JPS6090924A - Internal-combustion engine with supercharger - Google Patents

Abstract

PURPOSE:To lower the specific fuel consumption of an Otto-cycle engine in which a supercharger consisting of at least two pumps connected in parallel with each other is connected to an output shaft of the engine, by employing such an arrangement that the output power of the pumps is transmitted to the output shaft of the engine at the time of low-load operation of the engine and supercharging of intake air is started at the time of high-load operation of the engine. CONSTITUTION:In a supercharger 2 which consists of two pumps 3, 3' and is driven by a driving means selectively according to the operational conditions of an engine 1, the pumps 3, 3' are disposed respectively in intake passages 8, 8' connected in parallel with each other, and supercharged intake air is supplied to the engine 1 via discharge passages 10, 10'. At the time of racing operation of the engine 1, throttle valves 11, 12 are closed completely and a shut-off valve 18 is fully opened so that work is done only the pump 3 and the output power of the pump 3 is transmitted to the engine 1. On the other hand, when the engine output is increased with opening of the throttle valve 12, intake air is supplied also into a work chamber 7' via passage 13-16 and the engine output is increased. With further opening of the throttle valve 12, the throttle valve 11 begins to open and supercharging of the engine 1 is started.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a supercharged internal combustion engine with improved fuel efficiency.

In general, in internal combustion engines with a supercharger, engine failure occurs due to reasons such as drive horsepower loss caused by driving the supercharger, excessive heat load and combustion pressure on the engine, and compression ratio reduction to avoid knocking. Fuel efficiency is poor.

The present invention is intended to solve these drawbacks, and will be described below with reference to the drawings.

FIG. 1 shows an embodiment of a supercharged internal combustion engine according to the present invention.
A supercharger 2 is provided which is connected to the output shaft of an engine 1 (an Otto engine) via a chain belt or the like.

A plan view of the supercharger 2 is schematically shown in FIG.
(Fig. 1 - Referred to as Repshield pump) and pump 3' (
Fig. 2 - Repshield pump) are connected to each other, and the rotors 4 are engaged with each other in a non-contact state (while maintaining an extremely small gap) by means of synchronous teeth (not shown). Pump 3' in Figure 2 is pump 3 in Figure 1.
Figures 1 to 3 will be comprehensively explained below.

From the suction side passages 8, 8' to the working chamber 7 (referring to the space in which the volume is changed in the supercharger, in the figure, referring to the space formed by the rotor 4, the rotor housing 5, and the side housing 6), 7' (the The supply air that has flowed into the engine (Figure 2) is supplied to the engine 1 via the discharge side passages 10, 10' (a fuel injection device is preferable as the fuel supply device).

9 and 9' indicate reed valves.

Now, considering the idling state of the engine, the throttle valves 11 and 12 are fully closed and the closing valve 18 is fully open, and the supply that has flowed into the pump 3 (into the working chamber 7) from the suction side passages 8' and 8. Air is supplied to the engine 1 through the discharge side passages 10, 10', thereby maintaining the idle state of the engine (the maximum volume of the working chamber 7 is, for example, 1/1/1 of that of the working chamber 7'). 5 to 1/6).

In this case, it is desirable not to restrict the supply air flowing through the suction side passage 8, but the supply air may be restricted to some extent.

Figure 4 shows a PV diagram (pressure-volume diagram) of the working chamber 7 when the throttle valves 11 and 12 are fully closed and the closing valve 18 is fully opened. 3 (supercharger 2) generates work corresponding to the shaded area, that is, power, and transmits this to the engine.

(As for the pump 3', since the communication passage 17 is fully open, there is no loss of supply air compression work.) Po indicates the pressure on the suction side (suction side passage 8) of the pump 3 (atmospheric pressure), and Pi indicates the pressure on the suction side (suction side passage 8) of the pump 3. The discharge side of the pump 3 (discharge side passage 10
) indicates the pressure (negative pressure).

