JPH0612237Y2 - Supercharging control device for supercharging device - Google Patents

Description

TECHNICAL FIELD The present invention relates to a supercharging control device for a supercharging device of an internal combustion engine used in a vehicle such as an automobile, and more particularly to an internal combustion engine in which exhaust gas recirculation is performed. The present invention relates to a supercharging control device for a supercharging device.

BACKGROUND ART Turbochargers and superchargers are well known as superchargers used in internal combustion engines for automobiles.
This type of supercharging device may cause damage to the internal combustion engine and other related equipment unless the supercharging operation is properly performed in relation to the operating state of the internal combustion engine. Therefore, it has already been proposed to forcibly stop the supercharging action of the supercharging device when the internal combustion engine is abnormal, which is disclosed in JP-A-60-153.
No. 425 publication.

Further, in an internal combustion engine in which exhaust gas recirculation is performed, particularly in a supercharger that is a mechanically driven supercharging device, when supercharging is performed, the intake passage internal pressure becomes higher than the exhaust passage internal pressure. Since the exhaust gas for exhaust gas recirculation does not flow from the exhaust passage to the intake passage, the supercharging action of the supercharger is required for exhaust gas recirculation in the operating range where exhaust gas recirculation is performed. It has already been proposed to forcibly stop it, which is disclosed in Japanese Patent Laid-Open No. 61-58653.

Problem to be solved by the invention If the exhaust gas recirculation control valve is stuck in the open state and the exhaust gas recirculation passage is always open, the excess flow rate will be uncontrolled when supercharging is stopped. The exhaust gas recirculation is performed with the supercharged air flowing through the exhaust gas recirculation passage to the exhaust passage during supercharging. This is the same as supplying a large amount of secondary air to the exhaust passage, and in this case, the internal combustion engine is generally operated at a rich air-fuel ratio in the supercharging working range. As a result, the catalytic action in the catalytic converter becomes abnormally active, and there is a possibility that the durability of the catalytic converter may decrease due to the increase in the catalyst temperature.

In the present invention, even if the supercharging device or the internal combustion engine is normal, if the exhaust gas recirculation device has the above-mentioned malfunction, the supercharging action is forcibly stopped to prevent the occurrence of the secondary failure. It is an object of the present invention to provide a supercharging control device for a supercharging device.

According to the present invention, an object of the present invention is to operate a supercharging device incorporated in an internal combustion engine having an exhaust gas recirculation device and capable of on / off control for selectively supercharging intake air. And a temperature detection means for detecting the temperature at one location of the exhaust gas recirculation device, and the operation of the supercharger when the temperature detection means detects a temperature equal to or higher than a predetermined temperature. And a supercharging release device that forms an intake passage that is stopped and bypasses the supercharging device.

When the supercharging device is provided in the internal combustion engine, it is generally desired to supercharge the intake air by the supercharging device when the internal combustion engine is operating at medium load or high load, and when the internal combustion engine is operating at low load. Sometimes supercharging is usually not needed. Therefore, when the supercharging device is selectively on / off controlled by a structure in which the crankshaft of the internal combustion engine is driven through a clutch, etc., the supercharging device is controlled by the supercharging device during low load operation of the internal combustion engine. The supercharging of intake air can be released. On the other hand, it is preferable that the exhaust gas recirculation apparatus is generally operated during low-load to medium-load operation of the internal combustion engine and stopped during high-load operation of the engine so that output performance is not impaired. Therefore, when both an exhaust gas recirculation device and a supercharger capable of on / off control are installed in the internal combustion engine, the exhaust gas recirculation is performed by operating the supercharger only during medium- or high-load operation of the internal combustion engine. In combination with the operating characteristics of the exhaust gas recirculation device itself, in which the rate decreases as the load of the internal combustion engine increases, the exhaust gas recirculation region and the internal combustion engine corresponding to the low load to medium load operation region of the internal combustion engine It is possible to obtain a state in which the supercharged operation region corresponding to the medium load to high load operation region is divided so as not to overlap with each other.

