JPS63143319A - Engine with supercharger - Google Patents

Abstract

PURPOSE:To obtain favorable supercharging and fuel consumption with a simple structure by carrying out a partial-cylinder supercharging, etc. at the time of a high load operation, while operating a supercharging pump utilizing intake negative pressure by means of the whole intake air of cylinders and recovering power at the time of a low load operation. CONSTITUTION:At the time of a high load operation of an engine E, both of a second control valve 17 and a throttle valve 18 are controlled to be full open, negative pressure generated in a natural intake passage 6 is introduced into an actuator 16 through a negative pressure introducing passage 15 which is connected to a branch part 14, and a first control valve 12 is closed to shut off the natural intake passage 6 from a supercharging passage 5. Thereby, the first and fourth cylinders 1, 4 of the engine E is fed with supercharged air, whereas, non-supercharged natural intake air is taken into the second and third cylinders 2, 3. On the other hand, at the time of a low load operation, the second control valve 17 is closed to make the whole of the intake air which is to be taken into the whole cylinders 1-4 flow into the supercharging passage 5 through the throttle valve 18. Also, the first control valve 12 is opened.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] This invention relates to an improvement in a supercharged engine equipped with a supercharging passage and a naturally aspirated passage.

F. Prior Art] When supercharging is performed using a so-called mechanical supercharger, which uses part of the engine power to drive an air pump for supercharging, conventionally, fuel consumption has been reduced due to pump drive resistance. deterioration was a major problem.

In particular, in the case of all-cylinder supercharging, the supercharging pump becomes large, so in addition to the problem of deterioration of fuel efficiency, there are also problems regarding installation space and mountability. For the above all-cylinder supercharging system,
In order to improve engine output to a certain extent and alleviate the problems associated with supercharging using mechanical superchargers, so-called partial cylinder supercharging is used to limit supercharging to only some cylinders. The method is known from the past. According to this partial cylinder supercharging system, the supercharging pump can be downsized, reducing engine power consumption associated with pump drive, improving fuel efficiency, and reducing the size of the engine intake system. can be achieved.

In addition, in the supercharging method using a mechanical supercharger, as another method of downsizing the supercharging pump and reducing driving resistance, in addition to the natural intake air taken into the cylinder, supercharging that is pressurized by the supercharging pump A so-called partial supercharging system is known in which air is supplied to the cylinder from a supercharging passage separate from the naturally aspirated passage (see Japanese Patent Laid-Open No. 59-200014).
. In this case, the supercharging pump only pressurizes a portion of the air taken into each cylinder of the engine, so the driving resistance is small and a small pump is sufficient.

On the other hand, a pump connected to the engine is interposed in the pump passage leading to the cylinder by bypassing the throttle valve provided in the intake passage of the cylinder, and this pump is connected to the intake flow rate when the throttle valve is fully opened. If the intake flow rate is made sufficiently small compared to the intake flow rate of the engine, the pump will be driven by the pressure on the suction side of the pump being higher than the pressure on the discharge side, and the pump torque generated at this time will be applied to the engine. It is known that it is possible to improve fuel efficiency by transmitting energy to the engine (see Japanese Patent Laid-Open No. 156429/1983).

In addition, as another method to further improve the problem of poor fuel efficiency caused by supercharging with a mechanical supercharger, we have installed an electromagnetic clutch on the supercharging pump to drive or stop the pump, thereby reducing the need for supercharging. It is also known that the electromagnetic clutch is used to stop the driving of the supercharging pump during light load operation, thereby reducing the consumption of engine power associated with driving the pump.

Problems to be Solved by the Invention However, as described above, when a pump is interposed in the pump passage of a cylinder and the pump is driven using the pressure difference between the upstream side and the downstream side of the pump, the pump The lower the pressure on the downstream side, the greater the effect of improving fuel efficiency, but conventionally,
Since the intake passage of the cylinder and the pump passage are not connected downstream of the pump, the negative suction pressure due to all the intake air of the cylinder cannot be applied to the downstream side of the pump, and the pressure on the upstream and downstream sides of the pump increases. It was not possible to make the difference large enough. Therefore, the effect of improving fuel efficiency was not as sufficient as compared to the case where the pump was driven using the suction negative pressure generated by all the intake air in the cylinder.

In addition, when stopping the supercharging pump during light load operation using an electromagnetic clutch, the electromagnetic clutch is turned 0N-OFF.
When switching, there is a problem that fluctuations in the engine output torque, so-called torque shock, occur, and in practice, there is a problem that the rotation of the pump cannot be stopped due to the reliability of the electromagnetic clutch in the medium-speed or high-speed rotation range. be.

