JPH0211727B2 - - Google Patents

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a multi-cylinder internal combustion engine in which some of the cylinders are configured as cylinders for supercharging other combustion cylinders. The present invention relates to a device that controls supercharging pressure for combustion cylinders according to the load state of an internal combustion engine.

[Prior art]

In this way, some cylinders out of multiple cylinders,
It is configured as a supercharging cylinder for other combustion cylinders,
A suction passage from an air cleaner is connected to an intake port with a suction valve in the supercharging cylinder, while a discharge port with a discharge valve in the supercharging cylinder is connected to
A multi-cylinder internal combustion engine that is connected to the intake ports of other combustion cylinders via supercharging passages was proposed in Japanese Patent Application Laid-open No. 1983-63320 as a prior art, and this prior art Unexamined Japanese Patent Publication 1983-
Publication No. 63320 provides a control valve that opens in a low load range of an internal combustion engine in a bypass passage connecting a supercharging passage from the supercharging cylinder and an intake passage to the supercharging cylinder. Accordingly, it is proposed to control the boost pressure in the low load range so that it does not exceed a certain value.

[Problem that the invention seeks to solve]

However, as in this prior art, control is provided in the bypass passage that connects the supercharging passage from the supercharging cylinder and the intake passage to the supercharging cylinder to open in the low load range of the internal combustion engine. If a valve is provided to control the supercharging pressure in the low load range, when the piston moves downward in the supercharging cylinder, air from the air cleaner closes the intake valve. The air is sucked in while being pushed open against the spring force used to hold it closed, and then when the piston moves upward, the air that was sucked in first is discharged while pushing the discharge valve open against the spring force used to keep it closed. As they say,
Even when the control valve of the bypass passage is open, air enters and leaves the supercharging cylinder while pushing and opening the intake valve and the discharge valve against the spring force for keeping them closed. The flow resistance of air going in and out of the supercharging cylinder is large, and therefore, the pumping loss in the supercharging cylinder is large by the amount of flow resistance, so there is no need for supercharging in the supercharging cylinder, such as idling. This resulted in an increase in fuel consumption in the low load range.

Moreover, in the prior art, air is compressed once in the supercharging cylinder to a pressure that pushes open the discharge valve, is sucked into the supercharging cylinder via the bypass passage, and is compressed again to the pressure that pushes the discharge valve open. By repeating this circulation, the temperature of the air increases rapidly, which reduces the efficiency with which air is filled into the combustion cylinders, which in turn reduces the output of the internal combustion engine and increases the fuel consumption rate. be. In this case, in order to avoid a rise in temperature due to air circulation, it is necessary to install a cooler for the air in the bypass passage that connects the intake passage to the supercharging cylinder and the supercharging passage from the supercharging cylinder. However, it is not a good idea to do so because it would significantly increase the overall size of the internal combustion engine and increase the weight of the internal combustion engine.

The present invention provides a multi-cylinder internal combustion engine in which some of the cylinders are configured as supercharging cylinders for other combustion cylinders, and the supercharging pressure for the combustion cylinders is adjusted according to the load of the internal combustion engine. It is an object of the present invention to solve the problems in the prior art when performing control using the following methods.

[Means to solve the problem]

In order to achieve this object, the present invention configures some cylinders among a plurality of cylinders as supercharging cylinders for other combustion cylinders, and connects an air cleaner to an intake port with an intake valve in the supercharging cylinder. In a multi-cylinder internal combustion engine, the supercharging cylinder is connected to an intake passage, and a discharge port with a discharge valve in the supercharging cylinder is connected to an intake port in another combustion cylinder via a supercharging passage. A normally open port that is always open is provided in the interior, and the normally open port and a portion of the suction port upstream of the suction valve or the suction passage are connected via a bypass passage for the suction valve, and the bypass passage is connected to the suction passage. A supercharging control valve that opens in a low load range of the internal combustion engine is provided inside.

[Effect]

The above technical means works as follows.

In other words, in the low load range of the internal combustion engine, the supercharging control valve in the bypass passage that connects the normally open port in the supercharging cylinder and the intake passage to the supercharging cylinder opens. When the piston moves downward in the charging cylinder, air from the air cleaner is sucked into the supercharging cylinder from both the intake valve, the bypass passage and the normally open port, and when the piston moves upward, air is drawn into the supercharging cylinder from the air cleaner first. The air sucked into the supercharging cylinder is discharged from both the discharge valve, the bypass passage, and the normally open port, so that the flow resistance when air enters and exits the supercharging cylinder is reduced, as in the prior art described above. The amount of air flowing in and out of the supply cylinder is much smaller than when the intake and discharge valves are pushed open against the spring force that keeps them closed. This makes it possible to significantly reduce the pumping loss of the supercharging cylinder in low load ranges such as idling, where supercharging by the cylinder is not required.

Furthermore, since the flow resistance of air flowing in and out of the supercharging cylinder is small as described above, the temperature rise when air flows in and out of the supercharging cylinder is much greater than in the case of the prior art. It is small.

〔Example〕

Hereinafter, a case will be described in which an embodiment of the present invention is applied to a three-cylinder internal combustion engine. In the figure, reference numeral 1 indicates that the first cylinder 2 and the third cylinder 4 are four-cycle combustion cylinders, and the second cylinder 3 is a four-cycle combustion cylinder. The figure shows an in-line three-cylinder internal combustion engine with two-cycle supercharging cylinders, and the first cylinder 2 and third cylinder 4 have intake ports 7 and 8 with intake valves 5 and 6, and exhaust ports with exhaust valves 9 and 10. ports 11 and 12, respectively.