Therefore, as described above, the supercharging operation is performed by providing the temperature detecting means for detecting the temperature at one location of the exhaust gas recirculation device and monitoring whether the temperature detecting means detects a temperature equal to or higher than a predetermined temperature. In the exhaust gas recirculation region that does not overlap with the region, the amount of exhaust gas recirculation increased abnormally, that is, control was performed with the exhaust gas recirculation control valve in the exhaust gas recirculation device remaining abnormally open. It is possible to detect that the user is in an impossible state.

Therefore, as described above, if the supercharging canceling means for stopping the operation of the supercharging device and forming the intake passage bypassing the supercharging device when the temperature detecting means detects a temperature equal to or higher than the predetermined temperature is provided, the load of the internal combustion engine is reduced. Even when the state reaches the supercharging operation range, intake supercharging is not performed, and therefore a large amount of air is introduced into the exhaust system through the exhaust gas recirculation system that is wide open during supercharging operation, and the oxygen exhausts the exhaust gas. Occurrence of failures such as the burning of unburned components therein, which results in overheating of the catalytic converter, is avoided.

Embodiments Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 shows an embodiment of an internal combustion engine with a supercharging device having a supercharging control device according to the present invention. In the figure, 1
Reference numeral 0 denotes an internal combustion engine, and the intake port 12 of the internal combustion engine 10 has an intake manifold 14, an intake hose 16, a supercharger 18, an intake hose 20, a throttle valve 22,
An air flow meter 24 and an air cleaner 26 are sequentially connected. An exhaust manifold 30, an exhaust pipe 32, and a catalytic converter 34 are sequentially connected to the exhaust port 28 of the internal combustion engine 10.

The exhaust manifold 30 is provided with an exhaust gas intake port 42 for exhaust gas recirculation, and the intake manifold 14 is provided with an exhaust gas injection port 44. The exhaust gas intake port 42 and the exhaust gas injection port 44 are provided. Are connected to each other by a conduit 46, an exhaust gas recirculation control valve 50 and a conduit 48.

The exhaust gas recirculation control valve 50 has an inlet port 52 and an outlet port 54, the inlet port 52 is communicatively connected to the exhaust gas intake port 42 by a conduit 46, and the outlet port 54 is exhaust gas injected by a conduit 48. It is communicatively connected to the port 44.

The exhaust gas recirculation control valve 50 includes a valve port 56 and a valve element 58.
The valve port 56 is opened and closed by the valve element 58 and its opening degree is controlled to control the exhaust gas recirculation flow rate. The valve element 58 is connected to the diaphragm 62 of the diaphragm device 60, and is pushed down by the spring force of the compression coil spring 66 to close the valve port 56 when the negative pressure larger than a predetermined value is not introduced into the diaphragm chamber 64, thereby closing the diaphragm. When a negative pressure larger than a predetermined value is introduced into the chamber 64, the negative pressure rises against the spring force of the compression coil spring 66 in response to the negative pressure, and the valve port 56 increases.
Is designed to open.

The diaphragm chamber 64 of the exhaust gas recirculation control valve 50 includes an intake pipe negative pressure provided in the intake hose 20 via a conduit 68, a back pressure control negative pressure control valve 70, a conduit 72, a temperature sensing valve 74 and a conduit 76. It is connected to the take-out port 78 for communication. As shown in the drawing, the intake pipe negative pressure extraction port 78 is located upstream of the throttle valve 22 in the fully closed position, and is opened when the throttle valve 22 is opened by a relatively small predetermined opening or more. It is provided to be located on the downstream side.

The negative pressure control valve 70 has a valve element 82 for opening and closing the valve port 80, and a diaphragm 84 carrying the valve element. The diaphragm 84 is open to the atmosphere open to the atmosphere on the upper side in the figure. A chamber 86 and a diaphragm chamber 88 on the lower side are respectively defined, and the diaphragm is operated by a compression coil spring 90 when a pressure (positive pressure) higher than a predetermined value is not introduced into the diaphragm chamber 88. The element 82 is separated from the valve port 80 and is located at the position where the valve port is opened. On the other hand, when a pressure equal to or higher than a predetermined value is introduced into the diaphragm chamber 88, the action is prevented against the action of the compression coil spring 90. The valve element 82 is displaced upward to move the valve element 82 to the valve port 80.
To a position to close the valve port.

