JPH0422749A - Extra cylinder combustion engine with regeneration heat exchanger - Google Patents

Abstract

PURPOSE:To simplify a device by halving the number of cylinders by providing a cylinder which performs air compression and expansion of combustion gas in order, and providing a heat exchanger which heats the compressed air with exhaust air using the heated compressed air a burner which combusts full, outside the cylinder. CONSTITUTION:When a piston is lowered, an intake valve VA is opened and compressed air at a turbocharger 9 is flowed into a cylinder 11 from an intake pipe 12. Next, when an air valve VC is closed, the air inside the cylinder is compressed at the piston 10. When the air valve VC is opened, fuel 6 is combusted in a burner 5 after the compressed air is discharged toward a heat exchanger 3 through a compressed air pipe 14. When a gas flow valve VB is opened, the combusted gas is flowed between the piston which started to lower and the cylinder 11. When the gas flow valve VB is closed, the combusted gas is expanded so as to lower the piston 10. An exhaust valve VE is opened, the combusted gas discharged to a discharge pipe 15 so as to heat the compressed air flow through the compressed air pipe 14.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention can be used as a power device that generates power by pushing down a piston by expanding high-temperature, high-pressure gas obtained by burning fuel.

(Prior Art) Power devices that burn fuel to produce high-temperature, high-pressure gas and expand it to drive turbines, pistons, etc. have been widely used.

Among these engines, an internal combustion engine that burns a mixture of fuel and air within a cylinder is generally used as an engine that drives a piston that is engaged with a cylinder.

The present inventor first described a compression cylinder that compresses air;
An expansion cylinder that expands the combustion gas is provided separately, air compressed by the compression cylinder is guided to a burner to burn separately supplied fuel, and the high temperature and high pressure gas obtained in this way is guided to the expansion cylinder to push down the piston. In an engine that generates power, we have invented an engine (Japanese Patent Application No. 2-066882) in which compressed air discharged from a compression cylinder is heated by exhaust gas from an expansion cylinder and supplied to a burner to improve thermal efficiency.

As schematically shown in FIG. 8, the engine of the earlier invention has an expansion cylinder in which air compressed in a compression cylinder 2 by a rising piston 1 is passed through a heat receiving part 3a of a heat exchanger 3 and then passed through a heating part 3b. The compressed air is heated by the exhaust gas from No. 4, the compressed air is put into the burner 5, and the fuel 6 is combusted, and the resulting high-temperature, high-pressure gas is put into the expansion cylinder 4, where it expands and pushes down the piston 7 to generate power. be.

In this example, a positive displacement turbine or exhaust turbine 8 drives a positive displacement supercharger or turbocharger 9 to pressurize the air supplied to the compression cylinder.

This is shown in a pv diagram as shown in FIG. 9.

(Problems to be Solved by the Invention) In the above invention, since the compression cylinder and the expansion cylinder are provided separately, the device configuration inevitably becomes complicated.

If the number of required cylinders is reduced, the device configuration can be simplified.

(Means for Solving the Problems) This invention has a cylinder that sequentially performs air compression and combustion gas expansion, and a heat exchanger that heats this compressed air with exhaust gas, and uses this heated compressed air. The above problem was solved by configuring the engine in such a way that a burner is installed outside the cylinder that burns fuel, and high-temperature, high-pressure combustion gas produced by the burner is sent to the cylinder to expand and push down the piston to generate power. It is something.

(Function) The air compressed in the cylinder as the piston rises,
It is led out of the cylinder, passes through a heat exchanger, is heated by the exhaust of combustion gas, enters a burner, burns the supplied fuel to create high-temperature, high-pressure combustion gas, enters the same cylinder again, expands, and pistons. Press down to generate power.

Even if there is a time lag between the end of the compression stroke and the end of the tension stroke, compressed air can be heated efficiently by exhaust gas by using a heat storage type heat exchanger.

