JPH0324568B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an intake pressure control device for a supercharged engine, and more particularly, to a device for controlling the intake pressure of a supercharged engine. This invention relates to an intake pressure control device for a supercharged engine.

[Prior Art] As a conventional device of this type, there is a technique described in Japanese Patent Application Laid-open No. 101536/1983.

The technique disclosed in the above publication provides a supercharger passage having a supercharger in parallel with the intake passage, and communicates the upstream passage of the supercharger with the downstream passage of the turbocharger passage through a recirculation passage. A boost pressure control valve is provided in the middle of the recirculation passage, and a coupling mechanism is provided for controlling opening and closing of the boost pressure control valve in conjunction with a predetermined opening degree of the throttle valve. Specifically, it is constructed and operates as shown in FIG.

In FIG. 4, a throttle valve 2 provided in an intake passage 1 of a carburetor is composed of a butterfly valve or the like that rotates around a throttle shaft 3. As shown in FIG.

A supercharger 1 installed in parallel with the intake passage 1 of the carburetor.
0 is constructed as follows. The supercharger passage 11 is formed in a U-shape, and the rotating cylinder 12 of the cylindrical compressor is located at the center of curvature of the U-shaped supercharger passage 11.
locate the center of An eccentric shaft 13 is provided inside the rotary cylinder 12, and a plurality of blades 14 are made to protrude outward from the slit of the rotary cylinder 12 on the eccentric shaft 13. As the rotary cylinder 12 rotates, the blades 14
A space is formed between the four spaces, and the intake air is forced out.

Further, a recirculation passage 17 is connected between an upstream passage 15 and a downstream passage 16 of the intake air of the supercharger 10 in the turbocharger passage 11, and a supercharging pressure control valve is provided in the middle of the recirculation passage 17. 20 is provided.

A connecting mechanism 30 is provided that controls opening and closing of the supercharging pressure control valve 20 depending on the opening degree of the throttle valve 2.

The coupling mechanism 30 is configured as follows. A cam 4 is disposed on the throttle shaft 3, a rotor 5 that rolls on the outer periphery of the cam 4 is provided at one end of a connecting rod 6, and a connection between the other end of the connecting rod 6 and the supercharging pressure control valve 20 is provided. Connect with connecting lever 2.

The intake pressure control device for a supercharged engine configured as described above operates as follows.

When the engine is under low or medium load, the throttle valve 2 is slightly opened, and the throttle shaft 3
The supercharging pressure control valve 20 is rotated about the shaft 22 by a connecting mechanism 30 such as the cam 4 and the connecting rod 6, and the recirculation passage 17 is slightly closed. Therefore, the intake air is recirculated by the supercharger 10, and the intake pressure is slightly increased by the boost pressure control valve 20.

Also, when the engine is under high load, the throttle valve 2 becomes almost fully open, and the connection mechanism allows
The supercharging pressure control valve 20 becomes substantially fully closed. As a result, the recirculation passage 17 is shut off, the boost pressure supplied by the supercharger 10 increases, and high output can be produced.

That is, it is possible to supply the engine with supercharging pressure that corresponds to the opening degree of the throttle valve 2 that corresponds to the load state of the engine.

[Problems to be Solved by the Invention] However, in the above-mentioned conventional intake pressure control device for a supercharged engine, the supercharger controls the opening of its supercharging pressure control valve in conjunction with the opening of the throttle valve. Since the boost pressure is supplied to the engine at a pressure corresponding to the engine speed, the boost pressure compressor operates even when boost pressure is not needed, such as when idling, and the mechanical loss of the engine is reduced accordingly. This caused the problem that the engine rotation during idling tended to become unstable.

As a known technique that recognizes this type of problem, there is a technique disclosed in Japanese Patent Application Laid-Open No. 57-203823.

The technology published in the above publication defines the range in which the clutch of the mechanical supercharger is controlled on and off based on engine rotation and throttle opening. When the clutch is on, the valve closes and stops the air flow. When the clutch is off, the valve is open to allow airflow to be sucked in. However, in this mechanical supercharger, since the clutch is controlled on and off, the supercharged state and non-supercharged state change rapidly, resulting in a large shock.

