JPH04116229A - Supercharger of engine - Google Patents

Abstract

PURPOSE:To improve a low speed torque of an engine by driving a two-stage supercharger of direct connection arranged in an intake passage by means of electric power regenerated through a turbine generator arranged in an exhaust passage. CONSTITUTION:A turbine generator 2 is arranged in an exhaust pipe 11 of an engine 1 so as to recover an exhaust energy as an electric power. A two- stage supercharger 3 of direct connection which is electrically driven is arranged in an upstream side of an intake passage 12. The two-stage supercharger 3 is driven by electric power regenerated through the generator 2. Due to the two-stage supercharger 3, high pressure supercharging air is obtained without reaching a surge line, so that a torque of the engine 1 is increased under a low engine speed condition.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an engine supercharging device that attempts to significantly increase engine torque at low speeds.

(Prior Art) Turbochargers are widely used, which guide exhaust energy from an engine to a turbine, rotate it at high speed, and drive a compressor connected to the turbine shaft to forcefully feed supercharged air to the engine.

In engines equipped with such a turbocharger, boost pressure is low in the low-speed rotation range where exhaust energy is low, and torque improvement is insufficient. JP-A-60-195329 discloses a proposal for increasing boost pressure by driving an electric mechanism as an electric motor during high loads as a turbocharger for an internal combustion engine.

In order to compensate for the decrease in battery charging capacity and turbine efficiency due to insufficient turbine torque at low engine speeds, Japanese Patent Application Laid-Open No. 1-117925 proposes increasing the gas flow rate by means of controlling the exhaust gas flow rate. ing.

(Problems to be Solved by the Invention) In the proposals shown in these publications mentioned above, the pressure of the compressor is reduced by applying torque from the energized electric mechanism when the engine rotates at low speeds, and by increasing the exhaust gas flow velocity. The operation becomes active and the supercharging pressure to the engine increases,
The engine torque improves as shown by the chain line in FIG.

However, with such a turbocharger compressor, even if the rotational speed is increased, only a low flow rate and high pressure ratio can be obtained, so it is difficult to obtain excellent low-speed characteristics such as the low-speed characteristics of a DC series motor, as shown by the chain line in Figure 3. There is a problem that torque characteristics cannot be obtained.

The present invention was made in view of such problems,
The purpose is to provide an engine supercharging device that dramatically improves the low-speed torque of the engine.

(Means for Solving the Problems) In order to achieve the above-mentioned object, the present invention provides a turbine generator disposed in an exhaust flow path of an engine to recover exhaust energy as electric power, and a turbine generator disposed in an exhaust flow path of an engine to recover exhaust energy as electric power; A supercharging device for an engine is provided, which includes a series-connected two-stage supercharger arranged and electrically driven, the two-stage supercharger being driven by regenerative power from the turbine generator.

(Function) In the present invention, a turbine generator is provided in the exhaust flow path of the engine to recover exhaust energy as electric power, and an electrically driven series two-stage supercharger is installed in the engine intake flow path to generate electric power from the turbine generator. The engine is rotated at high speed using regenerated power, and a two-stage supercharging mechanism supplies high-pressure supercharged air to the engine.

(Example) Next, an example of the present invention will be described in detail using the drawings.

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

In the figure, 1 is an engine, for example, a diesel engine. A turbine generator 2 is attached to an exhaust pipe 11 of the engine, and a rotating shaft of a turbine 21 that is rotationally driven by the exhaust energy of the engine 1 has an ultra-high-speed drive. A generator 22 that efficiently generates electricity is arranged, and the generator 2
The output from the second stator winding 23 is led to a power converter 41. Note that 24 is a silencer provided at the gas exhaust port of the turbine generator 2.

12 is an intake pipe of the engine 1, and a two-stage supercharger 3 is attached to the upstream side of the intake pipe via an intercooler 13. The two-stage supercharger 3 includes two stages connected in series, a high-pressure compressor 31 and a low-pressure compressor 32, on the same axis, and a driving electric motor 33 is disposed on the rotating shaft that connects the two. It is configured to be driven at high speed by the generated output of the generator 22 via the power converter 41.

Then, the outside air taken in from the air cleaner 34 first reaches the first stage of pressure air by the pressure operation of the low-pressure compressor 32 and reaches the intercooler 35. Upon operation, the air becomes high-pressure air in the second stage, is cooled via the intercooler 13, and is then force-fed to the engine 1 as high-pressure supercharging air.

4 is a controller, which is composed of a microcomputer and equipped with a central control unit, various memories, input/output circuits, etc., and is used to control predetermined signals such as engine speed, engine load, and two-stage supercharger speed. When input, a command is issued to the power converter 41 to convert the output from the turbine generator 2 into electric power at a frequency that drives the electric motor 33 of the two-stage supercharger 3 at high speed, thereby operating the two-stage supercharger. It is configured to allow

Next, the operation of this embodiment configured as described above will be described. Air taken into the engine 1 is first introduced into the low pressure compressor 32 of the two-stage supercharger 3 via the air cleaner 34.

