JPH06272576A - Throttle valve control device for internal combustion engine - Google Patents

Abstract

PURPOSE:To enable ISC(idle speed control) by preventing an engine stall at fast idle time. CONSTITUTION:The first throttle valve 10 and the second throttle valve 20 are arranged in series in an intake air passage 2 of an internal combustion engine, and the first throttle valve 10 is opened and closed electrically by a motor or the like, and the second throttle valve 20 if opened and closed mechanically by an accelerator pedal 26. A full closure position adjusting means 30 is arranged to adjust a full closure position of the second throttle valve 20 according to a warming-up condition of the internal combustion engine.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a throttle valve control device for an internal combustion engine.

[0002]

2. Description of the Related Art Throttle valve control devices for internal combustion engines include
Conventionally, the first is provided in the intake passage of an internal combustion engine (also called an engine).
The throttle valve and the second throttle valve are arranged in series,
There is a two-valve throttle body in which the first throttle valve is electrically opened and closed by a motor and the second throttle valve is mechanically opened and closed by an accelerator pedal.
Such a throttle valve control device is disclosed, for example, in Japanese Patent Publication No.
No. 54993.

[0003]

A two-valve type throttle body type throttle valve control device is one in which the first throttle valve is motor-controlled when the accelerator pedal is depressed and the second throttle valve is opened. . Such a conventional device does not have a function of idle speed control (also referred to as ISC) when the accelerator pedal is not depressed and the second throttle valve is closed. For this reason, in the past, an expensive ISC actuator was required separately from the throttle valve control device in order to adjust the amount of air flowing through the bypass passage of the throttle valve to control the target rotation speed.

As a countermeasure against this, it is conceivable to eliminate the ISC actuator by performing ISC by controlling the motor of the first throttle valve. But I
When performing SC, the fully closed position of the second throttle valve that is operated by accelerator is set to a position corresponding to the upper limit of the idle speed that is allowed after the engine is warmed up.
The idle speed is lower than the idle speed suitable for the first idle (also referred to as FI) before warm-up with a large engine load. Therefore, at the time of FI, the engine stops (so-called engine stall), and the IS
Implementation of C is difficult.

Therefore, the present invention has been made to solve the above-mentioned problems, and an object thereof is to provide a throttle valve control device for an internal combustion engine, which prevents engine stalling at the time of first idle and enables ISC. To provide.

[0006]

According to the present invention for solving the above-mentioned problems, a first throttle valve and a second throttle valve are arranged in series in an intake passage of an internal combustion engine, and the first throttle valve is electrically connected by a motor or the like. In a throttle valve control device for an internal combustion engine in which the second throttle valve is mechanically opened and closed by an accelerator pedal, a fully closed position for adjusting the fully closed position of the second throttle valve according to the warm-up state of the internal combustion engine. Position adjustment means are provided.

[0007]

According to the above means, the fully closed position of the second throttle valve is adjusted by the fully closed position adjusting means in accordance with the warm-up state of the engine, so that engine stall at the time of first idle can be prevented.

[0008]

Embodiments Embodiments 1 and 2 of the present invention will be described in order. [Embodiment 1] A throttle valve control apparatus of Embodiment 1 is shown in a block diagram in FIG. In FIG. 1, a body body 1 arranged in an intake system of an internal combustion engine has a substantially cylindrical shape, and a hollow portion thereof serves as an intake passage 2. Body 1
The two throttle valves for adjusting the intake air amount of the engine by opening and closing the intake passage 2, that is, the first throttle valve 10 of the motor control system and the second throttle valve of the accelerator operation system.
The throttle valve 20 and the throttle valve 20 are arranged in series vertically.
Both ends of the first throttle shaft 11 of the first throttle valve 10 and the second throttle shaft 21 of the second throttle valve 20 are rotatably supported by the body body 1 via bearings or the like.

In the accelerator operation system, a second return spring 22 is fitted and a throttle lever 23 is attached to one end portion (right end portion in the drawing) of the second throttle shaft 21. Both ends of the second return spring 22 are hooked by the hooking pin 5 on the body side and the lever stopper 23a of the throttle lever 23 to urge the second throttle valve 20 in the closing direction. . The lever stopper 23a extends toward the body body 1.

The second throttle lever 23 is, as is well known, an accelerator wire 27 and an accelerator linkage 2.
Accelerator pedal 2 on the floor of the driver's seat of the vehicle via 8
It is connected to 6. The accelerator pedal 26 is always biased in the counter-depressing direction by an accelerator return spring 29. Therefore, the second throttle valve 20
Is rotated to a desired opening degree by depressing the accelerator pedal 26, and when the depression is released, it is closed to the fully closed position by the urging of the second return spring 22.

