JPH0533668A - Turbo-compound engine - Google Patents

Abstract

PURPOSE:To dispense with any work for exhaust in a turbo-compound engine as well as to convert fuel combustion energy into power so effectively. CONSTITUTION:A turbocharger 2 equipped with a dynamo-electric machine is attached to a two cycle 3-cylindered engine 1 formed into a heat insulated structure, and further a turbine generator 3 is set up at the downstream. In succession, a highly efficient intercooler 23 is set up in a flow passage of supercharging air out of the turbocharger 2 and intake air is cooled to the full, while each output out of the dynamo-electric machine 24 and the generator 32 being driven by exhaust energy is fed to an electric motor 6 in mesh with a flywheel 14 via a rectification-voltage controller 4 and an inverter 5, thereby energizing the extent of engine torque. In addition, according to engine load, opening of an exhaust valve 13 is controlled by a valve controller 8.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention increases the intake pressure of an engine by connecting a turbocharger to the exhaust pipe of the engine.
Further, the present invention relates to a turbo compound engine that utilizes exhaust energy to improve engine torque.

[0002]

2. Description of the Related Art A turbocharger is widely used in which exhaust gas discharged from an engine is guided to a turbine for driving, and supercharged air is pumped to the engine by the turbine torque.
Various types of turbo compound engines have been proposed in which a generator is attached to the rotary shaft of a turbocharger of this type, and an electric motor provided on a crankshaft is driven to recover exhaust energy and convert it into engine output.

[0003]

When such a turbo compound system is used in a 4-cycle engine, when the expansion ratio is increased to improve the efficiency of the turbine, the work amount in the exhaust stroke of the engine increases. As a result, there is a problem that the efficiency is not improved so much and the work amount at the time of partial load of the engine is not improved.

This work will be explained with reference to the P-V diagram shown in FIG. 3, where a is atmospheric pressure, the compressor inlet, and b.
Is the compressor outlet, c is the compression end, d is the end of combustion,
e is an exhaust valve open, f is a blowdown, g is an exhaust end, h is an intake start, k is a turbine outlet, and i is P (pressure) and V (volume) in each state of the turbine inlet.

In this state, b-c-d-e is positive work, f-g-h-b is negative intake-exhaust stroke pumping work,
The f-i-k-a-b becomes positive turbine work, and in such a system, the negative side of the f-g-h-b pump work becomes large, and when the level of the turbine inlet state of i is raised, the exhaust gas is exhausted. There is a problem that the number of jobs increases.

The present invention has been made in view of the above problems, and its purpose is to reduce the negative work in the exhaust stroke of the engine and to efficiently recover the exhaust energy to improve the driving force of the engine. It is to provide a turbo compound engine that tries to convert.

[0007]

To achieve the above object, according to the present invention, a turbocharger is connected to an exhaust pipe of an engine to increase supercharging pressure to the engine, and exhaust energy is used as a power source. In a turbo compound engine to be recovered, an adiabatic 2
A rotary electric machine that uses a cycle diesel engine and is arranged on the rotary shaft of the turbocharger to generate electric power, a turbine generator connected downstream of the turbocharger, an electric motor connected to the crankshaft of the engine, and the rotary electric machine. There is provided a turbo compound engine having: and an electric power conversion means for supplying an output from the turbine generator to the electric motor for power running.

[0008]

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

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

In the figure, reference numeral 1 denotes an engine, which is a three-cylinder adiabatic diesel engine that operates in two cycles, and a heat insulating material such as heat-resistant ceramics is used in a relevant portion of the combustion chamber to increase the temperature. Therefore, engine cooling water is not required, cooling loss is reduced, and thermal efficiency is improved.

Reference numeral 2 is a turbocharger, which uses the exhaust gas from the exhaust manifold 11 of the engine 1 for the turbine 21.
Is driven, and the compressor 22 is driven by the turbine torque.
Is operated to pump supercharged air to the engine 1. An intercooler 23 having high efficiency is inserted in an intake passage from the compressor 22 to the intake manifold 12, and air having high density is pumped to the engine 1. .

Reference numeral 24 denotes a rotating electric machine provided on the turbine shaft, which serves as an electric-generator. When the exhaust gas flow rate from the engine 1 is large, the rotating electric machine 24 operates as a generator, and an electric motor 6 to be described later.
To drive the engine torque, and when the engine 1 has a low rotation and a high load, the engine is electrically operated by the electric power from the battery 7 to assist the pneumatic operation of the compressor 22 to boost the supercharged air pressure to the engine 1. Is configured to raise. In addition, 13 in the engine 1 is an exhaust valve provided in each cylinder, and the valve opening degree is controlled to increase or decrease according to the engine load by the operation of the valve control device 8.

A turbine generator 3 is a turbocharger 2.
A turbine 31 driven by the exhaust gas of, and a generator 32 driven by the turbine torque to generate electricity,
The output from the generator 32 is transmitted to the rectification / voltage controller 4 together with the power generated by the rotary electric machine 24 during the above-described power generation operation.

The rectification / voltage controller 4 rectifies the transmitted AC power, converts it into DC power of a predetermined voltage, and transmits the DC power to the inverter 5.

The inverter 5 is for converting DC power into AC power having a predetermined frequency, and is provided with a DC-AC converter for energizing the rotary electric machine 24 and a pinion 61 meshing with the flywheel 14 of the engine 1. Both of the converters for energizing the electric motor 6 are provided, and both of these converters are provided with the feedback line of the rotation signal from the rotating electric machine 24 and the generator 32 for supplying power, and the AC power of the frequency that causes powering when energized. Are configured to be supplied to each. Reference numeral 51 denotes a changeover switch, which switches the wiring between the rotary electric machine 24 and the inverter 5 in accordance with the electric or electric power generation operation of the rotary electric machine 24 of the turbocharger 2.

