JPS623139A - Throttle opening controller for starting - Google Patents

Abstract

PURPOSE:To improve the starting performance under high and low temperature by providing means for setting a target throttle opening at start with correspondence to the engine temperature and controlling the throttle valve upto said opening under the operating area prior to complete combustion. CONSTITUTION:In a system where the throttle valve 2 of carburetor (f) is feedback controlled through valve opening regulating mechanism 5 with correspondence to the difference between the engine rotation to be detected through rotation detecting means under idle rotation area and the target rotation, means A for setting the target throttle opening at start with correspondence to the temperature detected through temperature detecting means 19 is provided. Under the operating area prior to complete combustion of engine, the valve opening regulating mechanism 5 is functioned through closed-position control means B thus to control the closed-position of throttle valve 2 to said target opening. Consequently, the starting performance under high temperature can be improved without sacrifice of starting performance under low temperature.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a throttle opening degree control device for starting, which is applied to an engine of an automobile or the like.

[Prior Art] Modern automobiles are equipped with various devices for improving fuel economy, and many of them are equipped with an idle speed control device as one of them.

Therefore, this type of idle speed control device locks the rotation speed detecting means for detecting the engine speed and the throttle valve, which self-returns in the closing direction, to set the closing position of the throttle valve to the fI4 node. The valve opening adjustment mechanism and the valve opening adjustment mechanism are controlled and controlled in the operating range that is considered idling.13w! Feedback control means is provided for controlling the pulp opening adjustment w1 mechanism so that the engine rotation speed detected by the rotation speed detection means converges to the target rotation speed. Then, the target rotation speed is updated according to the engine cooling water temperature, so that the idle rotation speed can be stably maintained at the lowest possible value, for example, around 800 rpm, within a range that does not cause engine stall. It has become.

[Problems to be Solved by the Invention] However, in the conventional system, when starting an engine in which rotational speed feedback control cannot be performed, the valve opening adjustment mechanism is held at a constant position and the throttle valve is adjusted to the initial position for starting. It is fixed at the opening. However, since this initial opening for starting is determined based on a cold time, when restarting when the engine temperature has reached a high temperature,
This may cause an inconvenience in that the opening degree of the throttle valve is insufficient and the air-fuel mixture supplied to the engine tends to be rich. In other words, during a so-called dead soak, when the engine is stopped and left unattended after driving, the high temperature may cause the gasoline in the float chamber to evaporate and fill the carburetor, causing the mixture to become overrich and impair starting performance. The problem is that it gets worse.

In addition, as a prior art for preventing such deterioration of startability at high temperatures, as shown in Japanese Patent Application Laid-Open No. 52-107435, a branch passage is provided in the air bleed passage of the carburetor.
Some devices open and close this branch passage using a temperature-sensitive valve. However, in this case, when the ambient temperature is high, the degree of opening of the temperature-sensitive valve increases, and the amount of air introduced into the air bleed passage through the branch passage increases, so that the above-mentioned disadvantage cannot be solved. However, the temperature-sensitive valve is always activated regardless of whether the engine is started or after a complete explosion. That is, in such a device, when the temperature is high, auxiliary air leaks into the air bleed passage from the branch passage even after the engine has completely exploded. Therefore, unless the control range of the air control valve, which opens and closes the air bleed passage based on the feedback signal from the 02 sensor, is set very wide, there will be an operating range where the air-fuel ratio cannot be controlled to an appropriate value. This tends to lead to problems such as deterioration of emissions and fuel economy, and impairing drivability.

An object of the present invention is to reasonably and effectively improve engine startability at high temperatures without expanding the control range of the air bleed control valve.

