JPH07116952B2 - Mechanical supercharger for engine - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a mechanical supercharging device for an engine.

(Prior Art) In a mechanical turbocharger driven by a crankshaft of an engine via a belt, a variable pulley mechanism is adopted, and by changing the pulley ratio, the turbocharger is accelerated in a low engine speed range. However, in the high speed rotation range, decelerate the turbocharger,
It is known that the supercharging pressure is made constant and the rotation speed of the supercharger is suppressed (see, for example, JP-A-60-8427).

(Problems to be Solved by the Invention) By the way, when controlling the pulley ratio of the variable pulley mechanism according to the engine speed or the load, in the rapid acceleration operation from the light load region, from the state where the pulley ratio is small to the rapid acceleration operation. It takes time to reach the maximum pulley ratio suitable for, and it is difficult to improve the transient (acceleration) response.

Further, if the system in which the mechanical supercharger is always driven by the engine is adopted, when supercharging is not required as in the light load region, the output of the engine will be lost due to the drive of the supercharger. . On the other hand, it is possible to disconnect the drive system of the supercharger from the engine in the light load region and connect the drive system at the time of supercharging request (acceleration). Due to the sudden increase in the intake air amount, the output torque of the engine suddenly increases, which easily causes a torque shock.

(Means for Solving Problems) As a means for solving the above problems, the present invention provides a drive relationship between a mechanical supercharger driven by an engine through a variable pulley mechanism and a supercharger by the engine. Set the clutch means for disconnecting in the light load area, the means for detecting the acceleration operation of the engine, and the ratio of the pulley on the engine side to the pulley on the turbocharger side to the maximum in the light load area where the drive relationship is interrupted. Every other time, while the pulley ratio setting means for lowering the pulley ratio when detecting the slow acceleration operation of the engine is connected to the clutch means while maintaining the maximum pulley ratio when the rapid acceleration operation of the engine is detected, the slow acceleration operation is detected. There is provided a mechanical supercharging device for an engine, which is sometimes provided with a clutch control means for connecting and operating the clutch means after the pulley ratio decreases.

(Operation) That is, in the above mechanical supercharger, the supercharger is separated from the engine in the light load region with the maximum pulley ratio by the variable pulley mechanism. By immediately connecting to the engine in the state, the required boost pressure is immediately obtained. In addition, at the time of gentle acceleration, the supercharger is connected to the engine after the pulley ratio is once reduced, that is, in the state of the small pulley ratio, so the supercharging pressure at this connection is low and the intake air amount of the engine suddenly changes. Is prevented.

(Effects of the Invention) Therefore, according to the present invention, as described above, a high supercharging pressure is immediately obtained by the detection at the time of sudden acceleration to improve the transient response of the engine, and at the time of starting supercharging at the time of slow acceleration. Since the supercharging pressure is low and the sudden change of the intake air amount is prevented, the torque shock of the engine is alleviated, and it is possible to satisfy the two requirements of improving the transient response and alleviating the torque shock.

(Example) Hereinafter, the Example of this invention is described based on drawing.

In the engine mechanical supercharging device shown in FIG. 1, reference numeral 1 denotes a four-cylinder engine main body, and its intake system includes an air flow meter 2 and a crankshaft 3 of the engine main body 1 provided with a continuously variable transmission pulley from the upstream side. Mechanical supercharger 5 and throttle valve 6 driven via the variable pulley mechanism 4 used
And a bypass valve 8 for controlling the opening degree of the passage 7 that bypasses the supercharger 5.
Is provided.

In the drive system of the supercharger 5, a V-belt 13 is connected to a drive pulley 9 connected to the crankshaft 3 and a driven pulley 12 connected to the drive shaft of the supercharger 5 via an electromagnetic clutch (clutch means) 11. Has been suspended. In this case, the drive pulley 9
Receives the hydraulic pressure (may be air pressure) from the pressure unit 14 to change the groove interval, and the groove interval of the driven pulley 12 is changed accordingly. Further, the bypass valve 8 is provided with a valve actuator 15 for operating the bypass valve 8.

Then, the pressure unit 14, the electromagnetic clutch 11 and the valve actuator 15 of the variable pulley mechanism 4 include a throttle sensor 16 for detecting a change in the opening of the throttle valve 6,
Operated from a control unit 20 to which each signal is input from an engine rotation sensor 17 that detects the engine speed from the rotation of the driving pulley 9 and a supercharger rotation sensor 18 that detects the rotation speed of the supercharger from the rotation of the driven pulley 12. It is designed to receive signals.

