JPS61279735A - Multicylinder rotary piston engine with supercharger - Google Patents

Abstract

PURPOSE:To restrain supercharging air from blowing back, by installing a timing valve, specified at its opening period and being opened or closed synchronously with an engine speed, in a supercharging passage, in case of a device which installs a natural suction passage and the supercharging passage to be closed later than the said passage both independently. CONSTITUTION:A suction passage 13 of a rotary piston engine is branched off into a natural suction passage 16 and a supercharging passage 17 at the downstream side of an air meter 15, while this natural suction passage 16 is interconnected to a suction port 9 of each cylinder 2a, and in the midway, there are provided with a main throttle valve 18 and a surge tank 19 side by side. In addition, in the supercharging passage 17, there are provided with a supercharger 20 to be driven from the upstream side, an intercooler 21 and a surge tank 22 side by side. In this case, a timing valve 24 to be opened or closed synchronously with an engine is rotatably installed in the supercharging passage 17 of each cylinder 2a, and the opening 24b is set to size equivalent to a range of 180 deg.-240 deg. at a turning angle of an eccentric shaft 6. In addition, length of the supercharging passage 17 is specified in relation to a pressure wave at high speed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a supercharged multi-cylinder rotary piston engine.

[Conventional technology]

In vehicle engines, a so-called partial supercharging method is known as a supercharging method, in which a natural intake passage and a supercharging passage that closes later are provided, in addition to the natural intake from the natural intake passage. , the air (or mixture) pressurized by the supercharger is supplied as supercharging air from the supercharging passage to improve charging efficiency and increase engine output. In the partial supercharging method, even though the pressure of supercharged air is higher than the pressure of naturally aspirated air, both must be inhaled at the same time. The problem is that it inhibits inhalation.

In that case, in the conventional 0 partial supercharging system tvx>v>,
.

For example, as shown in Japanese Unexamined Patent Publication No. 55-137317, a timing valve that opens in synchronization with engine rotation is provided in the supercharging passage, and supercharging from the supercharging passage starts near the end of intake from the natural intake passage. And the side of the naturally aspirated passageway for the supercharged air.There is a line 6 which suppresses the blow back 5.

However, when the system described in the above-mentioned prior art publication is applied to a multi-cylinder rotary piston engine with a supercharger, there is still a problem that there is a concern that supercharged air may blow back.

[Purpose of the invention]

In view of these problems, the present invention aims to provide a multi-cylinder rotary piston engine with a supercharger that can suppress blowback of supercharged air and improve charging efficiency.

[Structure of the invention]

As a method for suppressing the blowback of supercharged air as described above, first, the timing of closing the natural intake passage is advanced, and the timing of opening of the supercharging passage is delayed, so that the opening periods of the natural intake passage and the supercharging passage overlap. However, with this method, there is a problem that if the timing of closing the natural intake passage is early, the supply amount of naturally intake air cannot be secured at high engine speeds, and if the timing of opening the supercharging passage is delayed, , a problem arises in that the supply amount of supercharging air cannot be secured.

In addition, as another method to suppress blowback of supercharged air,
One idea is to reduce the diameter of the natural intake passage, but with this method, the amount of naturally intake air supplied will decrease over the entire operating range. Therefore, in any of the above-mentioned methods, even if the blowback of the supercharged air can be suppressed, a new problem arises.

Now, considering the causes of supercharged air blowback in conventional multi-cylinder rotary piston engines with superchargers, in multi-cylinder, for example, two-cylinder rotary piston engines, conventionally, a common supercharging passage for both cylinders is A timing valve was provided, and this timing valve controlled the opening and closing of the two supercharging passages, but in this case, the pressure inside the timing valve fluctuated at a cycle of 180°, resulting in curve a in Figure 3.
), the pressure inside the timing valve is high at the start of supercharging in the supercharging passage (see part A in Figure 3), and this high-pressure supercharge air is supplied into the working chamber, causing blowback of supercharge air. It is thought that the Therefore, if the pressure inside the timing valve is reduced when the supply of supercharging air from the supercharging passage is started, it is expected that the blowback of supercharging air will be suppressed.

