JPS5917252B2 - Intake system for rotary piston engine with supercharger - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an intake device for a supercharged rotary piston engine.

Conventionally, the rotor was configured to rotate in a casing consisting of a rotor housing and side housings disposed on both sides of the rotor housing while slidingly contacting seal members installed on the top and side surfaces of the casing. There are well-known rotary piston engines in which a supercharger is installed in the intake passage to improve intake air filling efficiency and increase output.

By the way, in a rotary piston engine, when the working chamber defined by the casing and the rotor flank changes from the exhaust working chamber to the intake working chamber, a dead volume is formed between the casing and the rotor flank. This causes a problem in that part of the exhaust gas is brought into the intake working chamber as dilution gas, reducing the combustion efficiency of the air-fuel mixture.

In particular, during intake supercharging when the amount of intake air is large, the exhaust gas pressure and exhaust gas temperature in the exhaust working chamber become high, so the amount of illusion gas brought into the intake working chamber increases due to the dead volume. The temperature rises, and as a result, combined with the rise in intake air temperature due to supercharging, the air-fuel mixture in the intake working chamber is overheated, causing abnormal combustion, or so-called knocking, which impairs smooth operation. .

In order to solve the above problem, it is possible to configure the intake port and exhaust port to overlap, to allow supercharging air to flow into the dead volume, and to scavenge dilution gas to the exhaust port with this supercharging air. It is conceivable, but if the intake port and exhaust port overlap in this way, the intake negative pressure generated at the intake port during low-load operation with a small amount of intake air will conversely cause the air pressure on the mounting plate brought in by the dead volume. When a large amount of dilution gas flows into the intake working chamber, the contradictory problems remain in that, together with the low charging efficiency, the combustion efficiency is significantly reduced and the amount of unburned components in the exhaust gas is increased.

This invention was made in view of the above problem, and prevents exhaust gas from flowing into the intake working chamber during intake supercharging.
It is an object of the present invention to provide an intake device for a rotary piston engine with a supercharger that can suppress abnormal combustion of an air-fuel mixture and smooth the operation.

Embodiments of the present invention will be described below with reference to the drawings.

In Fig. 1, 1 is a casing, and the inner peripheral surface 2 has a polycylindrical hole shape.
The rotor housing 2 is composed of a rotor housing 2 having a diameter of 1.a, and a side housing 3 which is disposed on both sides of the rotor housing 20 in a hermetically sealed manner.

A rotor 4 is supported by an eccentric shaft 5 so as to be able to rotate planetarily in the casing 1, and slides on each top side while keeping the inner circumferential surface 2a of the rotor housing 2 airtight. Equipped with Apex Seal 6.

7 is the main intake port, which connects to the side housing 3.
An exhaust port 8 is provided in the rotor housing 2.

A spark plug 10 is screwed into a plug hole 9 formed in the rotor housing 2.

Reference numeral 11 denotes a turbo supercharger, which includes a turbine 13 connected to the exhaust port 8 via an exhaust passage 12 and rotated by exhaust gas pressure, and a turbine 13 that rotates simultaneously with the turbine 13 and connects to the main intake port 7. It consists of a blower 15 that takes in air through an intake passage 14.

Reference numeral 16 indicates a sub-intake port, which opens into the side housing 3 and merges into the intake passage 14 upstream of the main intake port I via an on-off control valve 17, as shown in FIG. .

As is clear from FIG. 1, the main intake port 7 opens at a position where the apex seal 6 corresponds to the exhaust port 8 but does not overlap with the exhaust port 8, whereas the auxiliary intake port 16 opens at the exhaust port 8. It opens at a position overlapping with 8.

18 indicates a diaphragm device.

This diaphragm device is for opening and closing the opening/closing control valve 17. One chamber 18a partitioned by a diaphragm 19 communicates with the exhaust passage 12 via a passage 20, and the other chamber 18b communicates with the exhaust passage 12 through a passage 20. It communicates with the intake passage 14 downstream of the turbocharger 11 via.

A spring 22 is inserted in the one chamber 18a to press and bias the diaphragm 19 toward the other chamber 18b.
The diaphragm 19 is operatively connected to the opening/closing control valve 1T via a connecting member 23 and a lever 23a.

24 indicates a throttle valve.

In the above configuration, during low load operation with the throttle valve 24 opening at a low opening, negative intake pressure downstream of the throttle valve 24 acts on one chamber 18b of the diaphragm device 18, and the diaphragm 19 moves toward the arrow A in FIG. □The force direction is shifted, and the connecting member 23 and lever 23a are moved in the direction of arrow A2 in FIG.
direction to close the on-off control valve 1T.

