JP2526052B2 - Reciprocating internal combustion engine for both spark ignition and compression ignition - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a single reciprocating internal combustion engine capable of selectively performing spark ignition and compression ignition.

[Conventional technology]

Internal combustion engines generally include a spark ignition engine and a compression ignition engine. A spark ignition engine mixes gaseous fuel such as natural gas and vaporized gasoline with air, sucks in and compresses the gaseous fuel mixed with air, and then ignites it with a spark plug attached to the combustion chamber of the cylinder. It is a method of burning. On the other hand, the compression ignition engine is a system in which only the air is sucked into the cylinder and compressed to a high pressure and a high temperature, and then the liquid fuel is blown from a fuel injection nozzle attached to the combustion chamber of the cylinder to burn the liquid fuel.

Conventionally, such a spark ignition engine and a compression ignition engine have been individually installed and used for applications according to their characteristics. For example, as a power generation facility in a large building,
A spark-ignition internal combustion engine that uses city gas as fuel is installed, and separately from this, a liquid that can be stored as an emergency power generation engine in case the supply of city gas is interrupted due to an earthquake or other accident. A compression ignition internal combustion engine that uses fuel such as light oil as a fuel is installed.

[Problems to be solved by the invention]

As described above, it is necessary to install a regular spark ignition internal combustion engine and an emergency compression ignition internal combustion engine as power generation equipment in a large building or the like. Therefore, there is a problem that a large space must be secured in the building and a large amount of equipment cost and maintenance cost are required.

If the spark ignition and the compression ignition can be used together in one internal combustion engine, the above-described problem can be solved, but this has been conventionally difficult in the following points.

That is, the maximum output of the supercharged spark ignition internal combustion engine is restricted by the knotting phenomenon that occurs at the upper limit of the output. The occurrence of the knocking phenomenon depends on the compression ratio, and when operating in a well-balanced supercharged spark ignition internal combustion engine with the air-fuel ratio controlled at 1, the upper limit of the compression ratio at which the knocking phenomenon does not occur is about 8

On the other hand, the lower limit of the compression ratio at which the startability and combustibility of the supercharged compression ignition internal combustion engine do not occur is about 12. The lower the compression ratio, the more difficult it is to start the engine and the worse the stable combustibility.

As mentioned above, a supercharged spark ignition internal combustion engine requires its compression ratio to be about 8 or less, while a compression ignition internal combustion engine requires its compression ratio to be about 12 or more. When spark ignition and compression ignition are used together in one internal combustion engine, the compression ratio of the internal combustion engine is constant by design and cannot be changed, so that the following problems occur.

That is, when the spark ignition operation is switched to the compression ignition operation, the combustion air during the spark ignition operation does not ignite in the cylinder due to the low temperature, and therefore the internal combustion engine does not operate. On the other hand, when the compression ignition operation is switched to the spark ignition operation, knocking occurs due to the high temperature of the combustion air, and the operation becomes impossible.

Therefore, from spark ignition operation to compression ignition operation, or
When switching from compression ignition operation to spark ignition operation,
It is necessary to suspend the operation, change the temperature of the combustion air to a temperature adapted to the spark ignition operation or the compression ignition operation, and then restart the operation.

In this way, temporarily stopping the operation of the internal combustion engine
For example, when this internal combustion engine is used as a power generator, the power supply becomes unstable, and OA equipment is now widely used, causing a great deal of problems in various fields.

Therefore, an object of the present invention is to switch the operation between the spark ignition operation and the compression ignition operation by instantaneously changing the temperature of the combustion air in the reciprocating internal combustion engine for both spark ignition and compression ignition. It is an object of the present invention to provide a single reciprocating internal combustion engine that can be continuously operated without occurrence of knocking, deterioration of startability and combustibility, and without stopping operation.

