JPS60153427A - Supercharged multi-cylinder internal-combustion engine - Google Patents

Abstract

PURPOSE:To improve the volumetric efficiency of a supercharging cylinder by opening one of both discharge valves of the supercharging cylinder, relating to one of both combustion cylinders when said cylinder makes suction stroke and opening the other of said valves relating to the other of said combustion cylinders when said cylinder makes suction stroke. CONSTITUTION:When a piston is lifted in the second cylinder 3 to make the initial compression stroke, the third cylinder 4 makes suction stroke therein and the exhaust valve 25 of the third cylinder 4 is opened. When the piston makes next compression stroke in the second cylinder 3, the suction stroke is made in the first cylinder 2 and the exhaust valve 24 of the first cylinder is opened. Mixture which is sucked into the second cylinder 3 when the piston is lowered and then compressed is sent into the first and the third cylinders 2 and 4, alternatively. Both the exhaust valves 24 of the second cylinder 3 which is a supercharging cylinder are closed when the compression stroke in the second cylinder 3 is completed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a multi-cylinder internal combustion engine in which one of three cylinders is configured as a supercharging cylinder for the other two combustion cylinders.

A multi-cylinder internal combustion engine in which one of the three cylinders is configured as a supercharging cylinder for the other two combustion cylinders is known from Japanese Patent Application Laid-Open No. 1976-76517 as a prior art, and this In the prior art, during the compression stroke in the supercharging cylinder, at least one combustion cylinder is set to be in the intake stroke, and the supercharging is performed during the intake stroke of one combustion cylinder among the reburning cylinders. The air compressed in the supercharging cylinder is supplied to the one combustion cylinder through the supercharging passage, and during the intake stroke of the other combustion cylinder, the air compressed in the supercharging cylinder is supplied to the one combustion cylinder. It is proposed that the fuel be supplied to the other combustion cylinder via another supercharging passage.

However, in this prior art, since both the supercharging passages from the supercharging cylinder to the reburning cylinder open into the cylinder chamber of the supercharging cylinder, the screws in the supercharging cylinder do not die. ill at the time when the compression path reaches the point and when the piston starts to suck air by the downward stroke from top dead center.
The volume of both supercharging passages from the cylinder chamber of the supercharging cylinder to the reburning cylinder is added to the cylinder volume.
The gap volume at the compression path and at the beginning of suction is large. Therefore, the gap volume ratio in the supercharging cylinder is large, and the volumetric efficiency in the supercharging cylinder decreases, so the volume of the supercharging cylinder is increased. As a result, the entire institution became larger.

Further, as prior art, Japanese Patent Application Laid-Open No. 52-39013 and Japanese Patent Application Laid-Open No. 51-91416 disclose that the supercharging passages to the re-combustion cylinder are combined into one and open into the cylinder chamber of the supercharging cylinder. By providing an exhaust valve in the opening that is operated by a valve mechanism similar to the valve mechanism for opening and closing the intake and exhaust valves in the reburning cylinder, the volumes of both supercharging passages are However, in this case, the exhaust valve of the supercharging cylinder, the intake/exhaust valve connected to the combustion cylinder opens and closes once per revolution of the crankshaft. In contrast, the crankshaft opens and closes twice per revolution, so in other words, the number of opening and closing movements of the exhaust valve in the supercharging cylinder is equal to the number of opening and closing movements of the intake and exhaust valves in the reburning cylinder. Since this is twice the number of times, this poses a problem in the durability and reliability of the discharge valve and its valve mechanism.

The present invention provides a multi-cylinder internal combustion engine in which one of the three cylinders is configured as a supercharging cylinder for the other two combustion cylinders as described above, in which the supercharging cylinder is connected to the reburning cylinder. The supercharging passages are separated and open into the cylinder chamber of the supercharging cylinder, and exhaust valves are respectively provided at both openings of the supercharging passages to the cylinder chamber of the supercharging cylinder. By opening and closing the exhaust valve separately in accordance with the stroke of the reburning cylinder, both supercharging passages are prevented from being added to the gap volume in the supercharging cylinder, and
This improves the durability and reliability of the exhaust valve in the supercharging cylinder and its valve mechanism.