A diaphragm type throttle opener 30 is installed in the body body 1 near the second throttle lever 23 via a bracket or the like (not shown). The throttle opener 30 includes a diaphragm chamber 33 defined by a diaphragm 32 that connects the rods 31 and a diaphragm spring 34 that urges the diaphragm 32 in the rod protruding direction. The diaphragm chamber 33 is connected to a port B of a vacuum switching valve (called VSV) 36 via a tube 35. The port C of the VSV 36 is open to the atmosphere, and the port A is connected to a negative pressure introducing pipe 38 on the body body 1 side via a tube 37. The negative pressure introducing pipe 38 introduces an intake negative pressure downstream of the second throttle valve 20 in the intake passage 2.

The VSV 36 switches the negative pressure circuit as follows in response to an electric signal from an engine control computer (referred to as ECU) 40. That is, when the VSV 36 is energized, the ports B and A are brought into conduction so that the diaphragm chamber 33
Throttle opener 3 by introducing negative pressure to
The rod 31 of 0 is pulled to the retracted position against the bias of the diaphragm spring 34. When the VSV 36 is not energized, the ports B and C are electrically connected to each other so that the diaphragm chamber 33
Is opened to the atmosphere, the rod 31 is projected to the forward position by the urging of the diaphragm spring 34.

The rod 31 of the throttle opener 30
The lever stopper 23a of the second throttle lever 23 is in contact with the second return spring 22 with the urging force of the second return spring 22. When the accelerator pedal 26 is depressed to open the second throttle valve 20, the lever stopper 23a of the throttle lever 23 separates from the rod 31 of the throttle opener 30. Also, the rod 31
The fully closed position of the second throttle valve 20 in the reverse position is set to an idle opening degree corresponding to the upper limit of the idle speed allowed after the engine is warmed up. Further, the fully closed position of the second throttle valve 20 at the forward position of the rod 31 is set to the first idle idle (FI) opening degree corresponding to the upper limit of the idle speed allowed before warming up.

A second sensor lever 24 is attached to the other end (the left end in the drawing) of the second throttle shaft 21,
A detection lever (not shown) of a second throttle sensor 25 installed on the side surface of the body 1 is engaged with the second lever 24. Second throttle sensor 25
Detects the opening degree of the second throttle valve 20 from the rotation amount of the second throttle shaft 21 and outputs the detection signal to the ECU 40.
To enter.

In the motor control system, the body 1
A control motor 16 composed of a step motor is provided on one side surface (right side surface in the drawing). A drive gear 17 is provided on the output shaft of the control motor 16, and a driven gear 18 that meshes with the drive gear 17 is provided on the first throttle shaft 11. The control motor 16 controls the opening and closing of the first throttle valve 10 based on the electric signal transmitted by the ECU 40. The fully closed position of the first throttle valve 10 is IS
Considering the implementation of C, the opening degree is set to be smaller than the idle opening degree of the second throttle valve 20 after warming up.

At the other end (the left end in the figure) of the first throttle shaft 11, a first return spring 12 is fitted and a first sensor lever 14 is attached. Both ends of the first return spring 12 are the retaining pin 4 on the body side and the retaining piece 14 of the first lever 14.
It is hooked on a and urges the first throttle valve 10 in the fully opening direction. A detection lever (not shown) of a first throttle sensor 15 installed on the side surface of the body 1 is engaged with the first lever 14. First
The throttle sensor 15 detects the opening degree of the first throttle valve 10 from the rotation amount of the first throttle shaft 11 and inputs the detection signal to the ECU 40.

The ECU 40 receives signals from the throttle sensors 15 and 25 and various input signals. As the input signal, for example, engine speed, electric load, power steering, engine water temperature, wheel speed,
Air-conditioners are included. The ECU 40 outputs a control signal to the control motor 16 based on these input signals.
That is, the ECU 40 operates the control motor 16 to suppress the engine output by activating the control motor 16 when it determines that the engine output is excessive based on the input signal at the time of starting and accelerating on a slippery road surface.
(Also called).

The ECU 40 also carries out an idle speed control (ISC) in which the engine output is suppressed by operating the control motor 16 so that the target speed will be in accordance with the state of the engine during idling. Further ECU4
0 determines whether the engine is in FI or idle after warming up from the engine water temperature, etc., and turns off the VSV 36 at FI,
After warming up, the VSV 36 is turned on at the time of idling.

In the above throttle valve control device,
At the time of FI, the fully closed opening degree of the first throttle valve 10 is set to an opening degree lower than the opening degree at which the minimum amount of air to flow at the time of idling control after warm-up is made to flow. On the other hand, VSV36 is ECU40
Since it is turned off, the rod 31 of the throttle opener 30 is in the forward position, and the second throttle valve 20 has an FI opening larger than the idle opening after warming up (see FIG. 1).
reference).

When the warm-up is completed, the VSV 36 makes the ECU 4
Since it is turned on by 0, the rod 31 of the throttle opener 30 is in the retracted position, and the second throttle valve 20 is closed to the idle opening degree after warming up. This prevents deterioration of the idle fuel consumption after warming up.

