JPH06173702A - Engine - Google Patents

Abstract

PURPOSE:To prevent generation of noise, improve heat efficiency and suppress generation of pollution substance by decreasing exhaust pressure. CONSTITUTION:A working gas compressing cylinder 16 for compressing working gas as well as sucking the working gas, a heating chamber 18 for heating the working gas compressed by the working gas compressing cylinder 16 and a power generating cylinder 22 for expanding the working gas at a high temperature and high pressure heated in the heating chamber 18, and also discharging the gas after end of expansion, are provided in an engine, and volume of the power generating cylinder 22 is made larger than the volume of the working gas compressing cylinder 16.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine, and more particularly to an engine which has improved thermal efficiency, prevents noise generation, and suppresses NOx generation.

[0002]

2. Description of the Related Art As a conventional engine, for example, a 4-cycle engine used in an automobile is known.

FIG. 9 schematically shows the operation of the cylinder 100 and piston 102 of such a conventional four-cycle engine. That is, as shown in FIG. 9, a conventional four-cycle engine has an intake stroke for sucking a working gas such as a mixture of fuel such as gasoline and air, a compression stroke for compressing the sucked working gas, and a working gas. One cycle is completed by the expansion stroke for burning and expanding the fuel gas and the exhaust stroke for discharging the burned working gas. Then, during this 1 cycle, the crank shaft (not shown) is rotated twice by the piston 102 that moves up and down in the cylinder 100, but it is effective to generate power in 1 cycle. During the expansion stroke only, during the other three strokes, the crankshaft continues to rotate due to the inertia of the flywheel.

[0004]

In the above-described conventional four-cycle engine, all the strokes of the intake stroke, the compression stroke, the expansion stroke and the exhaust stroke are performed by a single cylinder. However, there is a problem in that the exhaust pressure becomes high, which causes noise, and also causes a decrease in thermal efficiency.

That is, in order to facilitate understanding, it is a basic cycle (air cycle) of a 4-cycle engine.
Explaining the so-called Otto cycle, the P-V diagram of the Otto cycle (a diagram showing the change of gas by taking the gas pressure on the vertical axis and the gas volume on the horizontal axis) is shown in FIG. A → B: Adiabatic compression (aspirated working gas is adiabatically compressed) B → C: Equal volume heating (heating with constant volume accepts heat quantity Q ₁ from the outside. , The temperature and pressure of the working gas rises to the state of C. In an actual 4-cycle gasoline engine, the air-fuel mixture burns near B to generate heat, and the pressure rises to C. Go up.
In the Otto cycle, a heat quantity Q ₁ equal to this combustion heat
Is being received from outside during the period B → C. ) C → D: Adiabatic expansion (working gas expands adiabatically) D → A: Equal volume cooling (cooling with a constant volume releases heat quantity Q ₂ to the outside. For this reason, the temperature of the working gas And the pressure drops to A. Actual 4 cycles
A gasoline engine exhausts at D and inhales new air at A. This causes the amount of heat Q ₂ to be released to the outside, which corresponds to the working gas being cooled to an equal volume. ).

For example, when the cylinder total volume is "1" and the volume during combustion is "0.25", the rated operation is performed under the condition of the compression ratio (or expansion ratio) "4",
In A, a working gas of "300 K" (temperature is indicated in absolute temperature. The same applies hereinafter) is introduced into the cylinder by suction at normal pressure and adiabatically compressed. In B, the working gas becomes "7.0 atm." “(Pressure is indicated by atmospheric pressure. The same applies hereinafter.)” Becomes “520K”.

This working gas is heated to an equal volume, and C
At 8.4 atm "1370K", then adiabatic expansion. At this time, since it is expanded at the expansion ratio "4",
In the completed expansion D, the working gas becomes "790 K" at "2.6 atm", and this is cooled to the same volume.

Therefore, the pressure difference between D and A is the exhaust pressure difference from the normal pressure, which is "1.6 atm" in the above example, and this "1.6 atm" exhaust is used. The pressure difference causes noise.

This is because the adiabatic compression process and the adiabatic expansion process are performed in the same cylinder, so that the compression ratio in the adiabatic compression process and the expansion ratio in the adiabatic expansion process have the same value, so the exhaust pressure at D Was caused by the fact that

Particularly, as the engine is operated at high power, the exhaust pressure also becomes high, so that noise and thermal efficiency are significantly reduced during high power operation of the engine.

The present invention has been made in view of the above problems of the prior art. The object of the present invention is to reduce the exhaust pressure to prevent the generation of noise, and Aims to provide an engine designed to improve thermal efficiency.

