JPS63109233A - Intake device for engine with pressure wave supercharger - Google Patents

Abstract

PURPOSE:To prevent exhaust gas from being mixed into an intake system even when exhaust pressure is increased at the time of low rotation and low load by providing a one-way valve in a position on the upper course side of a pressure wave supercharger and on the lower course side of the branch part between an intake passage and an intake bypass. CONSTITUTION:In the low rotation and low load of an engine 11, a shutter valve 18 is closed and a control valve 22 is opened due to intake negative pressure, feeding intake air into combustion chambers 12 via an intake bypass 21 while bypassing a pressure wave supercharger 15. If water enters from a tail pipe 28 or should the tail pipe 28 or a silencer 27 be deformed causing the pressure in an exhaust passage 14 to rise, exhaust gas flows out into the upper course part 13a of an intake passage 13 via the slit-formed passage of a rotor 31. However, the exhaust gas will not flow backward into the intake passage 13 due to a one-way valve 17.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an intake system for an engine equipped with a pressure wave supercharger.

[Prior Art] Various types of superchargers are used to boost charging efficiency by supercharging intake air, and one of them is a so-called complex type pressure wave supercharger that utilizes the pressure wave energy of exhaust air. One thing is well known. In such a pressure wave supercharger, an exhaust pulse is introduced from one end into one of the many slit-like passages provided in the internal rotor, thereby causing the intake air introduced from the other end to The slit-like passages are continuously arranged and rotated, and the intake air in each slit-like passage is compressed one after another and supplied to the combustion chamber, thereby producing a supercharging effect.

However, with such a pressure wave supercharger, when the engine is running at low speeds and under low load, the pressure of the exhaust gas upstream of the pressure wave supercharger is low, so a sufficient supercharging effect cannot be obtained, and the intake pressure is low. Because of this, there was a problem in that scavenging of the exhaust gas was incomplete and exhaust gas was mixed into the intake air, causing the engine to stall.

Therefore, as shown in FIG. 8, an intake passage 3 that communicates between the air cleaner I and the combustion chamber of the engine 2, and an exhaust passage 5 that communicates with the atmosphere from the combustion chamber via the silencer 4, In a system configuration including a pressure wave supercharger 6, a Nyatta valve 7 is interposed downstream of the pressure wave supercharger 6 in the intake passage 3, and a Nyatta valve 7 is provided downstream of the air cleaner l in the intake passage 3 and the pressure wave supercharger 6. A bypass intake passage 8 is provided which bypasses the pressure wave supercharger 6 from an upstream position and communicates with the shutter valve 7 downstream of the intake passage 3.
It has been proposed that a control valve 9 is interposed at the junction of the bypass intake passage 8 with the intake passage 3 (for example, in
1-27926).

In such a system, when the operating state of the engine 2 is in a low rotation/low load range that corresponds to region I shown in FIG. The valve 9 is opened and the intake air is supplied into the combustion chamber through the bypass intake passage 8 without being supercharged, thereby preventing exhaust gas from entering the intake air. When the state is in the load region (nearly medium-high load region) as shown in region H in FIG. 9, the shutter valve 7 is opened and the control valve 9 is closed by the supercharging pressure, so that supercharging is performed. It has become.

In this way, even in the conventional example, the mixture of exhaust gas into the intake air is prevented during normal low rotation and low load conditions.

However, at low speeds and low loads, the bypass intake passage 8
If the intake air is supplied through the tailpipe IO, for example, as shown in FIG. , if a puddle of water depth d = 250 mm is retreated at 10 km/hour, the maximum water depth d2 = 4
It will be 50 mm. ), in an engine equipped with a pressure wave supercharger, the exhaust pressure downstream of the pressure wave supercharger is extremely low (for example, 300 mmAq), so water easily enters the tail pipe 10 or the exhaust passage 5. is partially blocked, and as a result, the exhaust pressure rises above a predetermined value, the balance between intake and exhaust in the pressure wave supercharger 6 is disrupted, and exhaust gas flows into the intake passage 8, Arrow A in Figure 8
, ,A, ,A, ,A4 flow into the combustion chamber, causing a problem of engine stalling. However, the height of the tailpipe 10 cannot be made very high due to the layout (for example, it cannot be more than 450 mm), and the flow resistance of the exhaust gas becomes large due to the deformation of the tailpipe 10. Since similar phenomena sometimes occur, there is a need for a fundamental solution to the above problem.

[Object of the Invention] The present invention has been made in view of the above-mentioned problems of the conventional technology. An object of the present invention is to provide an engine equipped with a pressure wave supercharger that can prevent exhaust gas from entering an intake system even if such occurrence occurs.