The present invention will be explained below with reference to drawings of embodiments. In the drawings, 1 is a size in which the first cylinder 2 and the third cylinder 4 are four-cycle combustion cylinders, and the second cylinder 3 is a two-cycle supercharging cylinder. The figure shows a three-cylinder engine, and the first cylinder 2 and the third cylinder 4 are each equipped with an intake boat 5.6 and an exhaust boat 7.8, and the openings of these boats to the cylinder chambers are equipped with conventionally known mechanisms. It includes an intake valve 9.10 and an exhaust valve 11.12 that are opened and closed by a valve mechanism (not shown), and a second
Cylinder 3 has a check valve type suction valve 13 and a suction boat 14.
and two discharge boats 15, 16, the pistons of the first cylinder 2 and the third cylinder 4 move up and down in the same phase, but the piston of the second cylinder 3 moves up and down in the same phase. 18 at the crank angle so that it moves up and down in the exact opposite direction to the piston.
On the other hand, the firing order of the first cylinder 2 and the third cylinder 4 is shifted by 360 degrees in terms of crank angle, so that when the first cylinder 2 is in the explosion stroke, the third cylinder 4 is in the intake stroke. , and the third cylinder 4 is set to be in the intake stroke during the first compression stroke of the second cylinder 3, and the first cylinder 2 is set to be in the intake stroke during the next compression stroke of the second cylinder 3. Also, the stroke volume in the second cylinder 3 is the same as that in the first cylinder 2 and the third cylinder.
The volume is set to be larger than the volume of the first cylinder 2 or the third cylinder 4 so as to provide the volume necessary for supercharging the cylinder 4.

Reference numeral 17 denotes an air cleaner for intake; the air cleaner 17 is connected to the intake boat 14 in the second cylinder 3 via an intake passage 18, and a throttle valve 19 for controlling intake air is provided in the intake passage 18. A carburetor 20 is provided as an example of a fuel supply device. In this case, when replacing the carburetor with a fuel injection type, an air flow meter is provided downstream of the air cleaner, and an amount of fuel corresponding to the amount of air measured by the air flow meter is supplied to the first cylinder 2 and the third cylinder 4. In addition, the exhaust boat 7.8 of the first cylinder 2 and the third cylinder 4 has an exhaust manifold 2.
1 is connected.

One discharge port 15 in the second cylinder 3, which is a supercharging cylinder, is connected to the intake port 5 in the first cylinder 2, which is a combustion cylinder, through a supercharging passage 22, and the other in the second cylinder 3. The discharge boats 16 are connected to the intake boats 1-6 in the third cylinder 4, which is a combustion cylinder, through supercharging passages 23, while the re-discharge boats 15 and 16 in the second cylinder 3 are connected to the cylinder chambers. At the opening,
A discharge valve 24.25 is provided respectively, and this re-discharge valve 24.25
Among them, the first cylinder exhaust valve 24 for the first cylinder 2 is the first cylinder exhaust valve 24.
The third cylinder exhaust valve 25 for the third cylinder 4 is configured to open during the intake stroke of the third cylinder 4 when the cylinder 2 is in the intake stroke. Note that even if the opening and closing operations of the re-exhaust valves 24 and 25 are performed by a valve mechanism similar to the valve mechanism that opens and closes the intake and exhaust valves in the first cylinder 2 and the third cylinder 4, Both charging channels 22,23 can also be formed in the cylinder head.

In this configuration, during the first compression stroke due to the upward movement of the piston in the second cylinder 3, the third cylinder 4 is in the intake stroke and the third cylinder exhaust valve 25 is opened, and the next compression stroke in the second cylinder 3 is started. When the first cylinder 2 is on the intake stroke and the first
Since the cylinder exhaust valve 24 is open, the air-fuel mixture that is sucked into the second cylinder 3 when the piston descends and is then compressed is alternately supplied to the first cylinder 2 and the third cylinder 4. In this case, the re-discharge valves 24 and 25 in the second cylinder 3, which is the supercharging cylinder, close when compression in the second cylinder 3 is finished, and the inside of the second cylinder 3 and both supercharging passages 22. 23
Since communication with the supercharging passage 22.
23 is not added, the gap volume can be reduced, and the volumetric efficiency can be improved.