[Means for Solving the Problems] In order to achieve the above object, the present invention includes a temperature detection means (19) for detecting engine temperature, and a temperature detection means (19) for detecting the engine temperature.
8) a target throttle opening setting means (A) for setting a target throttle opening for starting according to the detected value; and a valve opening adjustment mechanism (5) for operating the valve opening adjustment mechanism (5) in an operating range before complete engine explosion. closing position control means (B) for controlling the closing position of the throttle valve (2) to the target throttle opening degree;
) [Function 1 According to such a configuration, in the operating range before the engine complete explosion, the target throttle opening setting means (A) adjusts the engine temperature according to the engine temperature. A target throttle opening for starting is set, and the valve opening adjustment mechanism (5) receives a command from the closing position control means (B) to shift the closing position of the throttle valve (2) to the target throttle opening. hold it. Therefore, if the setting conditions of the target throttle opening setting means (A) are determined in advance through experiments or the like, the closing position of the throttle valve (2) before starting can be controlled to an appropriate position corresponding to the engine temperature. This makes it possible to improve startability at high temperatures without impairing startability at cold temperatures.

[Embodiment J] Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 2 to 4.

In the figure, 1 is a carburetor of an automobile engine, 2 is a throttle valve, 3 is a throttle lever that rotates together with the throttle valve 2, and 4 is a spring that biases the throttle valve 2 in the closing direction. A valve opening adjustment mechanism 5 locks the throttle lever 3 and adjusts the throttle valve 2 to a closed position.

The help opening adjustment me mechanism 5 includes a feed screw portion 8 provided on the output shaft 7 of the DC motor 6, and a cap nut-shaped actuator 9 screwed into the feed screw portion 8. By operating the actuator 9, the actuator 9, whose rotation is prohibited by a guide rail (not shown), can be screwed back and forth in the axial direction.

Further, 11 is a microcomputer system for controlling the valve opening adjustment mechanism 5, and also plays the role of target throttle opening setting means A and closing position control means B according to the present invention. This microcomputer system 11 includes a central processing unit 12, a memory 13, and an interface 14, 15. The interface 14 at the input end receives a signal a from the idle switch 16, a signal from the rotational speed detection means 17, a signal C from the transmission state detection means 18, a signal d from the temperature detection means 19, and a signal from the throttle opening sensor 21. The signal e from the air conditioner switch 22, the signal f from the air conditioner switch 22, etc. are respectively input, and the output side interface 15
A drive signal g is output from the valve opening g4 to the mechanism 5. The idle switch 16 is for detecting whether or not the throttle valve 2 has returned to the closed position, and is only activated when the throttle lever 3 is locked to the actuation P9 of the valve opening adjustment mechanism 5. The 0 rotation speed detecting means 17, which is set to turn on (vI), is for detecting the engine rotation speed, and utilizes an ignition valve or the like. The transmission state detection means 18 is for detecting whether or not the transmission state between the engine and the driving wheels is disconnected, and corresponds to a clutch switch, a neutral switch, and the like. The temperature detection means 19 is for detecting the engine temperature, and includes, for example, a thermistor that converts the engine cooling water temperature into an analog electrical signal, and an A/R that converts the output of this thermistor (not shown) into a digital electrical signal. D converter (
(not shown). The throttle opening sensor 21 includes a potentiometer (not shown) that converts the opening of the throttle valve 2 into an analog electrical signal, and a potentiometer A that converts the output of this potentiometer into a digital electrical signal.
/D converter (not shown). The air conditioner switch 22 is an ON/OFF switch for starting or stopping the air conditioner.
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However, at 17, the microcomputer system 11 is programmed to operate according to the procedure schematically shown in FIG.

First, when the ignition switch (not shown) is turned ON, first, in step 51, the engine temperature detected by the temperature detection means 19 is input, and the target throttle opening degree TAGET for starting is set according to the engine temperature. . In other words, the target throttle opening TAuE↑ is the basic target throttle opening TAGETI for starting and the learned value TAI.
It is the sum with DG. The basic target throttle opening value AGET1 for starting is a water temperature map value as shown in FIG. 4, and is set to show a larger value as the engine temperature increases. The learned value TAIDC is a value obtained by learning the throttle opening when idle rotation speed control is executed to set the target rotation speed to, for example, 800 rpm in a completely warmed-up state and the control is stabilized, and is stored in the backup memory. Then, in step 52, the valve opening adjusting mechanism 5 is driven to shift the closing position of the thrower I/le valve 2 to the target throttle opening TAGET.

