JPH0251051B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an engine control device that includes an auxiliary valve downstream of a throttle valve in an intake passage.

In general, an engine control device controls the air-fuel ratio of the mixture sucked into the engine, ignition timing, exhaust gas recirculation amount, etc. according to the engine operating condition, thereby maintaining the engine's combustion condition in good condition. Conventionally, the engine rotational speed and the intake negative pressure downstream of the throttle valve have been used as signals representing the operating state of the engine.

By the way, the air-fuel mixture sucked into the above engine is
At low loads, the amount of air is small, and as a result, the intake air flow velocity into the combustion chamber slows down, resulting in poor combustion performance of the engine. Conventionally, as a way to solve this problem, the intake passage downstream of the throttle valve is connected to the low-load intake passage. It is divided into a passage and a high-load intake passage, and an auxiliary valve is provided in the high-load intake passage to open and close it.
When the load is low, the auxiliary valve is closed and the air-fuel mixture is sucked in only from the low-load intake passage to increase the intake flow rate, and when the load is high, the air-fuel mixture is sucked in from both intake passages to increase filling efficiency. There was one that was designed to improve the combustibility of the engine.
(See Japanese Patent Application No. 175461/1983).

The present invention has been made in such a situation, focusing on the fact that in an engine equipped with the auxiliary valve, the amount of air-fuel mixture actually taken into the engine corresponds more accurately to the intake negative pressure downstream of the auxiliary valve. The intake negative pressure detection position is set downstream of the auxiliary valve in the high-load intake passage, and the combustion state of the engine is controlled based on the intake negative pressure detected in this area, thereby controlling the combustion state. The purpose of this invention is to provide an engine control device that can significantly improve accuracy.

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

1 to 4 show an embodiment of the present invention. In the figures, 1 is an engine, a combustion chamber 2 of which is equipped with a spark plug 3, and an exhaust passage 4 and an intake passage 5 communicate with each other. ing. A throttle valve 7 which is controlled to open and close in conjunction with an accelerator pedal 6 is installed in the middle of the intake passage 5, and a fuel injection nozzle 8 is installed upstream of the throttle valve 7. Further, a partition wall 9 is formed in the intake passage 5 near the combustion chamber 2 downstream of the throttle valve 7 along the flow direction of the intake air, so that the downstream portion of the intake passage 5 is formed into a low-load intake passage with a narrow passage area. 5a and a high-load intake passage 5b having a wide passage area, and the low-load intake passage 5a has a width that becomes narrower when viewed from above as it approaches the combustion chamber 2.

An auxiliary valve 1 is provided in the high-load intake passage 5b.
0 is attached to open and close the passage 5b,
One end of a piston rod 11a of a diaphragm device 11 is rotatably connected to a rotating lever 10c fixed to a rotating shaft 10a of the auxiliary valve 10, and a diaphragm 1 is connected to the other end of the piston rod 11a.
A position sensor 12 for detecting the position of the diaphragm 11b, that is, the opening degree of the auxiliary valve 10, is attached to the diaphragm 11b. Further, the lower side of the diaphragm 11b in FIG. 1 is a negative pressure chamber 1.
1c, the downstream end of the negative pressure introduction passage 13 communicates with the negative pressure chamber 11c, and the negative pressure introduction passage 13
The upstream end of the intake passage 5 communicates with the intake passage 5 slightly downstream of the throttle valve 7. Also, this negative pressure introduction passage 1
A three-way solenoid valve 14 is interposed in the middle of 3,
Furthermore, a first negative pressure sensor 15 is attached to the negative pressure introducing passage 13 near the intake passage 5 .

Further, 20 in FIG. 1 is a target position setting device for setting the target position of the auxiliary valve 10, that is, the target opening degree of the auxiliary valve 10, and this target position has the characteristics shown in FIG. 4 with respect to the intake negative pressure. It is determined. 21 is the target position setting device 20
A differential amplifier 22 compares the set opening of the position sensor 12 with the detected opening of the position sensor 12 and outputs an output corresponding to the difference between the two. This is a driver that opens and closes.

A second negative pressure sensor 16 is installed downstream of the auxiliary valve 10 in the high-load intake passage 5b to detect the intake negative pressure generated in the downstream portion.
The detection output of the negative pressure sensor 16 is input to a control device 17, and the control device 17 receives the detection output and the output of the rotation sensor 18 and drives the fuel injection nozzle 8 with an injection pulse of a predetermined width. Further, the ignition device 19 is configured to ignite the ignition plug 3 at a predetermined ignition timing.