The output from the turbine generator 2 that is driven by the exhaust energy of the engine 1 to generate electricity is transmitted to the power converter 4.
1 to the electric motor 33 of the two-stage supercharger 3, the low-pressure compressor 32 compresses the introduced air and sends it to the high-pressure compressor 31 via the intercooler 35 as first-stage pressurized air.

Next, a high-pressure compressor 31 coaxial with the electric motor 33 further compresses the pumped first-stage pressure air, cools it via an intercooler 13, and pumps supercharged air at a high boost pressure to the intake pipe 12 of the engine 1.

Therefore, due to the increase in fuel supplied to the engine, the third
As shown in the torque characteristics shown by the chain line in the figure, excellent torque increase at low speeds can be achieved.

Figure 4 is a curve diagram showing the compression characteristics of a general compressor.When the engine speed is low, the air flow rate is small, and when the pressure ratio is increased, it easily reaches the surge line. This shows that it is difficult.

FIG. 5 is a block diagram showing another embodiment of the present invention, and the same parts as in FIG.

In FIG. 5, 5 is a turbocharger with a rotating electrical machine connected to the exhaust pipe 11 of the engine 1, and a turbine 51 driven by the exhaust energy of the engine 1 is provided with a rotating electrical machine 53 and a compressor 52 on the same axis. ing.

After driving the turbine 51, the exhaust gas is guided to the turbine generator 2, and the output of the generator 22 is transferred to the power converter 4.
1 and becomes a power source for the electric motor 33 of the two-stage supercharger 3 , and the generated output from the rotating electric machine 53 is also supplied to the electric motor 33 via the power converter 41 . Note that the compressor 52 driven by the torque of the turbine 51 takes in outside air from the air cleaner 54 and compresses it.
The air is then sent to the low pressure compressor 32 of the two-stage supercharger 3 via the intercooler 56.

6 is a bypass pipe, which connects the intake pipe 12 of the engine 1 and the connecting pipe 5.
A bypass valve 61 is disposed in the middle of the bypass pipe 6 and is configured to open/close the bypass pipe 6 according to commands from the controller 4. .

In the embodiment shown in FIG. 5, a compressor 52 is disposed in the preceding stage of the two-stage supercharger 3 of the embodiment shown in FIG. Due to the high boost pressure generated by the operation, supercharging air of even higher pressure can be obtained, and the torque can be increased when the engine is running at low speeds and under high load. Note that, depending on the opening degree of the bypass valve 61 provided in the bypass pipe 6, the supercharging pressure is controlled according to the operating state of the engine 1.

Although the present invention has been described above 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.

(Effects of the Invention) As described above, according to the present invention, a turbine generator is provided in the exhaust flow path of the engine and driven by exhaust energy to perform electric power regeneration, and a two-stage supercharging by electric drive is installed in the intake flow path. Since the engine is installed and driven at high speed using the regenerated electric power, the two-stage supercharger allows high pressure air to be obtained without reaching the surge line, and the torque of the engine can be increased at low rotation speeds.

Further, according to the present invention, a turbocharger with a rotary electric machine is interposed between the turbine generator and the engine, and the exhaust gas from the turbocharger drives the turbine generator, and the pressure generated by the operation of the turbocharger is In addition to supplying power to the inlet of the two-stage supercharger, the power output from the rotating electrical machine drives the two-stage supercharger in addition to the regenerative power of the turbine generator, so supercharging to the engine is performed in three stages. The supercharging mechanism provides sufficient compression, making it possible to dramatically increase torque at low speeds.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a configuration of an embodiment of an engine supercharging device according to the present invention, FIG. 2 is a torque characteristic curve diagram of a normal turbocharger with an electric motor, and FIG. 3 is a desired torque characteristic curve diagram. FIG. 4 is a curve diagram showing the compression characteristics of a general compressor, and FIG. 5 is a block diagram showing another embodiment of the present invention. 1...Engine, 2...Turbine generator, 3...
Two-stage supercharger, 4... Controller, 5... Turbocharger with rotating electric machine, 6... Bypass pipe, 11...
Exhaust pipe, 12... Intake pipe, 31... High pressure compressor, 32... Low pressure compressor, 33... Electric motor,
41... Power converter, 53... Rotating electric machine, 55...
・Connecting pipe. Figure 1 Patent Applicant Isuf Automobile Co., Ltd. Agent Patent Attorney Tsuji Minoru Esodashi Old ■SSR → E, Shinino cat;

Claims (2)

[Claims] (1) It has a turbine generator placed in the exhaust flow path of the engine to recover exhaust energy as electric power, and a series-connected two-stage supercharger placed in the intake flow path of the engine and driven by electric power. A supercharging device for an engine, characterized in that a stage supercharger is driven by regenerated power from the turbine generator. (2) The turbine generator is driven by exhaust gas from a turbocharger with a rotating electrical machine interposed between the turbine generator and the engine, and the pressure generated by the operation of the turbocharger with a rotating electrical machine is The engine supercharger according to claim 1, wherein the power generation output of the rotating electric machine is supplied to the two-stage supercharger in addition to the regenerated power of the turbine generator. Feeding device.