JP3362986B2 - Engine with mechanical supercharger - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine having a mechanical supercharger in an intake passage, and more particularly to controlling the drive of the mechanical supercharger when the engine is used by being connected to a manual transmission. It is a thing.

[0002]

2. Description of the Related Art Conventionally, as disclosed in, for example, Japanese Patent Publication No. 2-52094, a mechanical supercharger is provided in an intake passage of an engine, and the mechanical supercharger is provided via an electromagnetic clutch and a transmission means. 2. Description of the Related Art There is known an engine with a mechanical supercharger which is connected to an engine output shaft and is capable of switching a supercharger between a driven state and a stopped state by turning on and off the electromagnetic clutch. Generally, in this type of mechanical supercharged engine, as shown in the above publication, in the low load range where the engine load is equal to or lower than a predetermined value, part of the engine output is consumed by the supercharger. To avoid this, the supercharger is stopped by turning off the electromagnetic clutch.On the other hand, in the high load range where the engine load is larger than a predetermined value, the intake torque is increased to increase the torque of the engine. The supercharger is driven by turning on the clutch.

Further, as disclosed in Japanese Patent Laid-Open No. 63-201325, the mechanical supercharger is stopped (the electromagnetic clutch is turned off) in a low load region where the intake pressure in the intake manifold is equal to or lower than a set value. In the high load range where the intake pressure is higher than the set value, the mechanical supercharger is driven (the electromagnetic clutch is turned on), but when the engine is started (the engine speed is 5
There is also known a drive control method for a supercharger in which the mechanical supercharger is stopped at the time of 00 rpm or less) or during idling (when the throttle valve is fully closed and at a low speed). In the method disclosed in this publication, when controlling the drive of the supercharger in accordance with the intake pressure, the intake pressure may exceed the above-mentioned set value even when the engine start or idle is low load. In such a case, driving of the supercharger is avoided.

[0004]

By the way, in a mechanical supercharger constituted by a roots pump as described in the above-mentioned respective publications or a Risholum pump which will be described later, a gear and an additional gear for interlocking a pair of rotors are added. Although a gear for speed is attached, according to the conventional engine with a mechanical supercharger, especially when applied to an MT vehicle equipped with a manual transmission, a low speed and high load state occurs at the time of starting acceleration etc. However, there is a problem that noise is generated due to the rattling noise of gears attached to the mechanical supercharger.

More specifically, when the engine load increases due to an acceleration operation immediately after starting the vehicle, in the case of an AT vehicle having a torque converter, the engine speed increases relatively quickly as the load increases. In the case of a car, since the engine speed gradually increases after the acceleration operation, immediately after the acceleration operation, the load is high and the engine speed is in a low speed state that is slightly higher than the idle speed. And
In a conventional engine with a supercharger, the supercharger is driven at a high load even in a low speed range near idle. That is, in the engine with a mechanical supercharger disclosed in Japanese Patent Publication No. 5-52094, the supercharger is driven at a high load regardless of the engine speed, and in Japanese Patent Laid-Open No. 63-201325. Even in the case shown, the supercharger is driven when the throttle valve is opened in the low speed range near the idling speed to be in the high load state.

When the mechanical supercharger is driven during start-up acceleration or the like as described above, the torque fluctuation of the engine is large in a low speed range near the idling speed, so that the torque fluctuation causes
A rattling noise is generated due to the backlash of the gear attached to the mechanical supercharger.

In this case, especially when the engine has a high compression ratio,
Moreover, in the case of an in-line engine having a relatively small number of cylinders, the rattling noise tends to increase because the torque fluctuation is likely to increase. Further, when the mechanical supercharger is provided with a gear and an accelerating gear for interlocking the rotors with each other, a gear rattling noise is generated in each gear and the speed is increased to accelerate the rotor. As the inertia increases, the rattling noise tends to increase. Further, when a mechanical supercharger having a small drive resistance or a large drive resistance variation is used, the rattling noise is likely to increase.