In addition, the second cylinder 3 has a check valve type suction valve 13.
A suction port 14 with a check valve type discharge valve 15 and a discharge port 16 with a discharge valve 15 also of a check valve type are provided.

The pistons in the first cylinder 2 and the third cylinder 4 reciprocate at the same time and in the same phase, but the piston in the second cylinder 3 reciprocates in the opposite direction to the pistons in the first cylinder 2 and the third cylinder 4. On the other hand, the firing order of the first cylinder 2 and the second cylinder 3 is 360 degrees apart in crank angle so that when the first cylinder 2 is in the explosion stroke, the third cylinder 4 is in the intake stroke. The third cylinder 4 is in the intake stroke during the first compression stroke of the second cylinder 3, and the first cylinder 2 is in the intake stroke during the next compression stroke of the second cylinder, and The stroke volume of the second cylinder 3 is larger than that of the first cylinder 2 or the third cylinder 4 so that the first and third cylinders 2 and 4 can be supercharged.

Reference numeral 17 indicates an air cleaner, and the air cleaner 17 is connected to the suction port 14 in the second cylinder 3 via an intake passage 18, and the discharge port 16 in the second cylinder 3 is connected to the air cleaner 17, which has a surge tank 19 for preventing pulsation. The intake ports 7 and 8 of the first cylinder 2 and the third cylinder 4 are connected to each other via the supercharging passage 20.
A carburetor 23 with a throttle valve 22 is provided in the supercharging passage 20 on the downstream side of the surge tank 19 .

Reference numeral 24 denotes a normally open port 24a that is always open in the second cylinder 3, the intake passage 18 to the second cylinder 3, or the intake valve 1 of the intake port 14.
A pressure transmission passage 2 is connected to the pressure in the intake manifold 21 in the bypass passage 24.
6, and is provided with a supercharging control valve 25 that opens when the pressure within the intake manifold 21 increases toward the vacuum side.

In this configuration, the third cylinder 4 is in the intake stroke during the first compression stroke of the second cylinder 3, and the first cylinder 2 is in the intake stroke during the next compression stroke of the second cylinder 3. The compressed air sucked into the second cylinder 3 and compressed in the second cylinder 3 is alternately supplied to the first cylinder 2 and the third cylinder 4 to supercharge the first cylinder 2 and the third cylinder 4. will be carried out.

This supercharging is achieved by making the stroke volume of the second cylinder 3 larger than the stroke volume of the first cylinder 2 or the third cylinder 4, so that the throttle valve 22 is fully closed or close to fully closed when idling or under low load. The throttle valve 22
During deceleration when the throttle valve 22 is suddenly closed, the supercharging of the first and third cylinders may become supercharging, or idling or low-load operation may become unstable. Therefore, when the pressure inside the intake manifold 21 increases toward the vacuum side, the supercharging control valve 25 in the bypass passage 24
opens, a part of the air that is about to be compressed by the rise of the piston in the second cylinder 3 escapes from the normally open port 24a to the upstream side of the intake valve 13 via the bypass passage 24, and Since the compression pressure in cylinder 3 is reduced, supercharging can be prevented when the internal combustion engine is decelerating, and the supercharging pressure can be controlled so that it does not exceed a certain value during idling or low load operation. .

Note that the means for detecting the load on the internal combustion engine is not limited to the pressure in the intake manifold of the above embodiment, but other means such as the opening of the throttle valve may also be used. Instead of using the two cylinders 3 as supercharging cylinders, the first cylinder or the third cylinder may be used as supercharging cylinders, and the other cylinders may be used as combustion cylinders. It goes without saying that the present invention can also be applied to a multi-cylinder internal combustion engine such as a six-cylinder engine.

〔Effect of the invention〕

As described above, according to the present invention, the temperature rise of the supercharging air when controlling the supercharging pressure in the low load range of the internal combustion engine is much smaller than that of the prior art, and a cooler for the supercharging air is not used. Since it is possible to improve the efficiency of filling air into the combustion cylinder even when the engine is in use, it is possible to avoid increasing the size and weight of the engine due to the use of a cooler for supercharging air. Since the pumping loss in the supercharging cylinder can be significantly reduced, fuel consumption in the idling or low-load operating range can be reduced.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an embodiment of the present invention, and FIG. 2 is an enlarged cross-sectional view taken from the side of FIG. 1. 1... Internal combustion engine, 2... First cylinder, 3... Second cylinder, 4... Third cylinder, 5, 6... Intake valve, 7,
8... Intake port, 9, 10... Exhaust valve, 11,
12...exhaust port, 13...intake valve, 14...
Suction port, 15...Discharge valve, 16...Discharge port, 17...Air cleaner, 18...Suction passage,
20...Supercharging passage, 22...Throttle valve, 24
... Bypass passage, 24a ... Normally open port, 25
...supercharging control valve, 26...actuator.

Claims (1)

[Claims] 1 Some cylinders among the plurality of cylinders are configured as supercharging cylinders for other combustion cylinders, and an intake passage from an air cleaner is connected to an intake port with an intake valve in the supercharging cylinder, while the In a multi-cylinder internal combustion engine in which a discharge port with a discharge valve in a supply cylinder is connected to an intake port in another combustion cylinder via a supercharging passage, a normally open port that is always open in the supercharging cylinder is provided. the normally open port and the suction port upstream of the suction valve or the suction passage are connected via a bypass passage for the suction valve, and in the bypass passage,
A supercharging pressure control device for a supercharged multi-cylinder internal combustion engine, comprising a supercharging control valve that opens in a low load range of the internal combustion engine.