Therefore, the present invention provides a multi-cylinder rotary piston engine with a supercharger that is equipped with a naturally aspirated passage and a supercharging passage that closes later than the naturally aspirated passage, and a timing valve is provided in the supercharging passage. The opening period of the timing valve is set in the range of 180 to 240 degrees, and the length of the supercharging passage connecting each timing valve is determined so that the pressure wave at high speed caused by the opening and closing of the timing valve is The length is set so that it can be transmitted between

In this invention, a timing valve is provided independently for each supercharging passage of each cylinder, and the opening period of the timing valve is set in the range of 180° to 240° in terms of the rotation angle of the eccentric shaft, so that supercharging can be started. At the same time, the pressure inside the timing valve is lowered by the low pressure in the working chamber where only natural intake is being performed, and due to this pressure drop, the pressure inside the timing valve increases during the latter half of supercharging, and the pressure inside the timing valve also increases. Because the connecting supercharging passage is set to a length that allows pressure waves to travel between the timing valves at high speeds, the resonance effect of the intake air increases, which further aggravates the above-mentioned pressure fluctuations inside the timing valve. be.

〔Example〕

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

1 and 2 show a supercharged multi-cylinder rotary piston engine according to an embodiment of the present invention.

In the figure, 1 indicates two cylinders 2 on the front side and rear side.
A two-cylinder rotary piston engine with a and 2b,
In the two cylinders 2a and 2b, side housings 4 are disposed on both sides of a rotor housing 3 having a multi-arc inner peripheral surface, and the rotor housing 3 and the side housing 4 constitute a casing 5. A polygonal rotor 7 that is supported by an eccentric shaft 6 and rotates planetarily is disposed within the casing 5. The above side housing 4 has intake stroke operation □
has been established.

An intake port 9 and a supercharging port 10 are formed opening into the chamber 8, and the supercharging port 10 is arranged at a position where it closes later than the intake boat 9. In addition, the rotor housing 3
An exhaust boat 11 is formed by opening into the exhaust stroke working chamber 8, and leading side and trading side spark plugs 12a, 12b facing the explosion stroke working chamber 8 are formed.
is installed.

On the other hand, an air cleaner 14 and an air meter 15 are provided at the upstream end of the intake passage 13 of the engine 1, and a natural intake passage 1 is provided at the downstream side of the air meter 15.
6 and a supercharging passage 17. A main throttle valve 18 that is interlocked with the accelerator pedal is disposed in the middle of the natural intake passage 16, and a surge tank 19 is formed downstream of the main throttle. The natural intake passage 16 communicates with the intake boats 9 of the corresponding cylinders 'la and 2b.

Further, a supercharger 20 driven by the engine is disposed in the supercharging passage 17, and an intercooler 21 and a surge tank 22 are disposed downstream of the supercharger 20, and the surge tank 22 and the main throttle A relief passage 23 is provided between the valve 18 and the natural intake passage 16 upstream of the valve 18, and a relief valve 23a that opens at a pressure equal to or higher than a set pressure is interposed in the middle of the relief passage 23. Further, the supercharging passage 17 is branched into two on the downstream side of the surge tank 22, and each supercharging passage 17
are communicated with the supercharging boats 10 of the corresponding cylinders 2a, 2b.

A timing valve 24 is rotatably provided in the middle of the supercharging passage 17 of the two cylinders 2a and 'lb. The timing valve 24 has an interior divided into two parts by a partition wall 24a, and an opening 24b that communicates the two interiors with the outside. The timing valve 24 has a rotating shaft 25. Pulley 26
．． Belt 27 and Boo! The driving force of the engine is transmitted through the shaft 128, so that the timing valve 24 rotates in synchronization with the rotation of the engine, and the eccentric shaft 6
Both supercharging passages 17 in the range of 180° to 240° with a rotation angle of
Each can be opened independently. Here, the opening period of the timing valve 24 is determined by the rotation angle of the eccentric shaft 6 from 180° to 24°.
The reason for setting the range to 0° is that in a range smaller than 180°, the timing valve 24 due to the low pressure in the intake stroke working chamber 8
However, if the timing valve 24 starts opening too early, for example around 270 degrees, the effect of pressure decrease cannot be obtained as described above. Even though this is obtained, the pressure inside the valve when the timing valve 24 is open is still in a high state, and the upper limit is set to 240° in consideration of the invalid period when the timing valve 24 is opened. Furthermore, the reason why the inside of the timing valve 24 is defined, that is, the reason why a timing valve is provided for each supercharging passage 17 is that when each supercharging passage is opened and closed with one timing valve as in the past, the timing valve Valve opening period is 180
This is because if the timing valve is set to 180 degrees, the open periods of the respective supercharging passages overlap, and in practice, the opening period of the timing valve cannot be made greater than 180 degrees.