The diaphragm chamber 88 of the negative pressure control valve 70 is formed by the conduit 92 between the valve port 56 of the exhaust gas recirculation control valve 50 and the orifice 94 provided downstream of the valve port 56.
The exhaust gas pressure in the pressure chamber is introduced into the pressure chamber.

The structure including the negative pressure control valve 70 and the orifice 94 as described above is a known back pressure control mechanism, and in the exhaust gas recirculation region where the intake pipe negative pressure is applied to the exhaust gas recirculation control valve 50, The negative pressure supplied to the diaphragm chamber 64 of the exhaust gas recirculation control valve 50 is adjusted so that the exhaust gas pressure in the pressure chamber 96 is always kept substantially constant, in other words, the valve port 56.
Of the exhaust gas recirculation flow rate to the intake air flow rate, that is, the EGR rate is always kept substantially constant.

The temperature-sensitive valve 74 is sensitive to the temperature of the cooling water of the internal combustion engine 10, and closes during the warm-up process in which the temperature of the cooling water is below a predetermined value, 60 ° C., to cut off the communication between the conduits 72 and 76, On the other hand, when the cooling water temperature is equal to or higher than the predetermined value, the conduits 72 and 76 are connected for communication.

The intake manifold 14 is provided with a fuel injector 100 for injecting and supplying a liquid fuel such as gasoline to each cylinder of the internal combustion engine 10. The fuel injection by the fuel injector 100 is performed by a fuel injection control signal from a computer 200 described later.

The supercharger 18 is a mechanically driven so-called supercharger composed of a roots blower 110, and a drive pulley 112 is drivingly connected to a crank pulley 116 attached to a crankshaft 11 of the internal combustion engine 10 by an endless belt 114, and an internal combustion engine is connected. The engine 10 is rotationally driven by the rotational output of the engine 10.

An electromagnetic clutch 118 is provided between the drive pulley 112 and the roots blower 110.
When the electromagnetic clutch 118 is in the connected state, it is drivingly connected to the crank pulley 116 as described above, and when the electromagnetic clutch 118 is in the released state, it is disengaged from the drive pulley 112 and stops rotating.

The intake hoses 16 and 20 are selectively used by the bypass intake hose 120, the bypass valve 122, and the bypass intake hose 124 to guide intake air to the internal combustion engine 10 when the roots blower 110 stops rotating, that is, when the supercharging device 18 stops supercharging. In addition, the supercharger 18 is bypassed and connected. The bypass valve 122 is a negative-pressure actuated on-off valve having a general structure, and when the negative pressure is not introduced into the diaphragm chamber 125, the compression coil spring 126 causes the valve element 128 to close the port 130, thereby closing the diaphragm. When a negative pressure is introduced into the chamber 125, the valve element 128 separates from the valve port 130 against the spring force of the compression coil spring 126 to open the valve. The diaphragm chamber 125 is communicatively connected to the port a of the electromagnetic switching valve 134 by a conduit 132.

The electromagnetic switching valve 134 has ports b and c in addition to port a.
When the power is on, the port a is connected to the port b, and when the power is off, the port a is connected to the port c. The port b is connected by a conduit 136 to an atmospheric pressure intake port 138 provided on the intake hose 20, and the port c is connected by a conduit 140 to an intake pipe negative pressure extraction port 142 provided on the intake hose 20. .

The microcomputer 200 outputs a fuel injection signal to the fuel injector 100 for fuel injection control, and the electromagnetic clutch 118 and the electromagnetic switching valve 13 for supercharging control.
4 is controlled, and a failure diagnosis of the exhaust gas recirculation device is further performed.