Therefore, the intake negative pressure prevents exhaust gas from being sucked through the sub-intake port 16, and prevents a large amount of illusion gas from flowing into the intake working chamber 25 during low-load operation.
As a result, it is possible to prevent an increase in unburned components in the exhaust gas due to a significant decrease in combustion efficiency.

As the throttle pulse 7''24 is fully opened and the engine speed reaches the third range, that is, intake supercharging, the pressure of exhaust gas rises and is in a state where it can flow into the intake working chamber 25 from the exhaust port 8. However, in this case, the pressure in the intake passage 14 increases significantly, so that the pressure in the other chamber 18b of the diaphragm device 18 becomes considerably larger than that in the one chamber 18a, and the intake pressure downstream of the turbocharger 11 increases. becomes a positive pressure above a predetermined value (at least atmospheric pressure), and moves the diaphragm 19, the connecting member 23, and the lever 23a in the directions of arrows B1 and B2 against the pressure in the one chamber 18a and the spring force of the spring 22. .

Therefore, the on-off control valve 17 is opened, and the intake working chamber 2
5 is in communication with the intake passage 14 via the auxiliary intake port 16, and the exhaust gas that is about to be brought into the intake working chamber 25 is scavenged to the exhaust port 8 by the positive pressure of supercharging air that is higher than the predetermined value. The exhaust gas is prevented from entering the intake working chamber 25.

As a result, abnormal combustion will not occur, and smoother operation can be expected.

Here, the positive pressure above the predetermined value refers to a pressure sufficient to prevent the exhaust gas from entering the intake working chamber 25.

When the engine speed further increases from this state, the exhaust gas pressure becomes greater than the intake pressure.

Therefore, the pressure in one chamber 18a of the diaphragm device 18 becomes greater than the pressure in the other chamber 18b, and the diaphragm 19, the connecting portion 23, and the lever 23a move as indicated by the arrow
1tA Move in two directions to close the on-off control valve 17.

In the above embodiment, the exhaust gas pressure is applied to one chamber 18a of the diaphragm device 18, and the opening/closing control valve 17 is controlled by the differential pressure between the intake pressure and the exhaust gas pressure, so that the engine speed during intake supercharging is reduced. This is preferable in that it is possible to prevent a large amount of exhaust gas from flowing into the intake working chamber 25 even if the exhaust gas pressure becomes higher than the intake pressure.
The present invention is not limited to this, but the point is that the on-off control valve 17 should be opened when the intake pressure is on the positive pressure side of a predetermined value or higher (and omitting the application of exhaust gas pressure to one chamber 18a). It's okay.

As explained above, the present invention has a main intake port that does not substantially overlap with the exhaust port, and a sub-intake port that overlaps with the exhaust port, which are opened on the inner surface of the casing, and a soil that joins these two ports. While connected to the intake passage downstream of the turbocharger, when the intake pressure downstream of the supercharged air reaches a positive pressure side of a predetermined value or more, the sub-intake port is opened by operating the opening/closing control valve. Therefore, during supercharging operation, especially during medium load operation, it is possible to prevent exhaust gas from flowing into the intake operating chamber, suppress abnormal combustion of intake gas, improve combustion efficiency, and smooth operation. This has the advantage that a large amount of exhaust gas is prevented from flowing into the intake working chamber during low-load operation, thereby preventing a reduction in combustion efficiency.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of a supercharged rotary piston engine equipped with an intake device according to the present invention, Fig. 2 is a partially enlarged sectional view showing the relationship between the main intake port and the sub-air intake port, and Fig. 3 is It is a characteristic line diagram of intake pressure - exhaust gas pressure. 1...Casing, 7...Main intake port, 8...Exhaust port, 11...Supercharger, 14...Intake passage , 16...Sub-intake port, 17...Opening/closing control valve.

Claims (1)

[Scope of Claims] 1. In an intake system for a rotary piston engine in which a supercharger is installed in an intake passage, a main intake, l-'-), which does not substantially overlap with an exhaust port. A sub-intake port that overlaps with the exhaust port is opened on the inner surface of the casing, and these two ports are merged and connected to the intake passage downstream of the supercharger, while the intake pressure downstream of the supercharger is set to a predetermined value. An intake system for a rotary piston engine with a supercharger, characterized in that an opening/closing control valve is provided that opens the auxiliary intake port when the pressure is on the positive pressure side.