Thereafter, in step 2 53, it is determined whether the engine rotation fiNE detected by the rotation speed detection means 17 exceeds a predetermined stop state determination rotation speed a, and if it does not exceed the predetermined stop state determination rotation speed a, The helving opening degree yJ4W1m structure 5 is maintained as it is and the determination is made again. On the other hand, if the rotation speed exceeds the determination rotation speed a, the process proceeds to step 54.
After a certain period of time has elapsed, the engine speed ME is read and the process proceeds to step 55. In step 55, 'the engine speed ME exceeds the start judgment speed ↑STR (changes to the optimum value according to the engine temperature). If the valve opening adjustment mechanism 5 is held at the same position and the process returns to step 53, if the valve opening adjustment mechanism 5 is not exceeded, the process proceeds to step 56, where a certain period of time has elapsed. Read the subsequent engine speed ME and proceed to step 57.
In step 57, it is checked whether the engine speed ME has fallen to the set speed b (for example, 200 rpm). If the number of revolutions has fallen below the set number, the process returns to step 53 and the judgment is made again, but if the number of revolutions has not fallen below the set number, it is determined that the complete explosion of the engine has been completed. In step 58, it is determined whether the conditions for executing low rotation speed control, which will be described later, are satisfied. If one condition is satisfied, the process proceeds to step 71 to control the low rotation speed. If the number control is executed and one condition is not satisfied, the process proceeds to step 59.In step 59, it is determined whether the conditions for executing idle rotation speed control, which will be described later, are satisfied, and if the conditions are satisfied. If the condition is met, the process proceeds to step 61 to execute idle rotation speed control, and if one condition is not satisfied, the process proceeds to step 60.
It is determined whether the conditions for executing the TASii control (hereinafter simply referred to as "TAsii control") are met, and if the conditions are met, the process proceeds to step 91 to execute the TAS control.

Here, the execution condition for low rotation speed control is "a certain amount of time has elapsed since the engine completely exploded."

``It means that the conditions 1 in which the engine rotation speed is 45 Orpm or less are both satisfied, and the low rotation speed control is performed at regular intervals until the engine rotation speed becomes t5orp or more. A pulse voltage is applied to the mechanism 5 to move the closed position of the throttle valve 2 in the open direction.

In addition, the conditions for executing idle rotation speed control are as follows: [The idle switch 16 remains in the ON state for 5 seconds or more.]
, "Vehicle speed is less than 2.8km/by", "Transmission is disconnected", "More than 3 seconds have passed since the air conditioner was turned off or the fuel cut valve was turned off" If all of these conditions are met, idle rotation speed control is executed. Idle rotation speed control is detected by the 1 rotation speed detection means 17 'i! Compare the current engine rotation speed HIE with the target rotation speed set according to the operating condition, and if the difference is greater than the allowable value, adjust the valve opening adjustment Iia mechanism 5 to reduce the difference. Activate. That is, the comparison operation is performed, for example, every second, and each time the comparison result is obtained, a pulse voltage is applied to the DC motor 6 of the valve relationship adjustment mechanism 5 to move the closed position of the slot valve 2. .

Furthermore, the execution conditions for performing TAS control include ``not in idle speed control'', ``not in low speed control'', and ``target throttle opening TACE due to air conditioner ON/OFF switching or fuel cut state switching.
TAS8 control is executed when all of these conditions are met. T
AS control is a target throttle opening TA that is changed in response to changes in operating conditions such as turning the air conditioner on and off.
GET and the memory throttle opening NTA corresponding to the operating position of the valve opening adjustment mechanism 5 are compared, and if the difference is greater than the allowable value, the valve opening adjustment mechanism 5 is adjusted in a direction to reduce the difference. Activate. Then, when the difference becomes less than or equal to the allowable value, the process is stopped. The memory throttle opening NTA is stored in the memory 13 of the microcomputer system 11, and is successively updated to correspond to the valve opening: the operating position of the A-cylinder mechanism 5. That is, when the idle switch 16 is ON, the same value as the actual throttle opening VTA detected by the throttle opening sensor 21 is set in the memory throttle opening MTA. When the valve opening 11-section mechanism 5 operates with the idle switch 16 in the OFF state, each time a driving pulse voltage is applied to the valve opening: sm mechanism 5, a constant angle value (valve opening adjustment mechanism The memory throttle opening degree MTA is updated by a value corresponding to a change in the throttle valve 2 that is expected to change when the throttle valve 5 is driven by one pulse.