Further, the first cylinder exhaust valve 24 and the third cylinder exhaust valve 25 are operated once per cycle of the first cylinder 2 or the third cylinder 4.
Since the exhaust valve 24 for the first cylinder and the exhaust valve 25 for the third cylinder open and close twice per cycle, the number of times the exhaust valve 24 for the first cylinder and the exhaust valve 25 for the third cylinder open and close can be reduced.

In the above embodiment, the central second cylinder 3 of a three-cylinder engine was used as a supercharging cylinder, and the first cylinder 2 and third cylinder 4 on both sides were used as combustion cylinders. The second or third cylinder 4 may be used as a supercharging cylinder, and the other cylinders may be used as combustion cylinders, or two three cylinders consisting of one supercharging cylinder and two combustion cylinders may be arranged side by side to form a 6 cylinder. It goes without saying that a cylinder engine would be fine.

As described below, the present invention provides a multi-cylinder internal combustion engine in which one cylinder out of three cylinders is configured as a supercharging cylinder for the other two combustion cylinders, in which the compression stroke of the supercharging cylinder is When, at least one combustion cylinder is set to be in an intake stroke, an intake passage having a fuel supply device is connected to an intake boat in the supercharging cylinder via a check valve type intake valve, and The supercharging cylinder is provided with two discharge boats to the reburning cylinder, and the redischarge port is connected to an intake boat with an intake valve in the reburning cylinder, and the supercharging of the reburning port is A discharge valve is provided at each opening to the combustion cylinder, and when the discharge valve for one combustion cylinder among the re-discharge valves is closed during the intake stroke of the combustion cylinder, the discharge valve for the other combustion cylinder is closed. The present invention is characterized in that the two combustion cylinders are configured to open during the intake stroke of the other combustion cylinder, which reduces the gap volume in the supercharging cylinder and improves the volumetric efficiency. It is possible to reduce the stroke volume of the cylinder, thereby making the internal combustion engine more compact, and because the number of opening and closing operations of the re-exhaust valve in the supercharging cylinder is small, the durability and reliability of the exhaust valve and its valve mechanism are improved. It can significantly improve sexual performance,
Moreover, in the present invention, by using a check valve type suction valve as the suction valve to the supercharging cylinder, the supercharging cylinder has
It is only necessary to provide two exhaust valves that can be opened and closed simultaneously by the valve mechanism for opening and closing the intake and exhaust valves in the combustion cylinder. Since this is not necessary, it does not cause problems such as complicating the valve mechanism, and has the effect that it can be effectively applied to diesel engines in which the top surface of the combustion chamber is flat.

[Brief explanation of drawings]

110- FIG. 1 is a plan view showing an embodiment of the present invention, and FIG. 2 is an enlarged sectional view taken along line H-II in FIG. 1. 1...Internal combustion engine, 2.3.4...Cylinder, 5.6
...Intake bow 1-19.10...Intake valve, 14
...Suction boat, 15.16...Discharge port,
18...Intake passage, 22.23...Supercharging passage,
24.25...Discharge valve. Patent applicant Daihatsu Motor Co., Ltd. 11-

Claims (1)

[Claims] +1+, in a multi-cylinder internal combustion engine in which one cylinder out of three cylinders is configured as a supercharging cylinder for the other two combustion cylinders, during a compression stroke in the supercharging cylinder,
a small combustion cylinder (set so that at least one combustion cylinder is in the intake stroke, and an intake passage having a fuel supply device is connected to the intake boat in the supercharging cylinder via a check valve type intake valve; In addition, the supercharging cylinder has two cylinders connected to the reburning cylinder.
two discharge boats 1- are provided, and both of the discharge boats are respectively connected to intake boats with intake valves in the reburning cylinder, and discharge valves are provided at the openings of the two discharge boats to the supercharging cylinder. , during the intake stroke of one of the two combustion cylinders,
A supercharged multi-cylinder internal combustion engine characterized in that the exhaust valves for the other combustion cylinder are configured to open during the intake stroke of the other combustion cylinder.