(Embodiment) Figs. 1 to 5 show an embodiment in which the present invention is applied to a four-cycle Playton type piston engine.

FIG. 1 is a schematic diagram showing the relationship between the four types of valves provided at the head of the cylinder 11 in which the piston 10 is loosely connected, the heat exchanger 3, the burner 5, etc., and vA is the relationship between the suction pipe 12 and the cylinder 11. Intake valve that controls communication, ■8 is combustion gas pipe 13 and cylinder 1
1, vc is a gas inlet valve that controls communication with cylinder II
The air valve V, which controls the communication between the cylinder 11 and the compressed air pipe 14 that discharges the compressed air inside, is the exhaust pipe 15.
This is an exhaust valve that controls communication between the cylinder 11 and the cylinder 11.

The combustion gas pipe 13 and the compressed air pipe 14 pass through the burner 5,
The compressed air pipe 14 and the exhaust pipe 15 pass through a heat exchanger 3 to transfer the heat of the exhaust gas to the compressed air. Being driven. exhaust turbine 8,
In place of the turbocharger 9, a positive displacement drive or compressor can also be used.

The multiple valves vA, VB, (6), (2) are arranged at the head of the cylinder 11 as shown in FIG.

Fig. 3 is a PV diagram showing the operation of this engine, in which the piston 10 rises while forcing air into the cylinder 11 between a and b by the turbocharger, and air is not sucked and compressed between b and c. This air is transferred to heat exchanger 3.
The combustion gas obtained is sent to the burner 5 to burn the fuel 6, and the obtained combustion gas is sent to the cylinder 11, expanded between de and e, and exhausted at e, and is sent to the exhaust turbine 8 between e and a. It moves to drive the turbocharger 9.

The operation of the valves in each stroke of this engine is from A to A in Figure 4.
F, and the valve diagram is A in Figure 5.
It will look like B. This will be explained next.

1) Air intake stroke (Fig. 4A) The piston 10 descends, the intake valve VA opens, and the air pressurized by the turbocharger 9 flows from the suction 12 into the cylinder 11.
flow inside.

In this air-pushing state, the piston 1o starts to rise (
Air valve V. (closed) Compression continues for a while after starting, and air suction stops at position b in Figure 3, leaving only compression.

2) Air compression stroke (Fig. 4B) Air valve ■. Since the cylinder is closed, the air trapped inside the cylinder is strongly compressed by the rising piston IO.

3) Air discharge stroke (Fig. 4 C) The air valve VC is closed and the strongly compressed air is sent to the compressed air pipe 1.
4 and discharged toward the heat exchanger 3.

This compressed air is heated by the engine exhaust gas in the heat exchanger 3 and then enters the burner 5, where it is supplied with fuel 6.
is combusted to produce high-temperature, high-pressure combustion gas.

4) Combustion gas inflow stroke (Fig. 4D) Open the gas inflow valve (3) to allow combustion gas to rapidly flow between the piston 10 and the cylinder 11, which have started to descend.

5) Expansion Stroke (Fig. 4E) Close the gas inlet valve ■8 to expand the high-temperature, high-pressure combustion gas trapped in the cylinder and push down the piston 10.

6) Exhaust stroke (FIG. 4F) The exhaust valve V is opened, and the residual pressure of the gas is pushed by the piston 10, which has started to rise, to discharge the combustion gas to the exhaust pipe 15. This gas heats the compressed air that has passed through the heat exchanger 3 and flowed through the compressed air pipes 14.

The opening and closing of these eight valves according to the rotation angle of the crankshaft is shown in FIGS. 5A and 5B.

Next, considering thermal efficiency, assume that the temperature of the compressed air rises to 350°C in the compression stroke and the temperature of the exhaust gas discharged in the exhaust stroke is 900°C. Suppose that it is heated to The amount of heat Q required to create combustion gas at 2000°C in the burner using this compressed air. X is Q if specific heat is cp
Hx# c p (2000-850) = 115
It is 0c p. If there is no heat exchanger 3, the required amount of heat at this time is Q. is Qo #CP (2000350)=1650CP, and therefore, with the heat exchanger 3 the thermal efficiency can be increased by 43% over the engine without it.

