JPH02201021A - Mechanical supercharger for internal combustion engine - Google Patents

Abstract

PURPOSE:To secure the smooth acceleration feeling always by keeping the change gear ratio small during the stop of the supercharger, and while moderately changing the open degree of a bypass control valve in a bypass for bypassing a supercharger at the start of the supercharge. CONSTITUTION:A mechanical supercharger 2 is driven by an internal combustion engine 1 through an electromagnetic clutch 6 and a non-stage transmission mechanism having a V-belt 5 wrapped to connect between a drive side pulley 3 and a driven side pulley 4 respectively having channels which width are variable with the oil pressure. A bypass control valve 24 is provided on the way of a bypass passage 23 provided so as to bypass the supercharger 2. In the internal combustion engine like that, a control unit 11 control a pressure control valve 10 so as to keep the change gear ratio small during the stop of the supercharger. At the start of the supercharge, the open degree of the bypass control valve 24 is moderately changed by exhausting the air from diaphragm type actuator 25 through an orifice 33.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an improvement in a mechanical supercharging device for an internal combustion engine, and more particularly to a mechanical supercharging device whose drive system is equipped with a continuously variable transmission mechanism and a clutch mechanism.

Conventional technology A mechanical supercharger such as a roots blower is driven by the crankshaft of an internal combustion engine via a belt transmission mechanism, but in a configuration in which the supercharger is driven at a constant gear ratio, Sufficient supercharging cannot be achieved at low engine speeds,
In addition, the supercharger rotates at an excessively high speed in the engine high speed range, resulting in problems such as reduced durability.

Therefore, a mechanical supercharging device equipped with a continuously variable transmission mechanism has been proposed, for example, in Japanese Patent Application Laid-Open No. 63-167027.

For example, by changing the groove width of the pulley using hydraulic pressure, the effective diameter of the pulley in contact with the belt is changed, which in turn changes the gear ratio between the crankshaft and the supercharger drive shaft. The system detects the engine speed and load (for example, throttle valve opening), determines the optimum gear ratio based on these, and performs variable control of the gear ratio.

In addition, when equipped with such a continuously variable transmission mechanism6, it is undesirable in terms of fuel efficiency to continue driving the supercharger in a low load range where supercharging is not required at all, so it is generally recommended to use an electromagnetic clutch, etc. A clutch mechanism is also used, and by disconnecting and connecting this clutch mechanism, it is possible to stop the supercharger and switch the drive.

Further, Japanese Utility Model Publication No. 62-36239 discloses a supercharging device in which a bypass passage is provided to bypass a mechanical supercharger, and a bypass control valve is interposed in the bypass passage. The bypass control valve L is used to turn the turbocharger OFF and OFF.
The bypass passage is opened and closed in a manner corresponding to N.

Problems to be Solved by the Invention However, in the conventional mechanical supercharging device described in L.
When acceleration is detected from a change in throttle valve opening, etc., the clutch mechanism is connected to start driving the supercharger, and at the same time, the bypass control valve 1- is fully closed, so the inertia of the supercharger is reduced. Torque decreases temporarily due to weight, which tends to cause suffocation and so-called engine stalling at the beginning of acceleration, and also tends to cause discontinuous acceleration feeling.

Means for Solving the Problems The present invention provides a mechanical supercharger, a continuously variable transmission mechanism and a clutch mechanism provided between a crankshaft of an internal combustion engine and a drive shaft of the supercharger, means for detecting the load of the engine; means for detecting the rotational speed of the engine; and control means for controlling the gear ratio and latch mechanism of the continuously variable transmission mechanism based on the detected load and rotational speed; ”] A bypass passage that bypasses the supercharger and communicates the -L flow side and the downstream side thereof, and a bypass passage that is interposed in this bypass passage and that corresponds to the In a mechanical supercharging device for an internal combustion engine, which includes a bypass control valve that opens and closes a bypass passage, the gear ratio is kept small while the supercharger is stopped, and the bypass control valve is configured to maintain a small gear ratio when the supercharger is stopped, and to It is characterized by the provision of a buffer means that moderates changes in opening degree.