In addition, the intake pressure control device of the conventional supercharged engine described above operates in conjunction with the opening degree of the throttle valve.
Since the supercharger supplies supercharging pressure to the engine according to its opening degree, it is not possible to control the supercharging pressure in accordance with the engine speed.

For example, in the technique disclosed in Japanese Utility Model Application Publication No. 58-6921, the supercharging control valve is controlled in conjunction with the throttle valve using a link mechanism, and cannot correspond to the engine speed. That is, when the engine speed is below the set value, the control valve is always open, and when the engine speed is above the set value, the control valve is linked to the throttle valve, so the throttle valve and engine speed are The control valve opening is not determined by both conditions, but the control valve opening is controlled separately for the throttle valve and engine rotation, and when the engine rotation is less than the set rotation, Since the engine is not being fed, even if the accelerator is pressed, the supercharging state does not occur, and there is a problem with its responsiveness.

On the other hand, Japanese Patent Laid-Open Publication No. 56-521 discloses a technique in which a branch path is created on the turbine side of a turbocharger, a control valve is provided in the branch path, and the exhaust gas flow rate is adjusted. The opening degree of the control valve in this technology is determined by the amount of fuel supplied and the engine rotation speed.
Or it is determined by intake pressure and engine speed. However, by creating a branch path for the exhaust gas flowing into the turbine of the turbocharger,
The amount of exhaust gas flowing through the branch path is controlled by a negative pressure actuator. Since the control valve is determined by the amount of fuel supplied and the engine speed, or the intake pressure and the engine speed, the fuel injection amount is determined by the intake air amount because the air-fuel ratio is constant, and the intake pressure is also determined by the amount of intake air. Therefore, even when the driver steps on the accelerator and opens the throttle, there is a time delay before the supercharger speeds up, the intake air increases, and the engine output increases, and the response to the driver's acceleration request is delayed. Does not respond immediately.

Therefore, the present invention eliminates the above problems, increases the accelerator response when the engine condition changes, and provides a smooth running feeling that does not give the driver shocks such as hunting due to speed changes. Moreover, it is an object of the present invention to provide an intake pressure control device for a supercharged engine that can disconnect the supercharger from the engine load when there is no demand for supercharging pressure.

[Means for Solving the Problems] The intake pressure control device for a supercharged engine according to the present invention includes a supercharger provided in an intake passage, and an upstream passage and a downstream passage of the supercharger. a recirculation passage that communicates with the recirculation passage, a boost pressure control valve disposed in the recirculation passage, a throttle opening sensor, an engine rotation speed sensor, and a sensor that detects the opening state of the boost pressure control valve. Detecting the opening degree setting value of the boost pressure control valve read from a memory storing the opening degree of the boost pressure control valve according to the load characteristics of the engine and the current opening degree of the boost pressure control valve. When the comparison output is greater than or equal to the allowable value, the actuator is controlled in a direction in which the output of the comparing means is reduced, and when the comparative output is not greater than the allowable value, the boost pressure is controlled. When the valve is fully open, the supercharger is opened by a clutch mechanism.

[Operation] According to the present invention, the opening instruction value of the boost pressure control valve according to the load characteristics of the engine is stored in the memory in advance, and the engine load state detection output and the engine rotation state detection output are stored in the memory in advance. In response to this, the specified opening value of the boost pressure control valve according to the load characteristics of the engine is read from the memory, and the current detection value of the opening of the boost pressure control valve and the opening instruction value read from the memory are read out. When the difference exceeds a predetermined allowable value, the opening indication value of the boost pressure control valve is updated to a new value, and the opening indication value of the boost pressure control valve is updated using the updated opening indication value. Since the opening degree is determined, control can be performed according to the detected output of the engine rotation state.

In addition, when the load condition of the engine is detected and the detected output is a request for boost pressure, the opening degree of the boost pressure control valve is quickly set to the opening degree according to the engine rotation condition, increasing the boost pressure. When the engine speed increases, the opening degree of the boost pressure control valve is set to an opening degree setting value corresponding to the increase in engine speed.
The actuator is controlled to lower the supercharging pressure, and when there is no demand for supercharging pressure, the clutch mechanism controls the supercharger to an open state.

[Embodiment] FIG. 1 is an overall configuration diagram of an intake pressure control device for a supercharged engine according to a first embodiment of the present invention.