Next, the contents of control by the control unit 20 will be described.

First, the control unit 20 includes a supercharging area determination means 21, an acceleration detection means 22, a pulley ratio setting means 23, a clutch control means 24 and a bypass opening control means 25 as shown in FIG.

The supercharging region determining means 21 determines that the engine is in the non-supercharging region when the engine is in the light load region, and is in the supercharging region when the engine is in the other medium / high load regions. The acceleration detecting means 22 detects a rapid acceleration operation when the rate of change of the throttle opening in the opening direction is larger than a set value, and a slow acceleration operation when the rate of change is less than the set value.

The pulley ratio setting means 23 receives the determination of the supercharging region and sets the pulley ratio (driving pulley / driven pulley) according to the operating state at that time. Basically, in the non-supercharging region (light load region) The maximum pulley ratio is set, a small pulley ratio corresponding to the acceleration is set when a slow acceleration operation is detected, and an operation signal is output to the pressure unit 14 so that the variable pulley mechanism 4 has the set pulley ratio. .

The clutch control means 24 outputs a connection signal in response to the determination of the supercharging region and a disconnection signal to the electromagnetic clutch 11 in response to the determination of the non-supercharging region, and also receives a detection of a sudden acceleration operation in the non-supercharging region. Then, the connection signal is immediately output, and when the slow acceleration operation is detected, the connection signal is output after the pulley ratio setting means 23 decreases the maximum pulley ratio to the small pulley ratio.
The bypass opening control means 25 basically outputs an operation signal to the valve actuator 15 so that the bypass opening becomes smaller as the throttle opening becomes larger.

The pulley ratio and the control flow of the electromagnetic clutch 11 are shown in FIG. 3. First, it is judged whether or not it is in the supercharging region, and if it is the supercharging region, a flag F (this flag is the electromagnetic clutch 11
It is determined whether the electromagnetic clutch 11 is off or not (steps S ₁ and S ₂ ) by determining whether the electromagnetic clutch 11 is turned on (connected) to 1 and turned off (disengaged to 0). If the electromagnetic clutch 11 is off, it is turned on and the flag F
Is set to 1, and if already turned on, the target pulley ratio according to the operating state is calculated as it is, the pressure is calculated according to this target pulley ratio, and the operation signal based on the calculated value is output to the pressure unit 14. (step S ₃ ~S _7).

On the other hand, if not supercharging region, the determination of the flag F if the acceleration state set by the control to turn off the electromagnetic clutch 11 to maximize the target pulley ratio (step S ₈ ~
S ₁₂ ). Then, when the acceleration state, if the rapid acceleration operation immediately turn on the electromagnetic clutch 11, the flag F to 1 (step S ₁₃ ~S _15). At this time, since the pulley ratio is set to the maximum when the vehicle is not in the previous acceleration state, the supercharger 5 is immediately driven at the maximum pulley ratio when the electromagnetic clutch 11 is turned on.

Further, in an acceleration state that is not sudden acceleration, that is, in the case of slow acceleration operation, a small pulley ratio corresponding to the acceleration is calculated, a pressure corresponding to the target pulley ratio is calculated, and a calculated value is output to the pressure unit 14, after whereby the pulley ratio is decreased to a small value, the electromagnetic clutch 11 is turned on, the flag F to 1 (step S ₁₆ ~S _20). That is, the supercharger 5 starts to be driven with a small pulley ratio.

In both cases of sudden acceleration and gentle acceleration, after starting the driving of the supercharger 5, if it is in the supercharging region, the pulley ratio is controlled according to the operating state at that time.

Pulley ratio and electromagnetic clutch in each acceleration operation
The control of 11 is shown in Fig. 4 in relation to the throttle opening. That is, in the case of sudden acceleration operation, when acceleration is detected in the non-supercharging region where the throttle opening is small,
As indicated by the solid line, the electromagnetic clutch 11 is turned on with the pulley ratio kept at the maximum, and in the case of slow acceleration operation, the electromagnetic clutch 11 is temporarily reduced after the acceleration is detected by the detection of acceleration as indicated by the chain line.
Is turned on, and then the pulley ratio increases with the throttle opening.

Therefore, in the case of sudden acceleration operation, a high supercharging pressure is immediately obtained at the maximum pulley ratio due to the detection, and the transient response becomes good, while in slow acceleration operation, the pulley ratio decreases and supercharging starts at the start of supercharging. The boost pressure is suppressed to a low level, a sudden increase in the intake air amount is prevented, and torque shock is mitigated.