By the way, before and after warming up the engine, even if the accelerator pedal 26 is depressed to release the second throttle valve 20 from the opened state, the lever stopper 23a of the throttle lever 23 causes the throttle opener 30 to warm the engine. Since the second throttle valve 20 is not closed more than necessary because it is held at the position according to the machine state, the engine does not stop. In this example, the diaphragm type throttle opener 30 including the VSV 36 corresponds to the fully closed position adjusting means in the present invention.

The relationship between the engine water temperature and the throttle valve opening when the engine is idle is shown in the characteristic diagram of FIG. In FIG. 2, the horizontal axis represents the temperature of the engine cooling water, the vertical axis represents the throttle valve opening, the opening of the first throttle valve 10 is shown by the broken line, and the opening of the second throttle valve 20 is shown by the solid line. ing. The opening degree of the second throttle valve 20 is adjusted to be large by turning off the VSV 36 below the set temperature T ° C. and small by turning on the VSV 36 above the set temperature T ° C. Further, the ISC by the first throttle valve 10 is given by controlling the first throttle valve 10 to an arbitrary opening degree according to the engine temperature and the engine load in the hatched portion between the broken line and the solid line.

The processing of the VSV 36 by the ECU 40 is shown in the flow chart of FIG. In this process, it is determined in step S101 whether the engine has been warmed up. Before warming up, the VSV 36 is turned off in step S102, and after warming up, the VSV 36 is turned on in step 103, and the process ends.

According to the throttle valve control device, the engine speed can always be controlled by the first throttle valve 10 during ISC irrespective of whether the engine is warmed up or not, and the expensive ISC actuator conventionally required is no longer necessary. Further, even if the first throttle valve 10 and its control system fail during the warming up of the engine, the second throttle valve 20
By closing, the engine speed will fall to the upper limit, which is allowed at least according to the warm-up state of the engine.
High security can be obtained.

[Second Embodiment] A throttle valve control device according to a second embodiment is shown in a block diagram of FIG. Since this example is a modification of a part of the first embodiment, the modified part will be described in detail, and the parts that are considered to be the same as or equivalent to those in the first embodiment will be denoted by the same reference numerals in the drawings and will be duplicated. The description is omitted. In this example, instead of the throttle opener 30 including the VSV 36 of the first embodiment, a temperature-sensitive wax type throttle opener 50 is adopted as the fully closed position adjusting means. The throttle opener 50 includes a temperature-sensitive wax 52 to which a rod 51 is connected, and a cooling water passage 53 that causes engine cooling water to flow around the wax.

The rod 51 of the throttle opener 50
Is to be axially moved by the temperature-sensitive wax 52 in accordance with the engine water temperature. After the engine is warmed up, the opening that is the upper limit of the engine speed allowed during idling is set to the second value.
The throttle valve 20 is moved to a position where the second throttle valve 20 is provided with an opening which is the upper limit of the engine speed allowed according to the engine water temperature.

When the relationship between the engine water temperature and the throttle valve opening when the engine is idle is shown according to FIG. 2, the characteristic diagram of FIG. 5 is obtained. According to this example, before warming up, the idle opening degree of the second throttle valve 20 decreases in proportion to the engine water temperature gradually increasing from the low temperature to the set temperature T ° C for warming up. According to the throttle opener 50 of the present example, the negative pressure circuit including the VSV 36 in the first embodiment can be eliminated.

In the first and second embodiments, the first throttle valve 10 of the motor control system is connected to the second throttle valve of the accelerator operation system.
Although the second throttle valve 20 is arranged upstream of the throttle valve 20, the second throttle valve 20 may be arranged upstream of the first throttle valve 10.

[0029]

According to the present invention, the engine stall at the time of first idle can be prevented, and the ISC can be performed by the motor control of the first throttle valve. Therefore, the conventional expensive ISC actuator can be eliminated and inexpensive engine control can be realized.

[Brief description of drawings]

FIG. 1 is a configuration diagram illustrating a throttle valve control device according to a first embodiment.

FIG. 2 is a characteristic diagram showing a relationship between engine water temperature and throttle valve opening.

FIG. 3 is a flowchart showing VSV processing by an ECU.

FIG. 4 is a configuration diagram showing a throttle valve control device of a second embodiment.

FIG. 5 is a characteristic diagram showing a relationship between engine water temperature and throttle valve opening.

[Explanation of symbols]

 2 Intake passage 10 First throttle valve 16 Control motor 20 Second throttle valve 26 Accelerator pedal 30 Throttle opener

Claims (1)

[Claims] 1. A first throttle valve and a second throttle valve are arranged in series in an intake passage of an internal combustion engine, the first throttle valve is electrically opened and closed by a motor or the like, and the second throttle valve is mechanically operated by an accelerator pedal. A throttle valve control device for an internal combustion engine, wherein a throttle valve control device for an internal combustion engine is provided with a fully closed position adjusting means for adjusting a fully closed position of the second throttle valve according to a warm-up state of the internal combustion engine. Control device.