[Purpose of the Invention] The present invention was made to solve the above-mentioned problems.In a supercharged engine that performs partial cylinder supercharging or partial supercharging, partial cylinder supercharging is performed during high-load operation. A simple configuration that improves engine fuel efficiency by performing charging or partial supercharging, and recovering power by driving the supercharging pump using the negative pressure generated by all intake air in the cylinder during light load operation. The aim is to achieve both improved fuel efficiency and supercharging.

[Means for solving the problem] Therefore, the present invention provides a supercharging passage in which a mechanical supercharger driven by the engine output shaft is interposed, and a naturally aspirated passage that supplies naturally aspirated air to the cylinder. In a supercharged engine that performs partial cylinder supercharging or partial supercharging, a communication passage that communicates a supercharging passage downstream of the supercharger with the natural intake passage, and the communication passage a first control valve provided in the natural intake passage upstream of the communication passage to control opening and closing of the communication passage; a second control valve provided in the natural intake passage upstream of the communication passage and controlling opening and closing of the natural intake passage; A control means is provided for controlling the first control valve to open the communication passage and controlling the second control valve to close the natural passage.

[Effects of the Invention] According to the present invention, partial cylinder supercharging or partial supercharging is performed during high-load operation, and during light-load operation, the supercharging pump is driven using the suction negative pressure due to all the intake air of the cylinder. The rotation ratio of the supercharging pump to the engine output shaft can be lowered by the Sashiroko, and the moving horn can be recovered, so a simple configuration can be used without using a complicated mechanism such as a variable boob mechanism. It is possible to achieve both improved fuel efficiency through power recovery and supercharging. In addition, since there is no need for an electromagnetic clutch, a small and simple supercharging pump is sufficient, which reduces costs, and also reduces the problem of drastic problems that occur when switching between ON and OFF states of the electromagnetic clutch. can also be resolved.

[Embodiments] Hereinafter, embodiments according to the present invention will be described in detail based on the accompanying drawings.

1 and 2 are system schematic diagrams of a partial cylinder supercharged four-cylinder engine showing an embodiment of the supercharged engine according to the present invention. As shown in these figures, the intake ports la and 4a of the first cylinder l and fourth cylinder 4 of the engine E communicate with the supercharging passage 5 through the intake branch pipe parts 1b and 4b, respectively, and and the intake bows of the third cylinder 3) 2a and 3a are the intake branch pipe portions 2b and 3, respectively.
It communicates with the natural intake passage 6 through b. A supercharging pump 8 for pressurizing the air sucked through the air cleaner 7 is interposed in the middle of the supercharging passage 5, and the supercharging pump 8 is attached to the output shaft 9 of the engine E. A transmission belt 11 installed between a driving pulley 9a and a driven pulley lOa attached to the rotating shaft IO of the supercharging pump 8
It is designed to be driven by the output shaft 9 of the engine E via.

A communication passage 13 is provided between the supercharging passage 5 and the natural intake passage 6 on the downstream side of the supercharging pump 8 and is selectively communicated with or shut off by a first control valve 12. 12 is the intake branch pipe portion 2a of the second cylinder 2 and the third cylinder 3.
Opening/closing is controlled by an actuator 16 connected to a negative pressure introduction path 15 communicating with a branch part 14 of the intake branch pipe part 3a according to the negative pressure of the branch part 14a. Further, a throttle valve 18 is provided in the supercharging passage 5 upstream of the supercharging pump 8 to control the amount of intake air supplied to the first cylinder 1 and the fourth cylinder 4. On the other hand, the second control valve 17 that controls the amount of intake air taken into the second cylinder 2 and the third cylinder 3 through the natural intake passage 6 is connected to the natural intake passage 6 upstream from the communication passage 13.
It is set in.

The second control valve 17 and the second throttle valve 18 are both connected to an accelerator mechanism (not shown), and the opening degree thereof is controlled according to the opening degree of the accelerator pedal (not shown), that is, the load of the engine E. It is supposed to be done.

In the above configuration, when engine E is operated under high load,
As shown in FIG. 1, both the second control valve I7 and the throttle valve I8 are fully open or approximately fully open, and the negative pressure generated in the natural intake passage 6 is transferred to the negative pressure introduction passage 15 connected to the branch part 14. The first control valve 12 is closed, and the natural intake passage 6 and supercharging passage 5 are cut off. Therefore, in this case, engine E
Supercharged air is supplied to the first cylinder 1 and fourth cylinder 4 through a supercharging passage 5, and naturally aspirated air that is not supercharged is supplied to the second and third cylinders through a natural intake passage 6. be done.

