JP5066723B2 - 2-stroke insulated composite engine - Google Patents

Description

  The present invention relates to an adiabatic composite engine that improves thermal efficiency by effectively using energy loss including exhaust loss and cooling loss.

  The thermal efficiency of a conventional positive displacement engine is approximately 40% for a diesel engine and approximately 30% for a gasoline engine, cooling loss and exhaust loss are approximately 30%, and friction loss is approximately 5%.

  A conventional positive displacement engine cools the outside of the cylinder with water or air, thereby suppressing a temperature increase of the engine body and enabling a constant continuous operation.

  On the other hand, an attempt was made to absorb the heat in the cylinder by injecting water into the cylinder without cooling the outside of the cylinder, to cool and vaporize the inside of the cylinder, and to increase the output by the expansion force of steam. (For example, Patent Document 1)

  A combination of an aviation diesel engine and an exhaust turbine in order to improve thermal efficiency by turning the exhaust turbine with the exhaust gas discharged from the positive displacement engine and combining the power from the positive displacement engine and the power from the exhaust turbine. An engine has been developed. (For example, Non-Patent Document 1)

  Since the 2-stroke engine has a simpler structure than the 4-stroke engine, it is widely used in small and light gasoline engines and low-speed large marine diesel engines whose environmental standards are not so strict.

General automobile engines rarely operate at the maximum output and often operate at a relatively low load.
JP-A-60-184923 Internal combustion engine handbook Asakura Shoten P647 Issued in 1969

  If both the cooling loss 30% and the exhaust loss 30% are recovered with a thermal efficiency of 17%, the thermal efficiency obtained from the energy loss is 30% x 2 x 17% = 10%, and the thermal efficiency is improved by approximately 10% for both gasoline and diesel engines. To do.

  Exhaust gas, which is an exhaust loss, is effectively used to improve output by turning the turbo and supercharging, but it does not directly take out the power from the turbo, so it improves both fuel efficiency and output. So-called thermal efficiency is not improved.

  In addition, the cooling loss has hardly been used even though it occupies the same amount of energy as the exhaust loss. Further, most of the conventional positive displacement engines except the small size have a forced cooling device for cooling the outside of the cylinder with water or air, and require power for forced cooling. As described above, in the conventional engine, the cooling loss has not been effectively used except for heating.

  As an example of in-cylinder cooling, the water injection type heat insulating ceramic diesel engine disclosed in Japanese Patent Application Laid-Open No. 60-184923 is a disadvantage of the heat insulating engine due to the absorption of the heat of vaporization caused by water injection in the expansion stroke following the compression stroke. It is supposed to compensate for a decrease in the intake efficiency of some fresh air and increase the output per unit fuel. However, in this case, the heat available is not used because the heat of vaporization is not used as a power source. Have been discharged.

  Although the power source of the exhaust turbine of the composite engine developed in the past was only the exhaust gas from the 2-stroke diesel engine, it is said that the fuel efficiency was good. Therefore, if the cooling loss is added as a power source, the thermal efficiency is further improved. . However, the compound engine at that time was said to have not been put into practical use due to its complicated structure.

  Since a 2-stroke engine explodes and expands once per revolution, it can produce nearly twice as much power as the original stroke volume compared to a 4-stroke engine. In this case, sweeping and exhausting must be performed in a short time, and the exchange of exhaust gas and fresh air tends to be incomplete, and the original output cannot be obtained and the exhaust gas is dirty. It is seldom used for automobiles where strict environmental standards are applied.

  The conventional gasoline engine has a problem that the pumping loss increases because the intake air amount must be reduced as the load becomes lower.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a two-stroke adiabatic composite engine that effectively uses exhaust loss and cooling loss as a power source, and improves heat efficiency by reducing pumping loss.

  Effective use of exhaust gas, which is an exhaust loss, has been proven and has been omitted. As for the cooling loss, since it is cooled outside the cylinder, it becomes a cooling loss. If the superheated steam is generated by the heat absorbed by the in-cylinder, the equipment and power for the outside-cylinder cooling are not required, and overheating Power can be obtained because the exhaust turbine can be turned using steam. In the conventional engine, energy loss, which was discarded as cooling loss and exhaust loss, is recovered by an exhaust energy recovery device and directly used.