Now, considering the idling state of the engine again, even if the throttle valve 11 is left slightly open, in other words, it will take up most of the supply air supplied to the engine (if the throttle valve 11 is fully closed). In the case of,
Even if the supply air is made to flow into the pump 3 (so as to account for all of the supply air supplied to the engine), the pump 3 (supercharger 2) can generate power.

When the throttle valve 12 (linked to the accelerator pedal, not shown) is opened in order to increase the engine output, the supply air flows through the suction side passage 13 and the connection part 14 (the side of the rotor 4' in the suction side passage 13). connection part), through the communication hole 15, and the suction side passage 16.
(formed in the side housing on the near side) also flows into the working chamber 7', the output of the engine is increased, and the throttle valve 1
When the throttle valve 2 is further opened, the throttle valve 11 also begins to open, and the engine is finally supercharged.

In this case, focusing on one working chamber 7' in which the pump 3' is located, the connection part 14 and the communication hole 15 (the rotor 4
When the throttle valve 11 is fully closed, the supply air flows into the working chamber 7' until this point in time. In FIG. 1, supply air is allowed to flow into the working chamber 7 at least up to the maximum volume of the working chamber (usually just after the maximum).

Furthermore, as shown in FIGS. 2 and 3, the negative pressure passage 19 opens immediately after the throttle valve 12, so that when the throttle valve 12 opens only slightly, atmospheric pressure is introduced into the diaphragm device 20, and the closing valve 1
8 is completely closed.

Throttle valve 12 opens slightly (throttle valve 11 is fully closed), and throttle valve 1 opens slightly.
Figure 6 shows a P-V diagram when the pressure immediately after step 2 becomes almost atmospheric pressure (the diameter of the throttle valve 12 should be made sufficiently large for this purpose), and as is clear from the figure. The pump 3' (supercharger 2) generates work, or power, corresponding to the shaded area.

As described above, according to the present invention, power is transmitted from the supercharger 2 to the engine 1 in the partial load range, including when the engine is idling, so the fuel consumption of the engine is significantly reduced even though it is an internal combustion engine equipped with a supercharger. will be improved.

By the way, in FIGS. 1 to 3, the supply air discharged from the pump 3 (the supply air flowing in the discharge side passage 10) joins the discharge side passage 10' and is guided to the engine. 5
It may be introduced into the combustion chamber 21 directly into the combustion chamber 21 at a position near the intake valve 22 as shown in the figure, or directly into the combustion chamber 21 via the auxiliary intake valve 23 as shown by the two-dot chain line.

As a result, (because the cross-sectional area of the discharge side passage 10 is sufficiently small), a fast jet of the supply air sent from the pump 3 (a fast jet of the supply air jetted from the discharge side passage 10) causes the inside of the combustion chamber 21. It is possible to further improve the fuel efficiency of the engine by suppressing the turbulence in the supply air that is formed.

The turbocharger according to the present invention is characterized in that at least two pumps are connected, and therefore, three pumps are connected as shown in FIG.
two pumps are connected, and when the engine is idling, the throttle valve 11,
11' is fully closed (or nearly fully closed), and the engine is maintained in an idling state by the supply air flowing into the pump 3 (at almost atmospheric pressure), thereby causing the supercharger 2 to generate power. ,
The throttle valve 11 may be opened after the throttle valve 11' is sufficiently opened.

In FIG. 1, supply air is allowed to flow into the working chamber 7 until the middle of the process from the minimum volume state to the maximum volume state of the working chamber 7,
FIG. 8 shows an embodiment in which the idling state of the engine is maintained by this. .

That is, in FIG. 8, focusing on one working chamber 7 of the pump 3, from the middle of the process from the minimum volume state to the maximum state of the volume of the working chamber 7 (hereinafter, this point is referred to as the Vc point), The communication hole 26 formed in the rotor 4 is connected to the suction side passage 25.
, 27, supply air flows into the working chamber 7, thereby maintaining the engine in an idling state (the throttle valve 24 is fully closed).

That is, the supply air is made to flow into the working chamber 7 so as to account for all of the supply air supplied to the engine via the working chamber 7 up to the Vc point.

