JP2929329B2 - Turbo compound engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field 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 improves engine torque using exhaust energy.

[0002]

2. Description of the Related Art Turbochargers are widely used in which exhaust gas discharged from an engine is guided to a turbine and driven, and supercharged air is pressure-fed to the engine by the turbine torque.
Various turbo compound engines have been proposed in which a generator is mounted on a rotating shaft of a turbocharger of this type, and a motor provided on a crankshaft is driven to recover exhaust energy and convert it to engine output.

[0003]

When such a turbo compound system is used in a four-stroke engine, when the expansion ratio is increased to improve the efficiency of the turbine, the work 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 workload at the time of partial load of the engine is not improved.

[0004] Such work will be described with reference to a PV diagram shown in FIG. 3.
Is the compressor outlet, c is the compression end, d is the end of combustion,
e indicates exhaust valve opening, f indicates blowdown, g indicates combustion termination, h indicates intake start, k indicates turbine outlet, and i indicates P (pressure) and V (volume) in each state of the turbine inlet.

In this state, bcde is the positive work, fghb is the pumping work of the intake and exhaust strokes, f
-I-kab becomes turbine work, and in such a system, the negative side of fghb pump work becomes large, and increasing the turbine inlet state level of i increases exhaust work. There is a problem of increasing.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to reduce the amount of work on the minus side in the exhaust stroke of an engine and to efficiently recover exhaust energy to improve the driving force of the engine. It is to provide a turbo compound engine to be converted.

[0007]

According to the present invention, a turbocharger is connected to an exhaust pipe of an engine to increase a supercharging pressure to the engine and to recover exhaust energy. A two-cycle, three-cylinder engine as the engine, a methanol injector disposed in an exhaust manifold of the engine, and a rotating electric machine mounted on a rotating shaft of a turbocharger for power generation operation. A turbine generator driven by exhaust gas from a turbocharger, an electric motor connected to a crankshaft of an engine, and power conversion means for powering the electric motor by a power output of the rotating electric machine and the turbine generator. A turbo compound engine is provided.

[0008]

Next, an embodiment of the present invention will be described in detail with reference to the drawings.

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

In FIG. 1, reference numeral 1 denotes an engine, which is a three-cylinder engine that operates for two cycles, and has a crank angle of 1 engine.
The operation is performed by explosion of light oil supplied from the respective injection nozzles 11, 12, 13 every 20 degrees. The turbocharger 2 is connected to the exhaust manifold 14 and the intake manifold 15.

The turbocharger 2 includes a turbine 21 and a compressor 22, and an exhaust manifold 1 of the engine 1.
The compressor 22 is driven by the torque of the turbine 21 due to the exhaust energy discharged from the compressor 4, and the supercharged air is pumped to the intake manifold 15 by the pneumatic operation thereof. It is also configured to recover electricity.

Reference numeral 3 denotes a turbine generator, which is a turbine 31 driven by exhaust gas from the turbocharger 2.
And a generator 32 for recovering the residual energy of the exhaust gas of the turbocharger 2 into electric power. The recovered electric power and the power output of the rotating electric machine 23 are supplied to the electric motor 6 described later and supplied to the engine 1. Are connected so as to energize the output.

Reference numeral 4 denotes a rectifier, which includes a rectifier circuit for rectifying the output of the rotating electric machine 23 and a circuit for rectifying the output of the generator 32, and combines the two outputs.
Is an inverter, which converts the DC power added by the rectifier 4 into AC power of a predetermined frequency and supplies the AC power to the motor 6 for power running. The rotation signal of the motor 6 is fed back to the inverter 5. A pinion 61 is attached to a rotating shaft of the electric motor 6, and is configured to mesh with a gear on an outer peripheral portion of the flywheel 16 of the engine 1 so as to increase the output of the engine 1 by powering of the electric motor 6.

Reference numeral 7 denotes a light oil injection pump for supplying fuel to the engine 1. Reference numeral 8 denotes a methanol injection pump which supplies methanol to an injector 81 attached to the exhaust manifold 14, and which burns unburned gas. Combustion is performed to achieve complete combustion.