The microcomputer 200 receives information about the intake air amount from the air flow meter 24, and outputs it to the engine speed sensor 202.
More information about the rotational speed of the internal combustion engine 10, information about the opening of the throttle valve 22 from the throttle opening sensor 204, information about the oxygen concentration of the exhaust gas from the O ₂ sensor 206, the temperature of the conduit 48 from the temperature sensor 208, That is, the information about the exhaust gas recirculation passage temperature is given, and the fuel injection amount control, the supercharging control, and the exhaust gas recirculation failure diagnosis are performed according to the information.

FIG. 2 shows an example of a procedure for implementing supercharging control by the microcomputer 200. The flowchart of FIG. 2 is a supercharging control routine, and in the first step 10, it is determined whether or not the excess EGR failure flag is set. This excess EGR failure flag is set in the failure determination routine of the exhaust gas recirculation device shown in FIG. 3. When the excess EGR failure flag is set, the exhaust gas recirculation control valve 50 is It is when it is left open for some reason and becomes exhaust gas recirculation with an excessive flow rate in an uncontrolled state,
At this time, the process proceeds to step 40 in order to forcibly stop the supercharging action of the supercharging device 18, and when not so, that is, when the exhaust gas recirculation device is not in failure, the process proceeds to step 20.

In step 20, it is determined whether or not it is in the supercharging operation range. The supercharging operation range is predetermined according to the throttle opening, the engine speed, the intake air amount, and the like. The supercharging operation area is within the exhaust gas recirculation stop operation area, so that the supercharging operation area and the exhaust gas recirculation operation area do not overlap.
Both operating ranges are predetermined. If it is in the supercharging operation range, proceed to step 30, otherwise step 4
Go to 0.

In step 30, the electromagnetic clutch 118 is energized to engage it, and the electromagnetic switching valve 134 is energized to connect its port a to its port b. At this time, the roots blower 110 is the internal combustion engine 1
The crankshaft 11 of 0 is driven and rotatably driven, and the bypass valve 122 is closed to perform supercharging.

In step 40, both the energization of the electromagnetic clutch 118 and the energization of the electromagnetic switching valve 134 are stopped. At this time, the electromagnetic clutch 118 is released, the rotation of the roots blower 110 is stopped, the supercharging action of the supercharging device 18 is stopped, and the electromagnetic switching valve 13 is stopped.
4, the negative pressure is introduced into the diaphragm chamber 124 of the bypass valve 122 by connecting the port a to the port c, and the negative pressure is opened, so that the intake air to the internal combustion engine 10 is bypass intake hose 120, bypass valve 122 and bypass intake hose 124. After that, the supercharging device 18 is bypassed and supplied.

When the excess EGR failure flag is set as described above, that is, when the failure such that the exhaust gas recirculation control valve 50 is left open, the supercharging operation by the supercharging device 18 is stopped, and thus the supercharging operation is performed. Exhaust gas recirculation device, that is, conduit 48, exhaust gas recirculation control valve 50
And flow to the exhaust manifold 42 via conduit 46 is obviated.

FIG. 3 shows a failure determination routine of the exhaust gas recirculation device.

In the first step 100, it is judged whether or not the exhaust gas recirculation passage temperature Te detected by the temperature sensor 208 is a second predetermined value Teset ₂ , which is, for example, 300 ° C. or higher. . If Te> Teset ₂ , it means that the temperature is abnormally high and that the exhaust gas recirculation control valve 50 is open, and the excessive EGR failure occurs.
Otherwise go to step 110.

In step 110, it is judged whether or not it is in the exhaust gas recirculation operation range. Whether or not it is in the exhaust gas recirculation operation range is determined according to the intake air flow rate detected by the air flow meter 24 and the rotation speed of the internal combustion engine 10 detected by the rotation speed sensor 202. If it is a range, the routine proceeds to step 120, and if not, it is reset.

In step 120, the continuous time after the exhaust gas recirculation operation range is determined in step 110, that is, the count value Cegr of the counter indicating the EGR duration is greater than or equal to a predetermined value Cj. Whether or not there is is determined. If Cegr> Cj, the routine proceeds to step 130, and if not, the routine is reset.