[Means for solving problems]

The reciprocating internal combustion engine of the present invention is provided with a spark ignition plug, a liquid fuel injection nozzle, a mixture of a gaseous fuel and air for spark ignition, or an intake pipe for air for compression ignition, which is provided in a combustion chamber of a cylinder. And an exhaust pipe, a gas carburetor for adjusting the air-fuel mixture blown into the intake pipe, an air supply conduit having one end connected to a supercharger for supplying air to the gas carburetor, An air cooler provided in the middle of the air supply conduit for cooling combustion air for spark ignition operation and steady operation of compression ignition, and in parallel with the air cooler via a branch pipe. An air heater provided for heating the combustion air for starting the compression ignition, and for supplying a gaseous fuel to the gas carburetor,
A gas fuel supply conduit provided with a valve on the way, and a gas supply conduit provided with a flow rate adjusting valve on the way for supplying the air-fuel mixture or the air for compression ignition to the intake pipe, A bypass pipe branched from a portion of the air supply conduit on the outlet side of the air cooler and the air heater and on the inlet side of the gas carburetor and connected to the gas supply conduit; and the air cooler. And a control valve provided in an air supply conduit on the inlet side of the air heater for selectively guiding air passing through the air supply conduit to either the air cooler or the air heater. Provided in the middle of each of the air supply conduit on the outlet side of the air heater and the bypass pipe for selectively guiding either the air-fuel mixture or the compression ignition air to the gas supply conduit. Valve A liquid fuel supply conduit connected to the liquid fuel injection nozzle via a fuel injection pump and having a valve in the middle, and an opening degree of a flow rate adjusting valve provided in the middle of the gas supply conduit. A governor for adjusting the flow rate of the gas sucked into the combustion chamber by adjusting or for adjusting the fuel injection pump to control the injection speed of the liquid fuel injected into the combustion chamber, By instantaneously changing the temperature of the combustion air by the air cooler and the air heater, switching between the spark ignition operation and the compression ignition operation can be continuously performed without stopping the operation of the internal combustion engine. It is characterized in that it can be performed in an objective manner.

Next, the present invention will be described with reference to the drawings. First
FIG. 1 is a system diagram showing an embodiment of the present invention, FIG. 2 is a conceptual diagram of an air supply / exhaust system, and FIG. 3 is a schematic vertical sectional view showing one cylinder thereof. As shown in FIGS. 1 to 3, in each combustion chamber 3 of the cylinder 2 in the internal combustion engine 1 configured by a plurality of (two in the illustrated example) cylinders 2,
A spark plug 4 for spark ignition, a liquid fuel injection nozzle 5 for compression ignition, an intake pipe 6 for a mixture of gaseous fuel and air for spark ignition or air for compression ignition, and an exhaust pipe 7. Is provided. An ignition device 8 is connected to the spark plug 4, and a fuel injection pump 9 is connected to the liquid fuel injection nozzle 5. 10 is a piston.

A gas supply conduit 11 is connected to an intake pipe 6 provided in the combustion chamber 3 of the cylinder 2, and a gas fuel supply conduit 13 is connected to the gas supply conduit 11 via a gas carburetor 12.
Is connected. A flow rate adjusting valve 14 is provided in the middle of the gas supply conduit 11, and a valve 15 and a pressure adjusting valve 16 are provided in the middle of the gas fuel supply conduit 13.

The gas carburetor 12 is connected to the other end of an air supply conduit 18 whose one end is connected to the supercharger 17. Supercharger 17
Rotates the turbine with the exhaust gas discharged from the exhaust pipe 7 of the cylinder 2, compresses the air sucked from the air supply pipe 31 by the generated power, and sends the compressed air to the air supply conduit 18.

The gas carburetor 12 forms a mixture of gaseous fuel sent through the gaseous fuel supply conduit 13 and air sent through the air supply conduit 18. A gas mixture supply mechanism is formed by the gas carburetor 12, the gas fuel supply conduit 13 and the gas supply conduit 11 as described above.

In the middle of the air supply conduit 18, an air cooler 19 is provided in parallel via a branch pipe 18a, and an air heater 20 is provided in parallel via a branch pipe 18b. A control valve 21 is provided at a branch portion of the air supply conduit 18 between the branch pipe 18a and the branch pipe 18b.

Cooling water circulates in the air cooler 19, cools the air compressed by the supercharger 17 flowing through the branch pipe 18a, and sends it to the gas carburetor 12. A cooling / drainage conduit 22 through which high-temperature cooling / drainage from the internal combustion engine 1 flows is connected to the air heater 20, and heats the compressed air by the supercharger 17 flowing through the branch pipe 18b.

A first bypass pipe 23 and a second bypass pipe 24 are connected between the air supply conduit 18 on the inlet side of the gas carburetor 12 and the gas supply conduit 11. 26 is a cooling water conduit for cooling the internal combustion engine 1, 27 is a cooling drain conduit 22 and a cooling water conduit 26.
And a cooling drain circulation conduit that connects and in the middle of each.

