control means 34. The fuel control means 30 is controlled according to the difference between the maximum idle speed and the target speed to reduce the fuel supply amount so that the idle speed becomes the target speed.

〔Example〕

 Embodiments of the present invention will be described below with reference to the drawings.

2 to 4 show an engine controller according to an embodiment of the present invention. In FIG. 2, 1 is an engine,
An intake pipe 3 is connected to the engine 1 in communication with the intake port 2, and the intake port 2 and the intake pipe 3 constitute an intake passage 4. A downstream side of the intake passage 4 is defined by a partition wall 5 into a high load intake passage 6 and a low load intake air amount 7 for swirl generation, and a swirl control valve 8 is provided in the high load intake passage 6.
Is installed.

Further, a fuel injection valve 9 is arranged downstream of the swirl control valve 8 in the intake passage 4, while a surge tank 10 is formed upstream of the swirl control valve 8 in the intake passage 4 and upstream thereof. Is provided with a throttle valve 11, and an upstream end of the intake passage 4 reaches an air cleaner 12.

Further, the intake passage 4 is provided with an idle speed control mechanism 13. In this control mechanism 13, the intake passage 4
A bypass passage 14 is formed in a branched manner by bypassing the throttle valve 11, and a bypass valve 15 for controlling the amount of air flowing through the passage 14 is arranged in the middle of the bypass passage 14.

In the figure, 16 is a distributor having an electronic advance device 16a, 17 is a vane type intake air amount sensor that is provided near the upstream end of the intake passage 4, and detects the intake air amount, and 18 is the intake air temperature. Intake air temperature sensor, 19 is a throttle sensor that detects the opening of the throttle valve 11, 20 is a rotation speed sensor that detects the engine speed from the rotation angle of the engine, 21 is a water temperature sensor that detects the cooling water temperature of the engine,
22 is an O ₂ sensor for detecting the air-fuel ratio of the air-fuel mixture from the oxygen concentration in the exhaust gas, 23 is an idle switch, 24 is a neutral switch, 25 is an interface 26, a CPU 27 and a memory 28.
An engine control unit consisting of the above memory 28
Is a program for the arithmetic processing of the CPU 27 (see FIG. 3).
And various calculation maps (see FIG. 4) are stored.

Further, the CPU 27 calculates the ignition timing of the engine from the engine speed and the intake air amount, and distributes this to the distributor.
In addition to the 16 electronic advance devices 16a, it controls the ignition timing of the engine, and when the engine load is low, the swirl control valve 8 is closed and intake air is supplied only from the low load intake passage 7 to generate swirl in the combustion chamber. Then, when the load is high, the swirl control valve 8 is opened to supply the intake air from both the low load and high load intake passages 7 and 6, thereby controlling the swirl control valve 8.

Then, the CPU 27 performs a feedback correction on the fuel injection pulse according to the intake air amount during the idling operation of the engine according to the output of the O ₂ sensor, and adds this to the fuel injection valve 9 to feedback-control the fuel supply amount while After feedback-controlling the opening of the bypass valve 15 so that the rotation speed becomes the target rotation speed, increase the opening of the bypass valve 15 so that the idle rotation speed becomes maximum with the fuel supply amount kept constant. The intake air amount is increased, and the fuel supply amount is decreased so that the idle speed becomes the target speed, and thereafter, the opening degree of the bypass valve 15 and the opening degree of the bypass valve 15 in which the fuel supply quantity is increased as described above. , The control at idle is performed to control the reduced fuel supply amount.
Further, during normal operation of the engine, the CPU 27 controls the fuel supply amount by performing feedback correction or enrichment correction on the fuel injection pulse according to the intake air amount according to the output of the O ₂ sensor, and also opens the bypass valve 15 at a predetermined opening. It is controlled to hold each time.

In addition, in the above configuration, the fuel injection valve 9 and
The CPU 27 is the fuel control means 30 shown in FIG. 1, the idle speed control mechanism 13 and the CPU 27 are the idle speed control means 31 shown in FIG.
Reference numeral 7 realizes the functions of the first and second idle control means 33, 34 shown in FIG.

Next, the operation will be described with reference to FIGS. 3 and 4.
Here, FIG. 3 shows a flow chart of the calculation processing of the idle control of the CPU 27, and FIG. 4 shows the fuel correction amount ΔQf according to the rotational speed difference ΔN.

First, the operation of idling control will be described. When the engine operates, CPU27 will input the engine speed
N, intake air amount Air, engine cooling water temperature T _W , intake air temperature Tair,
After reading the O ₂ sensor output V _S , the signals Sid and Sn from the idle switch 23 and the neutral switch 24 (step 4
0), the basic pulse width Tp of the fuel injection pulse is obtained according to the intake air amount Air (step 41), and it is determined whether the engine is in the idle operation from the states Sid, Sn of the idle switch 23 or the neutral switch 24 and the engine speed N. It is determined whether or not (switch 42), and at the time of idle operation, the basic pulse width Tp obtained above is corrected for the intake air temperature according to the intake air temperature Tair, and is also subjected to feedback correction according to the O ₂ sensor output V _S for the actual pulse. The width is calculated, and the fuel injection pulse having the actual pulse width is added to the fuel injection valve 9 to perform feedback control of the fuel supply amount (step 43), and the target idle speed ND is set according to the engine coolant temperature T _W. The basic opening degree of the bypass valve 15 is calculated according to the target rotational speed ND, and the intake air temperature is corrected for the basic opening degree to obtain the target opening degree D. The idle speed is feedback-controlled to the target speed (step 44), the internal timer T1 is down-counted by 1 and whether or not this is zero, that is, the set time has elapsed since the feedback control of the fuel and the idle speed was started. Whether or not (step
45, 46), and the above-described processing (steps 40 to 46) is repeated until the set time has elapsed.

