JPS5857019A - Supercharge device of multi-cylinder engine - Google Patents

Abstract

PURPOSE:To efficiently distribute supercharged air to each cylinder, by constituting a supercharger with a compound positive displacement pump having plural delivery ports, connecting each delivery port to a different cylinder through respectively independent auxiliary intake system and preventing a supercharge change. CONSTITUTION:In case of application to a 6-cylinder engine, an intake system is constituted by main and auxiliary intake systems 3, 4, and the auxiliary intake system 4 is formed by equipping a manifold passage 14, the upstream end of which is communicated to a place in the vicinity of the downstream branch part of a manifold passage 5 in a main intake passage 8 of the main intake system 3. Branch passages 15a, 15b are divided from the manifold passage 14, and a supercharger 18, consisting of a compound positive displacement pump, is arranged across these passages 15a, 15b. Then upstream and downstream sides of the branch passages 15a, 15b are connected to intake ports 19a, 19b and delivery ports 20a, 20b provided in symmetrical positions of the supercharger 18. Further downstream ends of the branch passage 15a, 15b are connected to each cylinder 1a-1f through each independent branch passage 16a-16f.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a supercharging device for a multi-cylinder engine, and particularly to a supercharging device for a multi-cylinder engine that is equipped with a main intake system that naturally sucks fresh air and an auxiliary intake system that supplies supercharged air. This relates to a feeding device.

Conventionally, as an engine supercharging device, it is known that a turbo supercharger is installed in a single intake system of the engine, and the output performance of the engine is improved by supercharging the intake air into the engine. ing.

However, in this turbocharging method, the blower is driven by a turbine rotated by the exhaust flow, and the intake air is supercharged by the blower, so the reduction in the exhaust flow can lead to insufficient supercharging, especially in the low engine speed range. Therefore, there were problems in that the output performance could not be sufficiently improved and the responsiveness was poor.

Therefore, conventionally, as disclosed in Japanese Patent Application Laid-Open No. 55-69'i'22, the intake system of the engine is composed of a main intake system and an auxiliary intake system, and the auxiliary intake system is supercharged. In addition to supplying fresh air to the engine from the main intake system, supercharging air is supplied to the engine from the auxiliary intake system at a predetermined timing (that is, at least during the compression stroke of the engine). , a so-called partial supercharging system has been proposed that uses a supercharger driven by the engine to perform intake supercharging with good responsiveness without causing insufficient supercharging even in the low engine speed range. .

However, when such a partial supercharging system is adopted for a multi-cylinder engine, as disclosed in the above-mentioned publication, a single supercharger separates the supercharged air from the supercharger into separate branches. If each cylinder is supplied via an auxiliary intake system, the rotation speed of the supercharger must be increased as the number of cylinders increases (4 cylinders, 6 cylinders, etc.), which reduces the durability of the supercharger. There was a problem with that.

Furthermore, in such a partial supercharging system, when a positive displacement pump is used as a supercharger, pressure changes occur between when the positive displacement turbocharger discharges supercharged air and when it does not discharge supercharged air. Pulsation occurs. Therefore, if the supercharged air discharge timing of the positive displacement supercharger and the engine-side supercharging timing (at least during the engine's compression stroke) do not always correspond, the supercharged air will not be efficiently supplied to the engine. There will be times when the engine speed is not the same, and supercharging fluctuations will occur per engine revolution. As a result, there is a problem that the original supercharging effect cannot be fully exhibited.

Therefore, the present invention has been made in view of these points, and in a supercharging device for a partially supercharging multi-cylinder engine as described above, the supercharger is replaced by a multi-chamber displacement pump having a plurality of discharge ports. Each of the above-mentioned discharge ports is connected to a different cylinder via an independent auxiliary intake system, and the above-mentioned discharge ports are connected to different cylinders via independent auxiliary intake systems. By synchronizing the charge air discharge timing with the operating stroke of each cylinder, there is no need to increase the rotation speed of the supercharger as the number of cylinders increases, and while improving the durability of the supercharger, it is possible to A supercharging system for multi-cylinder engines that prevents supply fluctuations, efficiently and reliably distributes supercharging air to each cylinder, and effectively utilizes the supercharging effect of the auxiliary intake system. This is what we intend to provide.