In view of the above circumstances, the present invention prevents generation of gear rattling noise at the time of starting acceleration in an MT vehicle while maintaining the output performance required by using a mechanical supercharger. An object of the present invention is to provide an engine with a mechanical supercharger that can reduce noise.

[0009]

The invention according to claim 1 is
An engine connected to a manual transmission, a mechanical supercharger arranged in the intake passage, a gear attached to the mechanical supercharger, and power transmitted to the mechanical supercharger. In the engine with a mechanical supercharger, which is provided with a clutch means that can be switched between a connected state that disconnects the transmission of power and a disengaged state that cuts off power transmission, the clutch means is disengaged in a low speed and low load range. Even in the range, a clutch control means for controlling the clutch means to be in a disengaged state is provided in a region lower than the set rotation speed, and the set rotation speed is higher than the idle rotation speed and is close to the idle rotation speed. It is what

The invention according to claim 2 is the engine with a mechanical supercharger according to claim 1, which is an in-line engine having 5 or less cylinders and a compression ratio of 9.0 or more. It is a thing.

The invention according to claim 3 is the invention according to claim 1 or 2.
In the engine with a mechanical supercharger described in (1), the mechanical supercharger is an internal compression pump.

According to a fourth aspect of the present invention, in the engine with a mechanical supercharger according to any one of the first to third aspects, the mechanical supercharger includes a pair of rotors, and gears for interlocking the two rotors. And the speed-increasing gear are attached to the mechanical supercharger.

According to a fifth aspect of the present invention, in the engine with a mechanical supercharger according to any one of the first to fourth aspects, the clutch control means has a predetermined value higher than the set rotational speed in a low load region. The clutch means is controlled so that the clutch means is disengaged on the low speed side and the clutch means is engaged on the high speed side at the rotational speed.

The invention according to claim 6 is the engine with a mechanical supercharger according to any one of claims 1 to 5,
A bypass passage for bypassing the mechanical supercharger and a bypass valve for opening the bypass passage when the clutch means is in a disengaged state are provided, and the engine speed is set from the low speed side in the high load region during acceleration. Bypass valve control means is provided for delaying the closing operation of the bypass valve when the number is exceeded.

According to a seventh aspect of the present invention, in the engine with a mechanical supercharger according to the sixth aspect, the opening / closing valve control means corresponds to the shift stage of the manual transmission, and the bypass valve of the bypass valve is closer to the higher shift stage. It is designed to increase the delay of the closing operation.

[0016]

According to the engine with a mechanical supercharger of the invention according to claim 1, when an acceleration operation is performed in a low speed range near the idle speed when the MT vehicle is started, the load increases due to the acceleration operation. Even if the engine speed reaches the set speed, the clutch means is in the disengaged state, so that driving of the mechanical supercharger in the low speed and high load range where the torque fluctuation of the engine is large is avoided, The gear rattle of the gear attached to the mechanical supercharger is prevented. The set rotational speed is higher than the idle rotational speed but is set to a rotational speed in the vicinity of the idle rotational speed. When the engine rotational speed exceeds the set rotational speed after the acceleration operation, the clutch means is engaged and the mechanical supercharger is driven. Therefore, the acceleration performance is kept good.

Particularly, in the case of an in-line engine having five or less cylinders and a high compression ratio engine having a compression ratio of 9.0 or more (claim 2), torque fluctuations in the low speed and high load range are apt to increase. It is highly useful to stop the mechanical supercharger to prevent rattling noise in the area.

When the mechanical supercharger is composed of an internal compression type pump (claim 3), since the fluctuation of the driving resistance is large, the gear tooth flapping when driven in the operating range where the torque fluctuation of the engine is large. When the sound is apt to increase and the mechanical supercharger is additionally provided with a gear for interlocking a pair of rotors and a speed-up gear (claim 4), when the driving is performed in an operating range where the torque fluctuation is large. While gear rattle is generated in each of the above gears, the inertia of the rotor is increased by increasing the speed, and the gear rattle of the gear is apt to increase, but in these cases as well, in the low speed and high load region, By disengaging the clutch means and stopping the mechanical supercharger,
The rattling noise is effectively prevented.

