JPH05113128A - Two-cycle adiabatic engine - Google Patents

Abstract

PURPOSE:To provide a two-cycle adiabatic engine wherein a bypass valve is opened or closed so as to reduce an exhaust pressure to a pressure lower than a boost pressure. CONSTITUTION:In a two-cycle adiabatic engine 1, a torbocharger 2 having a rotary electric unit 7 arranged on an exhaust system and an energy recovery device 3 are arranged serially to the flow of exhaust gas, while a bypass valve 4 is provided between the turbocharger 2 and the energy recovery device 3. A sensor 5 is arranged on an exhaust passage 10 for detecting an exhaust pressure P2, while a sensor 6 is arranged on an intake passage 14 for detecting a boost pressure P1. A controller 20 is controlled such that the bypass valve 4 is opened in response to the detected values of the sensors 5, 6 for lowering the exhaust pressure P than the boost pressure P1. Supercharge is enabled in the full operation range of the engine 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a two-stroke adiabatic engine having an exhaust port in a cylinder head and a scavenging port in the lower part of the cylinder, and having a combustion chamber of adiabatic structure equipped with a turbocharger and an energy recovery device.

[0002]

2. Description of the Related Art In general, an adiabatic engine operated by two strokes, that is, two cycles, has a combustion chamber in which an exhaust port is provided in a cylinder head and a scavenging port is provided under a cylinder in an adiabatic structure. 1
It explodes once for each rotation, and completes the four actions of suction, compression, combustion, and exhaust / scavenging in two strokes of the piston. The two-cycle engine introduces intake air and scavenging from the scavenging port at the same time. As the heat insulation structure of the combustion chamber, the main chamber formed in the piston head portion, the cylinder head portion or the cylinder portion, or the sub chamber formed in the cylinder head is formed by using a heat insulating material such as ceramics or a heat resistant material. Further, in an adiabatic engine in which a subchamber formed in a metal cylinder head and a main chamber formed in an upper portion of the cylinder have a heat insulating structure, a heat insulating block made of ceramics may be arranged in a hole formed in the cylinder head. it can.

Conventionally, as a two-cycle adiabatic engine, for example, there is one disclosed in Japanese Patent Laid-Open No. 3-50363. In this two-cycle heat insulation engine, the lower surface of the head and the upper part of the liner are constructed in a heat insulating structure, an exhaust valve is arranged in an exhaust port formed in the lower surface of the head, and a heat insulating gasket is arranged at the boundary between the upper part of the liner and the lower part of the cylinder. However, a large number of intake ports are formed in the lower part of the cylinder, and the intake ports are opened to intake ports formed in the outer periphery of the lower part of the cylinder.
Further, in a two-cycle adiabatic engine, a supercharger is usually connected to the intake port.

[0004]

In the adiabatic engine, the wall surface of the combustion chamber has a higher temperature than that of a normal water-cooled engine, so that the intake air expands in the intake stroke and the air supply amount decreases. Become. In particular, since the intake air receives heat from the cylinder inner wall, the combustion chamber inner wall, etc. in the compression stroke,
The compression end temperature becomes high. When the compression end temperature becomes higher, the work of compression becomes larger than that in the water-cooled engine, which hinders the improvement of the cycle efficiency of the adiabatic engine. Moreover, when the compression end temperature is high, it causes deterioration of combustion. Furthermore, when the compression end temperature becomes high, the temperature of the working gas in the engine is high, and the temperature difference between the wall surface and the wall surface becomes large even though the wall surface is maintained at a high temperature. Heat dissipation energy increases through the chamber wall surface and the cylinder head.

Therefore, in the adiabatic engine, there is a two-cycle engine in which intake air is introduced from a scavenging port formed in the lower portion of the cylinder where the temperature is relatively low and exhaust gas is exhausted from an exhaust port formed in the cylinder head. Would be preferable.