25 is a flow rate adjusting valve provided in the middle of the gas supply conduit 11.
The opening of 14 is adjusted to control the intake flow rate of the gas sucked into the combustion chamber 3 of the cylinder 2, or the fuel injection pump 9
Is a governor for controlling the injection speed of the liquid fuel injected into the combustion chamber 3 of the cylinder 2 by adjusting

A valve 30 is provided in the middle of the branch pipe 18b on the outlet side of the air heater 20.
However, a valve for air-fuel ratio control is provided in the middle of the first bypass pipe 23.
28 and a valve 29 in the middle of the second bypass pipe 24, respectively.

32 is a pump provided in the middle of the cooling water conduit 26, 33 is a pump provided in the middle of the cooling / drain circulation conduit 27, and 34 is a feed water heater.

Between the exhaust pipe 35 for guiding the exhaust gas from the exhaust pipe 7 of the combustion chamber 3 to the supercharger 17 and the exhaust pipe 36 of the supercharger 17, an exhaust relief valve 38 operated by a pilot air control valve 37. Is provided.

A liquid fuel supply conduit 39 is connected to the fuel injection pump 9 provided in each of the cylinders 2, and a heavy oil conduit 41 from a heavy oil tank 40 that stores heavy oil is connected to the conduit 39.
It is connected to a light oil conduit 43 from a light oil tank 42 that stores a fuel having good ignitability, for example, light oil. A liquid fuel return conduit 44 is connected to the fuel injection pump 9.
In the return conduit 44, a heavy oil return conduit 45 to the heavy oil tank 40,
A light oil return conduit 46 to the light oil tank 42 is connected.
Such heavy oil tank 40, light oil tank 42, each conduit 39,41,
A liquid fuel supply mechanism is formed by 43, 44, 45, 46 and the like.

A valve 47 is provided in the middle of the heavy oil conduit 41, a valve 48 is provided in the middle of the heavy oil return conduit 45, a valve 49 is provided in the middle of the light oil conduit 43, and a valve 50 is provided in the middle of the light oil return conduit 46. ing.

Reference numeral 51 is a pump provided in the middle of the liquid fuel supply conduit 39, and 52 is a filter.

[Action]

Next, the case where the internal combustion engine of the present invention is operated by spark ignition using a gaseous fuel will be described.

The control valve 21 of the air supply conduit 18 is switched to the side of the branch pipe 18a where the air cooler 19 is provided. Then, the valve 15 of the gas supply conduit 13, the valve 49 of the light oil conduit 43, and the valve 50 of the light oil return pipe 46 are opened. On the other hand, the valve 30 of the branch pipe 18b on the outlet side of the air heater 20 and the second bypass pipe 2
The valve 29 of 4 is closed, the valve 28 of the first bypass pipe 23 is opened, and the valve 47 of the heavy oil conduit 41 and the valve 48 of the heavy oil return conduit 45 are closed.

As a result, the gaseous fuel flows through the gaseous fuel supply conduit 13 and is mixed in the gas carburetor 12 with the cooled air in the air cooler 19 flowing through the air supply conduit 18 and then through the gas supply conduit 11. Through, cylinder 2
The air is taken into the combustion chamber 3 from the intake pipe 6. At this time,
A part of the air cooled in the air supply pipe 19 is guided to the first bypass pipe 23 branched from the air supply pipe 18, and an appropriate amount of air is adjusted by adjusting a valve 28 provided in the middle of the first bypass pipe 23. Cooling air flows into the flow rate adjusting valve 14. Therefore, the air-fuel ratio of the air-fuel mixture that is sucked into the combustion chamber 3 from the intake pipe 6 is finely adjusted. In this way, the low-temperature air-fuel mixture is sucked into the combustion chamber 3, so that the operation of the piston by the spark ignition of the spark plug 4 is efficiently performed.

At this time, the fuel injection pump 9 is not operated by the governor 25, and the heavy oil in the heavy oil tank 40 is not supplied to the fuel injection pump 9 by the closed valves 47 and 48. Even during this period, the light oil tank 42 is
The light oil therein is fed to the fuel injection pump 9 to be lubricated, and the fuel injection pump 9 is provided so that it can operate at any time.