According to the engine with a mechanical supercharger of the fifth aspect of the present invention, the clutch means is maintained in the connected state from a low load to a high load at a speed higher than the predetermined speed, so that the clutch is engaged in the high speed range. It is possible to avoid a situation in which the clutch means is switched on and off and an excessive load is applied to the clutch means.

According to the engine with a mechanical supercharger of the sixth aspect of the present invention, the clutch means is engaged while the engine speed is increasing after the engine load increases due to the acceleration operation in the low speed range. When the feeder is switched to the driving state, the closing operation of the bypass valve is delayed, so that a situation in which sudden supercharging is performed and the torque suddenly changes can be avoided, and a smooth acceleration feeling can be obtained. .

Particularly, if the delay of the closing operation of the bypass valve is increased toward the higher gear according to the gear of the manual transmission (claim 7), a smoother feeling of acceleration can be obtained. .

[0022]

Embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows an outline of an engine with a mechanical supercharger. In this figure, the engine is composed of an engine body 1, an intake passage 2 provided with a mechanical supercharger 10, an exhaust passage 3 and the like. The output side of the engine is a manual transmission via a clutch. 50 are connected. The engine is an in-line engine with five or less cylinders, for example, a four-cylinder in-line engine, and the compression ratio is 9.0 or higher.

In the intake passage 2, an air cleaner 4, an air flow meter 5, a throttle valve 6, a mechanical supercharger 10, an intercooler 7, a surge tank 8, in that order from the upstream side.
A fuel injection valve 9 is provided. The mechanical supercharger 10
Is mechanically driven by an engine output shaft (not shown) to supercharge intake air. In the illustrated example, a Risholum pump, which is a type of internal compression pump, is used.

Supercharger 10 consisting of this Lisholm pump
2, as shown in FIG. 2, a pair of rotor 11 and rotor 1
2 and blades (not shown) corresponding to both rotors 11 and 12 are provided. By rotating both rotors 11 and 12 at a predetermined rotation speed ratio, intake air is compressed and discharged. The rotating shafts of both rotors 11 and 12 are provided with interlocking gears 13 and 14 that mesh with each other. Further, between the input shaft 15 and one of the rotating shafts, the input shaft 15
There are speed-increasing gears 16 and 17 for increasing the speed of rotation and transmitting it to the rotors 11 and 12. The rotation of the engine output shaft is transmitted to the supercharger drive pulley 18 via a belt (not shown).
An electromagnetic clutch 19 serving as a clutch means is provided between and, and when the electromagnetic clutch 19 is turned on (connected state), the rotation of the pulley 18 is transmitted to the input shaft 15 to drive the supercharger 10. State, electromagnetic clutch 1
When 9 is turned off (disconnected state), the pulley 18
The transmission of rotation from the input shaft to the input shaft is blocked, and the supercharger 10 is stopped.

Further, a bypass passage 21 for bypassing the supercharger 10 is provided in the intake passage 2 of the engine shown in FIG. 1, and the bypass valve 22 is provided in the bypass passage 21.
Is installed. The bypass valve 22 has a valve body 24 inside a housing 23 formed in the bypass passage 21 and an actuator 25 that operates the valve body 24.

The actuator 25 includes the valve body 24.
And a negative pressure chamber 27 and an atmospheric pressure chamber 28 provided on both sides of the diaphragm 26, which are connected to each other via a rod, and arranged on one side of the diaphragm 26 to urge the valve element 24 in the valve closing direction. And a spring 29. The negative pressure chamber 27 includes a negative pressure passage 33 communicating with a negative pressure source 32 such as a vacuum pump, an atmospheric pressure passage 34 communicating with the intake passage 2 upstream of the throttle valve 6, and a solenoid valve 31.
And the atmospheric pressure chamber 28 is connected via the throttle valve 6
It is connected to a passage 35 that communicates with the intake passage 2 that is located further upstream. Then, the solenoid valve 31 operates in response to a duty signal from the ECU described later, and thereby the introduction ratio of the negative pressure and the atmospheric pressure to the negative pressure chamber 27 is adjusted, whereby the valve body 24 of the bypass valve 22. The degree of opening is adjusted from fully closed to fully open.