Further, a partition wall 2 is provided downstream of the timing valve 24 in the supercharging passage 17.
9 is formed, and an on-off valve 30 is provided to open and close the passage 29a defined by the partition wall 29, and the on-off valve 30 is provided with an actuator 31 that is operated by exhaust pressure and closes at low speed. A sub-throttle valve 32 is provided downstream of the on-off valve 20 and starts to open when the load exceeds a set load. In addition, the length l of the supercharging passage 17 that communicates the two chambers of the timing valve 24 increases the engine speed.
15,000 rpm to 7,000 rpm I11 (7) Pressure wave at high speed is ta Timing valve 24
For example, the standard engine speed is 6000 rpm. Yo16, Kay, a7. Oh. 4o2. . □ Supercharging passage 1 connecting i
7 may be set to approximately 1600 mm.

Next, the operation will be explained using FIG. Here the third
The figure shows the front side of the timing valve 24 and the side (111!
JF'3(7)EEka. i2, k, 7ke+2407o
'□7F side and Ya side. Open,. It's a change. 4 o, □, l.

□1J In the figure, characteristic curve a is the timing in the conventional method.
□＋noa kawai, ya, tr, 1 inbc yo ai
iiTh, J! -) 10'□゛ shows the change in the opening area, and the two-dot chain line C shows the change in the opening area of the intake boat 9.

When the engine is running at a high speed of 500 rpm to 7,000 rpm, which is higher than the set load, the sub-throttle valve 32 opens in conjunction with the main throttle valve 18, and the actuator 31 opens the on-off valve 30 in accordance with the exhaust pressure. In this state, for example, when the intake boat 9 starts to open in the front cylinder 2a (see C in FIG. 3), the main throttle valve 1
The amount of intake air corresponding to the opening degree of 8 begins to be naturally drawn into the intake stroke working chamber 8 via the natural intake passage 16 and the intake boat 9, and the supercharging boat 10 also begins to open later than this (
(see b in FIG. 3), at this time the opening 2 of the timing valve 24
4b is closed and supercharging air is not yet supplied. When the rotor 6 rotates and the opening 24b of the timing valve 24 begins to open (see f in Fig. 3), the timing valve 24
The air inside is sucked and the pressure inside the timing valve 24 decreases (see arrow B in Fig. 3), and as the pressure inside the intake stroke working chamber 8 rises, the pressure inside the timing valve 24 also begins to rise.
This pressure is the supercharging pressure from the supercharger 20 and the timing valve 2.
The height of the opening 24b of the timing valve 24 of the rear cylinder 2b with a phase difference of 180° increases due to the influence of the pressure drop when the valve 4 is opened (see arrow C in Figure 3). The pressure wave is propagated to the chamber on the front side of the timing valve 24 (see the arrow in Fig. 3), and the pressure in the chamber on the front side of the timing valve 24 increases significantly. During the second half of the supercharging stroke from the supply boat 10, the air is supplied into the intake stroke working chamber 8, and when the engine is running at high speeds and under high load, a large amount of intake air is naturally drawn in from the natural intake passage 16 during the first half of the intake stroke, and during the second half of the intake stroke. A large amount of supercharged air with increased pressure is supplied to the

Also, when the engine is under low rotation and high load, which is less than 500 Orpm and more than the set load, the actuator 31 operates the on-off valve 3.
Close 0. Then, the timing at which the opening 24b of the timing valve 24 starts to open is delayed compared to when the rotation speed is high, and the timing valve 24 starts opening later.
The opening period of the timing valve 24 is shortened, and when the engine is running at low speed and under high load, supercharging air is supplied at a delayed timing compared to when the engine is running at high speed and for a short period of time depending on the opening time of the timing valve 24. That will happen.