[0012]

In order to achieve the above object, an engine according to the present invention comprises a first cylinder for inhaling working gas and compressing the inhaled working gas,
A heating chamber that heats the working gas compressed by the first cylinder, and a second cylinder that expands the high-temperature and high-pressure working gas heated by the heating chamber and exhausts the gas after the expansion is completed. The volume of the cylinder is configured to be larger than the volume of the first cylinder.

[0013]

The working gas sucked and compressed in the first cylinder is delivered to the heating chamber. Then, the working gas is heated in the heating chamber to obtain high-temperature and high-pressure working gas, and the second cylinder is expanded to obtain power.

That is, the working gas is compressed in the first cylinder, while the working gas is expanded in the second cylinder.

Since the volume of the second cylinder is larger than the volume of the first cylinder, the expansion ratio can be made larger than the compression ratio, and the exhaust pressure at the end of expansion is lowered. be able to.

[0016]

Embodiments of the engine according to the present invention will now be described in detail with reference to the drawings.

FIG. 1 is a diagram showing the construction of an engine 10 according to the first embodiment of the present invention. In the first embodiment, intake air is compressed by a working gas compression cylinder 16, this is heated to an equal volume in a combustion heating chamber 18, this is expanded in a power generation cylinder 22 to obtain power, and then exhausted. It is shown that.

FIG. 2 schematically shows an engine 10 according to a first embodiment of the present invention, in which the cylinder block 12 has a top dead center (TDC) to a bottom dead center. (B.
D. C. ) Is provided with a working gas compression piston 14 that moves up and down with a stroke S.
4, a working gas compression cylinder 16 for compressing the working gas inside by a downward movement of 4, and a combustion heating chamber 18 for burning and heating the working gas compressed by the working gas compression cylinder 16,
Similar to the working gas compression cylinder 16, the power generation cylinder includes a power generation piston 20 that rises / falls in a stroke S from a top dead center to a bottom dead center, and expands the working gas that is combustion-heated in the combustion heating chamber 18. And 22 are formed.

The stroke volume of the working gas compression cylinder 16 and the combustion chamber volume of the combustion heating chamber 18 are set so that the compression ratio is "4". That is, the ratio of the total volume of the compression side, which is the sum of the stroke volume of the working gas compression cylinder 16 and the volume of the combustion chamber of the combustion heating chamber 18, to the volume of the combustion chamber of the combustion heating chamber 18 (compression side total volume / combustion chamber volume). ) The barrel side is sized so that the compression side compression ratio is “4”.

The stroke volume of the power generation cylinder 22 and the combustion chamber volume of the combustion heating chamber 18 are set so that the expansion ratio is "8". That is, the ratio of the total volume of the power generation side, which is the sum of the stroke volume of the power generation cylinder 22 and the volume of the combustion chamber of the combustion heating chamber 18, to the volume of the combustion chamber of the combustion heating chamber 18 (total volume of the power generation side / combustion chamber). The dimensions are set so that the expansion ratio on the power generation side, which is the volume, is “8”.

That is, the power generation cylinder 22 is dimensioned so as to be twice as large as the working gas compression cylinder 16.

Further, the cylinder block 12 is formed with an intake passage 24 for introducing the working gas into the working gas compression cylinder 16. An intake valve 26 that controls the opening and closing of the intake passage 24 is disposed in the intake passage 24, and the working gas is compressed into the working gas compression cylinder 16 only when the intake valve 26 opens the intake passage 24. Is configured so that it can be introduced.

Further, the cylinder block 12 has a compressed working gas introduction passage 28 for delivering the working gas compressed in the working gas compression cylinder 16 to the combustion heating chamber 18, and the combustion heating in the combustion heating chamber 18. A combustion working gas introduction passage 30 for sending the generated working gas to the power generation cylinder 22 is formed, and a valve 32 is provided in each of the compressed working gas introduction passage 28 and the combustion working gas introduction passage 30. And a valve 34 are provided.

Further, the cylinder block 12 is formed with an exhaust passage 36 for exhausting the combustion working gas in the power generation cylinder 22. An exhaust valve 38 for controlling opening / closing of the exhaust passage 36 is disposed in the exhaust passage 36, and the combustion working gas in the power generating cylinder 22 is provided only when the exhaust valve 38 opens the exhaust passage 36. Is configured to be exhausted.

In the above construction, in order to operate the engine 10, the working gas compression piston 14 and the power generation piston 20 are operated in synchronization in the same phase. That is, since the working gas compression piston 14 and the power generation piston 20 have the same stroke S,
It is possible to easily control the ascending / descending at the same timing.