In the figure, the same reference numerals and symbols as in FIG. 4 indicate the same or equivalent parts as in the conventional device. Here, only the points that are different from the conventional device will be described.

In the conventional example shown in FIG. 4, the supercharger 10 is directly connected to the engine rotating shaft, but when implementing the present invention, a clutch is connected between the engine rotating shaft and the compressor shaft of the supercharger 10. The engine rotating shaft and the compressor shaft of the supercharger 10 are connected through a mechanism CL. The clutch mechanism
The CL is intermittent in response to the output of the boost pressure control circuit CPU, which will be described later. Preferably, the clutch mechanism CL itself is an electromagnetic clutch, so that the clutch mechanism CL can be intermittent in response to an electrical signal. Things are good. This clutch mechanism CL is connected to the supercharging pressure control circuit which will be described later via the driver circuit DR1.
Intermittent with CPU output.

The throttle sensor SS is a well-known sensor that detects the opening degree of the throttle valve 2. In this embodiment, a potentiometer PM1 is directly connected to the throttle shaft 3 of the throttle valve 2 to detect the opening degree of the throttle sensor SS. It is detected as the potential at the connection point between the series resistor R1 and the potentiometer PM1. Instead of the potentiometer PM1, mechanically connect a rotating shaft such as a rotary switch or a code plate, and convert a change in contact or a change in resistance value into a change in potential.
Alternatively, a code plate that detects the code and determines its opening degree can also be used. Since the object detected by the throttle sensor SS is the engine load condition, when implementing the present invention,
It is not necessarily necessary to use the output of the throttle sensor SS, and the rotation speed, torque, fuel supply state, accelerator pedal depression amount, etc. may be used. However, by using the throttle sensor SS as the engine load condition, it is easiest to obtain a condition that approximates the load condition.

The engine rotation speed sensor ES, which detects the engine rotation status, creates resistance due to the rotation of the permanent magnet MG, which is connected directly or indirectly to the engine shaft.
Turn on the reed switch inserted in series with R2.
It is turned off to obtain pulses with a frequency proportional to the engine speed. When detecting engine speed as vehicle speed, the speed at which a pulse with a frequency proportional to the engine speed is obtained is obtained from the on/off signal of a reed switch placed near the permanent magnet MG connected to the speedometer cable. A sensor may be used. Note that these engine rotational speed sensors or speed sensors are well known, and other known sensors other than those having the mechanical switch can also be used. Alternatively, the engine rotational state may be determined by detecting pulses of an ignition signal from an ignition circuit, and the number of pulses may be used as the engine rotational speed. In this case, the engine speed can be detected simply by adding an electrical circuit to a conventional engine.

The control valve CV has a solenoid that connects the output of the boost pressure control circuit CPU to the driver circuit DR.
When the solenoid is energized through 2, negative pressure is sent from the surge tank ST side to the actuator AC side, and when the solenoid is de-energized, the negative pressure of the actuator AC is discharged to the atmospheric pressure side.

In addition, the same type of sensor as the throttle sensor SS can be used as the boost pressure control valve opening sensor VS, and in this embodiment, the boost pressure is controlled by a series circuit of potentiometer PM2 and resistor R3. The degree of opening of the valve 20 is detected by the rotation of the rotating shaft of the potentiometer PM2 directly connected to the shaft 22 of the valve 20 as a change in potential.

The actuator AC controls the boost pressure control valve 20 based on the output of the boost pressure control circuit CPU.
Surge tank ST accumulated by a vacuum pump (not shown), etc. with a known negative pressure actuator
The negative pressure is led to the negative pressure chamber through the control valve CV, and the movement of the rod LT rotates the supercharging pressure control valve 20 to open and close it. Normally, the negative pressure in the negative pressure chamber is created by controlling the duty ratio of a solenoid of a control valve CV. The actuator AC used here controls the opening and closing of the boost pressure control valve 20 in response to the electrical output of the boost pressure control circuit CPU, so when implementing the present invention, the negative pressure actuator is not necessarily used. It is not necessary to use it, and an electromagnetically controlled actuator or the like can also be used. For example, known solenoids, motors, etc. can be used.

The boost pressure control circuit CPU receives the output of the throttle sensor SS and the output of the engine speed sensor ES and controls the duty ratio of the solenoid of the control valve CV. A computer is used.