In the device of this embodiment as described above, a timing valve is provided independently for each supercharging passage of each cylinder, and the opening period of the timing valve is set in the range of 180° to 240°. As a result, blowback of supercharged air when the timing valve is opened can be suppressed, and a large amount of intake air can be naturally taken in from the natural intake passage.

In addition, in this device, the pressure inside the timing valve is reduced when the timing valve is opened, so the pressure fluctuation inside the timing valve increases and it is possible to increase the pressure inside the timing valve, that is, the supercharging pressure in the latter half of the supercharging period. It is possible to supply a sufficient amount of supercharging air.

In addition, in this device, the length of the supercharging passage connecting the openings of the timing valve is set to a length that allows the pressure wave to be transmitted between the openings of the timing valve, so the resonance effect of the intake air is increased, and this increases the pressure inside the timing valve. Pressure and force fluctuations become even larger, and as a result, it is possible to more reliably suppress the above-mentioned blowback of supercharged air when the timing valve is opened, and increase the amount of supercharged air in the latter half of the supercharging period. (see d in FIG. 3) is lower than in the conventional system, and as a result, the capacity of the supercharger may be smaller.

By the way, when the engine is running at low speeds and under high load, the Opara 7 between the intake boat and the supercharging boat will change as the engine speed decreases.
As the pumping time increases, the blowback of supercharging air increases and the supercharging time becomes unnecessarily long. However, in this device, a partition wall and an on-off valve are installed to delay the opening timing of the timing valve.
Since the valve opening period is shortened, the blowback of supercharging air does not increase, and the supercharging time does not become too long.

Although a two-cylinder rotary piston engine has been described in the above embodiment, the present invention can of course be similarly applied to a multi-cylinder rotary piston engine other than two cylinders.

Further, the timing valve may be provided separately instead of defining the interior.

〔Effect of the invention〕

As described above, according to the present invention, in a multi-cylinder rotary piston engine with a supercharger that includes a naturally aspirated passage and a supercharging passage that closes later than the naturally aspirated passage, and a timing valve is provided in the supercharging passage, the timing valve is are provided independently for each cylinder, the opening period of the timing valve is set in the range of 180° to 240°, and the length of the supercharging passage connecting the timing valves is set to allow the timing valve to open and close at high speeds caused by the opening and closing of the timing valve. Since the length is set so that the pressure wave can be transmitted between the timing valves, it is possible to suppress blowback of supercharged air in the first half of the intake stroke and increase the natural intake amount, and a sufficient amount of supercharged air can be delivered in the second half of the intake stroke. There is an effect that can be supplied.

[Brief explanation of drawings]

FIG. 1 is a side view of a multi-cylinder rotary piston engine with a supercharger according to an embodiment of the present invention, FIG. 2 is a front view of the main parts of the engine, and FIG. 3 is a timing diagram for explaining the operation of the engine. FIG. 6 is a diagram showing a timing chart of pressure changes in the front and rear chambers of the valve and changes in the opening area of the front and rear timing valves. 1... Rotary piston engine, 6... Eccentric shaft,
16...Natural intake passage, 17...Supercharging passage, 2o.
...Supercharger, 24...Timing valve. Patent Applicant: Mazda Motor Corporation Agent, Patent Attorney Ken Hayase - Figure 2 Figure 3 Figure 2/C' or I Skin-

Claims (1)

[Claims] (1) In a multi-cylinder rotary piston engine with a supercharger that has a naturally aspirated passage and a supercharging passage that closes later than the naturally aspirated passage, the supercharging passage of each cylinder is synchronized with the rotation of the engine. A timing valve that opens and closes is provided independently, and each supercharging passage is connected to the upstream side of the timing valve.
The length of the supercharging passage connecting each timing valve is set to such a length that pressure waves generated at high speeds due to the opening and closing of the timing valve are transmitted between the timing valves during a rotation angle of 180° of the eccentric shaft, and The valve period is 18 by the rotation angle of the eccentric shaft.
A multi-cylinder rotary piston engine with a supercharger, characterized in that the angle is set in the range of 0° to 240°.