When the internal combustion engine accelerates from the non-supercharged region, the clutch mechanism is connected and supercharging begins. At this time, since the gear ratio of the continuously variable transmission mechanism is kept small, the load required to start driving the supercharger becomes small. At the same time, the bypass control valve in the bypass passage is fully opened, but the change in opening degree is moderated by the buffer means, providing a smooth sensation of acceleration.

EXAMPLE Hereinafter, an example of the present invention will be described in detail based on the drawings.

FIG. 1 is a structural explanatory diagram showing the overall structure of a mechanical supercharging device according to the present invention.

In the figure, reference numeral 1 indicates an internal combustion engine, and reference numeral 2 indicates a mechanical supercharger including a Roots blower and the like supported on the side of the internal combustion engine I. A driving pulley 3 is attached to the crankshaft 1a of the internal combustion engine, and a driven pulley 4 is attached to the supercharger 2, and a V-belt 5 is wound around both. The drive side pulley 3. As will be described later, the driven pulley 4 is configured so that its groove width changes depending on the oil pressure, and these constitute a continuously variable transmission mechanism. And the driven pulley 4
An electromagnetic clutch 6 is interposed between the drive shaft 2a of the supercharger 2 and the drive shaft 2a of the supercharger 2 as a clutch mechanism.

The gear ratio of the continuously variable transmission mechanism is controlled by the hydraulic pressure supplied via the hydraulic passage 8. This oil pressure uses an oil pump 9 built into the internal combustion engine I as the oil pressure source, and is variably controlled to an appropriate pressure by a pressure control valve 10. In detail, the control unit 11 is attached to the pressure control valve lO.
A driving pulse signal with a constant period is given from the oscillator, and the pressure is controlled by controlling the ON duty ratio. Note that 12 is a return passage for returning surplus oil from the pressure control valve IO to an oil pan (not shown), 13 is a check valve, and 14 is an accumulator.

The control unit II is composed of a so-called microcomputer system that executes control according to a predetermined program. 15 is a crank angle sensor that detects the engine rotation speed, that is, the rotation speed of the crankshaft 1a, and 16 is a throttle valve I7 as a load of the internal combustion engine l.
A throttle valve opening sensor 18 detects the opening of the engine, and an air flow meter 18 detects the intake air of the engine, and these detection signals are manually input to the control unit 11 indicated by L.

Further, a bypass passage 23 is provided to communicate the intake port 21 of the supercharger 2 with the intake outlet 22, and a bypass control valve 24 is interposed in the bypass passage 23. The diaphragm actuator 25 that drives the bypass control valve 24 has a diaphragm 26 defining a second pressure chamber 28 and a second pressure chamber 28.
A return spring 29 is disposed on the second pressure chamber side, and the second pressure chamber 28 communicates with the downstream side of the bypass control valve 24 via the pressure passage 30, and the first pressure The chamber 27 communicates with the throttle valve 17 and the flow 111Nj via pressure passages 31,32. An orifice 33 and a check valve 34 are provided in parallel between the pressure passage 3m and the pressure passage 32.

FIG. 2 is a sectional view showing details of the drive side boo'J3. This driving pulley 3 has a lubricating oil passage 4 in the center.
1, a fixed pulley member 43 fixed to the crankshaft 1λ by the bobbin fixing bolt 42, and a flange fixed to the tip of the crankshaft 1a by the same two-legged bobbin identification bolt 42. Member 44
and the fixed boolean member 43 and the flange portion It44.
and a movable pulley member 45 that is located between the two legs and is slidable in the axial direction.
5a, a belt groove 46 is formed. The movable boom member 45 is urged by a return spring 47 in a direction in which the groove width of the belt ii'146 is reduced. Furthermore, an oil chamber 48 into which lubricating oil is introduced is formed between the movable pulley member 45 and the flange member 44, and the oil pressure similarly acts in a direction to reduce the groove width of the belt 1i146. ing. Note that 49 is a guide bin. Further, 50 is a water pump driving pulley that is integrally provided with the fixed pulley member 43.