However, in the two-cycle engine,
Since it is necessary to perform intake and scavenging at the same time during the operation stroke of the piston, the pressure in the exhaust port or exhaust pipe formed in the cylinder head where the exhaust gas of the engine is discharged, that is, the exhaust pressure, is the pressure of the supply air, that is, the boost pressure. It is more difficult to raise, and it cannot be supercharged by a turbocharger in most operating areas of the engine. Therefore, as shown in FIG. 3, in the two-cycle engine 40,
In order to perform sufficient intake and scavenging through the intake passage 42, a mechanical supercharger such as a roots blower 41 (in some cases, an electric supercharger) is used. In FIG. 3, reference numeral 43 indicates an exhaust passage. Generally, a roots blower is a pump that sends out air by a pair of cocoon-shaped rotors that rotate in opposite directions in a housing.When it is attached to an engine, the rotational force of the engine, for example, the rotational force from a crankshaft drives the gears. It is configured to be transmitted via. Therefore, the roots blower has a problem that the boost pressure is insufficient in a high rotation range because the rotation speed corresponds to the engine rotation speed.

Therefore, an object of the present invention is to solve the above-mentioned problems, and a turbocharger having an electric rotating machine and an energy recovery device are arranged in series in the flow of exhaust gas, and the turbocharger and the energy recovery device are connected to each other. A two-cycle adiabatic engine is provided in which a bypass valve is provided between the two, and the opening / closing of the bypass valve is controlled by a controller so that the exhaust pressure is always lower than the boost pressure.

[0008]

In order to achieve the above object, the present invention is configured as follows. That is, the present invention relates to a two-cycle adiabatic engine having an exhaust port formed in a cylinder head and a scavenging port below a cylinder and having a combustion chamber of an adiabatic structure, a turbocharger having a rotating electric machine arranged in an exhaust system, and the turbocharger. Energy recovery device having a generator disposed downstream of the, a bypass valve provided between the turbocharger and the energy recovery device, a sensor for detecting boost pressure and exhaust pressure, and in response to the detection value of each sensor. A two-cycle adiabatic engine having a controller that opens and closes the bypass valve to control the exhaust pressure to be lower than the boost pressure.

Further, in this two-cycle adiabatic engine, when the boost pressure is higher than the exhaust pressure, the controller operates the rotating electric machine as an electric motor and closes the bypass valve to send exhaust gas to the energy recovery device. Power generation is performed and the electric power is directly supplied to the rotary electric machine. Further, when the exhaust pressure is higher than the boost pressure, the bypass valve is opened to allow the exhaust gas to escape and the exhaust pressure to be reduced.

[0010]

The present invention is constructed as described above and operates as follows. That is, in this two-cycle adiabatic engine, a turbocharger having a rotating electric machine is disposed in the exhaust system, an energy recovery device having a generator is disposed downstream of the turbocharger, and an energy recovery device having a generator is disposed between the turbocharger and the energy recovery device. Since the bypass valve is installed and the controller controls the opening and closing of the bypass valve in response to the detection values of the sensor that detects the boost pressure and the exhaust pressure, the boost pressure can be controlled to always be higher than the exhaust pressure, and the intake and scavenging air can be controlled. Even if both are performed at the same time, it is possible to achieve high boost pressure in a high rotation range and supercharging at a low load.

That is, when the exhaust pressure is high, the bypass valve is throttled to allow exhaust gas to escape from the bypass passage, the energy recovery device is deactivated, and the rotary electric machine of the turbocharger is operated by a motor to perform supercharging. Done,
To ensure proper boost pressure and good combustion, and when the exhaust pressure is high, the turbocharger can perform turbo operation, so the bypass valve is opened to send the exhaust gas to the energy recovery device, The energy recovery device can be operated to generate electric power with a generator, and the electric power can be directly supplied to the rotating electric machine or, depending on the case, stored in a battery.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a two-cycle adiabatic engine according to the present invention will be described below with reference to FIG. FIG. 1 is a schematic explanatory view showing an embodiment of a two-cycle adiabatic engine according to the present invention.