Next, the operation of this embodiment constructed as described above will be described. The injection nozzles 11, 12, and 13 of the three cylinders of the engine 1 have the crankshaft 120
The engine 1 is smoothly operated by sequentially supplying light oil every degree rotation, and exhaust gas generated by combustion of light oil is sent to the turbocharger 2 via the exhaust manifold 14 to drive the turbine 21. During this time, the exhaust manifold The unburned portion of the light oil is completely burned by the combustion of the methanol ejected from the injector 81 attached to the fuel tank 14, and the exhaust gas with high combustion efficiency drives the turbine 21. Therefore, the compressor 22 of the turbine shaft increases the supercharging pressure to the engine 1, and the rotating electric machine 23, which is driven at the same time, transmits the power generation output to the rectifier 4, and further discharges the electric power from the turbocharger 2. The output of the generator 32 of the turbine generator 3 driven by the supplied gas is also transmitted to the rectifier 4.

Next, in the rectifier 4 to which the electric power is transmitted from the rotating electric machine 23 and the generator 32, the rectifier 4 converts the electric power into direct current by the respective rectifier circuits and adds them to the inverter 5 to supply it to the inverter 5. The AC power having a frequency to be run according to the input rotation signal is transmitted to the electric motor 6 to be run, thereby increasing the output of the engine 1 via the gear mechanism.

FIG. 2 is a P / V diagram in such a system of the present embodiment. At the bottom dead center position of the piston in a two-cycle engine such as the engine 1, the intake valve and the exhaust valve cross each other. The intake valve is closed and the intake valve closes at a point a in accordance with the rise of the piston to perform a compression stroke. At a point b, compression ends, and at a point c, main combustion ends. Then, the exhaust valve is opened at point d, blows down to point e, and moves to point a while being supplied with air by the intake pressure. Here, after the exhaust valve is closed, the pressure of the exhaust gas discharged at point e rises due to the combustion of methanol from the injector 81 attached to the exhaust manifold described above, and reaches point f.
The gas expands inside the turbocharger 2 and the turbine generator 3 to reach point g.

Therefore, the expansion work in the turbocharger 2 is converted into the electric power generated by the rotating electric machine 23, and the expansion work in the turbine generator 3 is converted into the output of the generator 3, and the electric power is supplied to the electric motor 6. Being efficiently engine 1
Will be increased.

In the case of a two-cycle engine, the scavenging valve and the exhaust valve open near the bottom dead center, and their openings cross each other. Required, and no negative work for exhaust occurs.

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

[0021]

According to the present invention as in the above embodiment,
A methanol injector is attached to the exhaust manifold of a two-cycle three-cylinder engine to achieve complete combustion of the supplied fuel, and the exhaust gas is sequentially supplied to a turbocharger and a turbine generator to increase the supercharging pressure and increase the turbocharger pressure. Since the power generation output is obtained by the rotating electric machine of the charger and the turbine generator, the power from these is supplied to the electric motor connected to the engine crankshaft to energize the engine output,
The fuel combustion energy can be recovered efficiently,
There is no negative side work in the exhaust stroke of the engine, and an effect is obtained that a very efficient turbo compound engine can be realized.

[Brief description of the drawings]

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

FIG. 2 is a P / V diagram of a combustion stroke in the present embodiment.

FIG. 3 shows P / V of a combustion stroke in a four-cycle engine.
FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Engine 2 ... Turbocharger 3 ... Turbine generator 4 ... Rectifier 5 ... Inverter 6 ... Electric motor 14 ... Exhaust manifold 16 ... Flywheel 23 ... Rotating electric machine 32 ... Generator 81 ... Injector

Claims (1)

(57) [Claims] 1. A turbo-compound engine in which a turbocharger is connected to an exhaust pipe of an engine to increase a supercharging pressure to the engine and collect exhaust gas energy to increase an engine torque. In addition to the use of an engine, a methanol injector disposed in an exhaust manifold of the engine, a rotating electric machine mounted on a rotating shaft of a turbocharger for power generation operation, a turbine generator driven by exhaust gas from the turbocharger, and a crank of the engine A turbo compound engine, comprising: a motor connected to a shaft; and power conversion means for powering the motor by a power output of the rotating electric machine and a turbine generator.