The battery 7 is used as a power source when the rotary electric machine 24 is electrically operated, and is also used as a power source of the valve control device 8 that controls the exhaust valve 13 of the engine 1. It is configured to be charged by the output of the rotary electric machine 24.

Next, the operation of the present embodiment thus constructed will be described. When the engine 1 is operated, exhaust gas is pressure-fed to the turbocharger 2 through the exhaust manifold 11, and the turbine 21 is driven. The coaxial compressor 22 performs pneumatic operation and the rotating electric machine 2
4 is also driven and outputs AC power.

The compressed air from the compressor 22 is deprived of the heat of compression by the highly efficient intercooler 23, cooled, and compressed as fresh air having a high density through the intake manifold 12 to feed the engine 1. Become. In this case, since the fresh air introduced from the intake hole has a higher pressure than the exhaust gas, the exhaust gas is pushed out and a part of it flows out into the exhaust pipe, and the inner wall temperature of the combustion chamber is lowered to remove the heat and the fresh air exhaust system. Leading to. In addition, since the combustion chamber of the cooled fresh air is also cooled, the combustion is less deteriorated and the combustion is completed.However, because of the adiabatic combustion chamber, the combustion gas burns isobarically to perform the work. Become. Since the enthalpy of the exhaust gas is increased, it is possible to obtain a pressure ratio at which the work in the turbine can be sufficiently performed, and the pneumatic operation of the turbocharger 2 and the power generation operation by the rotary electric machine 24 are efficiently performed. Become.

Further, in this turbocharger 2, the air from the fresh air takes heat away during scavenging to increase the volume,
The work amount can be easily obtained even when the engine is partially loaded, and the leak amount of this fresh air is controlled to an appropriate flow rate by the valve control device 8 that controls the opening degree of the exhaust valve 13 according to the engine load. Will be done.

On the other hand, the electric power from the rotary electric machine 24 is input to the rectification / voltage controller 4, but here the electric power from the turbine generator 3 driven by the exhaust gas of the turbocharger 2 is also input and rectified. It is converted into direct current by the circuit and added together, and the direct current power of a predetermined voltage is output to the inverter 5.

Then, the inverter 5 converts the electric power into an electric power having an AC frequency that causes the electric motor 6 to power in response to a rotation signal from the electric motor 6 meshing with the flywheel 14 via a gear mechanism, and the electric motor 6 is converted. As a result, the flywheel 14 is energized and the torque of the engine 1 is increased.

FIG. 2 is a P / V diagram in such a system of this embodiment. In the two-cycle engine, the intake hole and the exhaust valve are opened at the bottom dead center of the piston for scavenging, At point A in the figure, the intake hole closes and compression starts,
The point B is the end point of compression, the point C is the end of fuel, the point D is the exhaust valve opening and exhaust start, and the point E is the exhaust valve close and exhaust end. The point F is the bottom dead center of the piston, the point G is the turbine inlet, the point H is the turbine outlet, and the point I is the compressor inlet, which represent the pressure and volume in each state. There is no negative work for exhaust, and an engine system with high fuel thermal efficiency can be obtained.

Although the present invention has been described with reference to the above embodiments, various modifications can be made within the scope of the gist of the present invention, and these modifications are not excluded from the scope of the present invention.

[0024]

According to the present invention as in the above embodiments,
A high-efficiency intercooler is installed in the supercharging air passage from the turbocharger attached to the two-stroke three-cylinder engine with the heat insulating structure to supply the intake air with a high density to the engine,
A rotary electric machine is arranged in the turbocharger for power generation operation, and electric power from a turbine generator driven by exhaust gas from the turbocharger and electric power of the rotary electric machine are supplied to an electric motor connected to a crankshaft. Since this increases engine output, heat loss due to engine cooling water is reduced in this system, and even if fresh air blows through during engine scavenging, incomplete combustion is prevented due to the adiabatic engine, and this combustion energy allows turbochargers and Sufficient work is performed in the downstream turbine generator, and the negative work for exhaust is reduced, so that an efficient turbo compound engine can be obtained.

Further, according to the present invention, since the valve control device which can freely control the opening degree of the exhaust valve according to the load condition of the engine is provided, it is possible to improve the work efficiency even with the exhaust gas at the partial load. Occurs.

[Brief description of drawings]

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

FIG. 2 shows P / V showing a state of combustion gas in the present embodiment.
It is a diagram.

FIG. 3 is a P / V diagram in a 4-cycle engine.

[Explanation of symbols] 1 ... engine 2 ... Turbocharger 3 ... Turbine generator 4 ... Rectifier / voltage controller 5 ... Inverter 6 ... electric motor 8 ... Valve control device 13 ... Exhaust valve 14 ... Flywheel 23 ... Intercooler 24 ... Rotating electric machine

Claims (3)

[Claims] 1. A turbo compound engine for connecting a turbocharger to an exhaust pipe of an engine to increase supercharging pressure to the engine and recovering exhaust energy as power, wherein an adiabatic two-cycle diesel engine is used as the engine. Along with the use, a rotary electric machine that is arranged on the rotary shaft of the turbocharger and operates to generate electricity, and a turbine generator connected downstream of the turbocharger,
A turbo compound engine, comprising: an electric motor connected to a crankshaft of an engine; and electric power conversion means for supplying the output from the rotating electric machine and the turbine generator to the electric motor to cause the electric power to run. 2. A turbo compound engine according to claim 1, wherein a highly efficient intercooler is interposed in the supercharging air passage from the turbocharger to the engine. 3. A turbo compound engine according to claim 1, further comprising a valve control device for controlling an opening of an exhaust valve of a cylinder of the engine according to an engine load.