The two-cycle adiabatic engine 1 shown in FIG.
It is a type that explodes once with one revolution of the crankshaft, is operated in two strokes, that is, two cycles, and four actions of intake, compression, combustion and exhaust / scavenging are performed with two strokes of the piston. The two-cycle heat insulation engine 1 includes a cylinder block 21 made of a metal material such as an aluminum alloy, and the cylinder block 21.
Cylinder head 1 made of a metal material such as an aluminum alloy, which is fixed to the inner surface with a gasket such as a metal gasket interposed therebetween.
Have nine. A plurality of holes corresponding to the number of cylinders of the engine 1 are formed in the cylinder block 21, and a cylinder liner forming a cylinder is fitted in the holes. Further, the cylinder head 19 has, for example, holes corresponding to the number of cylinders of the engine 1, that is, the holes. A headliner that constitutes a part of the main chamber is fitted in the hole, and the headliner is composed of a head lower surface portion and a liner upper portion. A piston 22 forming a part of a main chamber is incorporated in a cylinder formed in the upper part of the liner and a cylinder formed in the cylinder liner so as to reciprocate. In the case of a direct injection type combustion chamber, a fuel injection nozzle for injecting fuel is provided in the main chamber. Alternatively, the cylinder head 19 may be provided with a sub chamber having a heat insulating structure, in which case the fuel injection nozzle is arranged in the sub chamber.

The two-cycle adiabatic engine 1 has a uniflow type in which the exhaust valve 24 is arranged in the cylinder head 19 so that the scavenging action is performed by the airflow in a fixed direction with respect to the cylinder center line, and the efficiency of the engine 1 is improved. It is possible. The two-cycle adiabatic engine 1 has one or more ports formed in the cylinder head 19,
It functions as the exhaust port 18. A port liner having a heat insulating structure is arranged in the exhaust port 18. An exhaust valve 24 that opens and closes is arranged in a valve seat formed at the lower surface of the cylinder head or at the inlet of the exhaust port 18 formed in the headliner. A heat insulating block made of ceramics such as silicon nitride Si ₃ N ₄ and aluminum titanate Al ₂ TiO ₅ having heat resistance and heat insulating property is fitted into the hole formed in the cylinder head 19 to insulate the combustion chamber. Is configured.

In the two-cycle heat insulation engine 1, a scavenging port 25 is formed in the lower portion of the cylinder of the cylinder liner fitted in the hole of the cylinder block 21. In this two-cycle adiabatic engine 1, a plurality of (in some cases, one) scavenging port openings, that is, scavenging ports 25, are formed in the lower portion of the cylinder liner fitted to the cylinder block 21. The port 25 is always formed in communication with the annular scavenging passage formed around the hole of the cylinder block 21. The annular scavenging passage communicates with the intake passage 14. Air, that is, scavenging air sent from the supercharger of the turbocharger 2, that is, the compressor 9, is fed into the intake passage 14.

In the two-cycle adiabatic engine 1, the piston 22 that reciprocates in the cylinder formed by the cylinder liner and the headliner has the top surface of the piston head of the piston 22 lower than the upper wall surface of the scavenging port 25. Thus, scavenging air, that is, air, is introduced into the cylinder. The piston 22 is made of, for example, silicon nitride Si ₃ N ₄ ,
A piston head portion having a heat insulating structure made of ceramics such as aluminum titanate Al ₂ TiO ₅ and a piston skirt portion made of a metal material such as an aluminum alloy fixed to the piston head portion with a heat insulating gasket interposed by a metal flow metal or the like. It consists of

