JPH09100730A - Idle-up device in vehicular internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a sudden increase in an engine speed at the time of starting from an ambient temperature by switching a negative pressure switching valve to an intaken air negative pressure transmission ON operation at the time of passing a holding time set from the reaching of an engine speed to an explosive combustion continuance zone by the ON switching of a start switch so as to be long in proportion to the temperature of an internal combustion engine. SOLUTION: A control circuit 17 switches a negative pressure switching valve 15 from an intaken air negative pressure transmission ON operation to an intaken air negative pressure transmission OFF condition when a signal from a drive range sensor 18 is inputted and when a start switch 19 is switched ON. After the passage of a proper holding time from the time when the engine speed of an internal combustion engine 1 reaches an explosive combustion continuance zone, by using a signal from a rotation sensor 21 as an input, the negative pressure switching valve 15 is switched from an intaken air negative pressure transmission OFF to an intaken air negative pressure transmission ON. Further, by using a signal from a temperature sensor 20 as an input, a holding time is set to be longer in proportion to the temperature of the internal combustion engine 1. Thus, a sudden increase in an engine speed is prevented at the time of starting from an ambient temperature zone.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for increasing the idle speed of an internal combustion engine equipped with an automatic speed change mechanism mounted on a vehicle when the range of the automatic speed change mechanism is set as a drive.

[0002]

2. Description of the Related Art Generally, in an internal combustion engine having an automatic transmission mechanism, if the range of the automatic transmission mechanism is set to drive in idle operation, engine stall may occur due to load on the internal combustion engine. is there. Therefore, in this type of internal combustion engine, a pressure-operated dashpot, which is related to the intake negative pressure on the downstream side of the throttle valve via a negative pressure transmission passage, is provided for the throttle valve in the carburetor, and the automatic When the range in the speed change mechanism is set to a range other than drive, the intake negative pressure is transmitted to the dashpot to set the throttle valve to the idle position, while when the range in the automatic speed change mechanism is set to the drive, By cutting off the transmission of intake negative pressure to the dashpot and communicating the dashpot with the atmosphere, the throttle valve is operated in the open direction from its idle position to idle up.

[0003]

By the way, the starting of the internal combustion engine is carried out in a state where the range of the automatic transmission is set to neutral or parking. At the time of starting the internal combustion engine, the intake negative pressure is the same as that at the beginning of starting. Although it is small at the time of ranking, it becomes large when the number of revolutions reaches the explosion combustion continuation range, so the throttle valve closes to the idle opening degree from the idle up position at the beginning of the engine as intake negative pressure increases. On the other hand, when the operation of the internal combustion engine is stopped while the internal combustion engine is warm, the fuel vapor accumulates in the intake system.

In this case, if the idle-up device is configured to transmit the intake negative pressure to the dashpot as it is without delay, when starting from a high temperature range where the fuel vapor is accumulated in the intake system, the throttle is started. Since the valve rapidly closes to the idle opening degree, the fuel vapor cannot be rapidly released, and the air-fuel ratio of intake air to the internal combustion engine becomes overrich due to the fuel vapor accumulated in the intake system. Therefore, the rise of the rotation speed is low, and the startability from the high temperature range is deteriorated.

Therefore, in the conventional idle-up device, a delay means such as a throttle for delaying the transmission of the negative pressure to the dashpot is provided in the negative pressure transmission passage to the dashpot, whereby the fuel vapor is added to the intake system. It is configured to improve the startability from a high temperature range where the water is accumulated. However, in order to improve the starting performance from the high temperature range, if a delay means is provided in the negative pressure transmission passage to the dashpot, the throttle system will be used when starting from the normal temperature range where fuel vapor is not accumulated in the intake system. When the valve is closed to the idle position with a delay, an excessive air-fuel mixture is sucked into the internal combustion engine during that time, which causes a phenomenon in which the rotational speed rises sharply and the feeling is deteriorated. Become.

That is, the delay time by the delay means is
If a long time is set in order to improve the starting property from the high temperature range, the feeling at the time of starting from the normal temperature range is deteriorated, and the delay time by the delay means is,
If a short time is set in consideration of improving the feeling when starting from the normal temperature range, there is a problem that the startability from the high temperature range deteriorates.

SUMMARY OF THE INVENTION The present invention is to provide an idle-up device capable of reliably preventing a rapid increase in the number of revolutions at the time of starting from a room temperature range, while ensuring startability from a high temperature range. This is an issue.