Figure 9 shows a P-V diagram of the working chamber 7 when the throttle valve 24 is fully closed, and as is clear from the figure, the pump 3 (supercharger 2) corresponds to the shaded area. The job it does is to transmit power to the engine and improve fuel efficiency.

In this case, even if the throttle valve 24 is slightly opened when the engine is idling, in other words, most of the air supplied to the engine through the working chamber 7 up to the Vc point is Even if the supply air is made to flow into the same working chamber 7, the pump 3
It is possible to generate power (to the supercharger 2).

In order to increase the output of the engine, it is sufficient to open the throttle valve 24, and after the throttle valve 24 has opened sufficiently, the throttle valve 12 (
(Fig. 2) begins to open (the PV diagram of the working chamber 7 when the throttle valve 24 is fully opened will be similar to that shown in Fig. 4).

A tenth embodiment in which the pumps 3 and 3' are Roots pumps,
It is shown in Figure 11.

That is, in FIGS. 10 and 11, the turbocharger 2 is connected to pumps 28 and 28' (see FIG. 3), and when the engine is idling, the throttle valve 30 is fully closed (or almost fully closed) or closed. valve 32
is fully open, and the supply air flowing into the pump 28 from the suction side passage 8 is supplied to the engine via the discharge side passages 10, 10', thereby maintaining the idle running state of the engine.

At this time, the pressure on the suction side of the pump 28 (pressure in the suction side passage 8 - atmospheric pressure Po) is sufficiently higher than the pressure on the discharge side (pressure in the discharge side passage 10 - negative pressure Pi), so Power is generated in the pump 28 (in the supercharger 2), thus significantly improving the fuel efficiency of the engine.

In order to increase the output of the engine, the throttle valve 30 may be opened, which will eventually result in supercharging.

When the engine is being supercharged, the closing valve 3 is closed by a diaphragm device (not shown) that operates by sensing the pressure in the discharge side passage 10'.
2 is fully closed to prevent backflow of supply air.

In the first embodiment, the pumps 28, 28' are vane pumps.
Shown in Figures 2 and 13.

That is, in Figs. 12 and 13, the turbocharger 2 is connected to pumps 33 and 33' (see Fig. 3), and when the engine is idling, the throttle valve 30 is fully closed (or almost fully closed) and the closed valve is closed. 32
, 32', and 32'' are fully open, and as in Figures 10 and 11, the power generated by the pump 33 (supercharger 2) is transmitted to the engine, greatly improving fuel efficiency. .

The closing valves 32, 32', and 32'' are normally fully open to eliminate compression work loss of supply air, but when the engine is being supercharged, they are fully closed to prevent backflow of pressurized supply air. do.

14, 15, and 16 show the present invention applied to a supercharged diesel engine (the engine is not shown).

That is, in FIGS. 14, 15, and 16, the supercharger 2 has a pump 35 (roots pump) and a pump 35' (screw pump - of course, a roots pump may also be used) connected to each other, and rotors 29 and 40 on the lower stage side. The rotating shafts of the rotors 29 and 39 on the upper stage side are connected, but since the rotational speeds of the rotors 39 and 40 are different, the respective rotating shafts are not connected (the plane of the supercharger 2 (See FIG. 16, which shows the diagram schematically).

Therefore, another set of synchronizing teeth is required to mesh the rotors 39 and 40 without contacting each other.

Now, the low load range (especially the extremely low load range) including the engine idling state
Considering this, the throttle valve 42 is fully closed (or almost fully closed), the stop valve 43 is fully open, and the supply air flowing from the suction side passage 8 into the pump 35 (at atmospheric pressure) flows into the discharge side passage 10. , 10
′ is supplied to the engine (not shown), and the amount of fresh air (air) supplied to the engine is supplied to the engine through pump 3.
Compared to the case where the fresh air is supplied to the engine from the discharge side of the air at almost atmospheric pressure, the pressure is restricted to be lower (for example, the density of fresh air is made lower than the atmospheric pressure).

