JPS6321815B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fast idle air control device that increases the idle rotational speed of a supercharged internal combustion engine when auxiliary equipment (air conditioner, cooler, etc.) is activated.

When using auxiliary equipment such as a cooler while the engine is running at idle, the output is taken up to operate the auxiliary equipment, leaving no room for idle speed, so it is necessary to increase the amount of intake air and fuel to raise the idling speed. For this purpose, fast idle air control devices have been proposed for supercharged internal combustion engines that have a device that increases the amount of fuel injected according to the amount of intake air, and an example of this is shown in Figures 1 and 2.
53-52993). In Figure 1, engine 1
A compressor 4 of a supercharger 3 and a throttle valve 5 downstream thereof are interposed in the intake passage 2 of the engine 1, and a turbine 9 of the supercharger 3 provided in an exhaust passage 6 of the engine 1 is rotated by the exhaust gas. As a result, the compressor 4 is rotated integrally with the compressor 4 and supplies pressurized air to the engine. Fuel is injected into the pressurized air from a fuel injection valve 10 provided in the intake passage 2 in an amount corresponding to the amount of intake air measured by an air flow meter 22. The exhaust bypass control valve 7 senses that the internal pressure (supercharging pressure) of the intake passage 2 downstream of the compressor 4 has exceeded a predetermined value, and controls the opening of the bypass exhaust passage 8 that bypasses the turbine 9. Part of the exhaust gas is discarded to prevent excessive boost pressure.

The intake passage 2 is provided with a bypass intake passage 11 that bypasses the throttle valve 5 and guides intake air.
A fast idle air control valve 12 is installed at 1. Its specific configuration is shown in FIG.
1a and a second passage 11b that communicates with the intake passage 2 on the downstream side of the throttle valve 5 open to different wall surfaces of the valve chamber 13 of the fast idle air control valve 12 and communicate with each other, thereby forming the bypass intake passage 11. configured. The valve body 14 of the fast idle air control valve 12 is formed to open and close the opening M of the second passage 11b, and is connected to a diaphragm 15 forming one side wall of the valve chamber 13. The other side of the valve chamber 13 of the diaphragm 15 forms a negative pressure working chamber 16, and the valve body 14 closes the opening M via the diaphragm 15 by the elastic force of a spring 17 inserted therein. is energized by The negative pressure working chamber 1
6, the negative pressure of the negative pressure source is applied directly to the suction negative pressure on the downstream side of the throttle valve 5, or indirectly via the vacuum tank 19 as shown by the phantom line, or via the negative pressure passage 18. will be introduced. A solenoid valve 20 is interposed in the negative pressure passage 18, and opens when an auxiliary equipment switch 21 that is linked to the operation of auxiliary equipment (not shown) such as a cooler or heater is turned on, and shuts off and operates under negative pressure when the auxiliary equipment switch 21 is turned on. The configuration is such that the negative pressure in the chamber 16 is released to the atmosphere.

Therefore, when the engine is idling and the supercharger is not operating, the solenoid valve 20 is closed and the atmosphere is introduced into the negative pressure operating chamber 16 of the fast idle air control valve 12 when the auxiliary equipment switch 21 is turned off and the auxiliary equipment is not operating. , the spring force of the spring 17 moves the valve body 14 via the diaphragm 15 to the opening M of the second passage 11b.
Since there is no air flow that bypasses the throttle valve 5, the intake air for a predetermined idle rotation flows only through the gap around the outer circumference of the throttle valve 5, and a corresponding amount of fuel flows through the air flow (not shown). meter 2
2. The fuel is injected and supplied from the fuel injection valve 10 under the control of a computer that calculates other signals.

On the other hand, when the auxiliary equipment switch 21 is turned on and the auxiliary equipment operates, the engine load increases and the shaft torque becomes insufficient. At this time, the solenoid valve 20 opens to open the negative pressure passage 18, and the suction negative pressure downstream of the throttle valve 5 is introduced into the negative pressure operating chamber 16 of the fast idle air control valve 12, and the diaphragm 15 is activated by the elastic force of the spring 17. , and moves the valve body 14 away from the opening M to connect the first passage 11a and the second passage 11b,
The bypass air passage 11 is opened to increase the intake air amount of the engine. This increased intake air amount is sensed by the air flow meter 22, and the amount of fuel injected and supplied from the fuel injection valve 10 is increased accordingly, thereby increasing the output of the engine and increasing the idle speed.