On the other hand, as shown in Fig. 2, during light load operation that does not require supercharging, the second control valve 17 is set to close, and the intake air is supplied to all cylinders 1, 2, 3, and 4. All the intake air passes through the throttle valve 18 and flows into the supercharging passage 5. At this time, the actuator I6 opens the first control valve 12 due to the negative pressure of the branch portion 14, and the supercharging passage 5 and the natural intake passage 6 are communicated with each other. Therefore, in this case, all the intake air taken into all cylinders 1, 2, 3. through the supercharging passage 5, and to the second cylinder 2 and the third cylinder 3,
The air is inhaled through the communication passage 12 and the natural intake passage 6 downstream of the communication passage 12.

The opening/closing states of the first control valve 12, second control valve 17, and throttle valve 18 according to the load of the engine E are adjusted as follows.
Schematically shown in the graph of Figure. As shown by the dashed line in this figure, the opening degree of the throttle valve I8 increases substantially linearly as the load increases, and the opening degree becomes 100% at the maximum load (100% load). As shown by the broken line, the second control valve I7 does not open in the light load range where supercharging is not required, but only begins to open at high loads that require supercharging. ), the opening degree is also set to 100%. As shown by the solid line, the first control valve 12 remains open while the second control valve 17 is closed, and begins to close as the second control valve 17 begins to open. It is set to completely close when the opening degree of the second control valve 17 reaches 100%.

As described above, according to the above embodiment, partial cylinder supercharging is performed by closing the first control valve 12 and opening the second control valve 17 during high load operation, and the first control valve 12 is closed during light load operation. open, and close the second control valve 17 to open all cylinders 1, 2, and 3.
．． 4 is inhaled via the supercharging pump 8, and all cylinders 1
By driving the supercharging pump 8 using the suction negative pressure of . .

Although the above embodiment was applied to an engine using a partial cylinder supercharging method, the present invention can also be applied to a so-called partially supercharged engine that has a natural intake passage and a supercharging passage for each cylinder. Can be applied.

FIG. 3 is a system schematic diagram of a partially supercharged engine showing another embodiment of the supercharged engine according to the present invention. As shown in this figure, in addition to a natural intake passage 32 and an exhaust passage 33, a supercharging passage 35 for supplying supercharging air is connected to the combustion chamber 31 of the cylinder 30. The supercharging passage 35 is provided by branching from an intake passage 39 located upstream of the natural intake passage 32 and extending from an air cleaner 36 to a throttle valve 38 via an air flow meter 37 on the downstream side of the throttle valve 38. It is a thing,
A supercharging pump 34 is interposed in the middle. A communication passage 41 that is selectively communicated or closed by a first control valve 40 is provided between the supercharging passage 35 and the natural intake passage 32 on the downstream side of the supercharging pump 34 . On the other hand, this communication path 4! A second control valve 42 for controlling the natural intake air amount is provided in the natural intake passage 32 on the upstream side of the communication passage 41, and a second control valve 42 is provided in the natural intake passage 32 on the downstream side of the communication passage 41. A fuel injection valve 44 that injects fuel in accordance with a control signal from a control unit 43 that controls the fuel injection amount accordingly is inserted from the side. The second control valve 42 and the first control well 40 are connected to a second negative pressure introduction passage 45 that is downstream of the throttle valve 38 and upstream of the supercharging pump 34 and that introduces the negative pressure of the supercharging passage 35. The opening and closing of the throttle valve 38 is controlled by the second actuator 46 and the first actuator 48 connected to the first negative pressure introduction path 47, respectively, and the throttle valve 38 is connected to an accelerator mechanism (not shown) and is opened and closed according to the load of the engine E'. Its opening degree is controlled. Although not particularly shown, the supercharging pump 34 is driven by the output shaft of the engine E' by rotating a booby mechanism and a transmission belt, as in the embodiment shown in FIGS. 1 and 2. Ru.

In the above configuration, when the engine E' is operated under high load, the throttle valve 3
8 and the second control valve 42 are both fully open or substantially fully open, and the first control well 40 is closed. Therefore, in this case, the supercharging air is drawn into the combustion chamber 31 of the cylinder 30 via the supercharging passage 35 and the natural intake air via the second control valve 42 and the natural intake passage 32.