Next, the operation of the intake pressure control system for a supercharged engine according to this embodiment using a microcomputer as the supercharging pressure control circuit CPU will be explained using the flowchart shown in FIG.

First, the entire system of the intake pressure control device of the supercharged engine is activated by the ignition switch or the switch SW linked to the ignition switch. In step S1, the memory required to run this system is initialized, and each sensor input and boost pressure control valve 20 are
Performs input/output such as output. In step S2, the current opening degree of the throttle valve 2 is detected by the throttle sensor SS as the engine load state. In step S3, the engine rotation state is detected from the engine rotation speed sensor ES. In step S2 and step S3, the current engine load condition and engine speed are obtained. Then, in step S4, an opening command value θa of the boost pressure control valve is determined from the ROM based on the engine load condition and engine speed.
Read.

That is, as shown in the explanatory diagram of the memory map for setting the opening degree of the boost pressure control valve in Fig. 3, the ROM contains the following information:
In the relationship between the engine rotation speed (vehicle speed) and the throttle valve opening, the maximum opening in the area of the boost pressure control valve opening command value θa is θ1, and the minimum opening is θ5.
The range is set in five stages: θ1 > θ2 > θ3 > θ4 > θ5.

In addition, since the opening degree command value θ1 of the boost pressure control valve is the maximum opening state of the boost pressure control valve 20, the boost pressure becomes the minimum, and the opening degree command value θ5 of the boost pressure control valve Since this is the state where the boost pressure control valve 20 is at its minimum opening, the boost pressure is at its maximum.

The shaded area in the explanatory diagram of the memory map for setting the opening degree of the boost pressure control valve in Figure 3 is the region where the boost pressure is minimum and there is no need to supply boost pressure to the engine. It shows the area where the aircraft 10 is isolated from the engine load. The range of the opening degree command value θ1 of the boost pressure control valve in this embodiment is
This is the area in which the clutch mechanism CL, which transmits rotational force to the engine, is turned off. In addition, the clutch mechanism CL
The range where the OFF state is not necessarily set to the range of the opening degree instruction value θ1 of the boost pressure control valve. For example, the clutch mechanism CL may be set in the ON range near the boundary line between the opening command value θ1 and the opening command value θ2 of the boost pressure control valve, and the other parts may be set in the OFF range. In any case, the clutch mechanism CL may be turned off under conditions where the supercharging pressure is at its minimum.

This memory map for setting the boost pressure control valve opening is a ROM that stores data based on actual measurements or design values of engine load characteristics.

In step 4, the opening instruction value θa of the boost pressure control valve in the ROM is read out by specifying the address using information such as engine speed and throttle valve opening, and in step S5, the current boost pressure control valve opening sensor is read out. The detected opening value θx of the boost pressure control valve that is actually supplied to the engine is detected from the VS. Then, in step S6, the difference between the boost pressure control valve opening command value θa read from the memory map in step S4 and the detection value θx of the boost pressure control valve opening that is currently actually being supplied to the engine is calculated. , when the difference is less than the tolerance δ determined based on the range of the opening degree command value θa of the boost pressure control valve, the error of the sensor, the control error of the boost pressure control valve 20, etc., the output means is output in step S7. As a result, the movement of the rod LT of the actuator AC that drives the supercharging pressure control valve 20 is stopped in order to maintain the opening degree of the supercharging pressure control valve 20. Then, in step 8, it is determined whether the opening command value θa of the boost pressure control valve is an instruction of θa = θ1, and when it is determined to be the maximum opening command value θ1, the clutch mechanism CL is turned off in step 9. ,
Disconnect the supercharger 10 from the engine load.

When |θa−θx|>δ is determined in step S6, the difference between the boost pressure control valve opening command value θa set according to the ROM and the current boost pressure control valve opening detection value θx This means that there is a difference between the two, and the difference is larger than the tolerance δ. Therefore, when the opening command value θa of the boost pressure control valve is not the maximum opening command value in step S10, the clutch is closed in step S11. When the mechanism CL is turned on and the opening instruction value θa of the boost pressure control valve is the maximum opening instruction value θ1, the opening instruction value θa of the boost pressure control valve and the current value are changed in step S12. The increase speed and deceleration are determined by comparing with the detection value θx of the opening of the boost pressure control valve, and when the speed is increasing, the current detection value of the opening of the boost pressure control valve is outputted by the output means in step S13. The signal is output to the actuator AC to drive the supercharging pressure control valve 20 in the direction in which θx becomes larger. When the acceleration is reduced, in step S14, the output means outputs an output to the actuator AC in order to drive the supercharging pressure control valve 20 in a direction in which the current detected opening value θx of the supercharging pressure control valve becomes smaller.