In addition, in a region other than idle rotation, the pressure on the downstream side of the throttle valve also increases due to the operation of the supercharger, so the negative pressure in the negative pressure operating chamber 16 of the fast idle air control valve 12 decreases or becomes positive pressure. The spring force of the spring 17 causes the valve body 14 to move into the second passage 11.
The opening M of b is closed to block the bypass intake passage 11. However, at this time, the intake air amount is detected by the air flow meter 22 installed in the intake passage 2,
Since the fuel amount corresponding to this is calculated by a computer (not shown) and the output signal is sent to the fuel injection valve 10, the increase in the required engine output due to the operation of the auxiliary equipment is based on the operation of the throttle valve 5. , the engine output can be increased by increasing the amount of intake air.

However, it has been found that this conventional device causes problems in the actual operation of the fast idle air control valve. That is, in this case, even when the valve body 14 closes the opening M of the second passage 11b, the first passage 11a is open to the valve chamber 13, so the engine rotates at high speed when the supercharger is operating. In this region, the supercharging pressure upstream of the throttle valve acts on the diaphragm 15, and there is a risk that the valve body 14 will open against the spring force of the spring 17. In other words, when the pressure inside the intake passage on the upstream side of the throttle valve is positive pressure and the pressure inside the intake passage on the downstream side of the throttle valve is negative pressure, when the opening M opens, the negative pressure is introduced into the valve chamber 13. This results in a hunting phenomenon in which the pressure is lowered and the elastic force of the spring 17 overcomes, causing the valve to close again. Further, when the pressure in the intake passage on the upstream side of the throttle valve is positive pressure and the pressure in the intake passage on the downstream side of the throttle valve is positive pressure, the pressure acting on the diaphragm in the valve chamber 13 overcomes the spring force of the spring 17 to open the valve. The condition will be maintained and the bypass intake passage 11 will always be open.

The present invention has been made in order to eliminate the inconveniences of such conventional devices, and provides a fast idle air control device that can reliably maintain the blocked state regardless of an increase in boost pressure when the bypass intake passage is blocked. It is.

The main part of the embodiment of the present invention will be explained below based on FIG. FIG. 3 shows an example in which the present invention is applied to the bypass air control valve shown in FIG. 1, and the same parts as in the prior art example are given the same reference numerals to simplify the explanation. A first passage 31 communicating with the intake passage 2 on the upstream side of the throttle valve 5 and a second passage 32 communicating with the intake passage 2 on the downstream side of the throttle valve 5 are provided in the main body 33A of the fast idle air control valve 33. Valve chamber 34 formed
The second passage 32 has an opening on the same inner wall surface (the openings are designated as A and B), and the amount of intake air is measured to prevent the idle rotation speed from decreasing when the auxiliary equipment is operating. An orifice 35 is interposed. And the negative pressure working chamber 16 of the diaphragm 15
A valve body 3 made of a lightweight solid material such as aluminum is caulked and fixed together with an inner plate 37 disposed on the side.
A rubber sheet 36a is attached by baking to the end face of the valve body 36, and the valve body 36 is connected to the openings A and B through the rubber sheet 36a.
The openings A and B are configured to be able to be closed at the same time. The inner plate 37 comes into contact with the wall surface of the negative pressure working chamber 16 during the valve opening operation to regulate the maximum lift when opening the valve body. At this time, the valve body 36 is caused to reciprocate and slide against the circumferential side wall of the valve chamber 34 to prevent the valve body 36 from tilting during the lift stroke, thereby facilitating simultaneous opening and closing of the openings A and B. In addition, 38 connects the main body 33A to the intake passage 2.
These are screws that are fixed to the wall.