Hereinafter, the present invention will be described in detail based on embodiments shown in the drawings.

FIG. 1 shows an example in which the present invention is applied to a 6-cylinder engine,
1 is a six-cylinder engine having first to sixth cylinders 1a to 1f, 2 is a combustion chamber of each cylinder 1a to 1f, and 1st cylinder 1a - 4th cylinder 1d - 2nd cylinder 1b = 6th cylinder 1f - 1st cylinder 3 cylinder 1
The cylinders are ignited in the order of C-fifth cylinder 1e. 6 and 4 are a main intake system and an auxiliary intake system, respectively, which constitute the intake system of the engine 1. The main intake system 5 includes a collection passage 5 whose upstream end is connected to an air cleaner (not shown), and first and second group branch passages 6a and 6b branched into two from the downstream end of the collection passage 5. , first to third independent branch passages 7a to 7 which branch into three from the downstream end of the first group branch passage 6a and each independently communicate with each combustion chamber 2 of the first to third cylinders 1a to 1C.
C, and the combustion chambers 2 of the fourth to sixth cylinders 1d to 1f which are branched into three from the downstream end of the second group branch passage 6b and are independently connected to each other.
The main intake passage 8 is composed of fourth to sixth independent branch passages 7d to 7f communicating with each other. Each group branching passage 6a, 6b of the main intake passage 8 has a main throttle valve 9a that operates in conjunction with an accelerator pedal (not shown) to control the amount of intake air supplied to the engine 1 from each group branching passage 6a16b. , 9b
is installed.

Further, fuel injection valves 10a to 10f are installed in each of the independent branch passages 7a to 7f of the main intake passage 8, and an air flow meter 11 is installed in the collective passage 5 of the main intake passage 8 to detect the total amount of intake air.
are respectively arranged, and the detection signal of the air flow meter 11 is input to a fuel injection control circuit 12 that controls the amount of fuel injected from each of the fuel injection valves 10a to 10f,
Therefore, fuel injection is performed in which an amount of fuel corresponding to the intake air amount of the engine 1 is uniformly injected from each fuel injection valve 10a to 10f, and distributed and supplied to each cylinder 1a to 1f via each independent branch passage 7a to 7f. This constitutes a fuel supply device 15 of the type.

On the other hand, the auxiliary intake system 4 has an upstream end connected to the main intake passage 8.
A collective passageway 14 communicating with the vicinity of the downstream branch of the collective passageway 5, and a first and second group branch passageway 15a branched into two from the downstream end of the collective passageway 14.

151), and first to third independent branch passages 16a that branch into three from the downstream end of the first group branch passage 15a and each independently communicate with each combustion chamber 2 of the first to third cylinders 1a to 1C. ~16
C, and fourth to sixth independent branch passages 16d to 16d which branch into three from the downstream end of the second group branch passage 15b and each independently communicate with each combustion chamber 2 of the fourth to sixth cylinders 1d to 1f. 16f. A supercharger 18 is disposed in the auxiliary intake passage 17, spanning both group branch passages 15a and 15b. The supercharger 18 is constituted by a multi-chamber displacement pump, such as a rotary piston pump, and has first and second suction ports 19a, 19.
A triangular rotor 25 rotates planetarily within a trochoidal casing 21 having a symmetrical opening 2C and a first and second discharge ports 20al and 2C1 as the eccentric shaft 22 driven by the engine 1 rotates. The first suction port 19a and the first discharge port 20a communicate with the upstream and downstream sides of the first group branch passage 15a, respectively, and the second suction port 19
1) and the second outlet 20b are connected to the upstream and downstream sides of the second group branch passage 151), respectively, so that each discharge port 20a, 20b communicates with each independent branch passage 16.1 of the auxiliary intake passage 17. Each different cylinder 1a~ via a~16f
It is connected to 1f. Furthermore, the auxiliary intake passage 17
downstream of the supercharger 18 of each group branch passage 15a1151), the main throttle valve 9 is linked with the main throttle valves 9a+9b.
The main throttle valves 9a and 9b remain closed until they are opened to the set opening, that is, when the engine load is below the set load. Auxiliary throttle valve 2 opens when
4a, 24b are arranged, and the auxiliary throttle valve 24a,
When 24'b is equal to or higher than the set load of the engine that operates to open,
He is trying to supply supercharging air from each discharge port 20a, 20b of supercharger 18 to each cylinder 1FL-1f via auxiliary intake passage 17.

Further, each group branch passage 15a, 1 of the auxiliary intake passage 17 is
5b, each end has a group branching passage 15a1151.
) Auxiliary throttle valve 24 al 24 downstream of the turbocharger 18
Bypass passages 25a and 25 are provided which open upstream b and whose other end opens upstream of the supercharger 18 of the group branch passage 15a115b to bypass the supercharger 18, and each bypass passage 25a, 25bKli')+ )-7 valves 26a, 26b
is interposed, and the group branch passage 15a downstream of the supercharger 18
, 15b (supercharging pressure) exceeds the set pressure, the IJ valves 26a, 26b are opened and the pressure is transferred to the supercharger 1 via the bypass passages 25al and 25b.
The supercharging pressure is maintained at the set pressure by releasing the supercharging pressure to the group branch passages 15a and 15b upstream of the supercharging pressure.

Furthermore, each independent branch passage 7a to 7f of the main intake passage 8
A main intake valve 27 is disposed at each opening to the combustion chamber 2, and each independent branch passage 16a of the auxiliary intake passage 17 is provided with a main intake valve 27.
Auxiliary intake valves 28 are installed at the openings to the combustion chambers 2 to 16f, respectively.
As shown in FIG. 2, the valve timing of both intake valves 27 and 28 in each cylinder 1a to 1f is set at the auxiliary intake from the end of opening of the main intake valve 27, that is, from the latter half of the intake stroke to the compression stroke. The valves 28 are set to partially overlap and open. From the point of view of preventing backflow of supercharging air from the auxiliary intake passage 17 to the main intake passage 8, the auxiliary intake valve 28 should be opened after the main intake valve 27 is closed, that is, during the compression stroke, without overlapping. It is preferable to set it to . Moreover, 29 is an exhaust valve disposed at the opening of an exhaust passage (not shown) of the combustion chamber 2 of each cylinder 1a to 1f.

As a result of the above, when the engine load is below the set load, the main intake system
5 (main intake passage 8) to supply the air-fuel mixture as fresh air to the engine 1 (1st to 6th cylinders 1a to lf) by natural intake. In addition to air, the auxiliary intake system 4 (auxiliary intake passage 17) supplies pressurized air as supercharging air to the engine 1 (first to sixth A so-called partial supercharging system is configured to supply fuel to cylinders 1a to 1f).

As a feature of the present invention, the first to sixth cylinders 1a
-1f are divided into two groups, the first to third cylinders 1a to 1C group and the fourth to sixth cylinders 1d to 1f, as described above, and the ignition order of the first to third cylinders 1a to 1f is not consecutive. ~10
For the group, the first discharge port 20a of the supercharger 18 consisting of a multi-chamber displacement pump is connected to the first to third independent branch passages 16a to 16C of the auxiliary intake passage 17, respectively. The supercharger 18 is connected to each of the three cylinders 1a to 1C, while the fourth to sixth cylinder groups 1d to 1f are connected to the supercharger 18.
The second discharge port 20b connects the fourth to sixth independent branch passages 16d to 16f of the auxiliary intake passage 17,
It is connected to each of the sixth cylinders 1d to 1f.

Furthermore, as shown in FIG. 2, in the case of a four-cycle engine, the eccentric shaft 22 of the supercharger 18 rotates at a ratio of 2=3 with respect to the engine/engine rotation, so that the The supercharging air discharge timing from the 1 discharge port 20a is 1st to 3rd.
Opening timing of each auxiliary intake valve 28 of cylinders 1a to 1C (
In Figure 2, the range is indicated by a chain line. Note that the range indicated by the solid line is the opening timing of the main intake valve 27. ), preferably to always match, so that supercharging air is always supplied from the first discharge port 2°a at least in the compression stroke of each of the first to third cylinders 1a to 1C. The liquid is then discharged. Preferably, the timing of discharge of supercharged air from the second discharge port 20b of the supercharger 18 is always synchronized with the opening timing of each auxiliary intake valve 28 of the fourth to sixth cylinders 1d to 1f. At least the 4th to 6th cylinders 1
In each compression stroke from d to 1f, the second discharge port 20
1), the supercharging air is always discharged in a corresponding manner.

Therefore, in the above embodiment, when the engine is under a set load and is not supercharged, supercharging air (pressurized air) is not supplied from the auxiliary intake passage 17, and the first to sixth cylinders 1a to
Since only fresh air (mixture) from the main intake passage 8 is supplied into each combustion chamber 2 of 1f, good engine performance can be ensured as in a normal engine.

On the other hand, when the engine is supercharging at a load higher than the set load, each cylinder
In the combustion chambers 2 of a to 1f, supercharging air (pressurized air) is supercharged from the auxiliary intake passage 17 with good response to fresh air (air mixture) from the main intake passage 8, so that supercharging is achieved. Good output performance can be obtained without causing any shortage.

At that time, the supercharger 18 first and second discharge ports 20a, 2
01), and each discharge port 20a+20b connects the first to sixth cylinders 1a to 16 through the first to sixth independent branch passages 16a to 16f of the auxiliary intake passage 17, which are independent from each other. 1f, each cylinder 1a
Since the supercharged air is distributed and supplied to the combustion chamber 2 of ~1f, the number of revolutions of the supercharger 18 is half that of a single-chamber displacement pump, and the number of revolutions of the supercharger 18 is half that of a single-chamber displacement pump. In case 3
The rotation speed of the supercharger 18 may be the same as that of a cylinder engine, and there is no need to greatly increase the rotation speed of the supercharger 18 as the number of cylinders increases.
Therefore, the durability of the supercharger 18 can be improved.

Furthermore, the first and second discharge ports 20a of the supercharger 18
, 20b is synchronized with the opening timing of the auxiliary intake valve 28, which is the operating stroke of the first to sixth cylinders 1a to 1f, so that the timing of the discharge of the supercharged air from the first to sixth cylinders 1a to 1f is synchronized with the opening timing of the auxiliary intake valve 28, which is the operating stroke of the first to sixth cylinders 1a to 1f. Since supercharging air is always discharged from the outlets 20a, 201) in a corresponding manner, supercharging fluctuations in each cylinder 1a to 1f due to supercharging pulsations of the positive displacement supercharger 18 are prevented,
Supercharging air is always distributed efficiently and reliably to each cylinder 1a to 1f, so the supercharging effect of the auxiliary intake system 4 is effectively exhibited, further improving output performance during supercharging. can be done.

In addition, in the case of a 6-cylinder engine/1 as in the above embodiment,
can be divided into two groups, the first to third cylinders 1a to 1C group and the fourth to sixth cylinders 1d to 1f group, in which the ignition order is not consecutive, and for the first to third cylinders 1a to 10 group. The supercharged air is supplied from the first discharge port 20a of the supercharger 18, and the second discharge port 20b is supplied to the fourth to sixth cylinder groups 1d to 1f.
Since supercharging air is supplied to cylinder 1 as shown in Fig. 2,
Supercharging interference between a and 1f, that is, the auxiliary intake valve 28
This has the advantage that a reduction in supercharging efficiency caused by the attraction of supercharging air between cylinders whose 0 valve opening timings overlap is prevented, and the supercharging effect can be further improved.

It should be noted that the present invention is not limited to the above-mentioned embodiments, but also includes various other modifications. For example, in the above embodiment, the supercharging timing of the first to sixth cylinders 1a to 1f is controlled by the opening timing of the auxiliary intake valve 28, and the In addition, the timing of discharge of supercharged air from the second discharge ports 20a and 20b is synchronized, but the opening timing of the auxiliary intake valve 28 is expanded to increase the valve lift amount of the auxiliary intake valve 28. Each discharge port 20a of the supercharger 18
The supercharging timing for each cylinder 1a to 1f may be determined based on the supercharging air discharge timing from 1201). In this case, the increase in the valve lift amount of the auxiliary intake valve 28 reduces the supercharging resistance during supercharging, making it possible to further improve the supercharging effect, and further improving the supercharging effect.
The valve only needs to function as a check valve, and the valve operating mechanism can be simplified.

Further, in the above embodiment, an example was described in which the present invention was applied to a 6-cylinder engine, but it goes without saying that the present invention can also be applied to other multi-cylinder engines.
In the case of a cylindrical engine, this is preferable because supercharging interference can be prevented. In addition, two discharge ports 20al are used as the supercharger 18.
201), but a multi-chamber displacement pump having three or more discharge ports may also be used, and in addition to rotary piston type pumps, vane type pumps, etc. A variety of dual chamber positive displacement pumps may be used.

Furthermore, in the above embodiment, a fuel injection system was described as the fuel supply device 15 provided in the main intake system 6;
The present invention is also applicable to a vaporizer type. However, in the case of this carburetor system, since the fuel is sucked by the venturi negative pressure caused by the intake air flow, the fuel is vaporized at a position upstream of the opening at the upstream end of the auxiliary intake passage 17 of the main intake passage 8 through which all the intake air flows. Therefore, fuel flows into the supercharger 18 in the auxiliary intake passage 17 and the supercharger 1
8, so it is suitable for the fuel injection system as in the above embodiment. Further, the fuel supply device 1'5 may be provided in the auxiliary intake system 4 as well as the main intake system 6.

Furthermore, in the above embodiment, the supercharger 18 is connected to the engine 1.
Although the supercharger 18 is constantly driven and the supercharged air is relieved in the non-supercharging region, a clutch means may be used to drive the supercharger 18 only in the supercharging region, thereby reducing driving loss. It is advantageous in this respect.

As explained above, according to the present invention, in a supercharging device for a partially supercharging multi-cylinder engine, the supercharger is constituted by a multi-chamber displacement pump having a plurality of discharge ports, and each of the discharge ports are connected to different cylinders via independent auxiliary intake systems, and the supercharged air discharge timing of each discharge port is adjusted to each cylinder so that supercharged air is discharged from each discharge port at least during the compression stroke of each cylinder. Since the engine speed is synchronized with the operating stroke of each cylinder, there is no need to increase the rotational speed of the supercharger as the number of cylinders increases. It is possible to distribute supply air efficiently and reliably, and to effectively demonstrate the supercharging effect of the auxiliary intake system in the supercharging region, further improving output performance during supercharging. .

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIG. 1 is an overall schematic configuration diagram showing an application example of a six-cylinder engine, and FIG. FIG. 3 is an explanatory diagram showing the relationship between each discharge port of the positive displacement supercharger and the supercharged air discharge timing. 1...Engine, 1a to 1f...Cylinder, 2...Combustion chamber,
5... Main intake system, 4... Auxiliary intake system, 8... Main intake passage, 9a, 9b... Main throttle valve, 1'5... Fuel supply device,
17...Auxiliary intake passage, 18...Supercharger, 19a, 19
b, - Suction port, 20a, 20b--Discharge port, 24a. 24b...Auxiliary throttle valve, 27...Main intake valve, 28...Auxiliary intake valve. Figure 1

Claims (1)

[Claims] [+] The intake system of the engine is composed of a main intake system and an auxiliary intake system, and a supercharger is provided in the auxiliary intake system, and in addition to supplying fresh air to the engine from the main intake system, In the multi-cylinder Nishijin supercharging device which supplies supercharging air to the engine from the auxiliary intake system at the timing of , each of the discharge ports is connected to a different cylinder via the independent auxiliary intake system, and supercharged air is discharged from each of the discharge ports so that supercharged air is discharged from each of the discharge ports at least during the compression stroke of the engine. A supercharging device for a multi-cylinder engine, characterized in that timing is synchronized with the operating stroke of each cylinder.