Reference numeral 40 denotes an engine control ECU (control unit). The ECU 40 receives a signal from the air flow meter 5 and also detects a throttle opening sensor for detecting the opening of the throttle valve 6. 41, engine speed sensor 4 for detecting engine speed
2. Shift sensor 4 for detecting the gear stage of the manual transmission 50
The signal from 3rd grade is input. This ECU 40
Clutch control means 45 for controlling the electromagnetic clutch 19 according to the operating state, and bypass valve control means for controlling the bypass valve 22 by duty controlling the solenoid valve 31 according to the operating state and the gear stage of the manual transmission. 46 and.

The control of the electromagnetic clutch 19 according to the operating state by the clutch control means 45 of the ECU 40 will be described with reference to FIG.
Explained by. In the figure, the vertical axis represents the engine torque and the horizontal axis represents the engine speed, and a supercharger stop region I in which the supercharger 10 is stopped and a drive region in which the supercharger 10 is driven. It shows the turbocharger drive area II,
In the supercharger stop region I, the electromagnetic clutch 19 is turned off, and in the supercharger drive region II, the electromagnetic clutch 19 is turned on. Line A in the figure corresponds to the torque when the intake pressure downstream of the supercharger becomes atmospheric pressure, that is, the full-open torque without supercharging, and line B represents
This corresponds to the full-open torque when supercharging of intake air is performed by the supercharger 10.

As shown in the figure, at a speed lower than the first set engine speed N1, the supercharger 10 is stopped not only in the low load area but also in the high load area. This first set speed N1
Is higher than the idle speed of the engine and is near the idle speed (for example, 1000 rpm)
It is said that. Further, in the low load region, a predetermined rotation speed higher than the first set rotation speed N1 (for example, 2500 rpm).
After the second set rotational speed N2, which is m), the supercharger 10 is stopped on the low speed side and driven on the high speed side. Then, between the first set rotational speed N1 and the second set rotational speed N2, the low load side is bordered by a line having a predetermined torque that is somewhat lower than the line A at which the intake pressure downstream of the supercharger becomes atmospheric pressure. And the high load side, the supercharger 10 is switched between the stopped state and the driven state.

That is, the supercharger stop region I is in a region from a low load to a high load at a speed lower than the first set speed N1 and between the first set speed N1 and the second set speed N2. The low load side region is provided, and the supercharger drive region II is the high load side region between the first set rotational speed N1 and the second set rotational speed N2 and the second set rotational speed N2.
It is set as a region from a low load to a high load on the higher speed side than the set rotation speed N2.

The bypass valve control means 46 of the ECU 40 controls the bypass valve 22 as follows.

In the supercharger stop region I where the electromagnetic clutch 19 is turned off, the bypass valve 22 is opened, while
In the high load region of the supercharger drive region II where the electromagnetic clutch 19 is turned on, the bypass valve 22 is closed. Further, when the supercharger 10 is driven from a low load to a high load on the higher speed side than the second set rotational speed N2 as in the present embodiment, among the high speed side regions, The solenoid valve 31 is duty-controlled so that the bypass valve 22 is opened on the low load side, and the bypass valve 22 is gradually closed as the load increases.

Further, as indicated by the broken line arrow in FIG. 3, when the engine speed exceeds the first set speed N1 from the low speed side of the high load region during acceleration, the closing operation of the bypass valve 22 is delayed. To be done. That is, as also shown in FIG. 4, in the region on the lower speed side than the first set rotational speed N1, the engine rotational speed rises after the throttle opening becomes equal to or larger than the predetermined opening due to the acceleration operation, and the first set rotational speed N1 When the rotational speed N1 is exceeded, the electromagnetic clutch 19 is switched from off to on and the bypass valve 22 is operated from the open state to the closed state. At this time, the bypass valve control means 46 causes the bypass valve 22 to operate. The duty of the solenoid valve 31 is controlled so that the closing operation is gradually performed. In this case, the shift sensor 4
In response to the signal from 3, the delay of the closing operation of the bypass valve 22 is increased as the shift speed of the manual transmission 50 is closer to the high speed side. At the time of, the control is performed so that the closing operation of the bypass valve 22 is performed more gently.