In steps 1 to 4 of FIG.
It shows the cycle of the operation of step 1, step 2 → step 2 → step 3 → step 4, then step 4 returns to step 1, step 1 →
The cycle of process 2 → process 3 → process 4 is repeated.

First, in the process 1, the intake valve 26 and the valve 34 are opened, and the valve 32 and the exhaust valve 38 are closed. In this state, the working gas compression piston 14 is raised, and the working gas is sucked into the working gas compression cylinder 16 through the intake passage 24. On the other hand, in the power generation cylinder 22, the high-temperature and high-pressure combustion working gas that has been combustion-heated in the combustion heating chamber 18, which will be generated in the process 4 described later, is delivered and expanded, and the power generation piston 20 is moved. Power will be generated in synchronization with the rise.

In step 2, the working gas compressing piston 14 and the power generating piston 20 are located at the top dead center. The intake air is completed, and the power generation cylinder 22 is cooled.

As in step 1, in step 2, the intake valve 26 and the valve 34 are open and the valve 3
2 and the exhaust valve 38 are closed.

Next, in step 3, the intake valve 26 and the valve 34 are closed and the valve 32 and the exhaust valve 38 are opened. Then, the working gas compression piston 14 and the power generation piston 20 descend in synchronism with each other, the working gas in the working gas compression cylinder 16 is compressed, and fuel is injected into the combustion heating chamber 18. At the same time, the combustion working gas in the power generation cylinder 22 is exhausted.

Further, in step 4, the working gas compression piston 14 is located at the bottom dead center, and the operation of the working gas compression cylinder 16 is stopped.
In 8, the ignition gas is ignited by electric sparks or high compression temperature to proceed with combustion, and the working gas is heated by the combustion heat to generate high-temperature and high-pressure combustion working gas.

On the other hand, the power generation piston 20 is also located at the bottom dead center in synchronization with the working gas compression piston 14, and the exhaust of the power generation cylinder 22 is completed.

In this process 4, the intake valve 2
6, valve 32 and valve 34 are closed and exhaust valve 38
Will be closed after the exhaust is completed.

After this step 4, the process returns to the initial step 1, and steps 1 to 4 are repeated.

FIG. 3 shows the P-V of the engine 10 described above.
The diagram shows the compression side total volume "1", power generation side total volume "2", and combustion chamber volume "0.25", the compression side compression ratio is "4". And the power generation side expansion ratio is set to "8" and the calculation example in the case of setting the pressure in the power generation cylinder 22 to the normal pressure in the above process 2 is shown.

The above steps 1 to 4 are cycles unique to the present invention, that is, A → B: Adiabatic compression (the working gas sucked into the working gas compression cylinder 16 is adiabatically compressed and sent to the combustion heating chamber 18. B → C: equal volume heating (compressed working gas is burned in the combustion heating chamber 18. That is, the compressed working gas is burned in the vicinity of B to generate combustion heat and the pressure rises. Then, the temperature rises to C.) C → E: Adiabatic expansion (combustion working gas generated inside the combustion heating chamber 18 is sent out to the power generation cylinder 22;
The combustion working gas adiabatically expands in the power generation cylinder 22. ) E → A: Isobaric cooling (exhaust at normal pressure. This corresponds to cooling the combustion working gas in the power generation cylinder 22 at normal pressure and further supplying air to the working gas compression cylinder 16. .) Cycle.

That is, in rated operation, A is "300".
When the “K” working gas is introduced into the working gas compression cylinder 16 by suction at normal pressure, the working gas compression piston 14 descends to adiabatically compress the working gas, and the compressed working gas is delivered to the combustion heating chamber 18. At this time, the compression ratio "4"
In B, the working gas is "7.0.
It becomes "520K" in "atmospheric pressure".

This working gas is heated to a constant volume by combustion heating in the combustion heating chamber 18, and is made to be "1370K" at "18.4 atmospheric pressure" by C, and then the power generating cylinder 2
2 and adiabatically expand. At this time, the expansion ratio "8"
Since the expansion gas is expanded by, the working gas becomes "600K" at normal pressure in the expanded expansion gas E and is exhausted.

Therefore, since the exhaust pressure becomes normal pressure and there is no difference in the exhaust pressure, the generation of noise due to the exhaust pressure is prevented.

Further, as compared with the conventional Otto cycle, it becomes possible to take out extra power in the shaded area in FIG. 3, so that the thermal efficiency can be improved.

That is, the area ABCD is the power generated by the Otto cycle explained in the section of the prior art, but the power obtained by the same heating amount in the engine 10 becomes the area ABCE and the power generated by the Otto cycle. It can be increased by about 20% when compared with.