That is, all (when the throttle valve 42 is fully closed) or most (when the throttle valve 42 is slightly opened) of the supply air supplied to the engine through the supercharger 2 into the pump 35 is occupied. This allows supply air to flow in.

Thus, the pressure on the suction side of the pump 35 is equal to the pressure on the discharge side (
(negative pressure), power is generated in the pump 35 (in the supercharger 2) and transmitted to the engine.

As described above, according to the present invention, the amount of supply air (fresh air) supplied to the engine can be reduced compared to when only supply air is supplied to the engine from the discharge side of the supercharger 2 at almost atmospheric pressure. , so that the heat capacity inside the cylinder is appropriately reduced.

Therefore, since the compression end temperature rises sufficiently, combustion is improved, making complete combustion of the fuel possible, and misfires at extremely low engine loads are reduced, contributing to improved fuel efficiency (and reducing ignition delay). This has the advantage of reducing combustion noise because the combustion period is shortened and the rise in combustion pressure becomes more gradual.)

On the other hand, since the compression end pressure is reduced, engine friction loss is reduced and fuel efficiency is improved.

In general, if the amount of supply air supplied to the engine is restricted to be smaller than when only supply air is supplied to the engine from the discharge side of the supercharger at almost atmospheric pressure, the engine pump Fuel efficiency should suffer due to increased losses, but
In reality, it has the effect of improving fuel efficiency as mentioned above, so there is almost no negative effect on fuel efficiency.

According to the present invention, power is transmitted from the supercharger 2 to the engine in the low load range of the engine when the throttle valve 42 is fully closed or almost fully closed.

Therefore, the fuel efficiency of this branch engine is improved (normally, fuel efficiency suffers due to drive horsepower loss due to internal friction of the supercharger 2, etc.).

Furthermore, since there is no work loss in compression of the charge air in the supercharger 2, the fuel efficiency of the engine is greatly improved. Therefore, the object of the present invention is achieved.

When the amount of fuel injection increases and a larger amount of air is required to be supplied to the engine, the throttle valve 42, which starts opening from a predetermined opening degree of the accelerator pedal (not shown), is opened gradually or suddenly. This increases the pressure on the discharge side of the supercharger 2, and together with the increase in the amount of fuel injection, the output of the engine further increases (the throttle valve 42 is linked to the control rack that controls the amount of fuel injection). ).

Needless to say, the closing valve 43 is fully closed when the engine is supercharged.

Here, considering the low load region of the engine where the throttle valve 42 is fully closed or slightly opened, the discharge side of the supercharger 2 (discharge side passages 10, 10
'), a strong negative pressure is generated in the exhaust gas introduction passage 38 with an appropriate flow rate control device 37 as shown by the two-dot chain line.
By forming this, a large amount of exhaust gas flowing in the exhaust passage 36 can be introduced into the discharge side passages 10, 10'.

This has the advantage of further increasing the compression end temperature (since the temperature of the exhaust gas is extremely high), and also increases the amount of N in the exhaust gas.
It is also possible to reduce Ox.

In this case, when the flow rate of the exhaust gas introduced into the discharge side passages 10, 10' is gradually increased, the discharge side passage 1
The pressure inside 0 and 10' becomes almost atmospheric pressure, so no power is transmitted from the supercharger 2 to the engine, but at the same time, no pumping loss occurs in the engine, so this is caused by There is no negative impact on fuel efficiency (at this time, the compression end temperature rises sufficiently, but this is not due to a decrease in the heat capacity inside the cylinder; the amount of air supplied to the engine, that is, the amount of fresh air (This is due to the additional restriction and the introduction of exhaust gas.)

Even in this way, the compression end temperature rises sufficiently to improve combustion, and the compression end pressure decreases, reducing engine friction loss, while also reducing charge air compression work loss of the supercharger 2. (Generally, in a diesel engine with a supercharger, the charge air is constantly pressurized to above atmospheric pressure by the supercharger), so the fuel efficiency of the engine is significantly improved.

Note that the means described in FIGS. 2, 7, 8, and 10 to 13 are also applied to the supercharged diesel engine according to the present invention shown in FIGS. 14, 15, and 16.