The operation of the engine with a supercharger of this embodiment as described above will be described below.

Since high torque is not required in the low speed and low load range of the engine, the electromagnetic clutch 19 is turned off and the supercharger 10 is stopped in order to avoid energy loss due to driving of the mechanical supercharger 10. To be in a state. Further, in the high load region, in the operating region on the higher speed side than the first set rotational speed N1, the electromagnetic clutch 19 is turned on, the supercharger 10 is driven, and supercharging of intake air is performed, so that engine torque is increased. Is increased.

By the way, in the MT vehicle in which the manual transmission 50 is connected to the engine with the mechanical supercharger, at the time of starting acceleration,
The engine load may be higher than a predetermined value and the engine speed may be lower than the first set speed N1. However, in such a low speed and high load range, the electromagnetic clutch 19 is turned off and the supercharger is operated. By stopping the driving of the gear 10, the generation of gear rattle is prevented.

That is, as described above, when the mechanical supercharger is driven in the low speed and high load range as in the prior art, the rattling noise is generated, but more detailed description will be made. The gear rattling noise is caused by rattling of gears due to backlash when the torque transmitted to the gears fluctuates. Specifically, the corresponding gear contact surfaces collide once they are separated. When the electromagnetic clutch is turned on when the load is high in the low speed range near the idle speed, the gear fluctuations occur due to large torque fluctuations, and the turbocharger Since the torque is increased by the driving, the impact when the gear contact surface collides becomes large, and a large tooth rattle is generated.

In this case, an engine in which torque fluctuation easily increases at low speed and high load, for example, a serial engine with a relatively small number of cylinders (5 cylinders or less) and a high compression ratio engine having a compression ratio of 9.0 or more. In this case, the gear rattle of the gear tends to increase. Further, when the mechanical supercharger is an internal compression type pump such as a Lisholm pump, the rattling noise is likely to increase because the driving resistance of the mechanical supercharger varies greatly. Furthermore, FIG.
When gears 13 and 14 and speed increasing gears 16 and 17 for interlocking the pair of rotors 11 and 12 are provided, as shown in FIG. Rotor 1 is accelerated by 16 and 17
The high rotation of 1 and 12 increases the inertia thereof, which also increases the impact and tends to increase the rattling noise.

On the other hand, according to the engine with a mechanical supercharger of this embodiment, the electromagnetic clutch 19 is turned off even when the load is high in a region where the torque fluctuation on the low speed side is larger than the first set rotational speed N1. By stopping the driving of the supercharger 10, the generation of rattling noise is reliably prevented.

Moreover, the electromagnetic clutch 19 is turned off in the high load range in the first rotation speed near the idle speed.
Since it is limited to the area on the lower speed side than the set speed N1,
Acceleration performance is kept good. That is, when an acceleration operation is performed from a low speed, low load state near idle during start-up acceleration, etc., the speed is temporarily lower than the first set speed N1 and high load, but from this state the engine speed Takes a short time to rise and exceed the first set rotational speed N1,
When the first set rotational speed N1 is exceeded, the electromagnetic clutch 19 is turned on and the supercharger 10 is driven to increase the engine torque, so that the acceleration is favorably performed.

In the supercharger stop region I where the electromagnetic clutch 19 is turned off, the intake valve is opened and the intake air is supplied to the engine body 1 through the bypass passage 21. In the high load region in the supercharger drive region II that is turned on, the bypass valve 22 is closed, so that the supercharger 1
The intake air pressurized by 0 is supplied to the engine body 1. When the engine speed exceeds the first set speed N1 from the low speed side of the high load range during acceleration, as shown in FIG. 4, the electromagnetic clutch 19 is switched from off to on and the bypass valve is turned on. 22 is closed, but the closing operation of the bypass valve 22 is delayed, and the delay of the closing operation of the bypass valve 22 is increased toward the higher speed according to the gear stage of the manual transmission 50. , It is possible to avoid sudden changes in acceleration during acceleration, and a smooth acceleration feeling can be obtained.