Next, a case where the internal combustion engine of the present invention is operated by compression ignition using liquid fuel will be described. Before starting and until the combustion chamber 3 of the cylinder 2 reaches a stable high temperature, each valve is opened and closed as follows. That is,
The control valve 21 of the air supply conduit 18 is switched to the side of the branch pipe 18b provided with the air heater 20. Then, the valve 30 of the branch pipe 18b on the outlet side of the air heater 20 and the valve 29 of the second bypass pipe 24 are opened, the valve 28 of the first bypass pipe 23 and the flow rate adjusting valve 14 are closed, and the light oil conduit Open valve 49 of 43 and valve 50 of light oil return conduit 46. On the other hand, the valve 15 of the gas fuel supply conduit 13 and the valve of the heavy oil conduit 41
47 and the valve 48 of the heavy oil return conduit 45 are closed.

As a result, the light oil in the light oil tank 42 flows through the light oil conduit 43 and the liquid fuel supply conduit 39, and is injected by the fuel injection pump 9 from the liquid fuel injection nozzle 5 into the combustion chamber 3 of the cylinder 2. .

The air compressed by the supercharger 17 flowing through the air supply conduit 18 is heated by the air heater 20 by the high-temperature cooling drainage from the internal combustion engine 1 flowing through the cooling drainage conduit 22.

Therefore, high temperature air is sucked into the combustion chamber 3 of the cylinder 2 from the intake pipe 6, and when high pressure and high temperature are reached, light oil is injected from the liquid fuel injection nozzle 5 and burned, and as a result, the piston 10 is Works effectively.

At this time, no gas fuel is supplied to the gas carburetor 12 by the closed valve 15, and the air heater is
The hot air, heated in 20, is fed into the gas carburetor 12
Do not pass. Therefore, the large amount of air required for the compression ignition operation does not cause troubles such as excessive pressure loss and blockage in the gas carburetor 12.

In this way, at the time of start-up and until the combustion chamber 3 of the cylinder 2 reaches a stable high temperature, light oil is burned by the high-temperature compressed air, so that startability and combustibility are extremely good.

Next, after the steady operation, and after the combustion chamber 3 of the cylinder 2 reaches a stable high temperature, each valve is opened and closed as follows. That is, the control valve 21 of the air supply conduit 18 is switched to the side of the branch pipe 18a provided with the air cooler 19. And the first
By closing the valve 28 of the bypass pipe 23 and the flow rate adjusting valve 14,
The valve 29 of the second bypass pipe 24 is opened, and the heavy oil conduit
The valve 47 of 41 and the valve 48 of the heavy oil return conduit 45 are opened. On the other hand, the valve 15 of the gas fuel supply conduit 13 and the valve 30 of the outlet pipe 18b of the air heater 20 are closed, and the valve 49 of the light oil conduit 43 and the valve 50 of the light oil return conduit 46 are closed.

As a result, the heavy oil in the heavy oil tank 40 flows through the heavy oil conduit 41 and the liquid fuel supply conduit 39, and is injected by the fuel injection pump 9 from the liquid fuel injection nozzle 5 into the combustion chamber 3 of the cylinder 2. .

In the combustion chamber 3 of the cylinder 2, low-temperature air is sucked from the intake pipe 6 through the air supply conduit 18 and the second bypass pipe 24, and the liquid fuel injection nozzle 5
As a result of injecting and burning heavy oil from the piston 10, the piston 10 operates efficiently.

At this time, the gas fuel is not supplied to the gas carburetor 12 by the closed valve 15 similarly to the above.

As described above, during steady operation, the heavy oil is burned by the low-temperature compressed air, so that the combustibility is improved.

In addition, at the time of starting, in order to sufficiently perform the heating of the air in the air supply conduit 18 by the air heater 20, by the feed water heater 34 provided in the middle of the cooling and draining circulation conduit 27,
The cooling drainage flowing through the cooling drainage conduit 22 is heated.

The switching of spark ignition using gaseous fuel or compression ignition using liquid fuel, and switching of fuel and air temperature during compression ignition described above are all performed by opening / closing and controlling each valve and governor 25 by remote control. Is automatically performed by.

〔The invention's effect〕

As described above, according to the present invention, by a single reciprocating internal combustion engine, the occurrence of knocking, spark ignition using gas fuel at any time without deterioration of startability and combustibility, Also, compression ignition using liquid fuel can be selectively performed.