This two-cycle adiabatic engine has a turbocharger (TCG) 2 having a rotating electric machine 7 arranged in the exhaust passage 10 of the engine 1, and a turbogenerator (generator 11 arranged downstream of the turbocharger 2). T
G) That is, the energy recovery device 3, the bypass valve 4 provided in the exhaust passage 13 between the turbocharger 2 and the energy recovery device 3, the sensor 6 for detecting the boost pressure P ₁ , the sensor 5 for detecting the exhaust pressure P ₂ , And a controller 20 for controlling the boost pressure P ₁ to be higher than the exhaust pressure P ₂ by opening / closing the bypass valve 4 in response to the detection values of the respective sensors 5, 6. The turbocharger 2 includes a turbine 8 driven by the exhaust gas energy of exhaust gas EG exhausted from the engine 1 through an exhaust manifold, an exhaust passage such as an exhaust pipe, a compressor 9 attached to a shaft 23 connected to the turbine 8, It is composed of a rotating electric machine 7 which is a generator / motor arranged between a turbine 8 and a compressor 9. The compressor 9 is operated through the shaft 23 by driving the turbine 8 with the exhaust gas EG, compresses the air A and sends the compressed air A to the engine 1 through the intake passage 14.

Further, the energy recovery device 3 has a turbine 1 arranged in an exhaust passage 13 downstream of the turbocharger 2.
2 and a generator 11 for generating power by the turbine 12. It is preferable that the generator 11 is manufactured according to the specifications of the rotary electric machine 7 of the turbocharger 2, and the electric power generated by the generator 11 can be directly supplied to the rotary electric machine 7. The bypass valve 4 functions as a waste gate and opens / closes according to a command from the controller 20. When the bypass valve 4 closes the exhaust passage 13 to the energy recovery device 3, the bypass passage 26 that is open to the atmosphere is opened, and the exhaust passage 13 upstream of the bypass valve 4 is opened to the atmosphere. The exhaust pressure P ₂ decreases. Further, when the bypass valve 4 opens the exhaust passage 13 to the energy recovery device 3, the bypass passage 26 open to the atmosphere is closed, and the turbine 12 of the energy recovery device 3 is driven so that the generator 11 generates electricity. Become. At this time, the exhaust pressure P _{2 in} the exhaust passage 13 on the upstream side of the energy recovery device 3 increases.

In this two-cycle adiabatic engine 1,
The controller 20 includes an exhaust pressure P ₂ detected by a sensor 5 installed in the exhaust passage 10 and a boost pressure P ₁ detected by a sensor 6 installed in the intake passage 14.
Is entered. Furthermore, the engine speed N detected by the rotation sensor 15 and the engine load L detected by the load sensor 16 are input to the controller 20. The controller 20 controls the rotary electric machine 7 of the turbocharger 2 to perform either electric motor operation or generator operation in response to the detection signals, that is, the operating state of the engine 1, and also controls the bypass valve 4 to operate. The opening / closing control is performed so that the generator 11 of the energy recovery device 3 generates electric power or makes it inactive. When operating the rotating electric machine 7 as an electric motor, the electric power generated by the generator 11 is directly supplied to the rotating electric machine 7, or the battery 17 is used.
To supply electric power to the rotating electric machine 7 (power running), and when the rotating electric machine 7 operates as a generator, the electric power generated by the rotating electric machine 7 is stored in the battery 17 (regeneration). Further, the electric power generated by the generator 11 of the energy recovery device 3 is stored in the battery 17 (regeneration).

Further, the controller 20 controls the boost pressure P
_{When 1} is higher than the exhaust pressure P ₂ , the rotary electric machine 7 is operated as an electric motor, the bypass valve 4 is closed, and the exhaust gas EG is sent to the turbine 12 of the energy recovery device 3 through the exhaust passage 13 to generate power in the energy recovery device 3. Power is generated by machine 11. Further, when the exhaust pressure P ₂ is higher than the boost pressure P ₁ , the controller 20 releases the exhaust gas EG by opening the bypass valve 4 and does not send the exhaust gas EG to the energy recovery device 3, but the exhaust pressure applied to the inside of the exhaust passages 10 and 13. The control is performed to reduce P ₂ .

Next, the operation of this two-cycle adiabatic engine will be described with reference to FIG. FIG. 2 is a process flow chart showing an operating state of the two-cycle adiabatic engine shown in FIG. This two-cycle adiabatic engine 1 is, as described above,
A turbocharger 2 and a high-speed generator 1 equipped with a rotating electric machine 7 that performs electrically driven supercharging, that is, electric motor operation or generator operation.
1 is provided with an energy recovery device 3 to enable a high boost pressure P ₁ in a high rotation range of the engine 1 and supercharging in a low load operation range of the engine 1. ..