This operation will be described with reference to FIG. This figure shows the change in acceleration when the operating state changes as indicated by the broken line arrow in FIG. 3 at the time of starting acceleration or the like, for each of the first speed and the second speed. As shown in this figure, during acceleration, as the engine load increases,
First, the acceleration increases to some extent while in the supercharger stop region I (lines C1 and D1), and then the engine speed becomes the first
When the set rotational speed N1 is exceeded, the supercharger 10 is driven and the torque is increased to further increase the acceleration, but if the closing operation of the bypass valve 22 is rapidly performed at this time, it will not be so much. In comparison, the acceleration increases sharply (lines C2 ', D2'), giving the driver a feeling of strangeness. On the other hand, when the closing operation of the bypass valve 22 is delayed as in the present embodiment, a part of the air discharged from the supercharger 10 immediately reaches the upstream of the supercharger through the bypass passage 21 immediately after the start of the supercharger drive. As the bypass valve 22 is recirculated and the bypass valve 22 is closed, the boost pressure is increased, whereby the acceleration gradually increases (lines C2 and D2), and a rapid increase in acceleration is avoided, and a smooth acceleration feeling is obtained.

The increase in acceleration while the supercharger stop region I is present is 2 more than when the gear stage is the first speed (line C1).
In the case of the high speed (line D1), since the delay of the closing operation of the bypass valve 22 is increased in the second speed as compared with the first speed, the acceleration after the supercharger drive is started is increased. It will be adjusted appropriately according to the gear stage.

Further, as shown in FIG. 3, in the low load region, the higher speed side than the second set rotational speed N2 is the supercharger drive region II, and in the low load region on the high speed side, the electromagnetic clutch 1 is operated.
9 is turned on, and the opening degree of the bypass valve 22 is controlled according to the engine load. In this way, the electromagnetic clutch 19 is kept in the on state from a low load to a high load on the higher speed side than the second set speed N2, so that the electromagnetic clutch 19 does not switch from the off to the on in the high speed range. Excessive load is prevented from being applied to the electromagnetic clutch 19 and the transmission mechanism, so that their reliability is ensured. In this case, if the region where the supercharger 10 is stopped in the low load region is unnecessarily narrowed, it is disadvantageous in terms of fuel consumption. Therefore, the second set rotational speed N2 is the first set rotational speed N1.
It is higher than that, for example, about 2500 rpm.

In the example shown in FIG. 3, the first set rotational speed N1 at which the electromagnetic clutch 19 is switched on and off is set to a constant value in the high load range, but the mechanical supercharger is operated in the low speed range. When the gear is driven, the gear rattling noise tends to increase on the higher load side, so as shown in FIG. 6, the higher the load in a high load region above a predetermined load, the higher the first set rotational speed N1.
May be set to shift to the high speed side.

[0046]

As described above, the present invention is an engine with a mechanical supercharger equipped with a mechanical supercharger provided with a gear and clutch means for connecting and disconnecting the transmission of power to the mechanical supercharger. In the one connected to the machine, in addition to disengaging the clutch means in the low speed and low load range, in the high load range, the clutch means is disengaged in the speed range lower than the set speed. Therefore, it is possible to reliably prevent the rattling noise of the gear attached to the mechanical supercharger when an MT vehicle enters a low-speed high-load state in which torque fluctuation is large during start-up acceleration or the like. it can. Moreover, the set rotational speed is set to be higher than the idle rotational speed and in the vicinity thereof so that the drive of the mechanical supercharger is stopped only in the area near the idle rotational speed where torque fluctuation easily occurs in the high load range. Therefore, the acceleration performance can be kept sufficiently good.

The present invention is also effective when applied to an engine in which torque fluctuations tend to increase particularly in a low speed and high load range, for example, an in-line engine having 5 or less cylinders and a compression ratio of 9.0 or more. Toothing noise can be prevented. Also, when using an internal compression type pump for the mechanical supercharger,
In the case where the mechanical supercharger is provided with a gear and a speed-increasing gear for interlocking the pair of rotors, the gear rattling noise is apt to increase when the engine is driven in an operation range where torque fluctuations are large,
In these cases as well, the rattling noise can be effectively prevented.