According to the above configuration, when the engine is idling and the supercharger 3 is not performing supercharging operation, and the auxiliary equipment is operating, the suction negative pressure downstream of the throttle valve 5 increases, and this increases in the negative pressure operating chamber 16. is introduced through the diaphragm 15 to lift the valve body 36 against the spring force of the spring 17, opening the openings A and B of the first and second passages 31 and 32 simultaneously. Therefore, the idle intake air amount is increased by the amount measured by the opening of the bypass intake passage 11 and the orifice 35, and this compensates for the lack of output due to the operation of the auxiliary equipment in cooperation with a device that increases the injected fuel according to the increase in the intake air amount. , increase the idle speed. After the valve starts to open, pressure from the first passage 31 is applied to the diaphragm 15 through the valve chamber 34, but it is not strong enough to affect the valve operation.

When the auxiliary equipment is not in operation, the negative pressure passage 18 is shut off, thereby cutting off the suction negative pressure into the negative pressure working chamber 16. Alternatively, when the engine is not idling, the supercharging pressure increases due to the operation of the supercharger 3, and the pressure within the intake passage 2 downstream of the throttle valve 5 increases accordingly. That is, during idle rotation and other than when the auxiliary equipment is operating, the pressure in the negative pressure working chamber 16 increases and the spring force of the spring 17 causes the valve body 3 to
6 is seated via the rubber seal 36a and closes the two passage openings A and B at the same time. Therefore, once the valve is closed, the areas of the openings A and B are sufficiently small, so even if the boost pressure on the upstream side of the throttle valve 5 increases and the pressure on the downstream side of the throttle valve 5 becomes positive, the diaphragm 15
Since the structure is such that the boost pressure does not occur on the valve body 3.
The closed state of the valve is reliably maintained without lifting the valve 6. Of course, the same applies even if the pressure on the downstream side of the throttle valve 5 becomes negative pressure. In addition, from the viewpoint of the setting load of the spring 17, since the areas of the openings A and B are smaller than the effective area of the diaphragm 15 when the valve is closed, there is no need to set the spring 17 very large. Can satisfy working pressure requirements.

As described above, according to the present invention, it is possible to provide a fast idle air control valve for a supercharged internal combustion engine that can increase the amount of intake air when the engine is idling and operating auxiliary equipment, and can reliably close the bypass intake passage at other times. I made it. Therefore, it is possible to eliminate the inconvenience of the fast idle air control valve opening when not in use or causing hunting.

[Brief explanation of drawings]

Fig. 1 is a schematic system diagram showing an example of a fast idle air control device for a supercharged internal combustion engine, Fig. 2 is a vertical cross-sectional view of a conventional fast idle air control valve used in the above, and Fig. 3 is a diagram showing an example of a fast idle air control device for a supercharged internal combustion engine. FIG. 2 is a longitudinal sectional view of the fast idle air control valve according to the present invention used in the figures. DESCRIPTION OF SYMBOLS 1... Engine, 2... Intake passage, 3... Supercharger, 4... Compressor, 5... Throttle valve, 6... Exhaust passage, 9... Turbine, 11... Bypass intake passage, 15... Diaphragm, 16... Negative pressure working chamber, 18... Negative pressure passage, 2
0... Solenoid valve, 21... Auxiliary machine switch, 31... First passage, 32... Second passage, 33... Fast idle air control valve, 34... Valve chamber, 36... Valve body.

Claims (1)

[Claims] 1. In a fast idle air control valve that opens and closes a bypass intake passage that bypasses a throttle valve provided in an intake passage downstream of a compressor of a turbocharger and allows intake air to flow, the 1 passage and a second passage of a bypass intake passage communicating with an intake passage on the downstream side of the throttle valve are opened to the valve chamber, and the first and second passages located in the valve chamber are opened to the valve chamber; A valve element that can be closed simultaneously by a spring force is connected to a diaphragm forming one side of the valve chamber, and when the auxiliary equipment is activated, negative pressure is applied to a negative pressure operating chamber containing a spring on the opposite side of the diaphragm from the valve chamber. A fast idle air control device for a supercharged internal combustion engine, which opens and closes a bypass intake passage by introducing negative pressure from a source.