When the set time elapses, the CPU 27 increases the target opening degree D of the bypass valve 15 by a predetermined opening degree ΔD while keeping the fuel supply amount Qf constant, and determines whether or not the idle speed has decreased (Nn> Nn). -1), the target opening D is increased to increase the intake air amount until the idle speed becomes maximum (CPU47, 48, 49), and when the idle speed becomes maximum, this time, the actual The fuel correction amount ΔQf (see FIG. 4) is calculated according to the difference ΔN between the idle speed N and the target speed ND, and the current fuel supply amount is also calculated with this fuel correction amount ΔQf.
The Qf is reduced and corrected to determine whether the idle speed N has reached the target speed ND, and thus the fuel supply amount Qf is reduced until the idle speed N reaches the target speed ND (step
50, 51, 52), when the idle speed N reaches the target speed ND, thereafter, the bypass valve 15 is controlled to the increased target opening degree D and the fuel supply amount is controlled to the decreased supply amount Qf. It will be. (Steps 53, 54).

Next, when the engine is in normal operation, the CPU 27 in the feedback control region performs the intake pulse temperature correction on the basic pulse width Tp according to the intake air amount and the feedback correction according to the output of the O ₂ sensor to perform the fuel injection pulse of this pulse width. Is added to the fuel injection valve 9 to perform feedback control of the fuel supply amount.
Intake temperature correction and enrichment correction are performed on Tp, the fuel injection valve 9 is supplied with fuel in an amount corresponding to the pulse width after the correction, and the bypass valve 15 of the idle speed control mechanism 13 is set to a predetermined opening degree. , For example, the neutral opening is controlled.

Further, the CPU 27 calculates the ignition timing according to the engine speed and the intake air amount, adds this to the electronic advance device 16a of the distributor 16 to cause the engine to ignite at the above ignition timing, and the throttle sensor 19 The output of the engine detects the load condition of the engine, and when the load is low, an open signal is applied to the swirl control valve 8 to close the swirl control valve 8 and the intake air is supplied from only the low load intake passage 7 at a high flow rate. To generate a strong swirl in the combustion chamber, and when the load is high, a close signal is applied to the swirl control valve 8 to open the swirl control valve 8 to open both the low load and high load intake passages 7,6.
Therefore, a large amount of intake air can be smoothly supplied.

In this device as described above, after performing normal fuel supply amount control and idle speed control during engine idle operation, the intake air amount is increased at a constant fuel to maximize the idle speed and the fuel supply amount is increased. Since the idle speed is controlled to the target speed by reducing the amount, the intake air amount and the fuel supply amount can always be controlled to the optimum values even if various engine conditions such as aging change. It is possible to prevent deterioration of fuel efficiency.

Further, after the feedback control of the fuel supply amount and the idle speed is performed for a predetermined period, the fuel supply amount is decreased so that the idle speed becomes the target speed. The rotational stability does not deteriorate in combination with the other unstable conditions.

In the above embodiment, the bypass type idle speed control system has been described, but the present invention can be applied to a system of a system for controlling the throttle valve opening.

〔The invention's effect〕

As described above, according to the present invention, in an engine having an idle speed control system, the fuel supply amount is made constant, and in that state, the intake air amount is increased to control the idle speed to the maximum, after which the actual idle speed is controlled. Since the fuel supply amount is reduced according to the difference between the rotation speed and the target rotation speed, there is an effect that the optimum fuel consumption can always be ensured even if the engine conditions change. Further, before the fuel supply amount is reduced, the fuel supply amount and the idle rotation speed are feedback-controlled for a predetermined period to stabilize the air-fuel ratio and the idle rotation speed. The effect is that it can be secured.

[Brief description of drawings]

FIG. 1 is a functional block diagram showing the configuration of the present invention, FIG. 2 is a schematic configuration diagram of an engine control device according to an embodiment of the present invention, and FIG. 3 is a diagram showing a flowchart of arithmetic processing of the CPU 27 in the above device. , FIG. 4 is a diagram showing the fuel correction amount with respect to the rotational speed difference. 30 ... Fuel control means, 31 ... Idle speed control means,
32 ... Revolution sensor, 33, 34 ... First and second idle control means, 1 ... Engine, 9 ... Fuel injection valve, 13 ...
Idle speed control mechanism, 20 ...... speed sensor, 27 ……
CPU.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hideo Shiraishi 3-3 Shinchi, Fuchu-cho, Aki-gun, Hiroshima Prefecture Mazda Co., Ltd. (56) References JP 61-28733 (JP, A) JP 61- 1846 (JP, A)

Claims (1)

[Claims] 1. A fuel control means for controlling a fuel supply amount according to an intake air amount supplied to an engine, and an idle rotation for controlling an intake air amount to control an idle rotation speed during idle operation to a target rotation speed. A speed control means, a rotation speed sensor for detecting an engine rotation speed, and an output of the rotation speed sensor, the fuel control means and the idle rotation speed control means are controlled for a predetermined period to keep the fuel supply amount constant and idle. First idling control means for increasing the intake air amount so that the rotation speed becomes maximum, and the fuel supply means for receiving the output of the rotation speed sensor and depending on the difference between the maximum idle rotation speed and the target rotation speed. Control to reduce the fuel supply amount so that the idle speed becomes the target speed.
And an idle control means for controlling the engine.