Further, when the engine speed exceeds the set speed from the low speed side in the high load region during acceleration, the closing operation of the bypass valve in the bypass passage bypassing the mechanical supercharger is delayed. If this is done, it is possible to avoid a sudden change in acceleration when the supercharger is switched to the driving state by connecting the clutch means while the engine speed is increasing from the low speed side of the high speed range during acceleration, and it is smooth. It can give a sense of acceleration.

[Brief description of drawings]

FIG. 1 is an overall schematic diagram showing an embodiment of an engine with a mechanical supercharger of the present invention.

FIG. 2 is a cross-sectional view showing an example of a mechanical supercharger.

FIG. 3 is a diagram showing an example of setting of an operating region in which a supercharger is stopped and an operating region in which a supercharger is driven.

FIG. 4 is an explanatory diagram showing operations of an electromagnetic clutch and a bypass valve during acceleration from a low speed range.

FIG. 5 is a diagram showing a change over time in acceleration when the engine speed exceeds a set speed from the low speed side of the high load range during acceleration.

FIG. 6 is a diagram showing another example of setting of an operating region in which a supercharger is stopped and an operating region in which a supercharger is driven.

[Explanation of symbols]

1 engine body 2 Intake passage 10 Mechanical supercharger 11,12 rotor 13,14 Gears for interlocking 16,17 Speed-up gear 19 Electromagnetic clutch 20 Bypass passage 22 Bypass valve 40 ECU 45 Clutch control means 46 Bypass valve control means 50 manual transmission

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tomomi Oshima, 3-1, Shinchi Fuchu-cho, Aki-gun, Hiroshima Prefecture Mazda Co., Ltd. (72) Inventor Yukio Mizaki 3-1-1 Shinchu, Fuchu-cho, Hiroshima Prefecture Mazda Incorporated (58) Fields investigated (Int.Cl. ⁷ , DB name) F02B 33/00 F02B 39/12 F02D 29/00

Claims (7)

(57) [Claims] 1. An engine connected to a manual transmission, comprising a mechanical supercharger arranged in an intake passage, a gear attached to the mechanical supercharger, and the mechanical supercharger. With a mechanical supercharger equipped with clutch means that can switch between a connection state for transmitting power to the connection state and a disconnection state for cutting off power transmission, and that makes the clutch means in the disconnection state in a low speed and low load region. In the engine, clutch control means for controlling the clutch means to be in a disengaged state in a region lower than the set speed even in the high load region is provided, and the set speed is higher than the idle speed and idle speed. An engine with a mechanical supercharger, which has a rotational speed in the vicinity of. 2. The engine with a mechanical supercharger according to claim 1, which is an in-line engine having five or less cylinders and a compression ratio of 9.0 or more. 3. The engine with a mechanical supercharger according to claim 1, wherein the mechanical supercharger comprises an internal compression type pump. 4. The mechanical supercharger comprises a pair of rotors, and a gear for interlocking the rotors and a speed increasing gear are attached to the mechanical supercharger. An engine with a mechanical supercharger according to any one of 1. 5. The clutch control means disconnects the clutch means at a low speed side and connects the clutch means at a high speed side with a predetermined rotation speed higher than the set rotation speed as a boundary in a low load region. The engine with a mechanical supercharger according to any one of claims 1 to 4, wherein the engine is controlled so as to be in a state. 6. A bypass passage for bypassing a mechanical supercharger, and a bypass valve for opening the bypass passage when the clutch means is in a disengaged state,
6. A bypass valve control means is provided for delaying the closing operation of the bypass valve when the engine speed exceeds a set speed from the low speed side of the high load range during acceleration. An engine with a mechanical supercharger according to Crab. 7. The opening / closing valve control means is adapted to increase the delay of the closing operation of the bypass valve toward the higher speed side according to the shift speed of the manual transmission. Engine with a mechanical supercharger.