By the way, in the case of the above-described slow acceleration operation, although the supercharging pressure at the start of supercharging is suppressed by the above control, the following passage of the air is switched from the bypass passage 7 to the supercharger 5 side. The phenomenon may still occur.

That is, when the electromagnetic clutch 11 is off, air is flowing in the bypass passage 7, but at the same time when the electromagnetic clutch 11 is turned on, the discharge air from the supercharger 5 collides with the air in the bypass passage 7, The pressure downstream of the supercharger 5 increases for a moment. Therefore, there is a problem that the intake air amount increases and a small torque shock occurs. For example, as shown in FIG. 7, when the electromagnetic clutch 11 is turned on in the slow acceleration operation, the output of the acceleration sensor (installed in front of the passenger seat of the automobile) becomes high for a moment. It is preferable to perform the following control for this problem.

<Example 1> As shown in the time chart of FIG. 5, the electromagnetic clutch 11
The bypass valve 8 is fully opened for a certain period of time when
After that, the normal set opening is gradually set. This increases the effective area of the bypass passage 7 at the start of supercharging,
The supercharged air easily escapes to the upstream side of the supercharger 5 through the bypass passage 7, and the pressure increase downstream of the supercharger 5 is suppressed. The opening degree of the bypass passage 7 can be controlled by the bypass opening degree control means 25 in response to the command from the clutch control means 24, but the valve actuator is controlled by the differential pressure between the upstream side and the downstream side of the throttle valve 6. When the electromagnetic clutch 11 is turned on, the pressure on the downstream side of the throttle valve 6 with respect to the valve actuator is set to atmospheric pressure by using the electromagnetic three-way valve, and the bypass valve 8 is used.
May be fully opened. Further, instead of controlling the bypass valve 8, a dedicated passage connecting the upstream and the downstream of the supercharger 5 may be provided, and the dedicated passage may be opened for a moment when the electromagnetic clutch 11 is turned on. .

<Example 2> As shown in the time chart of FIG. 6, the opening amount of the throttle valve 6 is decreased for a certain time at the same time when the electromagnetic clutch 11 is turned on, and then gradually returned to the normal opening amount, whereby the intake air amount is increased. May be temporarily limited to suppress an increase in torque. In this case, the same control can be performed even if the throttle valve is on the upstream side of the supercharger.

<Example 3> Further, by temporarily delaying the ignition timing of the engine at the same time as turning on the electromagnetic clutch 11, it is possible to suppress an increase in torque.

The control of Examples 1 to 3 may be performed only for a certain period of time after the electromagnetic clutch is turned on, but may be performed even after that even when the pressure downstream of the supercharger is higher than expected in the gentle acceleration state. .

[Brief description of drawings]

The drawings show an embodiment of the present invention, FIG. 1 is an overall configuration diagram, FIG. 2 is a block diagram of a control system, FIG. 3 is a flow chart of control, and FIG. 4 is a diagram showing the electromagnetic clutch and pulley ratio during acceleration. Fig. 5 is a characteristic diagram showing the relationship, Fig. 5 is a time chart of bypass valve control accompanying the operation of the electromagnetic clutch, Fig. 6 is a time chart of control of the throttle valve similarly, and Fig. 7 is a fluctuation of acceleration accompanying the operation of the electromagnetic clutch. It is a time chart shown. 1 ... Engine body, 3 ... Crankshaft, 4 ... Variable pulley mechanism, 5 ... Supercharger, 7 ... Bypass passage, 11 ...
Electromagnetic clutch.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-61-98922 (JP, A) JP-A-61-272419 (JP, A) JP-A-62-191631 (JP, A) Actual development Sho-61- 32525 (JP, U) Actually opened 61-140134 (JP, U)

Claims (1)

[Claims] 1. A mechanical supercharger driven by an engine via a variable pulley mechanism, clutch means for interrupting a drive relationship of the engine with the supercharger in a light load region, and acceleration for detecting acceleration operation of the engine. The ratio of the detection means and the pulley on the engine side to the pulley on the supercharger side is set to the maximum in the light load region where the drive relation is cut off, and the pulley ratio is reduced when the engine is slowly accelerated. A ratio setting means and a clutch control means for immediately engaging and operating the clutch means while maintaining the maximum pulley ratio when detecting a sudden acceleration operation of the engine, and for engaging and engaging the clutch means after a decrease in the pulley ratio when detecting a slow acceleration operation. A mechanical supercharging device for an engine, comprising: