JP2796762B2 - V-type engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a V-type engine.

[0002]

2. Description of the Related Art As a V-type engine, Japanese Utility Model Publication No. 62-143
There is one disclosed in Japanese Patent Publication No. 44-44. In this V-type engine, a pair of exhaust manifolds is arranged inside a V bank of a cylinder arranged in a V shape, a pair of air supply manifolds are arranged outside a V bank, and a pair of exhaust turbochargers is provided at one end of an engine body. A supercharger is arranged, and a pair of supply air cooling intercoolers is arranged at the other end of the engine body. Further, the delivery pipes of the supply air sent from each exhaust turbocharger are connected to form a single supply pipe, and this supply pipe is disposed inside the V bank. This air supply pipe is branched and connected to each intercooler, and air is sent from one intercooler to one air supply manifold, and air is sent out from the other intercooler to the other air supply manifold.

[0003]

In the above-mentioned conventional V-type engine, air is supplied from one intercooler to one air supply manifold, and air is supplied from the other intercooler to the other air supply manifold. Is done. Therefore, the amount of supply air and the mixing ratio of air and fuel to the cylinders in one row of the V-shape and the mixing ratio of air and fuel to the cylinders in the other row Are different, and problems such as a decrease in output, a decrease in thermal efficiency, and occurrence of knocking occur.

In the above-described conventional V-type engine, since the exhaust manifold and the air supply pipe are arranged inside the V bank, the air supply is heated by radiant heat from the exhaust manifold, and the capacity of the intercooler is increased. I needed to.

Further, in the conventional V-type engine, in a branch pipe connecting the air supply manifold and each combustion chamber, a change in cross-sectional area is made as small as possible in order to make the flow of the air supply smooth. Was. However, since the distance from the inlet of the air supply manifold to each combustion chamber is not uniform, the flow path resistance from the inlet to the combustion chamber far from the inlet increases. for that reason,
Even if the change in the cross-sectional area in the branch pipe is reduced, the supply air cannot be supplied uniformly, and there is a problem that the thermal efficiency is reduced and the nitrogen oxides are increased.

An object of the present invention is to solve the above-mentioned problems of the prior art.

[0007]

The present invention is characterized in that a pair of exhaust manifolds are arranged inside a V bank of a cylinder arranged in a V shape, and a pair of air supply manifolds are arranged outside the V bank. A pair of exhaust turbochargers is disposed at one end of the engine main body, and a pair of supply air cooling intercoolers is disposed at the other end of the engine main body, and a supply pipe of the supply air supplied from each exhaust turbocharger. Are connected to form a single first air supply pipe, the first air supply pipe is branched and connected to each intercooler, and a supply pipe for air supplied from each intercooler is connected to form a single second air supply pipe. The second air supply pipe is branched and connected to each air supply manifold. The first air supply pipe and the second air supply pipe are arranged inside the V bank, and the second air supply pipe is provided above the first air supply pipe. In that it is arranged.

Preferably, a throttle valve is provided inside the second air supply pipe.

It is preferable that the first air supply pipe is a double pipe, the air supply flows inside the inner pipe, and the cooling water flows between the inner pipe and the outer pipe.

[0010] It is preferable that a restricting portion for restricting the flow of supply air is formed in a branch pipe connecting the supply manifold and each combustion chamber.

[0011]

In the case of a V-type engine, it is difficult to use a single exhaust turbocharger, and the efficiency of the exhaust turbocharger is improved. This is because it is preferable to use a pair for miniaturization.

The reason why the intercooler is paired is that if it is made single, the size becomes large and the V-type engine cannot be made compact.

The reason why the delivery pipes of the supply air sent from the respective exhaust turbochargers are connected to form a single first supply pipe is that the amount of the supply air and the air supplied from one of the exhaust turbochargers are different. This is because the amount of air supplied from the other exhaust turbocharger and the mixing ratio of air and fuel are different from the mixing ratio of the fuel and the fuel, so that the difference is eliminated and the mixture is made uniform.

The reason why the delivery pipes for the air supplied from each intercooler are connected to form a single second air supply pipe is to make the amount of air supply and the mixing ratio of fuel and air uniform. .

By arranging the first air supply pipe and the second air supply pipe inside the V bank, the V-type engine becomes compact.

By arranging the second air supply pipe above the first air supply pipe, the piping from the second air supply pipe to the air supply manifold arranged outside the V bank is shortened.

By providing the throttle valve inside the second air supply pipe, the amount of air supplied to the combustion chamber can be controlled by a single throttle valve, and the control mechanism of the throttle valve is simplified.

The first air supply pipe is a double pipe, and the air supply flows inside the inner pipe and the cooling water flows between the inner pipe and the outer pipe, so that the air supply is heated by radiant heat from the exhaust manifold. Is prevented, and the capacity of the intercooler can be reduced.

By forming a throttle for reducing the flow of the supply air in the branch pipe connecting the air supply manifold and each combustion chamber, the flow rate of the air supplied from each branch pipe to the combustion chamber is made uniform. Is done.

[0020]

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

First, a fuel system of a multi-cylinder sub-chamber lean-burn V-type engine 1 according to an embodiment of the present invention will be described with reference to FIG.

This V-type engine 1 has 12 cylinders,
A cylinder block 2 forming a cylinder arranged in a V-shape as viewed from the front, a piston 3 reciprocating in the cylinder block 2, a crankshaft 4 connected to the piston 3, and a cylinder covering the cylinder block 2 from above And a head 5. The upper part of the piston 3 in the cylinder block 2 is the main combustion chamber 6. A sub-combustion chamber 7 communicating with the main combustion chamber 6 is formed inside the cylinder head 5.

The main combustion chamber 6 is supplied with supply air having a low fuel concentration. First, the fuel gas supplied from the fuel supply main pipe 10 is reduced to approximately atmospheric pressure by the regulator 11, and thereafter, the pair of flow control devices 12a, 12b
Supplied to Each of the flow control devices 12a and 12b includes flow control valves 13a and 13b and on-off valves 14a and 14b. Each valve 13a, 13b, 14a, 14b is connected to the control device 1
The control device 115 is connected to a speed sensor 116 of the engine 1. Thereby, each valve 1
The opening degree of each of 3a, 13b, 14a, and 14b is adjusted by the control device 115 in accordance with the speed of the engine 1.
The flow rate of the fuel gas according to the rotation speed of the
a, 12b.

The fuel gas sent from each of the flow controllers 12a and 12b is supplied to a pair of mixers 15a and 15b. Each of the mixers 15a and 15b mixes the fuel gas and the air supplied through the air filters 16a and 16b by using a Venturi tube, and sends out a supply air with a low fuel concentration.

The air supplied from one mixer 15a is supplied to one of a pair of exhaust turbochargers 17a and 17b.
The air supply supplied to the compressor a and supplied from the other mixer 15b is supplied to the compressor of the other exhaust turbocharger 17b.

The supply pipe 18a for supplying air supplied from the compressor of one exhaust turbocharger 17a and the supply pipe 18b for supplying air supplied from the compressor of the other exhaust turbocharger 17b are connected to form a single unit. Is the first air supply pipe 19.

The first air supply pipe 19 is branched and connected to a pair of water-cooled intercoolers 20a and 20b for cooling the air supply.

A supply pipe 21a for supplying air supplied from one intercooler 20a and a supply pipe 21b for supplying air supplied from the other intercooler 20b are connected to form a single second supply pipe 22.

The second air supply pipe 22 is branched and connected to a pair of air supply manifolds 23a and 23b. From one air supply manifold 23a, air is supplied via a branch pipe 24a to each main combustion chamber 6 of the cylinders of the V-type engine 1 along the row on the left side in FIG. In addition, the supply air is supplied from the other supply manifold 23b to the main combustion chambers 6 of the cylinders along the other row of the V-type engine via the branch pipe 24b.

Fuel gas is supplied to the sub-combustion chamber 7.
That is, a bypass pipe 30 branched from the fuel supply main pipe 10 is formed, and a compressor 31 for increasing the pressure of the fuel gas flowing through the bypass pipe 30 is provided. The delivery pipe for the fuel gas delivered from the compressor 31 is branched into a first gas main pipe 32a and a second gas main pipe 32b. Fuel gas is supplied from the first gas main pipe 32a to the sub-combustion chamber 7 along the left column in FIG. 2 via the branch pipe 33a. Further, the fuel gas is supplied from the second gas main pipe 32b to the sub-combustion chamber 7 along the other row via the branch pipe 33b. A check valve 70 shown in FIG. 8 is interposed between each branch 33a, 33b and the sub combustion chamber 7 so that the fuel gas does not flow backward from the sub combustion chamber 7 to the gas main pipes 32a, 32b. The check valve 70 includes a housing 71, a fuel gas inlet 75 formed in the housing 71, and a fuel gas outlet 72.
And a valve 73 for opening and closing the fuel gas outlet 72. The valve 73 is urged by a spring 74 in a direction to close the outlet 72. Thereby, when the pressure of the sub-combustion chamber 7 communicating with the outlet 72 side in the intake process becomes small,
The valve 73 moves downward due to the spring 74 and the pressure of the fuel gas flowing from the inlet 75, and the outlet 72 opens to supply the fuel gas to the sub-combustion chamber 7. In addition, when the pressure in the sub-combustion chamber 7 increases in the exhaust step or the compression step, the valve 73 moves upward to close the outlet 72, so that backflow of fuel from the sub-combustion chamber 7 is prevented.

The exhaust gas is supplied from a pair of exhaust manifolds 90a, 90b to the turbines of the exhaust turbochargers 17a, 17b through exhaust pipes 91a, 91b.
After that, it is discharged from the V-type engine 1.

A throttle valve 40 is disposed inside the second air supply pipe 22. This throttle valve 4
0 operates according to the engine load. When the engine load increases, the opening degree of the second air supply pipe is increased to supply a large amount of supply air to the main combustion chamber 6, and when the engine load decreases, the supply to the main combustion chamber 6 is performed. Less air supply. The operation of the throttle valve 40 is controlled by the electronic governor device 100. Further, the opening degree of the second air supply pipe 22 is minimized by shutting off the engine load, and the supply of air supply to the main combustion chamber 6 is minimized. The engine load cutoff signal is sent from the engine load control device 105 to the electronic governor device 100, and the electronic governor device 100 immediately operates the throttle valve 40 to the minimum opening position.

The amount of fuel gas sent to the sub-combustion chamber 7 is adjusted in response to the change in the amount of air supplied to the main combustion chamber 6 according to the engine load. That is, the regulators 41a and 41b are provided in the middle of the first gas main pipe 32a and the second gas main pipe 32b, respectively. Each of the regulators 41a and 41b includes a main body block 44 as shown in FIG.
a, an inlet 42 communicating with the upstream side of 32b,
a and an outlet 43 communicating with the downstream side of 32b. An on-off valve 45 for adjusting the opening of a passage 47 between the inlet 42 and the outlet 43 is provided. This on-off valve 45
7 is urged in a direction to close the passage 47 by being pressed downward in FIG. The on-off valve 45 is connected to a diaphragm 48, and a pressure chamber 49 is formed below the diaphragm 48. A spring 150 that pushes the diaphragm 48 upward in FIG. 7 is disposed inside the pressure chamber 49. Further, a connection port 51 is formed in the pressure chamber 49, and a connection pipe 50 connected to the connection port 51 connects the inside of the pressure chamber 49 and an air supply passage downstream of the throttle valve 40.

Thus, when the engine load increases and the degree of opening of the second air supply pipe 22 by the throttle valve 40 increases, the air supply pressure downstream of the throttle valve 40 increases, so that the pressure in the pressure chamber 49 increases. Become.
Then, as the diaphragm 48 moves upward in FIG. 7, the on-off valve 45 moves upward, and the opening of the passage 47 increases. Accordingly, in response to an increase in the amount of supply air supplied to the main combustion chamber 6, the gas main pipes 32a and 32b
The amount of fuel gas supplied to the fuel cell increases.

When the opening of the second supply pipe 22 by the throttle valve 40 is reduced due to a decrease in the engine load, the supply pressure on the downstream side of the throttle valve 40 decreases, so that the pressure in the pressure chamber 49 decreases. . Then
When the diaphragm 48 moves downward in FIG. 7, the on-off valve 45 moves downward, and the opening of the passage 47 decreases.
Accordingly, the amount of fuel gas supplied from the gas main pipes 32a and 32b to the sub-combustion chamber 7 decreases in response to the decrease in the amount of supply air supplied to the main combustion chamber 6.

When the throttle valve 40 is actuated by a load cutoff signal and the opening of the second supply passage 22 is minimized, the amount of air supplied to the main combustion chamber 6 sharply decreases. In this case, the amount of fuel gas passing through the regulators 41a and 41b also decreases. However, the fuel gas that has passed through the regulators 41a and 41b immediately before the load cutoff signal is
It remains in the fuel gas passage downstream of the regulators 41a and 41b. The amount of fuel gas remaining in the fuel gas passage downstream of the regulators 41a and 41b is V
As the number of cylinders of the engine 1 increases, the number of fuel gas passages increases because the length of the fuel gas passage increases. If a large amount of fuel gas remaining in the fuel gas passage is supplied to the sub combustion chamber 7, the main combustion chamber 6
The amount of air supplied to the sub-combustion chamber 7 is insufficient because oxygen is insufficient to burn the fuel gas in the sub-combustion chamber 7 and a misfire occurs. Then, unburned fuel gas explodes in the exhaust manifolds 90a and 90b.

In order to prevent such a situation from occurring, the first gas main pipe 32 downstream of the regulators 41a and 42b
a, a fuel gas passage inside 32b, and an air filter 1
Communication passages 60a and 60b are provided for communicating the air supply passages between the mixers 6a and 16b and the mixers 15a and 15b. In addition, electromagnetic on-off valves 61a and 61b for opening and closing the communication passages 60a and 60b are provided. The electromagnetic on-off valves 61a and 61b are of a normally closed type, and open the communication paths 60a and 60b for a predetermined time in response to an engine load cutoff signal from the control device 105. As a result, when the engine load is cut off, the fuel gas remaining in the fuel gas passage downstream of the regulators 41a and 41b reaches the supply passage through the communication passages 60a and 60b. No fuel gas is supplied and misfires and exhaust manifold 90
Explosion accidents at a and 90b can be prevented.
The time for opening the electromagnetic on-off valves 61a and 61b is appropriately set according to the number of cylinders, the displacement, etc. of the V-type engine 1.

The first gas main pipe 32a and the second gas main pipe 32b are communicated downstream of the regulators 41a and 41b by a communication pipe 65, and both gas main pipes 32a and 32b are connected.
The fuel gas pressure in the chamber is made uniform.

Next, the structure of the V-type engine 1 will be described with reference to FIGS.

The V-type engine 1 drives the generator 80 as an engine accessory. The V-type engine 1 and the generator 80 are installed on a common bed 81.

As shown in FIG. 5, a pair of exhaust manifolds 90a and 90b are arranged inside a V bank of a cylinder formed in a V shape when viewed from the front. By arranging the exhaust manifolds 90a and 90b inside the V-bank in this way, safety when the exhaust manifolds 90a and 90b explode is achieved. Exhaust manifold 90a,
Since 90b is arranged inside the V bank, the pair of air supply manifolds 23a and 23b are arranged outside the V bank.

One end of the engine body (left end in FIG. 1)
A pair of exhaust turbochargers 17a and 17b is arranged above the. It is difficult to use a single exhaust turbocharger in the V-type engine 1 because the exhaust turbochargers 17a and 17b are paired, and the efficiency of the exhaust turbocharger is improved. This is to reduce the size. As shown in FIG. 3, a mixer 15a for mixing the fuel gas supplied from the fuel supply main pipe 10 and the air supplied through the air filters 16a and 16b is provided outside the exhaust turbochargers 17a and 17b. 15b are arranged.

A pair of intercoolers 20 for cooling air supply is provided above the other end (right end in FIG. 1) of the engine body.
a and 20b are arranged. Intercooler 20a, 2
The reason why 0b is paired is that if it is made single, it becomes large,
In order to make the V-type engine 1 compact, a pair is used.

The delivery pipes 18a for the supply air supplied from the compressor of each exhaust turbocharger 17a, 17b,
18b are connected to form a single first air supply pipe 19. The first air supply pipe 9 is disposed inside the V bank and below the exhaust manifolds 90a and 90b, as shown in FIGS. Thereby, the air supplied from each of the exhaust turbochargers 17a and 17b is supplied to the first air supply pipe 1
9 and the amount of air supply and the mixing ratio between fuel and air are made uniform. Then, the first air supply pipe 19 is branched and connected to each of the intercoolers 20a and 20b.

The supply pipes 21a and 21b for supplying the air supplied from the intercoolers 20a and 20b are connected to form a single second air supply pipe 22. This second air supply pipe 22
Is located inside the V bank and above the first air supply pipe 19 and the exhaust manifolds 90a, 90b.
Thereby, the air supplied from each of the intercoolers 20a and 20b is mixed inside the single second air supply pipe 22b, so that the amount of air supply and the mixing ratio of air and fuel are made uniform. In addition, since the second air supply pipe is located inside the V bank and above the first air supply pipe 19, the width of the V-type engine 1 can be reduced to make it compact.

The second air supply pipe 22 is branched and connected to each of the air supply manifolds 23a and 23b. Supply air is supplied from the respective supply manifolds 23a and 23b to the main combustion chamber 6 of the V-type engine 1 via branch pipes 24a and 24b. As shown in FIG. 5, each of the branch pipes 24a and 24b has an L-shape, and the cross-sectional area of the flow passage decreases toward the main combustion chamber 6 in order to reduce the air supply. Thereby, even if the flow path resistance is not uniform due to the difference in the distance from the inlets of the air supply manifolds 23a, 23b to the respective main combustion chambers 6, the air supply flow rate is made uniform by the throttle portions in the branch pipes 24a, 24b. Thus, the amount of air supplied to each main combustion chamber 6 is made uniform.

As shown in FIGS. 1 and 6, the second air supply pipe 22
The throttle valve 40 provided inside is connected to the electronic governor device 100 via a link 101. The electronic governor device 100 is cooled by being arranged near the intercooler 20a.

As shown in FIG. 3, a bypass pipe 30 for supplying fuel to the sub-combustion chamber 7 of the V-type engine 1 branches at one end of the V-type engine 1. As shown in FIG. 1, a first gas main pipe 32 branched from the bypass pipe 30
a and the second gas main pipe 32b are arranged outside the V bank. Regulators 41 a and 41 b provided in the middle of each gas main pipe 32 a and 32 b are arranged at one end of the V-type engine 1. A communication passage 60 that communicates a fuel gas passage downstream of the regulators 41a and 41b with a passage between the air filters 16a and 16b and the mixers 15a and 15b.
a and 60b are constituted by piping at one end of the V-type engine 1. Electromagnetic on-off valves 61a, 61b for opening and closing the communication passages 60a, 60b are arranged at one end of the V-type engine 1. A communication pipe 6 that connects the first gas main pipe 32a and the second gas main pipe 32b downstream of the regulators 41a and 41b.
5 is disposed on the other end side of the V-type engine 1 as shown in FIGS.

As shown in FIGS. 5 and 6, the first air supply pipe 19
Is a double pipe, air supply flows inside the inner pipe 19a, and cooling water flows between the outer pipe 19b and the inner pipe 19a. As the cooling water, a part of the cooling water flowing through the cooling water jacket inside the cylinder block 2 of the V-type engine 1 is used. Therefore, the first air supply pipe 19 and the cylinder block 2 are connected via the cooling water pipe 110. Also, this inner tube 19a
The cooling water flowing between the cooling water and the outer pipe 19b is discharged through the cooling water collecting pipe 111.

Generator 8 driven by V-type engine 1
0 is disposed below the intercoolers 20a and 20b. Cooling water pipes 120a and 120b for supplying cooling water to the intercooler and the intercooler 20
a, cooling water pipe 1 for discharging cooling water from 20b
The pipes 21b and 121a are piped outside the generator 80. Thereby, the pipes 120a, 120b, 1
This prevents water leaks from 21a and 121b from falling onto generator 80.

The interior of the bed 81 on which the V-type engine 1 and the generator 80 are installed is the oil pan 8 of the V-type engine 1.
3 and through a pipe 84. Thus, the interior of the bed 81 is a tank for lubricating oil. The cooling water pipes 120b and 121b of the one intercooler 20b penetrate the inside of the bed 81. Thus, the lubricating oil of the V-type engine 1 is cooled by the intercooler cooling water, and the capacity of the lubricating oil cooler (not shown) can be reduced. The engine accessory is not limited to the generator, but may be, for example, a compressor.

[0052]

According to the V-type engine of the present invention, the amount of air supplied to the combustion chamber and the mixing ratio of fuel and air can be made uniform with a compact structure.

Further, by providing the throttle valve inside the second air supply pipe, the amount of air supplied to the combustion chamber can be controlled by a single throttle valve, so that the control mechanism is simplified and the cost is reduced. it can.

By cooling the air supply using cooling water with the first air supply pipe being a double pipe, the capacity of the intercooler can be reduced and the engine can be downsized.

Further, by providing the throttle portion in the branch pipe connecting the air supply manifold and the combustion chamber, the amount of air supply to each combustion chamber can be made uniform.

[Brief description of the drawings]

FIG. 1 is a side view of a V-type engine according to an embodiment of the present invention.

FIG. 2 is a diagram showing a fuel system of a V-type engine according to the embodiment of the present invention.

FIG. 3 is a front view of a V-type engine according to the embodiment of the present invention.

FIG. 4 is a rear view of the V-type engine according to the embodiment of the present invention.

FIG. 5 is a cross-sectional view of a V-type engine according to the embodiment of the present invention.

FIG. 6 is a longitudinal sectional view of a main part of a V-type engine according to the embodiment of the present invention.

FIG. 7 is a sectional view of a regulator according to an embodiment of the present invention.

FIG. 8 is a sectional view of a check valve according to an embodiment of the present invention.

[Explanation of symbols]

 1 V-type engine 17a, 17b Exhaust turbocharger 19 First air supply pipe 20a, 20b Intercooler 22 Second air supply pipe 23a, 23b Air supply manifold 40 Throttle valve 90a, 90b Exhaust manifold

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Nobuo Kasai 1-32 Chaya-cho, Kita-ku, Osaka-shi, Osaka Inside Yanmar Diesel Co., Ltd. (56) References JP-A-61-279733 (JP, A) Hei 3-23620 (JP, U) Japanese Utility Model 63-73531 (JP, U) Japanese Utility Model Utility Model 61-65243 (JP, U) Japanese Utility Model 62-14344 (JP, Y2) (58) Fields surveyed (Int) .Cl. ⁶ , DB name) F02B 37/00

Claims (4)

(57) [Claims] 1. A pair of exhaust manifolds are disposed inside a V bank of a cylinder arranged in a V shape, a pair of air supply manifolds are disposed outside a V bank, and a pair of exhaust turbochargers are provided at one end of an engine body. A charger is disposed, a pair of supply air cooling intercoolers is disposed at the other end of the engine body, and supply pipes for supply air supplied from the respective exhaust turbochargers are connected to form a single first supply pipe. The first air supply pipe is branched and connected to each intercooler, and a supply pipe for air supplied from each intercooler is connected to form a single second air supply pipe. The second air supply pipe is branched and connected to each other. Connected to the air supply manifold,
A V-type engine, wherein an air supply pipe and a second air supply pipe are arranged inside a V bank, and a second air supply pipe is arranged above the first air supply pipe. 2. The V-type engine according to claim 1, wherein a throttle valve is provided inside the second air supply pipe. 3. The air supply system according to claim 1, wherein the first air supply pipe is a double pipe, air supply flows through the inner pipe, and cooling water flows between the inner pipe and the outer pipe. The V-shaped engine according to the above. 4. The branch pipe for connecting the air supply manifold to each combustion chamber, wherein a throttle portion for reducing the flow of the air supply is formed. The V-shaped engine according to the above.