Further, FIG. 3 is a sectional view showing details of the driven pulley 4 and the electromagnetic clutch 6. The driven pulley 4 is generally composed of a fixed bobbin member 51 fixed to the pulley shaft 4a together with a boss portion 511, and a movable pulley member 52 fitted to the outer periphery of the boss portion 51a so as to be slidable in the axial direction. and
A belt WII53 is formed by both. The movable pulley member 52 is connected to the belt 1f153.
The return spring 54 is biased in a direction in which the groove width is reduced. The bipedal driven pulley 4 includes an auxiliary drive pulley 55 for driving auxiliary machines such as a power steering oil pump and an air conditioner compressor.
56 are integrally provided. Moreover, the electromagnetic clutch 6 is
A clutch rotor 57 is fixed to the pulley shaft 4a via an auxiliary drive pulley 56, and an armature plate 58 is attached to the drive shaft 2a of the supercharger 2 and is movable into and out of contact with the clutch surface of the clutch rotor 57. and a solenoid 59 that attracts the armature plate 58 toward the clutch rotor 57.

FIGS. 2 and 3 show the lower half ζ when the oil pressure in the oil chamber 48 is low, and the lower half ζ shows the state when the oil pressure is high. That is, when the pressure control valve 10 controls the oil pressure supplied to the oil chamber 48 to be low, the belt 5
The groove width of the belt Wlt46 of the driving pulley 3 naturally expands due to the tension.

Therefore, the effective diameter on the driving side is reduced. At the same time, in the driven pulley 4, the shoulder width of the belt groove 53 is reduced by the biasing force of the return spring 54, and its effective diameter becomes large. Therefore, the gear ratio (driven side rotation speed/drive side rotation speed)
becomes small, and the supercharger 2 is driven to decelerate.

When the hydraulic pressure supplied to the oil chamber 48 is controlled to be high by the pressure control valve IO, the belt 1i14 of the driving pulley 3
The groove width of No. 6 is reduced, and the effective diameter on the driving side becomes large. At the same time, in the driven pulley 4, the width of the belt groove 53 is expanded due to the belt tension, and its effective diameter becomes smaller. Therefore, the gear ratio increases, and the supercharger 2 is driven to increase its speed.

In the embodiment described above, the speed ratio is variably controlled based on the engine speed and the load, that is, the throttle valve opening. Similarly, ON/OFF of the electromagnetic clutch 6, that is, engagement/disengagement of the clutch, is controlled based on the engine speed and the throttle valve opening. Here, when the electromagnetic clutch 6 is off, that is, when the supercharger 2 is stopped, the oil pressure supplied to the oil chamber 48 is controlled to be low. Therefore, the driven pulley 4 idles while the gear ratio is kept at the minimum. Further, at this time, the downstream side of the throttle valve I7 becomes negative pressure, and as a result of this negative pressure being introduced into the second pressure chamber 28 of the actuator 25, the bypass control valve 24 is in a fully open state. Therefore, intake air is introduced into the engine through the bypass passage 23.

From this state, when the throttle valve (7) is suddenly opened to enter the supercharging region, the electromagnetic clutch 6 is turned on and the supercharger 2 starts operating. At this time, since the continuously variable transmission mechanism is set to the minimum gear ratio in advance, the load required to start up the supercharger 2 is relatively small, and therefore, a temporary decrease in engine torque is suppressed. Further, since the downstream side of the throttle valve I7 becomes atmospheric pressure, the bypass control valve 24 tends to close due to the urging force of the return spring 29, but the discharge of air from the first pressure chamber 27 is suppressed by the check valve 34 and the orifice 33. As a result, the bypass control valve 24 gradually closes. Eventually, the bypass control valve 24 is fully closed, and the entire amount of intake air is sent to the engine through the supercharger 2.

That is, during sudden acceleration, after the electromagnetic club chiro is connected at the minimum gear ratio, the gear ratio of the continuously variable transmission mechanism is controlled to gradually increase, but as the gear ratio increases, the bypass control valve 24 is gradually close. The speed of change in the opening degree of the bypass control valve 24 changes depending on the size of the orifice 33, but it is designed so that the time it takes to fully close is shorter than the time it takes for the continuously variable transmission mechanism to reach its maximum gear ratio. is set to . Therefore, as shown by the solid line (a) in FIGS. 4 and 5, the supercharging pressure rises smoothly, and smooth acceleration can be performed without hunting or a feeling of step. The broken line (b) in Figure 4.5 shows the characteristics when the gear ratio is fixed, and the dashed line (c) shows the characteristics when the bypass control valve 24 is suddenly fully closed in a vehicle equipped with a continuously variable transmission mechanism. The characteristics when closed are shown.