FIG. 3 is a detailed block configuration diagram of the control device 17. In the figure, 31 is an injection pulse width setting device that sets the injection pulse width according to the operating condition of the engine, and 32 is the injection pulse width setting device 31. The driver 33 that drives the fuel injection nozzle 8 according to the output pulse width of the engine 1 is an ignition timing setter that sets the ignition timing according to the operating state of the engine 1, and the ignition timing setter 19 is a spark plug that sets the ignition timing according to the ignition timing setter 33. 3
It is an ignition device that ignites.

Next, the operation will be explained.

First, to explain the opening/closing control of the auxiliary valve 10, the target position setter 20 receives the intake negative pressure from the first negative pressure sensor 15, sets a target position with the characteristics shown in FIG. The target position is input to the differential amplifier 21, where it is compared with the detection position detected by the position sensor 12, and an output corresponding to the difference between the two positions is input to the driver 22.
2 drives the three-way solenoid valve 14 in response to the input to open and close the negative pressure introduction passage 13. Then, the intake negative pressure generated downstream of the throttle valve 7 in the intake passage 5 is introduced into the negative pressure chamber 11c of the diaphragm device 11 through the negative pressure introduction passage 13, which causes the diaphragm 11b to move up and down, and as a result, the auxiliary valve 10
is controlled to open and close to the degree of opening shown in FIG.

Next, control of the combustion state of the engine 1 will be explained.

The engine speed detected by the rotation sensor 18 and the auxiliary valve 1 detected by the second negative pressure sensor 16
The intake negative pressure generated in the high-load intake passage 5b downstream of 0 is input to the injection pulse width setting device 31,
The setting device 31 outputs a set injection pulse having a width according to the operating state of the engine 1 at this time, and the driver 32 drives the fuel injection nozzle 8 according to the output.
As a result, a predetermined amount of fuel is injected into the intake passage 5, and as a result, the air-fuel mixture is taken into the engine 1 at a predetermined air-fuel ratio.

The outputs of both the sensors 18 and 16 are also input to the ignition timing setter 33, which sets and outputs the ignition timing according to the operating state of the engine 1 at this time, and adjusts the ignition timing according to the output. 19 causes the spark plug 3 to ignite at a predetermined ignition timing.

In this way, in the device of this embodiment, the high-load intake passage 5b is opened and closed by the auxiliary valve 10.
The intake flow rate increases at low loads, and the charging efficiency improves at high loads, which improves combustibility, and also reduces the fuel injection amount even with the intake negative pressure generated in the high-load intake passage 5b downstream of the auxiliary valve 10. Since the ignition timing and ignition timing are controlled, it is possible to perform control that more accurately corresponds to the amount of air-fuel mixture actually drawn into the engine 1, improving responsiveness during transients such as when starting acceleration. In particular, the occurrence of knocking at this time can be suppressed, and the control accuracy of the combustion state of the engine 1 can be greatly improved. Although the case where the fuel ratio and ignition timing are controlled has been described, the amount of exhaust gas recirculation may also be controlled using the intake negative pressure.

As described above, in the engine control device according to the present invention, the intake negative pressure detection position is set on the downstream side of the auxiliary valve in the high-load intake passage, and the engine combustion is performed based on the intake negative pressure detected in this part. Since the state is controlled, there is an effect that the control accuracy of the combustion state of the engine can be greatly improved.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an engine control device according to an embodiment of the present invention, FIG. 2 is a cross-sectional plan view of the intake passage and auxiliary valve portion, FIG. 3 is a block diagram of the control device, and FIG. 4 is a block diagram of the control device. FIG. 3 is a characteristic diagram of the target opening degree of the auxiliary valve with respect to the intake negative pressure. 1... Engine, 5... Intake passage, 6... Accelerator pedal, 7... Throttle valve, 10... Auxiliary valve, 16... Second negative pressure sensor.

Claims (1)

[Claims] 1. A high-load engine equipped with a combustion state control means for controlling the combustion device of the engine, and an auxiliary valve that controls the intake passage downstream of the throttle valve to a passage area according to the operating state of the engine by the operation of the drive means. an intake passage, and a low-load intake, which has one end connected to the intake passage upstream of the auxiliary valve and the other end connected to the combustion chamber, and whose passage diameter is smaller than the high-load intake passage diameter. An intake negative pressure detection means for detecting intake negative pressure generated in a high-load intake passage downstream of the auxiliary valve, and an intake negative pressure signal detected by the intake negative pressure detection means in an engine having a branched passage and a passage. and a control amount setting means for setting a control amount for controlling the combustion device of the engine based on the control amount, and a control amount setting means for controlling the combustion state control means based on the control amount set by the control amount setting means. engine control device.