JPH066211Y2 - Engine intake control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of use] The present invention relates to an intake control device for an engine, and more particularly to an intake control device for an in-vehicle engine having a linkless throttle valve.

[Conventional technology]

In recent automobile engines, a fuel cut mode in which fuel is cut during deceleration operation to prevent HC and improve fuel economy, and to prevent engine overspeed, for example,
It is generally equipped with a high-speed fuel cut mode that executes fuel cut at a predetermined engine speed or higher such as 7000 rpm.

Among these, in the high-speed fuel cut mode, engine over rotation is prevented to prevent damage to engine parts,
The main points are to prevent overheating of the exhaust system and to reduce fuel consumption. Fuel cut to prevent over-rotation during high-speed engine rotation has been generally
When the engine speed exceeds a certain fuel cut speed, the fuel injection from the fuel injection valve is stopped. In this method, until the throttle valve is closed, fuel cut and return are repeated in the vicinity of the fuel cut rotation speed, and the engine continues to rotate at high speed in the hunted state. Therefore, if such a state continues for a while regardless of the driver's intention, wear and deterioration of various parts of the engine are promoted, and particularly in a vehicle equipped with a catalytic converter, the temperature of the catalyst is rapidly raised to cause the deterioration. Had the problem of promoting.

In order to improve such problems, Japanese Patent Laid-Open No. 60-128957
The publication discloses a method for preventing over-rotation of an engine in which the fuel cut speed is controlled to be gradually reduced when high speed fuel cut-return is continued. Further, in the Japanese Patent Application No. 61-104864 filed previously, the applicant of the present application gradually reduces the fuel cut rotation speed and the fuel return rotation speed when high-speed fuel cut-return is continued,
We proposed a method to prevent engine over-rotation by controlling the difference between both speeds so that the difference gradually increases.

Meanwhile, JP-A-56-132428, JP-A-55-115178, and JP-A-
Japanese Patent No. 55-123327 discloses an engine speed control device using a so-called linkless throttle valve. That is, a rotation speed control device using a linkless throttle valve detects the amount of depression of the accelerator pedal and controls the throttle valve opening in accordance with the detected amount of depression of the accelerator pedal. By electrically performing the control, various controls can be performed as compared with the conventional system in which the accelerator pedal and the throttle valve are mechanically linked.

[Problems to be solved by the device]

However, in the method of preventing over-rotation of the engine by fuel cut, since the engine continues to rotate at high speed in the hunting state, there is a problem that shock vibration and deterioration of fuel consumption due to hunting occur. This problem is somewhat improved in the above-mentioned JP-A-60-128957 and Japanese Patent Application No. 61-104864, but these technologies also try to prevent overheating of the engine by high-speed fuel cut, so hunting It does not completely solve the shock and the deterioration of fuel efficiency.

The present invention has been made in view of the above circumstances, and an object of the present invention is to stop a vehicle without causing a shock or the like due to engine hunting in an engine in which a linkless throttle valve is provided in an intake passage. It is an object of the present invention to provide an intake control device for an engine that effectively prevents overheating of the engine.

[Means for Solving the Problems] In order to solve the above-mentioned problems of the prior art, the present invention, as shown in the block diagram of FIG. 1, includes a main throttle valve that interlocks with an accelerator pedal in an intake passage. ,
In an intake control device for a vehicle-mounted engine in which a linkless throttle valve that is controlled to open and close by a control unit is arranged in series, an engine speed detection unit, at least one of an engine temperature detection unit and a timer, and whether or not the vehicle is stopped Vehicle stop state determination means for determining whether or not, engine idling state detection means for detecting whether or not transmission of engine output to the vehicle drive wheels is cut off, and engine rotation speed when the vehicle is stopped and the engine idling state is The state of being equal to or more than a predetermined value has passed for a predetermined time, or the engine speed is at least a predetermined value and the engine temperature is at least a predetermined value. An engine intake control device is provided, which is provided with a means for detecting a racing state and a control means for gradually controlling the linkless throttle valve toward the closing side when the racing state is detected.