At this time, the control stage of the control region of the detected opening value θx of the boost pressure control valve 20 read out by specifying the address of the ROM is set according to the engine speed and the throttle valve opening. If the opening degree command value θ5 moves in the direction of the opening degree command value θ1, the supercharging pressure control valve 20 becomes stepwise controlled.

For example, suppose that when the access pedal is depressed to increase the acceleration, the opening command value θ5 of the boost pressure control valve 20 enters the control range. If the amount of depression of the accelerator pedal is kept constant, the engine speed will gradually increase, and the control range of the opening command value θ5 of the supercharging pressure control valve 20 will change from the control range of θ4 to the opening command values θ3, θ2, θ1. The boost pressure supplied to the engine can be gradually reduced by opening in stages. Therefore, the actuator
The supercharging pressure control valve 20 is gradually opened by the AC rod LT, and the supercharging pressure supplied from the supercharger 10 to the engine can be gradually reduced.

As described above, the intake pressure control device for a supercharged engine of this embodiment includes a supercharger 10 provided in a supercharger passage 11 linked to an intake passage 1, and a supercharger in the supercharger passage 11. A recirculation passage 17 that communicates the upstream passage 15 and the downstream passage 16 of the feeder 10, a supercharging pressure control valve 20 disposed in the middle of the recirculation passage 17, and the supercharger 10 and the engine. A clutch mechanism that can electrically control the rotational force between the
CL, a throttle sensor SS that detects the engine load condition, an engine rotation speed sensor ES that detects the engine rotation condition, and the opening and closing of the supercharging pressure control valve 20 is controlled by the output of each of these sensors. In an intake pressure control device for a supercharged engine that includes a supercharging pressure control circuit CPU that controls an actuator AC, a supercharging pressure control valve 2 according to engine load characteristics of the supercharging pressure control circuit CPU.
A comparison means for comparing a memory storing an opening of 0, an opening setting value θa of the boost pressure control valve 20 read from the memory, and a current detected opening value θx of the boost pressure control valve 20. Therefore, when the output of the comparison means is equal to or greater than the allowable value, the output means for controlling the actuator AC that opens and closes the boost pressure control valve 20 in a direction in which the output of the comparison means becomes smaller; and the output of the comparison means. a clutch mechanism that releases the supercharger 10 when the supercharging pressure control valve is not in a boost pressure requesting state, that is, when the output of the comparison means is not above a permissible value, and when the supercharging pressure control valve is fully open;
CL.

Therefore, according to the intake pressure control device for a supercharged engine of this embodiment, the supercharging pressure is controlled according to the engine rotation state and the engine load state by detecting the engine rotation speed and the throttle valve opening. Therefore, control corresponding to engine load characteristics becomes possible. In addition, when supercharging pressure is no longer required, the clutch mechanism CL can disconnect the supercharger 10 from the engine load, making it possible to maintain a stable engine rotational state, especially during idling. . Furthermore, by disconnecting the supercharger 10 from the engine load during idling, it is possible to prevent the generation of noise due to the operating sound of the compressor of the supercharger 10, and when the supercharger 10 is no longer required, Since the supercharger 10 is stopped, the life of the supercharger 10, in particular, the life of the compressor can be extended.

In addition, when the driver suddenly depresses the accelerator pedal and requests an increase in speed, the opening degree of the throttle valve 2 changes rapidly according to the engine rotation state and engine load state, and the engine load state reaches the target value. When this happens, the boost pressure gradually decreases, which reduces waste in fuel consumption, and allows smooth driving without giving the driver shocks such as hunting due to speed changes due to the decrease in boost pressure.

