JPS6095148A - Opening control device for throttle valve - Google Patents

Abstract

PURPOSE:To make easy the restarting of an engine at a high temperature by controlling the opening of a throttle valve when starting the engine based on the water temperature and intake air temperature. CONSTITUTION:The temperature of a cooling water for an engine 1 is detected by a water temperature detecting device 7, and the temperature of an intake air is detected by an intake air temperature detecting device 5. When the state of starting an engine is detected by a starting state detecting device 8, the opening of a throttle valve is obtained by an opening signal generating device 14 based on the water and intake air temperatures. Based on this throttle valve opening, an open/close device 15 opens/closes the throttle valve to prevent the air-fuel ratio from rising too high when restarting at a high temperature. In this way, the air-fuel ratio can be prevented from getting too high even when percolation occurs, and the engine can be easily restarted.

Description

[Detailed description of the invention] (Technical field) The present invention relates to a throttle valve opening control device for an engine.

(Prior art) As a conventional throttle valve opening control device, for example,
There is one described in Publication No. 108432. This device controls the opening and closing of a throttle valve of a carburetor installed in the intake passage using a negative pressure responsive actuator that operates using negative pressure, and the negative pressure of this actuator is introduced into the engine's intake negative pressure. An electromagnetic on-off valve is interposed in the middle of this negative pressure introduction path, and the electromagnetic on-off valve is energized and controlled by, for example, a cooler switch that detects the operation of the cooler. When the cooler operates at high temperatures, the electromagnetic on-off valve opens and the opening degree of the throttle valve increases due to the negative pressure of the actuator. Therefore, a decrease in engine speed that occurs when the cooler is activated is prevented, and drivability is improved. Note that such a control device is generally a 1.I CD (First
1dle cooler device) (for example, 1" Service Bulletin No. 459" 1932
(Refer to June 7, published by Nissan Motor Co., Ltd.).

However, such conventional throttle valve opening control devices only prevent the idle rotation from decreasing when an electric power load such as a cooler is activated, and do not control the throttle valve opening when restarting at a high temperature. Since the configuration was such that no adjustment means was provided, there was a problem in that it was difficult to restart the engine at high temperatures.

In other words, when restarting at a high temperature, a portion of the fuel (gasoline, etc.) from the fuel pump to the carburetor is vaporized by the heat of the engine when the engine is stopped, and due to the pressure, liquid fuel along with vapor flows from the fuel passage of the carburetor to the intake passage. be swept away.

This phenomenon is generally referred to as percolation (Percolation).
When this percolation occurs, the mixture ratio becomes too rich and restarting becomes difficult.

In order to prevent such problems, for example, a sign requesting the driver to press the accelerator pedal may be pasted in advance, or the driver may press the accelerator pedal based on his/her experience, increasing the opening of the throttle valve to increase the mixing speed. This is merely an attempt to prevent the ratio from becoming too concentrated.

(Purpose of the Invention) Therefore, the present invention automatically adjusts the opening of the throttle valve based on the cooling water temperature and intake air temperature when restarting at a high temperature, thereby preventing the mixture ratio from becoming too rich in order to prevent percolation. The purpose of this system is to prevent this from occurring, making it easier to restart the engine and improving drivability.

(Structure of the invention) FIG. 1 is an overall configuration diagram for clearly explaining the present invention.

The water temperature detection means 7 detects the temperature of the cooling water of the engine 1,
The intake air temperature detecting means 5 detects the temperature of the intake air, and the starting state detecting means 8 detects the starting state of the engine l. The opening signal generating means 14 outputs a throttle valve opening signal SO based on the outputs of the water temperature detecting means 7 and the intake air temperature detecting means 5 when the engine 1 is in a starting state.

The opening/closing means 15 opens and closes the throttle valve based on the throttle valve opening degree signal SO to prevent the mixture ratio from becoming excessively rich when restarting at a high temperature.

(Example) Hereinafter, the present invention will be explained based on the drawings.

FIG. 2.3 is a diagram showing an embodiment of the present invention, which is applicable to an engine with a dual carburetor specification.

In FIG. 2, l is an engine, and an air-fuel mixture mixed in a carburetor 4 is supplied to the engine l from an air cleaner 2 through an intake passage 3. The temperature TA of the intake air is detected by the intake air temperature sensor (intake air temperature detection means) 5 installed in the air cleaner 2, and the temperature TW of the cooling water flowing through the water jacket 6 of the engine 1 is detected by the water temperature sensor (water temperature detection means) 7. Detected. Further, the starting state of the engine 1 is detected by a starter switch 8, and the stark switch 8 outputs a start signal ST when the ignition switch is rotated at the STΔRi' grain position when starting the engine. And the primary side throttle valve 9 of the carburetor 4
is a negative pressure responsive actuator 11 via a lever 10.
(hereinafter simply referred to as an actuator), the throttle valve 9 is opened and closed by the actuator 11. The actuator +1 has an internal negative pressure chamber and an atmospheric chamber partitioned by a diaphragm, and the rod 12 is connected to this diaphragm. The suction negative pressure downstream of the throttle valve 9 is introduced into the negative pressure chamber via a duty-controlled electromagnetic on-off valve 13, and the actuator 11 responds as the negative pressure increases as the negative pressure is introduced into the negative pressure chamber.