[Configuration of the Invention] In order to achieve the above object, the present invention provides a shutter valve that is closed at low load in the intake passage downstream of the pressure wave supercharger, and reduces the pressure in the intake passage when the shutter valve is closed. "Wave supercharger" In an engine equipped with a pressure wave supercharger, which is provided with a bypass intake passage that communicates the first flow position and the downstream position of the shutter valve, the pressure wave supercharger is installed in the intake passage. A pressure wave supercharger characterized in that a one-way valve that only allows intake air flow to the downstream side is provided upstream of the machine and at a position downstream of the branching point between the intake passage and the bypass intake passage. Provides engine intake equipment.

[Effects of the Invention] According to the present invention, only the flow of intake air in the downstream direction is allowed in the intake passage at a position upstream of the pressure wave supercharger and downstream of the branching part between the intake passage and the bypass intake passage. However, since a one-way valve is installed to shut off the gas flow in the upstream direction, pressure wave supercharging can occur due to water entering the exhaust passage or deformation of the exhaust passage at low rotation speeds and low loads where the engine is likely to stall. Even if the exhaust pressure downstream of the machine increases and the exhaust gas flows into the intake passage through the pressure wave supercharger, it will not flow back upstream through the intake passage. Since the valve is also closed, exhaust gas does not flow into the combustion chamber, which prevents the engine from stalling. Furthermore, during medium and high loads, engine stalling does not occur even if exhaust gas flows into the combustion chamber, so according to the present invention, engine stalling due to causes specific to pressure wave superchargers can be reliably prevented in all operating ranges. can.

[Example code] Examples of the present invention will be specifically described below.

As shown in FIG. 1, the engine 11 includes a combustion chamber 12,
Intake passage 13 for supplying intake air to 12.12.12
is provided, while the combustion chamber 12゜12.12.12
An exhaust passage 14 is provided for exhausting combustion gas therein, and a pressure wave supercharger 15, which will be described in detail later, is provided spanning both the intake passage 13 and the exhaust passage 14.

The intake passage 13 is provided with an air cleaner 6 and a one-way valve I for blocking the flow of gas in the intake passage 13 in the flow direction.
On the other hand, downstream of the pressure wave supercharger 15, butterflies are closed in order from upstream to low rotation/low load ranges and other predetermined operating ranges to close the intake passage 13. In order to improve filling efficiency, an ink cooler I9 is provided to cool the intake air, which is adiabatically compressed and whose temperature has increased during supercharging. Further, from a position downstream of the air cleaner 16 and upstream of the one-way valve 17 in the intake passage 13, the pressure wave supercharger 15 is bypassed, and the shutter valve 1 of the intake passage 13 is
Bypass intake passage 2 communicating with a position slightly downstream of 8
1 is provided in the bypass intake passage 2I, and an intake passage I is provided in the bypass intake passage 2I.
3, a one-way type control valve 22 is interposed which is opened by the effect of intake negative pressure when the shirt valve 18 is closed.

On the other hand, the exhaust passage 14 has a branch section 23 located slightly upstream of the pressure wave supercharger I5, which bypasses the pressure wave supercharger 15, and is connected to a branch section 23 located slightly downstream of the pressure wave supercharger 15. A piper 7 inlet/exhaust passage 25 communicating with the section 24 is provided, and the collecting section 24
is provided with a waste gate valve 26 that opens and closes the bypass exhaust passage 25. The waste gate valve 26 is opened when the exhaust pressure rises excessively, and discharges a part of the exhaust gas through the bypass exhaust passage 25 to eliminate the excess exhaust gas. The supply pressure is adjusted so that it does not exceed the set value. Further, downstream of the gathering portion 24, the exhaust passage 14 is provided with a xylencer 27 and a tail pipe 28 in this order from upstream.

By the way, the pressure wave supercharger 15 has a rotor 31 fixed to a rotating shaft 30 that is rotatably held within a goose song 29 and has a large number of radially arranged slit-shaped passages (not shown). is rotationally driven by the crankshaft 33 of the engine 11 via the timing belt 32, so that both ends of the slit-like passage are connected to the two-point portion 13a of the intake passage 13 and the exhaust passage at predetermined timings. 14, or to a downstream portion +3b of the intake passage 13 and a two-point portion 14a of the exhaust passage 14. Along with such an operation, compression waves and expansion waves based on the exhaust gas pressure are generated in the slit-shaped passage, thereby performing a supercharging action on intake air and a scavenging action on exhaust gas. .

Below and above '7.5-LO) 9-7 explanation of the action 60
,,r First, when the operating range of the engine 11 is in the region (lower, middle-to-high load range) shown in FIG. 13 is sequentially guided to the upstream part 13a of the intake passage 13 via the air cleaner 6 and the one-way valve 17, and then to the pressure wave supercharger 1.
After being inhaled into the slit-shaped passage of the rotor 31 of No. 5, it is discharged into the downstream portion 13b of the intake passage 13 as the rotor 31 rotates, and then sequentially passes through the shutter valve 18 and the ink clerk 19 into the combustion chamber. ] 2,12.12.12
supplied to At this time, a compression wave is generated in the slit-shaped passage by the exhaust gas introduced from the upstream portion 14a of the exhaust passage 14, and the intake air is supercharged by the action of this compression wave. On the other hand, when the exhaust gas in the slit-shaped passage No. 42 is discharged to the downstream part +4b of the exhaust passage 14, an expansion wave is generated, and the scavenging of the exhaust gas is performed by the action of this expansion wave. . Note that at this time, the intake passage 13 downstream of the pressure wave supercharger 15 is in a pressurized state, so the control valve 22 is closed by this pressure, and intake air is not supplied from the bypass intake passage 21.