  In order to cool the inside of the cylinder of the heat insulating cylinder, a nozzle is attached to the cylinder head or the cylinder, and water (including hot water, including hot water even if it is expressed only as water) or steam is used in the exhaust stroke. The inside of the cylinder, the upper part of the piston, the cylinder inner wall, and the cylinder head that have been injected and become hot are cooled. An appropriate amount of water or steam is injected so that the in-cylinder temperature always remains close to the set temperature. For this reason, the injection amount is controlled by measuring the temperature outside the cylinder and the exhaust gas temperature.

  Further, when the engine is cold at the time of starting or the like, the water injection is cut off, but since the engine is insulated, it warms up immediately, and so-called warm-up operation is unnecessary.

  Water to be injected into the cylinder is stored in a water tank (not shown). The water tank is connected to an exhaust pipe on the exhaust turbine outlet side, and cools and muffles exhaust gas and steam discharged from the exhaust turbine. The recovered steam returns to the water again in the water tank so that it can be circulated. Moreover, in order to cool the hot water in the tank which became high temperature efficiently, a radiator is used or a fin is attached to the outer periphery of a water tank.

Speed engines such as exhaust turbines have poor thermal efficiency and response.For example, when powering automobiles that are heavily used at medium and low loads and have large load fluctuations, the power is efficiently extracted and optimal power transmission corresponding to the operating conditions is achieved. To make a mechanism, the structure becomes complicated. Therefore, in a combined engine in which a positive displacement engine and a speed engine are combined, the power of the exhaust turbine, which is an auxiliary engine, is transmitted to the output shaft of the positive displacement engine, which is the main engine. If the power transmission mechanism adopts a one-way clutch so that the power is not transmitted to the output shaft of the exhaust turbine, the structure is simple and the power from the exhaust turbine can be taken out efficiently.
It is also possible to generate power by attaching a generator to the output shaft of the exhaust turbine.

  Even with a two-stroke engine that has a short stroke and rotates at a high speed, the exhaust gas is as clean as that of a four-stroke engine, and the exhaust gas is exhausted sufficiently and the required air is required to improve the output to nearly twice the original output. The quantity must be supplied to ensure good combustion.

  Therefore, by injecting the compressed air stored in the pressure accumulator into the cylinder from the compressed air injection nozzle, the cycle corresponding to the two strokes of the suction stroke and the compression stroke is replaced, and the explosion / expansion stroke and the exhaust stroke 2 are replaced. The exhaust gas can be sufficiently discharged and the required amount of air can be supplied by the stroke alone. The compressed air is obtained by a centrifugal compressor directly connected to an exhaust turbine and further compressed by a positive displacement compressor. High-pressure compressed air is temporarily stored in an accumulator, and a required amount of air is injected under the control of an ECU (electronic control unit) and an electromagnetic valve. Immediately thereafter, an appropriate amount of fuel is injected and combustion (explosion) starts.

As described above, the two-stroke adiabatic combined engine of the present invention cools the inside of the cylinder by injecting water or steam directly into the cylinder after the combustion gas is discharged to some extent during the exhaust stroke and the pressure in the cylinder drops. At the same time, heat in the cylinder is absorbed and superheated steam is generated. The superheated steam becomes a powerful power source for turning the exhaust turbine. In conventional engines, since cooling was performed outside the cylinder, the cooling loss could not be effectively used. However, in the in-cylinder cooling type two-stroke heat insulating composite engine, not only the exhaust gas that is the exhaust loss but also the cooling loss. In-cylinder waste heat can be used effectively.
For this reason, output can be improved and fuel consumption can be improved, and not only CO2 but also harmful substances such as NOX and PM can be reduced. Moreover, since superheated steam has a large cleaning ability, it also has an effect of cleaning the inside of the cylinder and the exhaust system.

  Unlike the short-time scavenging in the conventional two-stroke engine, the two-stroke heat insulation engine of the present invention exhausts exhaust gas and superheated steam in the exhaust stroke, and injects compressed air at the same time as the exhaust valve is closed. The exchange of fresh air is almost complete. For this reason, combustion is performed satisfactorily and the exhaust gas is clean. In addition, since it explodes and expands once per rotation, the output is about twice that of a conventional four-stroke engine with the same stroke volume.

  Hereinafter, the best embodiment of the present invention will be described with reference to FIGS.

  1 and FIG. 2, FIG. 1 is a front sectional view, and FIG. 2 is a two-cylinder heat insulation engine, an exhaust turbine 8, a centrifugal compressor 9 directly connected to the exhaust turbine, and the centrifugal compressor. It is a plane sectional view of positive displacement compressor 10 which makes compressed air discharged from more high pressure.