In other words, the longer the time ratio that the electromagnetic on-off valve 13 is open (the larger the duty value), the wider the throttle valve 9 is opened. Note that the suction negative pressure introduced from the downstream side of the throttle valve 9 is adjusted to a constant pressure in front of the electromagnetic on-off valve 13 by a constant pressure valve (not shown) or the like. The start signal S and the signals TV and TA from the water temperature sensor 7 and intake air temperature sensor 5 are input manually to the microcomputer I4 as an opening signal generating means, and the microcomputer 14 inputs these signals ST, sw, sA.
Based on this, the opening time of the electromagnetic on-off valve 13 is duty-controlled and the opening degree of the ζ throttle valve 9 is controlled. The above lever 10, actuator 11, rod 12 and electromagnetic on-off valve 1
Reference numeral 3 constitutes an opening/closing means 15 for opening and closing the throttle valve 9 based on a signal from the microphone 1:J computer 14 (throttle valve opening signal So to be described later).

The microcomputer 14 mainly includes a CPU (central processing unit) 16, a memory (storage device) 17, and ■10 (
The input/output signal processing device (input/output signal processing device) 18 is thus configured, and each signal from each of the detection means 5, 7, and 8 is input to 1101B. The memory 17 temporarily stores external data from the l1018, and also stores the CPU.
16 and various data are written therein.

Then, the CPU 16 calculates the duty control value of the electromagnetic on-off valve 13 according to the program written in the memory 17, and outputs the throttle valve opening signal SO via l101B.

Next, the control program for the electromagnetic on-off valve 13 written in the memory 17 can be shown in the flowchart of FIG.
P and -P9 in FIG. 3 indicate each step of the flowchart.

When the program starts, the water temperature TV is first read at P, and the intake air temperature TA is read at P2. Next, in P3, it is determined whether or not the engine 1 is in the starting state, and if it is not in the starting state (for example, before starting or during operation), the process returns. On the other hand, when it is in the starting state, the water temperature is T at P4.
Determine whether or not w is 95°C or higher. If w is 95°C, proceed to P. 7 If w≧95°C, proceed to P9 to determine whether the intake air temperature 1'A is 65°C or higher. Discern. Then, if '＾≧65°C, P, the duty value of the electromagnetic on-off valve 13 is set to the high temperature duty value D?
+ as Pl] to the output register. In other words, when the water temperature Tw is 95°C or higher and the intake air temperature TA is 65°C or higher (for example, when restarting in the summer), the duty value of the electromagnetic on-off valve I3 should be adjusted. High temperature duty value 1) is set to H. 1rlj temperature duty value D)l is larger than the room temperature duty value described later (1) H>DL>1. It corresponds to the appropriate throttle valve opening at the time of starting at l'lI temperature and restart temperature. Therefore, even if the opening degree of the throttle valve 9 is larger than at normal temperature and percolation is occurring, the mixture ratio is automatically increased without the need for the driver to press the accelerator pedal or the like. Thickening can be prevented. As a result, the engine can be restarted easily.

On the other hand, when T W < 95°C in P4 above or P
, when TA<65°C, the solenoid on-off valve 1 is set at P.
P as the duty value of 3 is the normal temperature duty value DL,
to move it to the output register. That is, when the water temperature TW is less than 95° C. or the intake air temperature TA is less than 65° C. when the engine is restarted after running, the above duty value is set as the normal temperature duty value DL. This normal temperature duty value DL is smaller than the high temperature duty value DH < (1
) L < DH) −”F? can be started.

In this embodiment, the opening degree of the throttle valve is changed using a negative pressure responsive actuator, but the present invention is not limited to this, and the opening degree of the throttle valve may be changed using, for example, a small motor. In that case, the throttle valve function can be adjusted to an appropriate value even in a state where there is no suction negative pressure, that is, before starting cranking, and the engine can be restarted even more smoothly.

In addition, in the present invention, for example, if a rotation speed detection means for detecting the rotation speed of the cone sink is provided, and the throttle valve opening is feedback-controlled so that the rotation speed at idle is always maintained at a predetermined rotation speed from low temperature to high temperature, Rotation becomes stable and drivability can be further improved.

(Effects) According to the present invention, it is possible to automatically adjust the opening of the throttle valve to a value of 1-1 when starting at 1rG temperature, and to maintain the mixing ratio regardless of the occurrence of percolation. Overconcentration can be prevented. As a result, the engine can be restarted easily and drivability can be improved.

[Brief explanation of drawings]

Fig. 1 is an overall configuration diagram of the present invention, Figs. 2 and 3 are diagrams showing an embodiment of the present invention, Fig. 2 is a schematic configuration diagram thereof, and Fig. 3 is a diagram showing an embodiment of the present invention.
The figure shows a flowchip of the program that controls the opening/closing means. 1---1-Engine, 5--1-Intake air temperature detection means, ? ----Water temperature detection means, 8----Start state detection means, 14----Opening degree signal generation means, 15--Opening/closing means. Patent Applicant Nissan Motor Co., Ltd. Representative Patent Attorney Agagun Part

Claims (1)

[Claims] water temperature detection means for detecting the temperature of cooling water; intake air temperature detection means for detecting the temperature of intake air; starting state detection means for detecting the starting state of the engine; opening signal generation means for generating a throttle valve opening signal based on the output of the temperature detection means;
A throttle valve opening control device comprising: opening/closing means for opening and closing the throttle valve based on a throttle valve opening signal.