Then, when the difference between the target throttle opening TACET and the memory throttle opening NTA falls within a tolerance value, T
When the AS control is completed, this memory throttle opening degree NTA is updated to A1, which is the same as the target throttle opening degree TACET. Target throttle opening degree TAG after complete explosion
ET is the basic target throttle opening TAC after complete detonation.
This is the sum of ETI and the above-mentioned learned value TAIIIG. Then, the basic target throttle opening degree TACET after completion of complete explosion.
I contains the water temperature map value TAPI (zero after warming up) and the idle up value TAAC for the air conditioner (when the air conditioner is turned off).
time is zero),""idle up value TADP for fuel cut (in principle zero when fuel cut is canceled)" or "idle up value TAH for high temperature.
T (zero except at abnormally high temperatures)" internal fluid is also selectively set to a large value.

If the configuration is like this, first, when the ignition switch is turned on, the basic target throttle opening TAGETI corresponding to the engine cooling water temperature is read out from the map, and this value is stored in the backup memory. The learned value is added to set the target throttle opening GET. However, this I mark throttle opening TACE
T is set to a low value when the engine cooling water temperature is low, and is set to a high value when the engine cooling water temperature is high. Therefore, at high temperatures when fuel vapor is significantly generated, the closed position of the throttle valve 2 is shifted to the open side compared to when it is cold, and the amount of intake air increases, causing the mixture to become overrich and starting the engine. The inconvenience of sexual deterioration can be resolved. Moreover, this control changes the closing position of the throttle valve 2 in accordance with the engine temperature at the time of starting, so there is no risk of auxiliary air leaking into the air bleed passage even after starting. ,
There is no need to expand the control range of the air bleed control valve, and implementation is easy.

Note that the temperature detection means is not limited to those in the above embodiments, and may, for example, detect gasoline temperature,
It may also be a device that detects the atmospheric temperature of the vaporizer.

Furthermore, the determination as to whether or not the engine has completely exploded is of course not limited to the one in the above embodiment, but if it is done as described above, it can be done without being confused by temporary fluctuations in the engine speed. A reliable judgment can be made.

Moreover, the control after the engine is started is not limited to the one described above, and various modifications can be made without departing from the spirit of the present invention.

[Effects of the Invention] Since the present invention has the above-described configuration, it is possible to easily and effectively improve engine startability at high temperatures without expanding the control range of the air bleed control valve. Therefore, it is possible to provide a throttle opening degree control device for starting.

[Brief explanation of drawings]

FIG. 1 is a configuration explanatory diagram for clearly explaining the present invention. FIG. 2 is a system explanatory diagram showing an embodiment of the present invention, FIG. 3 is a flowchart diagram showing a control procedure in the same embodiment, and FIG. 4 is an explanatory diagram showing control setting conditions. A...Target throttle opening setting means B...Closing position control means 1φ...Carburizer 2 fist-kai throttle valve 5...Valve opening adjustment mechanism 11-・φ Microcomputer system 19...Temperature Detection means

Claims (1)

[Claims] A throttle opening control device for starting an engine configured to operate a valve opening adjustment mechanism to adjust the closing position of a throttle valve, the device comprising: temperature detection means for detecting engine temperature; a target throttle opening setting means for setting a target throttle opening for starting according to the detected value of the temperature detecting means; A throttle opening degree control device for starting, comprising a closing position control means for controlling a closing position to the target throttle opening degree.