[Action]

When the vehicle is stopped and the engine is idling, the racing condition is detected when the engine speed is equal to or higher than a predetermined speed for a predetermined time, or when the engine speed is higher than a predetermined value and the engine temperature is higher than a predetermined value. The means detects that the engine is racing. When this racing state is detected, the control means controls the linkless throttle valve in the closing direction. Although it is desirable to control the linkless throttle valve to gradually close, it may be controlled to immediately close to a predetermined opening.

〔Example〕

The intake control device for an engine of the present invention will be described below in detail with reference to the embodiments shown in the drawings.

FIG. 2 shows an overall schematic configuration diagram of the present invention.
In the intake passage 12 of the engine indicated by 0, an air cleaner 14, an air flow meter 16, a main throttle valve 18, and a sub-throttle valve 20 are provided upstream of the main throttle valve 18. The main throttle valve 18 is connected to an access pedal 24 via a link 22, and the opening / closing of the main throttle valve 18 is controlled according to the depression amount of the access pedal 24.

On the other hand, the sub-throttle valve 20 is a linkless throttle valve whose opening / closing is controlled by the electric servomotor 26, and is normally held in the fully open position as shown in FIG. The sub-throttle valve 20 is controlled by an electronic control unit (ECU) 30, and the electronic control unit 30 includes a rotation speed sensor 31, a vehicle speed sensor 32, a water temperature sensor 33, and a neutral switch 3.
4 and signals from the idle switch 35 of the main throttle valve 18 are taken in, and the electronic control unit 30 controls the electric servomotor 26 based on these input signals to control the opening of the sub-throttle valve 20. It is like this.

The electronic control unit 30 is, for example, a microcomputer operated by a battery power source, and in the microcomputer, as shown in FIG. 3, a central processing unit (CPU) 40 and a read-on memory (ROM) 42 are provided.
And a random access memory (RAM) 44, of which the ROM 42 has a main routine,
Programs such as a fuel injection amount control routine and an ignition timing control routine, and various fixed data and constants necessary for these processes are stored. Further, an A / D converter 46 having a multiplexer and I / O devices 48 and 50 having a buffer memory are incorporated in the microcomputer, and these are connected to each other by a common bus 52.

In the A / D converter 46, the air flow meter 16,
The output signal of each sensor such as the water temperature sensor 33 is input to the multiplexer via the buffer, and these data are A / D
Converted and instructed by the CPU 40, the CPU 4 at a predetermined time
0 and output to RAM44. As a result, the latest detection data such as the intake air amount and the water temperature is fetched into the RAM 44, and these data are stored in the predetermined area.
Further, in the I / O device 48, the detection signals of the respective sensors such as the rotation speed sensor 31, the vehicle speed sensor 32, the neutral switch 34, the idle switch 35 of the main throttle valve 18 and the like are input, and these data are predetermined by a command of the CPU 40. The output is made to the CPU 40 and the RAM 44 at the time.

The CPU 40 controls the servo motor 26 for controlling the sub-throttle valve 20 via the I / O device 50 according to a program stored in the ROM 42.

If the accelerator pedal 24 is intentionally kept depressed while the vehicle is currently stopped, the main throttle valve 18 opens and the intake amount of the engine 10 increases, so that the engine speed extremely rises. If this state is continued for a predetermined time, there is no running wind and the engine may overheat, which may lead to engine damage. In order to prevent this, the present invention checks the engine speed at regular intervals to prevent the engine from overheating.
It controls the opening degree of the.

The operation of the engine intake control device according to the embodiment of the present invention will be described below with reference to the flowchart of FIG.

First, in step 101, whether the vehicle speed is 5 km / h or less,
That is, it is determined whether the vehicle is stopped. In step 102, it is determined from the signal from the idle switch 35 of the main throttle valve 18 whether the main throttle valve 18 is open. In step 103,
It is determined whether the neutral switch 34 is on. This is the case for an A / T car. In the case of an M / T car, the neutral switch is changed to determine whether the clutch switch is on. That is, in step 103, it is determined whether or not the engine is idling.

In step 104, it is determined whether or not the engine cooling water temperature is 70 ° C. or higher, and then it is determined in step 105 whether or not the engine speed NE of 5000 rpm or higher has passed for 5 seconds or longer.