Next, an engine 200 according to the second embodiment of the present invention will be described.

FIG. 4 is a structural explanatory view of an engine 200 according to a second embodiment of the present invention corresponding to FIG. In this second embodiment, the combustion heating chamber 18 is divided into a combustion chamber 18a and a heating chamber 18b, and the heating chamber 18b is externally heated to heat the working gas.
This is different from the first embodiment.

FIG. 5 is an explanatory diagram corresponding to FIG. Since the engine 200 is an external combustion engine, the heating chamber 18b
Is always heated. Therefore, FIG.
3 will be slightly different.

That is, the intake process is the same as in the case of the engine 10, but the next compression process is not the adiabatic compression but the heat compression, so that the end point is B ′ instead of B. In the isochoric heating process, the end point is the same as the engine 10 C
(18.4 atm, 1370K). In the expansion process, the expansion is not adiabatic expansion but thermal expansion, and the end point is not E but E ′.

Therefore, the expansion ratio of the power generation cylinder 22 needs to be larger than "8", and as a result,
Compared to the case of FIG. 3 in the first embodiment, the generated power is increased by the amount of power corresponding to (area CE′E−area ABB ′). Since it is the same as the case of 3, detailed description will be omitted.

As described above, the engine 200 uses the heat compression and the heat expansion instead of the adiabatic compression and the adiabatic expansion in the engine 10, so that the temperature of the working substance is distributed depending on the place. This causes the entropy to occur because the temperature changes toward the same temperature, which is one of the causes for lowering the thermal efficiency. However, in addition to the increase in the generated power, there is an advantage that the generation of pollution can be suppressed by changing the internal combustion system to the external combustion system.

That is, in the above-mentioned first embodiment,
Since the working gas is burned at a high pressure, it is impossible to prevent generation of NOx and the like, but in the second embodiment,
Since the combustion chamber 18a is gently and continuously burned under normal pressure, it is possible to reliably prevent the generation of pollution gas such as NOx.

Next, an engine 300 according to the third embodiment of the present invention will be described.

FIG. 6 is a structural explanatory view of an engine 300 according to the third embodiment of the present invention, which corresponds to FIG. In the third embodiment, a heat exchanger 302 for exchanging heat between intake air used for combustion in the combustion chamber 18a and exhaust gas after combustion.
Since the second embodiment is different from the second embodiment only in terms of the provision of, the explanation drawing corresponding to FIG. 5 is omitted.

That is, the engine 200 according to the second embodiment.
In the above, since the high temperature heat exhaust gas accompanying the combustion in the combustion chamber 18a is exhausted, the thermal efficiency is further reduced as compared with the engine 10 according to the first embodiment. However, due to the heat exchanger 302, the combustion chamber 18
By exchanging heat between the air used for combustion in a and the heat exhaust gas and recovering the heat of the exhaust heat exhaust gas,
It is possible to approach the thermal efficiency obtained by the engine 10 according to the first embodiment.

Since this heat exchange is carried out at normal pressure,
A well-known heat exchanger can be used as appropriate, and since the partition wall material used for the heat exchanger for passing the air used for combustion, the heat waste gas, etc. can be thin, it is efficient. Heat exchange can be performed.

Further, in each of the above embodiments, when the engine is operated at an output below the rated operation, the power generating cylinder 2 is used.
In the process of expansion in 2, there is a risk that the pressure of the working gas falls below normal pressure, water droplets and frost are generated in the power generation cylinder 22, and the power generation cylinder 22 and the power generation piston 20 are damaged. is there.

For example, the engine 10 according to the first embodiment.
As shown in FIG. 7, when the fuel supply is reduced in order to operate at an output less than the rated operation, the state of the combustion working gas combusted in equal volume does not become C, but in the middle as shown in FIG. It becomes F of. Here, when the combustion working gas in this state is adiabatically expanded in the power generation cylinder 22, the normal pressure point becomes G. However, since the power generation cylinder 22 continues to expand, the pressure of the combustion working gas becomes equal to or lower than the normal pressure, and the temperature further decreases. Therefore, in some cases, water droplets or frost may be generated in the power generation cylinder 22, which may damage the power generation cylinder 22 or the power generation piston 20.

Therefore, in each of the above embodiments, for example,
As shown in FIG. 8 according to the engine 10 of the first embodiment, a normal pressure maintenance control valve 40 such as a poppet valve is arranged so that the pressure in the power generation cylinder 22 becomes lower than the normal pressure. Only when the normal pressure maintenance control valve 40 is opened, the outside air is sucked in so that the pressure in the power generation cylinder 22 does not fall below the normal pressure, and the normal pressure in the power generation cylinder 22 is constantly maintained. Can be maintained.