  In FIG. 1, a positive displacement heat insulating engine having a piston 1, a cylinder 2 and an exhaust valve 3 has an accumulator 4 for storing compressed air, a nozzle 5 for injecting the compressed air, and an appropriate amount of air in the cylinder. Nozzle 6 that injects fuel after becoming exhausted, and nozzle that injects water or steam to obtain superheated steam by cooling the inside of the cylinder that has become hot after expelling to some extent high-temperature and high-pressure exhaust gas 7 is attached. The power from the exhaust turbine 8 using exhaust gas and superheated steam as the power source is transmitted to the flywheel 13 directly connected to the crankshaft via the speed reducer 11, and the power from the flywheel is transmitted to the exhaust turbine side. In order to prevent transmission, a one-way clutch (not shown) with a damper that absorbs vibration and impact force is incorporated in the speed reducer 11.

  In FIG. 1, the number of compressed air injection nozzles is one, but it may be two or more. Further, the mounting direction may be the center direction in the cylinder or the direction along the wall surface, but it is preferably directed to the direction in which combustion is always performed satisfactorily.

  In FIG. 2, a centrifugal compressor 9 directly connected to the exhaust turbine 8 and a positive displacement compressor 10 are provided for converting the compressed air discharged from the centrifugal compressor into higher-pressure compressed air. The type of the positive displacement compressor may be a piston type, a root type, or a vane type. Further, a centrifugal compressor may be multi-staged instead of the positive displacement compressor. In FIG. 2, the number of the exhaust turbines 8 is one for every two cylinders, but it may be one for each cylinder or one for many cylinders.

  In the case of a short stroke and a high speed rotation as shown in FIG. 1, there are no scavenging holes provided in a cylinder of a normal two-stroke engine, but a long stroke and a low speed rotation like a marine engine, etc. Is performed well for a relatively long time, a scavenging hole is provided as in a normal two-stroke engine, a water or steam injection nozzle 7 is attached to the scavenging hole, and scavenging and water or steam are supplied simultaneously with the opening of the scavenging hole. 1 and FIG. 2 is not equipped with the accumulator 4 and the compressed air injection nozzle 5, and the compressor is equipped with either a centrifugal compressor 9 or a positive displacement compressor 10 and is a two-stroke heat insulating composite. It is good as an engine.

  The shaft of the positive displacement compressor 10 is connected to the crankshaft of the positive displacement heat insulating engine via a clutch (not shown). When the air pressure in the accumulator exceeds a set value, the clutch is automatically disengaged, The positive displacement compressor 10 is not operated. In addition, a throttle valve (not shown) may be provided in the suction side manifold of the centrifugal compressor 9, and the intake air amount may be controlled by automatically throttling the valve.

  The reduction gear 11 is equipped to reduce the high-speed rotation of the exhaust turbine 8 so as to match the rotation speed of the positive displacement heat insulating engine.

  In order to efficiently recover the exhaust gas temperature so as not to be cooled as much as possible, the exhaust turbine 8 is attached as close to the exhaust valve 3 as possible. The type of exhaust turbine may be a radial turbine or an axial turbine, and the number of stages may be single or multistage.

  In order to effectively use the waste heat that has not been converted into motive power out of the heat energy from combustion, the cylinder 2 and the cylinder head are covered with a heat insulating material 12 in order to effectively use the heat without releasing it outside the cylinder.

  The mounting position of the water or steam injection nozzle 7 may be the cylinder head or the cylinder 2. An in-cylinder temperature and an exhaust gas temperature are measured to predict an in-cylinder temperature, and an appropriate amount of water or steam is injected in a timely manner so that the set in-cylinder temperature is always obtained. Also, no water or steam is injected when the engine is cold.

  The ECU controls the opening / closing timing of the exhaust valve, the injection timing of the compressed air and the fuel, and the injection amount so that a good combustion state can always be obtained according to the operating condition. In particular, since the injection amount of compressed air and fuel is controlled so as to always have an ideal mixing ratio or excess air ratio, a time lag like a turbocharger does not occur even during acceleration.

  Hot water or steam is easily generated by winding a small-diameter pipe around the exhaust pipe at the outlet side of the exhaust turbine and passing water through this pipe or by making the exhaust pipe into a double pipe and water through the outer pipe. be able to. This is a so-called heat exchanger (not shown) using waste heat of exhaust gas. Temperature management is performed by attaching a thermometer near the outlet of a small diameter pipe or double pipe and controlling the amount of water delivered. Further, since the exhaust pipe on the exhaust turbine outlet side is cooled, the exhaust turbine efficiency is improved.