Since the present invention is configured as described above, the fuel efficiency of the engine can be significantly improved.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a supercharged internal combustion engine according to the present invention, and FIG.
- Figures 3, 7, 8, 10 to 16 are diagrams of the supercharger in the present invention, Figures 4, 6, and 9 are PV diagrams, and Figure 5 is a diagram of the engine in the present invention. 1 is the engine, 2 is the supercharger, 3, 3', 3'', 28, 28
', 33, 33', 35, 35' are pumps, 4, 4',
29, 39, 40 are rotors, 5 is rotor housing, 6 is side housing, 7, 7', 41 is working chamber, 8
・8', 13, 16, 25, 27 are suction side passages, 9, 9
' is a reed valve, 10 and 10' are discharge side passages, and 11 and 12
・24, 30, 42, 11' are throttle valves, 14 is a connection part, 1
5 and 26 are communication holes, 17, 31, 31', 31'' are communication passages, 18, 32, 32', 32'', and 43 are closing valves,
19 is a negative pressure passage, 20 is a diaphragm device, 21 is a combustion chamber, 22 is an intake valve, 23 is a sub-intake valve, 34 is a notch, 36
37 is a flow rate control device, and 38 is an exhaust gas introduction passage. Patent applicant Shuichi Kitamura

Claims (8)

[Claims] (1) In an engine in which a supercharger connected to at least two pumps is connected to the output shaft of the engine, focus on one pump with the supercharger, and supply air is supplied to the engine into the pump. The supply air is reduced so that it occupies all or most of the air supply, and the pressure on the suction side of the pump is sufficiently greater than the pressure on the discharge side, thereby generating power for the pump, and the above When increasing the output of the engine from the above state, supply air is further supplied to the engine via the supercharger, and finally supercharging is performed. . (2) Focusing on one working chamber containing one pump containing a supercharger, supply air flows into the working chamber to at least the maximum capacity of the working chamber, thereby causing the pump to generate power. , when increasing the output of the engine from the above state, supply air is further supplied to the engine via the supercharger, and finally supercharging is performed. Internal combustion engine with supercharger. (3) Focusing on one working chamber in which one pump with a supercharger is located, it is necessary to Supply air is caused to flow into the working chamber so as to account for all or most of the supply air supplied to the pump, and the supply air is allowed to flow into the working chamber up to the Vc point, thereby generating power for the pump. , when increasing the output of the engine from the above state, supply air is further supplied to the engine via the supercharger, and finally supercharging is performed. Internal combustion engine with supercharger. (4) A patent that focuses on one pump in the supercharger, and is designed to strongly suppress the turbulence in the air supply that is formed in the combustion chamber of the engine due to the fast jet of air supplied from the pump. A supercharged internal combustion engine according to any one of claims 1 to 3. (5) In a diesel engine in which a supercharger connected to at least two pumps is connected to the output shaft of the engine, focus on one pump with the supercharger, and connect the engine into the pump via the supercharger. The amount of fresh air supplied to the engine is increased so that only the fresh air is at almost atmospheric pressure from the discharge side of the supercharger. If more air is required to be supplied to the engine, the pressure on the discharge side of the pump is restricted to be smaller than that when the air is supplied to the engine. An internal combustion engine with a supercharger, characterized in that the pressure on the discharge side of the supercharger is increased by further supplying air to the engine via the supercharger. (6) Generate power in the turbocharger so that the pressure on the discharge side of the turbocharger becomes negative pressure, and if more air is required to be supplied to the engine, the power is generated through the turbocharger. The internal combustion engine with a supercharger according to claim 5, wherein the pressure on the discharge side of the supercharger is increased by further supplying air to the engine. (7) The internal combustion engine with a supercharger according to claim 6, wherein exhaust gas is introduced into the discharge side of the supercharger. (8) With a supercharger according to claim 5, wherein the exhaust gas is introduced into the discharge side of the supercharger so that the pressure on the suction side and the pressure on the discharge side of the supercharger are approximately equal. Internal combustion engine.