[0008]

In order to achieve this technical object, the present invention is directed to "a throttle valve of a carburetor in an internal combustion engine equipped with an automatic speed change mechanism mounted on a vehicle, and an idle position of the throttle valve in the opening direction. It is equipped with a biasing spring and is related to the intake negative pressure downstream of the throttle valve via the negative pressure transmission passage. When the intake negative pressure increases, the idle position of the throttle valve moves in the closing direction against the spring. A pressure-operated dashpot is provided for switching the intake negative pressure transmission to the dashpot to OFF when the shift in the automatic transmission is driven in the negative pressure transmission passage to the dashpot. In the idle-up device provided with a negative pressure switching valve, the start switch of the internal combustion engine, the temperature and the rotation speed of the internal combustion engine are input. When the start switch is turned on, the negative pressure switching valve is switched to the intake negative pressure transmission OFF, and when the start switch is turned on, the internal combustion engine temperature is changed from the time when the rotation speed reaches the explosion combustion continuation range. There is provided a means configured to switch the negative pressure switching valve to the intake negative pressure transmission ON when a holding time set so as to be proportionally long has elapsed. "

[0009]

With the above arrangement, when the internal combustion engine is started, when the start switch is turned on while the shift of the automatic transmission is set to neutral or parking, the negative pressure transmission passage to the dashpot is opened. When the negative pressure switching valve is switched to the intake negative pressure transmission OFF state, the throttle valve is brought into an idle-up state in which the spring in the dashpot opens the idle position.

When the rotation speed of the internal combustion engine reaches the explosive combustion continuation range by turning on the start switch, the negative pressure switching valve is switched to the intake negative pressure transmission ON when the holding time has elapsed from this point. Then, since the intake negative pressure acts on the dashpot, the throttle valve is closed to the idle position by the intake negative pressure. In this case, with the operation of the internal combustion engine stopped,
The amount of fuel vapor accumulated in the intake system increases in proportion to the temperature of the internal combustion engine. Therefore, by setting the holding time so as to be long in proportion to the temperature of the internal combustion engine, the time for closing the throttle valve from the idle-up state to the idle position at the time of starting the internal combustion engine can be set from the normal temperature range. In the case of, it can be automatically shortened, and in the case of starting from a high temperature range, it can be automatically lengthened.

When the shift in the automatic transmission is driven, the negative pressure switching valve is switched to the intake negative pressure transmission OFF state, whereby the throttle valve is idled up by the spring in the dashpot and opened from the idle position. It becomes the state of. Therefore, according to the present invention, it is possible to improve startability from a high temperature range and feel at the time of starting from a normal temperature range under the condition that idle up can be achieved when the shift in the automatic transmission is driven. It has an effect that both improvement and improvement can be achieved at the same time.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to the drawing of FIG. In this figure, reference numeral 1 indicates an internal combustion engine, and reference numeral 2 indicates an intake manifold for the internal combustion engine 1, and the intake manifold 2 is provided with a throttle valve 5 which is opened / closed in conjunction with an accelerator pedal 3. A vaporizer 4 is attached, and an air cleaner 6 is connected to the upstream side of the vaporizer 4.

Reference numeral 7 denotes a pressure-operated dashpot attached to an appropriate portion of the carburetor 4, and in the dashpot 7, the diaphragm 9 forming the pressure chamber 8 thereof has a lever in the throttle valve 5. A rod 11 that abuts against the tip of the throttle valve 5 so as to prevent the throttle valve 5 from rotating in the closing direction is provided, and the throttle valve 5 is attached in the closing direction in the pressure chamber 8. A spring 12 for biasing the throttle valve 5 in the opening direction is provided against a biasing spring (not shown), and the pressure chamber 8 is provided with a negative pressure extraction port 13 provided in the intake manifold 2. In order to introduce the intake negative pressure on the downstream side of the throttle valve 5 into the pressure chamber 8, the negative pressure transmission passage 14
When a large intake negative pressure acts on the pressure chamber 8, the rod 11 is retracted against the spring 12 by the intake negative pressure to move the idle position of the throttle valve 5 in the closing direction. When the intake negative pressure does not act on the pressure chamber 8, the rod 12 is projected by the spring 12 to move the idle position of the throttle valve 5 in the opening direction.

Reference numeral 15 indicates a three-way negative pressure switching valve provided in the middle of the negative pressure transmission passage 14. The negative pressure switching valve 1
Reference numeral 5 denotes an intake negative pressure transmission ON state in which the communication of the atmosphere communication passage 16 to the pressure chamber 8 in the dash pot 7 is cut off and at the same time the negative pressure transmission passage 14 is communicated, and the negative pressure transmission passage 1
The pressure chamber 8 of the dashpot 7 is cut off at the same time as the communication of 4 is cut off.
Negative pressure transmission OF that communicates with the atmosphere communication passage 16
The operation is switched to the F state.