Next, in the embodiment shown in FIG. 6, a communication hole 61 is opened and closed by a solenoid valve 62 instead of the orifice 33 described above. The electromagnetic valve 62 is supplied with a drive pulse signal of a constant period from the control unit 11, and the amount of discharge from the communication hole 61 can be variably controlled by controlling its ON duty ratio.

In this configuration, when the supercharger 2 is stopped, the solenoid valve 62
is not energized, and the solenoid valve 62 completely closes the communication hole 6I. At the time of acceleration, that is, at the start of supercharging, energization is started, the communication hole 61 is opened appropriately, and the bypass control valve 2 is opened.
The closing operation of step 4 will be adjusted. Here, in particular, the duty ratio of the drive pulse signal of the electromagnetic valve 62 is variably controlled so that the exhaust amount in the early stages of acceleration is relatively large and the exhaust amount in the latter stages of acceleration is relatively small. Therefore, the bypass control valve 24 closes relatively quickly at the beginning of acceleration, and closes quickly after the acceleration. Therefore, as shown by the two-dot chain line (d) in Figure 4.5, it is possible to accelerate the build-up of the boost pressure at the start of acceleration and improve the acceleration, and also to achieve smooth acceleration without hunting or a sense of step. Acceleration is possible.

Furthermore, if the amount of discharge through the communication hole 61 is suppressed to a small value and the closing speed of the bypass control valve 24 is slowed down during slow acceleration when the opening degree of the throttle valve 17 changes slowly, the rate of change in the throttle valve 17 can be reduced. It is possible to obtain a feeling of acceleration corresponding to the acceleration, and the - layer becomes preferable.

In the above embodiment, an example of a continuously variable transmission mechanism controlled by hydraulic pressure was explained, but the present invention is not limited to this, and it is also possible to use a continuously variable transmission mechanism using pneumatic pressure or the like. be. It is also possible to mainly change the groove width of the pulley on the supercharger side, and to change the groove width of the pulley on the internal combustion engine side accordingly.

Effects of the Invention As is clear from the explanation in Section 1-1, according to the mechanical supercharging device for an internal combustion engine according to the present invention, during acceleration, the clubge mechanism is connected with a small gear ratio, and the bypass control valve is connected. Since it closes gently, it is possible to prevent the torque from decreasing at the beginning of acceleration due to the load when the turbocharger starts driving, and
Boost pressure can be built up smoothly, allowing smooth acceleration without hunting or bumpy sensations.

[Brief explanation of the drawing]

Fig. 1 is a configuration explanatory diagram showing one embodiment of a mechanical supercharging device according to the present invention, Fig. 2 is a cross-sectional view of the driving side boob, Fig. 3 is a cross-sectional view of the driven side pulley and the electromagnetic clutch, and Fig. 3 is a cross-sectional view of the driven side pulley and the electromagnetic clutch. FIG. 4 is a characteristic diagram showing changes in supercharging pressure during acceleration, FIG. 5 is a characteristic diagram showing changes in vehicle acceleration during acceleration, and FIG. 6 is an explanatory diagram showing a different embodiment of the present invention. 2... Mechanical supercharger, 3... Drive side pulley, 4...
Driven pulley, 6... Electromagnetic clutch, IO... Pressure control valve, 11... Control unit, 23...
Bypass passage, 24...Bypass control valve, 25...
Diaphragm actuator, 33... orifice, 34... double reverse valve. Figure 2

Claims (1)

[Claims] (1) A mechanical supercharger, a continuously variable transmission mechanism and a clutch mechanism provided between the crankshaft of the internal combustion engine and the drive shaft of the supercharger, a means for detecting the load of the engine, and a means for detecting the load of the engine. means for detecting rotational speed; control means for controlling the gear ratio of the continuously variable transmission mechanism and the clutch mechanism based on the detected load and rotational speed; A mechanical turbocharger for an internal combustion engine, comprising a bypass passage that communicates with the side, and a bypass control valve that is interposed in the bypass passage and opens and closes the bypass passage in response to turning off and on of the supercharger. The feeding device is configured to keep the gear ratio small while the supercharger is stopped, and
A mechanical supercharging device for an internal combustion engine, characterized in that a buffer means is provided to moderate changes in the opening degree of the bypass control valve at the time of starting supercharging.