In step 130, it is determined whether or not the exhaust gas recirculation passage temperature Te detected by the temperature sensor 208 is a predetermined first predetermined value Teset ₁ , for example, 100 ° C. or lower. When Te <Teset _1, it is determined that the exhaust gas recirculation is not normally performed, and the process proceeds to step 160. If not, the process proceeds to step 150.

In step 140, the excess EGR failure flag is set. After step 140, the process proceeds to step 160.

In step 150, it is determined that the exhaust gas recirculation system is operating normally.

In step 160, it is determined that the exhaust gas recirculation device is out of order, and, for example, an indicator lamp (not shown) is turned on.

When the exhaust gas recirculation passage temperature Te is equal to or higher than the second predetermined value Teset ₂ by executing the above failure determination routine, it is determined that the exhaust gas recirculation is being performed with an excessive flow rate, and the failure flag of the excess EGR is set. Is done.

The supercharging device to which the supercharging control device according to the present invention is applied is not limited to the mechanically driven supercharger, but may be a turbocharger driven by combustion gas.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of an internal combustion engine equipped with a supercharging control device for a supercharging device according to the present invention, and FIG. 2 is an example of a supercharging control routine for the supercharging control device according to the present invention. FIG. 3 is a flowchart showing an example of a failure determination routine of the exhaust gas recirculation control device used for supercharging control according to the present invention. 10 ... Internal combustion engine, 11 ... Crank shaft, 12 ... Intake port, 14 ... Intake manifold, 16 ... Intake hose, 18
... supercharger, 20 ... intake hose, 22 ... throttle valve, 24 ... air flow meter, 26 ... air cleaner, 28
... Exhaust port, 30 ... Exhaust manifold, 32 ... Exhaust pipe, 34 ... Catalytic converter, 42 ... Exhaust gas intake port, 44 ... Exhaust gas injection port, 46, 48 ... Conduit, 5
0 ... Exhaust gas recirculation control valve, 52 ... Inlet port, 54 ...
Outlet port, 56 ... Valve port, 58 ... Valve element, 60 ... Diaphragm device, 62 ... Diaphragm, 64 ... Diaphragm chamber, 66 ... Compression coil spring, 68 ... Conduit, 70 ... Negative pressure control valve, 72 ... Conduit, 74 ... Temperature-sensitive valve, 76 ... Conduit, 7
8 ... Intake pipe negative pressure extraction port, 80 ... Valve port, 82 ... Valve element, 84 ... Diaphragm, 86 ... Atmosphere opening chamber, 88 ...
Diaphragm chamber, 90 ... Compression coil spring, 92 ... Conduit,
94 ... Orifice, 96 ... Pressure chamber, 100 ... Fuel injector, 110 ... Roots blower, 112 ... Drive pulley,
114 ... Endless belt, 116 ... Crank pulley, 118
… Electromagnetic clutch, 120… Bypass intake hose, 122
… Bypass valve, 124… Bypass intake hose, 125…
Diaphragm chamber, 126 ... Compression coil spring, 128 ... Valve element, 130 ... Port, 132 ... Conduit, 134 ... Electromagnetic switching valve, 136 ... Conduit, 138 ... Atmosphere intake port, 140
... conduit, 142 ... intake pipe negative pressure outflow port, 200 ... microcomputer, 202 ... rotational speed sensor, 204 ... throttle opening degree sensor, 206 ... _{O 2} sensor, 208 ... temperature sensor

Claims (1)

[Scope of utility model registration request] 1. A supercharging control device for controlling the operation of a supercharging device which is incorporated in an internal combustion engine equipped with an exhaust gas recirculation device and is capable of on / off control so as to selectively supercharge intake air. A temperature detecting means for detecting the temperature at one location of the circulation device, and an intake passage for bypassing the supercharger by stopping the operation of the supercharger when the temperature detecting means detects a temperature higher than a predetermined temperature. A supercharging control device having supercharging canceling means.