Reference numeral 17 designates a drive range sensor 18 for detecting that the automatic transmission mechanism connected to the internal combustion engine 1 is used as a drive, a start switch 19 for the internal combustion engine 1, and a temperature sensor for the internal combustion engine 1. 20 and a rotation sensor 21 in the internal combustion engine 1 as a signal input from the control circuit for switching the negative pressure switching valve 15 between intake negative pressure transmission ON and intake negative pressure transmission OFF, as described below. Is.

That is, the control circuit 17 receives the signal from the drive range sensor 18,
When the start switch 19 is turned on, the negative pressure switching valve 15 is switched from the intake negative pressure transmission ON to the intake negative pressure transmission O.
Switch to FF. In addition, the rotation speed of the internal combustion engine 1 reaches an explosive combustion continuation region (for example, a rotation speed slightly lower than a normal idle rotation speed, such as 300 to 500 rpm) by using a signal from the rotation sensor 21 as an input. At the time when an appropriate holding time T has elapsed from that time, the negative pressure switching valve 15 is switched from the intake negative pressure transmission OFF to the intake negative pressure transmission ON. Further, by inputting a signal from the temperature sensor 20, the holding time T is, for example, T = 10 seconds when the temperature is 80 to 90 ° C., T = 18 seconds when the temperature is 100 ° C., and T = 18 seconds when the temperature is 110 ° C. The time is set to 20 seconds, which is set to be longer in proportion to the temperature of the internal combustion engine 1.

In this structure, when the internal combustion engine 1 is started, the start switch 19 is operated in a state where the shift in the automatic transmission is neutral or parking.
When turned on, the negative pressure transmission passage 1 to the dashpot 7
The negative pressure switching valve 15 in 4 switches the throttle valve 5 to the dashpot 7 by switching the intake negative pressure transmission to OFF.
The spring 12 can be set to an idle-up state in which it is opened from the idle position.

When the rotation speed of the internal combustion engine 1 reaches the explosive combustion continuation region by turning on the start switch 19, the negative pressure switching valve 15 is reached when the holding time T elapses from this time.
Is switched from the intake negative pressure transmission OFF to the intake negative pressure transmission ON, and the intake negative pressure acts on the pressure chamber 8 in the dashpot 7. Therefore, the throttle valve 5
Is closed to the idle position by the intake negative pressure.

In this case, when the operation of the internal combustion engine 1 is stopped, the fuel vapor accumulated in the intake system is
It increases in proportion to the temperature of the internal combustion engine 1. Therefore, by setting the holding time T so as to be long in proportion to the temperature of the internal combustion engine 1, at the time of starting the internal combustion engine 1, the time for closing the throttle valve 5 from the idle-up state to the idle position is set to room temperature. It can be automatically shortened when starting from a high temperature range and automatically lengthened when starting from a high temperature range.

When the shift in the automatic transmission is driven, the negative pressure switching valve 15 is switched from the intake negative pressure transmission ON to the intake negative pressure transmission OFF, so that the throttle valve 5 moves in the dashpot 7. The spring 12 enters the idle-up state in which it is opened from the idle position.

[Brief description of the drawings]

FIG. 1 is a diagram showing an embodiment of the present invention.

[Explanation of symbols]

 1 Internal Combustion Engine 2 Intake Manifold 4 Vaporizer 5 Throttle Valve 7 Dashpot 8 Pressure Chamber 9 Diaphragm 11 Rod 12 Spring 13 Negative Pressure Extraction Port 14 Negative Pressure Transmission Passage 15 Negative Pressure Changeover Valve 17 Control Circuit 18 Drive Range Sensor 19 Start Switch 20 Temperature sensor 21 Rotation sensor

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Ko Wada 2-1-1 Taoyuan, Ikeda-shi, Osaka Daihatsu Kogyo Co., Ltd.

Claims (1)

[Claims] 1. A throttle valve of a carburetor in an internal combustion engine equipped with an automatic speed change mechanism mounted on a vehicle is provided with a spring for urging an idle position of the throttle valve in an opening direction, and an intake negative pressure downstream of the throttle valve is provided. A pressure-operated dashpot is provided which is configured to move the idle position of the throttle valve in the closing direction against the spring when the intake negative pressure becomes large. When the shift in the automatic transmission is driven during the negative pressure transmission passage of
In an idle-up device provided with a negative pressure switching valve for switching the intake negative pressure transmission to the dashpot OFF, an internal combustion engine start switch, an internal combustion engine temperature and a rotation speed are input and the start switch is turned ON. The negative pressure switching valve is switched to the intake negative pressure transmission OFF,
When the start switch is turned on, the negative pressure is transmitted to the negative pressure switching valve at the time when the holding time set so as to become longer in proportion to the temperature of the internal combustion engine elapses after the rotation speed reaches the explosion combustion continuation region. An idle up device in an internal combustion engine for a vehicle, comprising means configured to be switched on.