If all of steps 101 to 105 are affirmative, step
Proceeding to 106, the sub-throttle valve 20 is controlled to the closing side at a speed of 1 ° / 0.5 sec so that the engine speed NE becomes 1500 rpm to prevent engine overheating.

On the other hand, if any of the conditions in steps 101 to 105 is not satisfied, the process proceeds to step 107 and the sub throttle valve 2
0 is controlled so as to be in a fully opened state. That is, in this case, there is almost no possibility of engine overheating, and if the sub-throttle valve 20 is controlled to the closing side, a problem may occur.

Next, a second embodiment will be described with reference to FIG.
First, in step 120, it is determined whether the vehicle speed is less than 10 km / h. In step 121, it is determined whether the main throttle valve 18 is open. Step 122
At, it is determined whether the neutral switch is ON. If all of steps 120 to 122 are affirmative, step
Continue to 123. On the other hand, if even one of steps 120 to 122 is determined to be negative, the process proceeds to step 124, and the sub-throttle valve 20 is controlled to the open side at the speed of 3 ° / 0.5 sec to the fully open position.

In step 123, it is determined whether or not the engine speed NE of 6000 rpm or more has passed for 10 seconds or more. In the case of affirmative determination, the routine proceeds to step 125, where the engine speed NE is 1500r.
Set the sub-throttle valve 20 to 1 ° / 0.5sec so that it becomes pm
Control to the close side at the speed of to prevent engine overheating.

When a negative determination is made in step 123, the routine proceeds to step 126, where it is determined whether the engine cooling water temperature is 110 ° C. or higher.
In step 127, it is determined whether the engine speed NE is 3000 rpm or more. If the determinations at steps 126 and 127 are affirmative, the routine proceeds to step 125, where the sub-throttle valve 20 is controlled to the closing side to prevent overheating of the engine.
Thereby, for example, it is possible to prevent overheating due to the engine speed NE that is slightly lower than the engine speed NE in the racing state and continues for a long time.

If either step 126 or 127 is negatively determined, the routine proceeds to step 124, where the sub throttle valve 20 is fully opened at a predetermined speed. That is, in this case, there is no possibility that the engine will overheat, and it is possible to avoid the trouble that occurs when the sub-throttle valve 20 is controlled to the closing side.

[Advantage of the Invention] Since the engine intake control device of the present invention is configured as described above in detail, it is possible to effectively prevent overheating of the engine while the vehicle is stopped. Further, since the linkless throttle valve is controlled to the closing side to reduce the engine speed, neither shock due to engine hunting nor deterioration of fuel economy will occur.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of an intake control device for an engine of the present invention, FIG. 2 is a schematic overall configuration diagram of an embodiment of the present invention, and FIG. 3 is a block diagram showing an example in which an electronic control device is configured by a microcomputer. FIG. 4 is a flow chart showing the operation of the first embodiment of the present invention, and FIG. 5 is a flow chart showing the operation of the second embodiment of the present invention. 12 ... Intake passage, 14 ... Air cleaner, 16 ... Air flow meter, 18 ... Main throttle valve, 20 ... Sub throttle valve, 22 ... Link, 24 ... Accelerator pedal, 26 ... Electric servo motor, 30 ... Electronic control unit.

Claims (1)

[Scope of utility model registration request] 1. An intake speed control device for a vehicle-mounted engine, comprising a main throttle valve that interlocks with an accelerator pedal in an intake passage and a linkless throttle valve that is controlled to be opened and closed by a control device, in series. At least one of an engine temperature detecting means and a timer, a vehicle stop state determining means for determining whether or not the vehicle is stopped, and an engine idle rotation for detecting whether or not the transmission of the engine output to the vehicle drive wheels is cut off. In the state detection means and the vehicle stopped and the engine idling state, the state where the engine speed is equal to or higher than a predetermined value has passed a predetermined time, or the engine speed is equal to or higher than a predetermined value and the engine temperature is equal to or higher than a predetermined value. A means for detecting a racing state, and a linkless throttle valve when the racing state is detected. Engine intake control apparatus characterized in that a control means for controlling the closing side gradually a.