The normal pressure maintaining control valve 40 is opened to suck the outside air to maintain the normal pressure in the power generating cylinder 22, and the cycle is A → B →
F → G → E → A.

Further, as described above, the exhaust valve 38 may be provided with the function of the normal pressure maintenance control valve 40 without separately disposing the normal pressure maintenance control valve 40.

Further, in each of the above embodiments, the working gas compression cylinder 16 and the power generation cylinder 22 are used.
I explained about the case where each one was provided,
The working gas compression cylinder 1 is not limited to this.
It is needless to say that either one of the 6 and the power generation cylinder 22 or a plurality of both may be provided.

[0059]

Since the present invention is constructed as described above, it has the following effects.

A first cylinder for inhaling the working gas and compressing the inhaled working gas, a heating chamber for heating the working gas compressed by the first cylinder, and a high-temperature and high-pressure working gas heated by the heating chamber And a second cylinder that exhausts after completion of expansion, and the volume of the second cylinder is configured to be larger than the volume of the first cylinder. The working gas thus produced is sent to the heating chamber, and the working gas of high temperature and high pressure is obtained by heating in the heating chamber.
Power can be obtained by expanding this with the second cylinder.

Therefore, while the working gas is compressed in the first cylinder, the working gas is expanded in the second cylinder, and the volume of the second cylinder is equal to the first cylinder. Since the volume is larger than the cylinder volume, the exhaust pressure at the end of expansion can be reduced.

Therefore, according to the engine of the present invention, the exhaust pressure can be reduced, which can prevent the generation of noise and improve the thermal efficiency.

Further, since it can be configured as an external combustion engine of external combustion type, generation of NOx and the like can be suppressed.

[Brief description of drawings]

FIG. 1 is a block diagram showing a main configuration of an engine according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram of the configuration and operation of the engine according to the first embodiment of the present invention.

3 is a P-V diagram of the engine shown in FIG. 2. FIG.

FIG. 4 is a block diagram showing a main configuration of an engine according to a second embodiment of the present invention.

5 is a P-V diagram of the engine shown in FIG.

FIG. 6 is a block diagram showing a main configuration of an engine according to a third embodiment of the present invention.

7 is a P-V diagram of the engine shown in FIG. 2 when not in rated operation.

FIG. 8 is a structural explanatory view of the engine shown in FIG. 1 provided with a normal pressure maintenance control valve 40.

FIG. 9 is an explanatory diagram showing the operation of a conventional 4-cycle engine.

FIG. 10 is a P-V diagram of the Otto cycle.

[Explanation of symbols]

 10 Engine 16 Working Gas Compressing Cylinder 18 Combustion Heating Chamber 18a Combustion Chamber 18b Heating Chamber 22 Power Generation Cylinder 40 Normal Pressure Maintenance Control Valve 200 Engine 300 Engine 302 Heat Exchanger

Claims (5)

[Claims] 1. A first cylinder for inhaling working gas and compressing the inhaled working gas, a heating chamber for heating the working gas compressed by the first cylinder, and a high temperature heated by the heating chamber. An engine having a second cylinder for expanding a high-pressure working gas and exhausting the expanded working gas after the expansion is completed, wherein the volume of the second cylinder is larger than the volume of the first cylinder. 2. A first cylinder that inhales air as a working gas and adiabatically compresses the inhaled working gas; and a working gas in which the fuel is burned in an equal volume in the working gas compressed by the first cylinder. Combustion heating chamber for heating, and adiabatic expansion of the high-temperature and high-pressure working gas heated by the combustion heating chamber to atmospheric pressure, and has a second cylinder to exhaust after expansion is completed, the second cylinder of An engine having a volume larger than that of the first cylinder. 3. A first cylinder for sucking air as working gas and compressing the sucked working gas; a heating chamber for heating the working gas compressed by the first cylinder to the same volume from the outside; It has a combustion chamber for externally heating the working gas in the heating chamber, and a second cylinder that expands the high-temperature and high-pressure working gas heated by the heating chamber to normal pressure and exhausts it after the expansion is completed. An engine, wherein the volume of the second cylinder is larger than the volume of the first cylinder. 4. The engine according to claim 3, further comprising heat exchange means for mutually exchanging heat between intake air required for combustion in the combustion chamber and exhaust gas generated by combustion in the combustion chamber. 5. In the expansion process of the working gas in the second cylinder, air is introduced into the second cylinder when the working gas in the second cylinder becomes lower in pressure than normal pressure, 5. An air introducing means for maintaining the inside of the second cylinder at a normal pressure is provided.
The engine according to any one of 1.