Next, when the operating region of the engine 11 is in the low rotation/low load region corresponding to region I in FIG. 9, the shutter valve 18 is closed, so the control valve 22 is opened by the action of the intake negative pressure. , the intake air bypasses the pressure wave supercharger 15 from the air cleaner 16 and enters the combustion chamber 12 through the bypass intake passage 21. +2. supplied to In this case, water may enter from the tail pipe 28,
Alternatively, the tail pipe 28 or the silencer 27
When the pressure in the downstream portion 14b of the exhaust passage 14 increases due to deformation of the do. However, the one-way valve 17 provided upstream of the upstream portion 13a of the intake passage 13 and downstream of the branching point with the bypass intake passage 21 prevents the exhaust gas from flowing backward in the intake passage 13. Therefore, the combustion chamber 12. +2.12.12 Exhaust gas is not mixed into the intake air supplied to the engine, thereby preventing engine stalling.

By the way, as shown in FIGS. 2, 3, and 4, the one-way valve 17 has a guide pin 33 that slides on the inner wall of the intake passage 13, and is fixed to the upper surface of the bulge 34 of the intake passage I3. A valve body 36 that opens and closes the intake passage 13 while slidingly contacting the guide member 35 is integrally formed. This one-way valve 17 is made extremely lightweight, and when even a very small amount of gas is guided into the intake passage 13 in the direction shown by arrow G in FIG. As shown, the one-way valve 17 slides the sliding portion of the guide pin 33-11 and the valve body 36 toward the inner surface of the intake passage 13 and the guide member 35 in the left direction in FIG. 2 until it is stopped by the stopper 37. It moves while making sliding contact, allowing intake air to circulate. At this time, the distance between the valve body 36 and the inner surface of the bulge 34 of the intake passage 13 is set sufficiently large to ensure a sufficient cross-sectional area of the passage so that the one-way valve 17 does not become a flow resistance. On the other hand, when gas is guided into the intake passage 13 in the direction shown by arrow G2 in FIG. It is moved to the right in FIG. 3 until it closes, completely blocking the flow of gas in the force direction (arrow G). In this way, the one-way valve 17 opens and closes in response to even the slightest differential pressure between the upstream and downstream sides of the one-way valve 17.

Note that the one-way valve 17 is not limited to the configuration described above; for example, as shown in FIG. It is also preferable that the butterfly valve is formed as a butterfly valve, and a weak tension spring 42 is attached between X and Y so that it can be opened and closed with a slight pressure difference.

In general, a check valve often vibrates in the direction of gas flow and makes a so-called chatter noise, so a resonator 43 is provided downstream of the one-way valve 17 in the intake passage 13, as shown in FIG. Alternatively, it is preferable to provide an expansion chamber 44 to cancel out the pulsation of the intake air.

[Brief explanation of the drawing]

FIG. 1 is a system configuration diagram of a pressure wave supercharged engine showing an embodiment of the present invention. FIG. 2 and FIG. 3 show the time when the valve is open and the time when the valve is closed, respectively.
FIG. 3 is a sectional view of a one-way valve. FIG. 4 is a sketch of the one-way valve. FIG. 5 does not show another embodiment of the one-way valve, but is a schematic cross-sectional view. FIG. 6 is a schematic diagram showing an example of a method for eliminating chattering noise of a one-way valve. FIG. 7 is a schematic diagram showing a state in which a car is moving backward through a puddle. FIG. 8 is a system configuration diagram of a conventional pressure wave supercharged engine. FIG. 9 is a diagram showing an example of an operating range in which the pressure wave supercharger is stopped. 11...Engine, 13...Intake passage, I4.
・Exhaust passage, 15...Pressure wave supercharger, 17...One-way valve, 18...Shutter valve, 2! ...Bypass intake passage, 22...Control valve.

Claims (1)

[Claims] (1) A shutter valve that is closed when the load is low is interposed in the intake passage downstream of the pressure wave supercharger, and when the shutter valve is closed, a position in the intake passage that is upstream of the pressure wave supercharger and a position downstream of the shutter valve In an engine with a pressure wave supercharger that is provided with a bypass intake passage that communicates with the position where An intake system for an engine equipped with a pressure wave supercharger, characterized in that a one-way valve is provided at a position downstream of a branching part to allow intake air to flow only to the downstream side.