The above explanation was about a 4-stroke engine, but in the case of a 2-stroke engine, a scavenging boat, scavenging valve, etc. are provided, but compression and expansion are performed in a single cylinder in the same way, and a heat exchanger and burner are installed outside the cylinder. The engine can be configured by providing the following.

In addition, when operating two sets of cylinders that operate as described above in parallel, the compressed air that has gone through the compression stroke and the combustion gas that has gone through the exhaust stroke in each cylinder must be alternately passed through one regenerative heat exchanger. Thus, two engines can be operated according to the method of the present invention using one heat exchanger.

When performing multi-cylinder operation, a heat exchanger 3 is attached to each cylinder 11 and a burner 5 is provided in common as in the embodiment shown in FIG. , the burner 5 may be provided in common.

In FIGS. 6 and 7, each cylinder 11 compresses the air taken in from path a, passes it through path C3 into the heat exchanger 3, heats it with exhaust air, and puts it into the burner 5 through path c2, which produces high-temperature, high-pressure combustion gas. This gas is introduced into the cylinder 11 through paths d3 and d2 and expanded, and the exhaust gas is discharged through the heat exchanger 3 through the path e.

In the case of multi-cylinder operation as described above, various types of heat exchangers 3 including a heat storage type can be used.

(Effects of the Invention) 1) This invention is an out-of-cylinder combustion engine that uses the same cylinder to reuse exhaust heat. Compressed air for combustion is absorbed externally, but the number of cylinders is halved compared to an engine with separate compression cylinders and expansion cylinders, which simplifies the equipment.

2) Since the engine of the present invention is a piston type engine, the compression ratio does not change much even during slow speed operation, so it can perform slow speed operation better than a gas turbine type engine.

Therefore, it can be used in devices such as automobiles where speed changes are large.

[Brief explanation of the drawing]

1 to 7 show embodiments of the present invention, FIG. 1 is a schematic diagram showing the relationship between various valves, heat exchangers, burners, etc., FIG. 2 is a plan view of the cylinder head showing the arrangement of the valves, Figure 3 is a pv diagram showing engine operation, Figures 4 A-F are schematic diagrams showing valve operation in each stroke, Figures 5 A-B are valve diagrams, and Figures 6 and 7 are multi-cylinder operation diagrams. FIG. 8 is a side view schematically showing the outline of the prior invention, and FIG. 9 is a PV diagram thereof. 1: Piston, 2: Compression cylinder, 3: Heat exchanger, 4:
expansion cylinder, 5: burner, 6: fuel, 7; piston,
8: exhaust turbine, 9: turbocharger, 10: piston, 11 cylinder, 12: suction pipe, 13: combustion gas pipe, 14: compressed air pipe, 15: exhaust pipe, VA = suction valve, ■,: gas inflow valve , vc; air valve, ■L: exhaust valve.

Claims (1)

[Claims] 1) A burner that has one cylinder that compresses air in a compression stroke and expands combustion gas in an expansion stroke, and that uses the compressed air to combust fuel and produce combustion gas; An out-of-cylinder combustion engine with a regenerative heat exchanger installed outside the cylinder to heat the compressed air to be sent using the exhaust air from the cylinder. 2) The regenerative heat exchanger according to claim 1, wherein a plurality of cylinders each having a heat exchanger attached to the outside of the cylinder are arranged in parallel, and the heat exchanger to be attached to each cylinder is shared by all the cylinders. Out-of-cylinder combustion engine. 3) An extra-cylinder combustion engine having a regenerative heat exchanger according to claim 1, wherein a plurality of cylinders are arranged in parallel, and the heat exchanger and burner attached to each cylinder are shared by all the cylinders.