In the two-cycle adiabatic engine 1, since intake and scavenging are performed simultaneously in the high engine speed N range, the engine 1 consumes a large amount of air, and the boost pressure P ₁ must be increased accordingly. Therefore, the rotary electric machine 7 is operated as an electric motor to improve the function of the compressor 9, and a large amount of supply air is sent from the scavenging port 25 to the engine 1 for supercharging. Further, when the engine load L is low, the exhaust pressure P ₂ is low and the exhaust energy is small, so the function of the turbocharger 2 deteriorates. Therefore, the rotating electric machine 7 is operated as an electric motor to improve the function of the compressor 9 and supercharge the engine 1 from the scavenging port 25 to cope with the problem.
In other engine operating areas, turbocharger 2
The energy recovery device 3 is configured to perform normal turbo operation and recovery operation.

First, by driving the two-cycle adiabatic engine 1, the sensor 5 installed in the exhaust passage 10 detects the exhaust pressure P ₂ and the sensor 6 installed in the intake passage 14 detects the boost pressure P ₁ . Detect (step 3)
0). The exhaust pressure P ₂ and the boost pressure P ₁ detected by the sensors 5 and 6 are input to the controller 20, which receives the detection signal to determine whether the boost pressure P ₁ is greater than the exhaust pressure P _2. A judgment is made (step 31).

If the boost pressure P ₁ is higher than the exhaust pressure P ₂ , supercharging by the turbocharger (TCG) 2 can be performed, and the following processing is performed. That is, the bypass valve 4 is opened according to a command from the controller 20, and the exhaust passage 13 is connected to the energy recovery device 3.
(Step 32). When the turbocharger 2 and the energy recovery device (TG) 3 communicate with each other through the exhaust passage 13, the exhaust gas EG discharged from the turbine 8 of the turbocharger 2 is sent to the turbine 12 of the energy recovery device 3 (step 33). At this time, the rotating electric machine 7 of the turbocharger 2 is operated as a generator to store electricity in the battery 17, or the electric motor is operated to make the operation of the compressor 9 strong and the compressor 9 causes the intake passage 14 to operate.
Air A is supercharged to the engine 1 through (step 3
4).

Further, the turbine 1 of the energy recovery device 3
Exhaust gas EG is sent to 2 and is generated by the generator 11 (step 35). The electric power generated by the generator 11 can be directly supplied to the rotating electric machine 7 to enhance the operation of the compressor 9, or in some cases, can be stored in the battery 17. When the electric power generated by the generator 11 is directly supplied to the rotary electric machine 7, the electric power is directly supplied without being transformed, which is extremely efficient. However, the generator 11
When the electric power generated in the above is stored in the battery 17, it becomes 100
In order to consume the electric power of the battery 17 by the rotating electric machine 7,
The volt must be transformed back to 100 volt.
Therefore, it is effective to directly supply the electric power generated by the generator 11 to the rotating electric machine 7 that is operating as an electric motor.

[0026] In step 31, if the boost pressure P ₁ is not higher than the exhaust pressure P ₂ is the exhaust pressure P ₂ is high,
Since the turbocharger 2 cannot be operated, the following processing is performed. That is, the bypass valve 4 is closed (step 36) and the exhaust passage 13 is connected to the bypass passage 26. When the turbocharger 2 and the bypass passage 26 communicate with each other through the exhaust passage 13, the exhaust gas EG discharged from the turbine 8 of the turbocharger 2 is discharged to the atmosphere through the bypass passage 26 (step 37). The exhaust gas EG is discharged from the bypass passage 26, so that the exhaust pressure P ₁ decreases (step 38).