Therefore, for example, if the internal combustion engine of the present invention is used for power generation equipment in a large building, it is not necessary to install an emergency compression ignition internal combustion engine in addition to the conventional spark ignition internal combustion engine as in the conventional case. As a result, the space for power generation equipment in the building can be reduced, and equipment costs and maintenance costs can be reduced.

In recent sewage treatment plants, a spark ignition internal combustion engine is used to generate electricity using fermentation gas as a fuel, and the exhaust heat is used as a heat source for fermentation. In preparation for re-fermentation when the generation of fermentation gas is reduced or the operation is stopped, a backup electric heat source facility is required. If the internal combustion engine of the present invention is used for power generation equipment in such a sewage treatment plant,
It is extremely economical because it is not necessary to install a backup electric heat source equipment as in the past.

In addition, the present invention can be widely used for power generation equipment in various plants and has various industrially excellent effects.

[Brief description of drawings]

FIG. 1 is a system diagram showing an embodiment of the present invention, FIG. 2 is a conceptual diagram of an air supply / exhaust system, and FIG. 3 is a schematic vertical sectional view showing one cylinder thereof. In the drawings, 1 ... Internal combustion engine, 2 ... Cylinder, 3 ... Combustion chamber, 4 ...
... spark plug, 5 ... liquid fuel injection nozzle, 6 ... intake pipe, 7 ... exhaust pipe, 8 ... ignition device, 9 ... fuel injection pump, 10 ... piston, 11 ... gas supply conduit, 12 ……
Gas carburetor, 13 …… Gas fuel supply conduit, 14 ……
Flow rate control valve, 17 …… Supercharger, 18 …… Air supply conduit, 19
...... Air cooler, 20 ...... Air heater, 21 ...... Control valve, 22
...... Cooling drainage pipe, 23 ...... First bypass pipe, 24 ...... Second
Bypass pipe, 25 …… Governor, 26 …… Cooling water conduit, 27…
… Cooling drainage circulation conduit, 39… Liquid fuel supply conduit, 40…
… Heavy oil tank, 41 …… Heavy oil conduit, 42 …… Light oil tank, 4
4,45,46 …… Return conduit.

Claims (1)

(57) [Claims] 1. A plug for spark ignition, a liquid fuel injection nozzle, an intake pipe and an exhaust pipe of a mixture of gaseous fuel and air for spark ignition or air for compression ignition, which are provided in a combustion chamber of a cylinder. A gas carburetor for adjusting the air-fuel mixture blown into the intake pipe, an air supply conduit having one end connected to a supercharger for supplying air to the gas carburetor, and an air supply conduit An air cooler provided on the way for cooling the combustion air for spark ignition operation and steady operation of compression ignition, and a compression provided in parallel with the air cooler via a branch pipe. An air heater for heating the combustion air for starting the ignition, a gas fuel supply conduit provided with a valve in the middle thereof for supplying the gas fuel to the gas carburetor, and the intake pipe For supplying the air-fuel mixture or the compression ignition air, a gas supply conduit provided with a flow rate adjusting valve in the middle thereof, and an outlet side of the air cooler and the air heater of the air supply conduit. And a bypass pipe branched from the inlet side portion of the gas carburetor and connected to the gas supply conduit, and provided in the inlet air supply conduit of the air cooler and the air heater, A control valve for selectively guiding the air passing through the air supply conduit to either the air cooler or the air heater, and the gas supply conduit for either the air-fuel mixture or the compression ignition air. A valve provided in the middle of each of the air supply conduit on the outlet side of the air heater and the bypass pipe for selectively guiding the liquid heater to the liquid fuel injection nozzle via a fuel injection pump. Was A liquid fuel supply conduit having a valve in the middle thereof, and controlling the flow rate of the gas sucked into the combustion chamber by adjusting the opening of a flow rate adjusting valve provided in the middle of the gas supply conduit, or A governor for adjusting the fuel injection pump to control the injection speed of the liquid fuel injected into the combustion chamber, and instantaneously changes the temperature of the combustion air by the air cooler and the air heater. By so doing, the operation switching between the spark ignition operation and the compression ignition operation can be continuously performed without stopping the operation of the internal combustion engine. Reciprocating internal combustion engine.