On the other hand, during light load operation that does not require supercharging, the throttle valve 38 is in a throttled state;
A supercharging passage 35 on the downstream side of the supercharging pump 34 and upstream of the supercharging pump 34
The second actuator 46 closes the second control valve 42 and the first actuator 48 opens the first control valve 40 due to the negative pressure inside. Therefore, in this case, all the intake air flows through the throttle valve 38 and the supercharging pump 3.
4, the fuel passes through the supercharging passage 35 or the communication passage 41, and then passes through the natural intake passage 32 downstream of the communication passage 41, and is sucked into the combustion chamber 3I of the cylinder 300.

FIG. 5 shows the opening and closing states of the first control valve 110 and the second control valve 42, which are controlled to open and close by the downstream pressure of the throttle valve 38, depending on the opening degree of the throttle valve 38, that is, the load of the engine E'. Shown schematically.

As shown by the broken line in this figure, the second control valve 42 does not open while the opening of the throttle valve 38 is small, that is, in the light load range, but the opening of the throttle valve 38 increases when the load is high. The valve is set so that it begins to open only when the load reaches 100%, and the opening degree is set to 100% at maximum load. Further, as shown by the solid line, the first control well 40 remains open while the second control valve 42 is closed, and begins to close as the second control valve 42 begins to open. The second control valve 42 is set to completely close when the opening degree reaches 00%.

As described above, according to this embodiment, partial supercharging is performed by closing the first control well 40 and opening the second control valve 42 during high load operation, and during light load operation, the first control well 40 is closed and the second control valve 42 is opened.
0 is opened and the second control valve 42 is closed, suction is also performed on the naturally aspirated side via the supercharging pump 34, and the supercharging pump 34 is driven using the suction negative pressure of all the intake air, thereby reducing supercharging. The rotation ratio of the supply pump to the engine output Mj can be lowered to recover power.

In all of the above embodiments, the supercharging pump is constantly driven, but an N@clutch is attached to this supercharging pump, and in areas where the amount of intake air is very small and power recovery is impossible, Alternatively, the electromagnetic clutch may be turned off to stop driving the supercharging pump. In this case, the supercharging pump is disconnected from the engine output shaft and is running at idle due to the engine's suction negative pressure. Then, if the electromagnetic clutch is turned on when the pump rotation speed becomes larger than the product of the engine rotation speed and the pulley ratio, and power is recovered by connecting the supercharging pump and the engine output shaft, efficiency can be improved. Good fuel efficiency can be improved.

As is clear from the above description, according to the present invention, partial cylinder supercharging or partial supercharging is performed during high-load operation, and supercharging is performed using the negative pressure of all intake air during light-load operation. By avoiding driving the pump, it is possible to reduce the rotation ratio of the supercharging pump to the engine output shaft and recover power, so power can be recovered with a simple configuration without using complicated mechanisms such as variable pulley mechanisms. This makes it possible to achieve both improved fuel efficiency and supercharging. In addition, since there is no need for an electromagnetic clutch, a small and simple supercharging pump is sufficient, which can reduce costs, and the torque generated when the electromagnetic clutch is turned on and off. Shock problems can also be resolved.

[Brief explanation of the drawing]

1 and 2 are system schematic diagrams of a partial cylinder supercharging type four-cylinder engine showing an embodiment of the present invention, and FIG.
The figure shows the opening and closing states of each valve during high-load operation, and FIG. 2 shows the open and closed states of each valve during light-load operation. FIG. 3 is a system schematic diagram of a partially supercharged engine showing another embodiment of the present invention, and FIG. 4 shows each valve I for the embodiment shown in FIGS. 1 and 2. 2, 17.18 is a diagram schematically showing the DM opening/closing state, and FIG. 5 shows the opening degree of the throttle valve 38, that is, the first control well with respect to the load of the engine E', for the embodiment shown in FIG. 40 and a second control valve 42; FIG. E, E'... Engine, 5.35... Supercharging passage, 6.32... Natural intake passage, 8.34... Supercharging pump, 9... Engine output shaft, 12.40 ...First control valve, 13.41...Communication path, 17.42...Second control valve.

Claims (1)

[Claims] (1) In a supercharged engine equipped with a supercharging passage in which a mechanical supercharger driven by the engine output shaft is interposed, and a natural intake passage supplying naturally aspirated air to the cylinder, the supercharger a communication passage that communicates the supercharging passage downstream of the supercharging passage with the natural intake passage; a first control valve provided in the communication passage for controlling opening/closing of the communication passage; a second control valve provided in the intake passage for controlling opening and closing of the natural intake passage; and a second control valve for controlling the first control valve to open the communicating passage and closing the natural passage when the load is light.
A supercharged engine characterized by comprising a control means for controlling a control valve.