In this two-cycle adiabatic engine, as described above, when the boost pressure P ₂ is higher than the exhaust pressure P ₁ ,
The rotary electric machine 7 of the turbocharger 2 is operated as an electric motor to increase the capacity of the compressor 9, and the air A is supercharged to the engine 1 through the intake passage 14. After that, by sending the exhaust gas EG to the turbine 12 of the energy recovery device 3, the generator 11 can generate electric power. The electric power generated by the generator 11 can be directly supplied to the rotating electric machine 7 that is operating as an electric motor to assist the electric power of the rotating electric machine 7, reduce the consumption of the battery 17 and prevent the battery 17 from rising.

Therefore, the generator 1 of the energy recovery device 3
By generating electricity at 1, the exhaust pressure P ₂ rises,
The exhaust pressure P ₂ may become higher than the boost pressure P ₁ depending on the operating conditions of the engine 1. In this case,
Exhaust gas EG is discharged through the bypass passage 26 without sending the exhaust gas EG to the energy recovery device 3 by closing the bypass valve 4. Therefore, the exhaust pressure P ₂ of the exhaust passage 10 is reduced.

Therefore, if the two-cycle adiabatic engine 1 is operated as described above, the two-cycle adiabatic engine 1 can be supercharged by the turbocharger 2 in the entire operating region of the engine, and the energy recovery device 3 is also used. By the electric motor operation of the turbocharger 2 battery 1
It is possible to supplement the discharge of battery 7, and it is possible to prevent the battery 17 from being consumed.

[0030]

The two-stroke adiabatic engine according to the present invention is constructed as described above and has the following effects. In this two-stroke adiabatic engine, a turbocharger having a rotating electric machine is arranged in an exhaust system, an energy recovery device having a generator is arranged downstream of the turbocharger, and a bypass valve is provided between the turbocharger and the energy recovery device. The controller controls the opening and closing of the bypass valve in response to the detection values of the sensors that detect the boost pressure and the exhaust pressure, so that the exhaust pressure is always lower than the boost pressure by opening and closing the bypass valve. Can be controlled.

Moreover, the boost pressure in the high rotation range of the engine can be secured by operating the rotating electric machine as an electric motor, and supercharging is performed by operating the electric motor of the rotating electric machine even when the engine is operated under a low load. You can Therefore, this two-cycle adiabatic engine does not need to be provided with a separate roots blower, and can be supercharged by the turbocharger in the entire operating region of the engine.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing an embodiment of a two-cycle adiabatic engine according to the present invention.

FIG. 2 is a process flow chart showing an example of the operation of the two-cycle adiabatic engine of FIG.

FIG. 3 is a schematic explanatory view showing an example of a conventional two-stroke adiabatic engine.

[Explanation of symbols]

1 2 cycle adiabatic engine 2 turbocharger 3 energy recovery device 4 bypass valve 5 sensor (exhaust pressure P ₂ ) 6 sensor (boost pressure P ₁ ) 7 rotating electric machine 8,12 turbine 9 compressor 10,13 exhaust passage 11 generator 14 intake Passage 17 Battery 20 Controller 26 Bypass passage

Claims (2)

[Claims] 1. A two-cycle adiabatic engine having an exhaust port formed in a cylinder head and a scavenging port below the cylinder and having a combustion chamber of an adiabatic structure, a turbocharger having a rotating electric machine arranged in an exhaust system, and a turbocharger of the turbocharger. An energy recovery device having a generator arranged downstream, a bypass valve provided between the turbocharger and the energy recovery device, sensors for detecting boost pressure and exhaust pressure, and in response to detection values of the respective sensors. A two-cycle adiabatic engine having a controller that opens and closes the bypass valve to control the exhaust pressure to be lower than the boost pressure. 2. When the boost pressure is higher than the exhaust pressure, the controller operates the rotary electric machine as an electric motor and closes the bypass valve to send exhaust gas to the energy recovery device to generate electric power, and to generate the electric power. The two-cycle adiabatic engine according to claim 1, wherein the two-cycle adiabatic engine is controlled so as to be supplied directly to the rotating electric machine, and when the exhaust pressure is higher than the boost pressure, the bypass valve is opened to release the exhaust gas and reduce the exhaust pressure.