Then, the supercharging state changes depending on the degree of acceleration required, and unnecessary supercharging is not performed, making it possible to improve acceleration performance and reduce fuel consumption. Furthermore, since the clutch mechanism releases the turbocharger only when the turbocharger is not needed and the boost pressure control valve is at its maximum opening, no fuel is wasted, and the clutch mechanism Even when the engine is turned on or off, there is almost no change in engine output, and the driver does not experience any discomfort due to changes in speed. Therefore, acceleration performance can be improved and fuel consumption can be reduced.

[Effects of the Invention] As described above, the intake pressure control device for a supercharged engine of the present invention has a recirculation passage provided in the intake passage that communicates the upstream passage and the downstream passage of the supercharger. , comprising a boost pressure control valve disposed in the recirculation line, a throttle opening sensor, an engine rotation speed sensor, and a sensor for detecting the opening state of the boost pressure control valve, Compare the opening setting value of the boost pressure control valve read from the memory that stores the opening degree of the boost pressure control valve according to the load characteristics with the current detection value of the opening of the boost pressure control valve. When the comparative output is above the allowable value, the actuator is controlled in a direction in which the output of the comparing means is reduced, and when the comparative output is not above the allowable value and the boost pressure control valve is fully open, the actuator is controlled to reduce the output. The feeder is opened using a clutch mechanism.

Therefore, when boost pressure is no longer required, the clutch mechanism can disconnect the supercharger from the engine load, making it possible to maintain a stable engine rotational state, especially during idling. . Further, by isolating the supercharger from the engine load during idling, it is possible to prevent the generation of noise due to the operating sound of the supercharger compressor. Since the supercharger is stopped when boost pressure is no longer needed, the lifespan of the supercharger, especially
The life of the compressor can be extended.

Further, a throttle opening sensor detects the load state of the engine, an engine rotation speed sensor detects the engine rotation state, a sensor detects the opening state of the boost pressure control valve, and the This is because the boost pressure control circuit includes an actuator that controls the opening and closing of the boost pressure control valve, and changes the boost pressure increase, which is performed by the boost pressure control circuit depending on the engine load state, depending on the engine rotation state. , it is possible to supply fuel according to the engine condition, and it is possible to suppress wasteful fuel consumption.

Even if the engine condition fluctuates, depending on the engine load condition and engine rotation condition,
Accelerator response can be uniformly increased depending on the engine condition. In addition, smooth driving can be achieved without giving the driver any shocks such as hunting due to speed changes.

[Brief explanation of the drawing]

FIG. 1 is an overall configuration diagram of an intake pressure control device for a supercharged engine according to a first embodiment of the present invention, and FIG. 2 shows an intake pressure control device for a supercharged engine according to a first embodiment of the present invention. A flowchart of the operating boost pressure control circuit, and FIG. 3 is a storage example of a memory map for setting the opening of the boost pressure control valve that constitutes the intake pressure control device for a supercharged engine according to the first embodiment of the present invention. An explanatory diagram of
FIG. 4 is an overall configuration diagram of a conventional intake pressure control device for a supercharged engine. In the figure, 1: intake passage, 10: supercharger, 1
1: Supercharger passage, 15: Upstream passage, 16: Downstream passage, 17: Recirculation passage, 20: Supercharging pressure control valve, ES: Engine speed sensor, SS: Throttle sensor, VS: Supercharging Pressure control valve opening sensor,
AC: actuator, CL: clutch mechanism. In addition, in the figures, the same reference numerals and symbols indicate the same or equivalent parts.

Claims (1)

[Scope of Claims] 1. A supercharger provided in an intake passage, a recirculation passage that communicates an upstream passage and a downstream passage of the turbocharger, and a supercharging pressure disposed in the recirculation passage. a control valve; a throttle opening sensor that detects the load condition of the engine; an engine rotation speed sensor that detects the rotation speed of the engine; a sensor that detects the opening condition of the boost pressure control valve; and the supercharging. an actuator that controls the opening and closing of the pressure control valve; a memory that stores the opening degree of the boost pressure control valve according to the load characteristics of the engine; and a set value of the opening degree of the boost pressure control valve read from the memory and the current value. a comparison means for comparing a detection value of the opening of the boost pressure control valve of the controller; and an output means for controlling the actuator in a direction in which the output of the comparison means becomes smaller when the output of the comparison means is equal to or higher than an allowable value. , a clutch mechanism that releases the supercharger when the output of the comparison means is not above a permissible value and the supercharging pressure control valve is fully open; Intake pressure control device.