  In the case of a diesel engine, the fuel injection nozzle 6 may be a normal fuel injection nozzle. However, in the case of a gasoline engine, the fuel injection nozzle 6 is limited to a direct injection type fuel injection nozzle.

  FIG. 3 is an operational state diagram showing compressed air injection, fuel injection, explosion / expansion, combustion gas discharge, water or steam injection, and superheated steam discharge. 01 is compressed air injection, 02 is fuel injection and explosion, 03 is expansion, 04 is combustion gas discharge, 05 is combustion gas discharge, water or steam injection, in-cylinder cooling and generation of superheated steam, 06 is superheated steam Indicates emissions.

  FIG. 4 is a diagram showing the strokes of explosion / expansion and exhaust, the injection timing of compressed air, fuel, water or steam in each stroke, and the timing of opening and closing the exhaust valve. The exhaust valve 3 is opened, and exhaust gas whose combustion pressure is still high is vigorously blown onto the exhaust turbine 8. Since the water or steam is injected to the place where the in-cylinder pressure has decreased, the injection pressure can be reduced, and the inside of the cylinder can be cooled without taking too much energy of the exhaust gas required to turn the exhaust turbine 8 to overheat. Steam can be generated.

  When the in-cylinder temperature is low and difficult to ignite at the time of starting or the like, the exhaust valve 3 is closed early by the variable valve timing mechanism and the compressed air is injected early, so that the compressed air in the cylinder rises as the piston 1 rises. Furthermore, since it is compressed and the temperature rises, the ignitability is improved. In addition, by allowing the compressed air injection nozzle 5 to be heated or attaching a heater to the cylinder head, the in-cylinder temperature can be raised and ignition is easy.

  The process number of FIG. 4 corresponds to the number of the operation state of FIG.

Front sectional view of an in-cylinder cooling type two-stroke heat insulation composite engine showing an embodiment of the present invention In-cylinder cooling system 2-stroke heat-insulated composite engine cross-sectional view Operation state diagram of each stroke of in-cylinder cooling type 2-stroke heat insulation engine Compressed air, fuel, water or steam injection timing diagram in two strokes

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Piston 2 Cylinder 3 Exhaust valve 4 Accumulator 5 Compressed air injection nozzle 6 Fuel injection nozzle 7 Water or steam injection nozzle 8 Exhaust turbine 9 Centrifugal compressor 10 Positive displacement compressor 11 Reducer 12 Heat insulating material 13 Flywheel 14 Bearing

Claims (2)

A positive displacement adiabatic engine that executes two strokes of an explosion / expansion stroke and an exhaust stroke, an exhaust turbine that uses exhaust gas and superheated steam exhausted from the positive displacement adiabatic engine, and a power source from the exhaust turbine as a crankshaft In a two-stroke adiabatic composite engine having an exhaust energy recovery device for transmitting to a compressor, a compressor for compressing air, an accumulator for storing the compressed air, and compressed air from the accumulator is injected into a cylinder A nozzle and a nozzle for injecting water (including hot water) or steam for cooling the high-temperature cylinder and absorbing the heat in the cylinder to generate superheated steam after exhaust gas is discharged in the exhaust stroke; and that the out-of-cylinder temperature and exhaust gas temperature so that the cylinder temperature is keep the set temperature is measured for controlling the injection quantity of water or steam, silencing of the exhaust gas and the steam discharged from the exhaust turbine 2-stroke insulation composite engine constructed from a water tank which also serves as a cooling A two-stroke heat insulation composite having a two-stroke heat insulation engine , an exhaust turbine that uses exhaust gas and superheated steam exhausted from the two-stroke heat insulation engine , and an exhaust energy recovery device that transmits power from the exhaust turbine to the crankshaft In the engine, after exhaust gas is exhausted in the exhaust stroke, the nozzle that cools the inside of the hot cylinder and absorbs the heat in the cylinder to generate superheated steam or hot water is injected, Measures the temperature outside the cylinder and the exhaust gas temperature so that the in-cylinder temperature is kept at the set temperature, and controls the injection amount of water or steam, and water that serves as both silencer and cooling of the exhaust gas and steam discharged from the exhaust turbine. 2-stroke insulated composite engine consisting of a tank

Images