JPH04159422A - Supercharger of engine - Google Patents

Abstract

PURPOSE:To obtain proper air flow amount over a wide range of operation of an engine by mounting a two-step supercharger which is driven electrically in a suction air flow passage, and providing a plural number of change-over valves so as to enable change-over and control between serial and parallel of two compressors of two-step supercharger. CONSTITUTION:A turbine generator 2 is mounted on an exhaust pipe 11 of a diesel engine 1 and rotated and driven by exhaust air energy. On the other hand, a motor 33 is mounted on a rotary shaft of a two-step supercharger 3 which is provided with first and second compressors 31, 32 mounted on a suction air pipe 2 on the same shaft. For example, when change-over valves 42, 44 are closed and a change-over valve 43 is opened, pressure air from the first compressor 31 is further changed into higher pressure air in the second compressor 32 to supercharge into the engine 1. On the other hand, when the change-over valves 42, 44 are opened and the change-over valve 43 is closed, pressure air from the first compressor 31 is sent directly to the engine 1 via a bypass suction air pipe 14, and air from an air cleaner 36 is compressed by the second compressor 32 and supplied to the engine 1.

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 an engine equipped with such a turbocharger, the boost pressure is low in the low speed range where exhaust energy is low and the increase in torque is insufficient, so the turbocharger is electrically driven using the battery as a power source to increase the boost pressure. Attempts are being made to raise it.

Then, a proposal to increase engine torque at low speeds by charging the battery that serves as a power source and controlling the flow rate of exhaust gas was proposed as a control device for a turbocharger with a rotating electrical machine in Japanese Patent Application Laid-Open No.
It is shown in the publication No.-117925.

However, in the proposal shown in the above-mentioned publication, the compressor of the turbocharger uses one stage compression and its pressure capacity is limited, so the applicant used a two-stage supercharger as shown in Figure 2. The proposal for an engine supercharging device has been filed as patent application No. 234128 of 1990.

(Problems to be Solved by the Invention) In the above-mentioned engine supercharging system proposal, two-stage supercharging is performed on the intake air of the engine, so the air flow rate is small in the low speed range of the engine, and sufficient boost pressure cannot be obtained. However, at high speeds where a large amount of air is required, there is a problem that the required amount of air cannot be obtained because the air flow path is single.

The present invention was made in view of such problems,
The purpose is to provide an engine supercharging device that can obtain an appropriate air flow rate and increase boost depending on a wide range of engine operating conditions.

(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 plurality of electrically driven superchargers are provided, and the air flow paths can be freely arranged in series/parallel.
An engine weekly pay device that switches parallel control is provided.

(Function) In the present invention, a plurality of superchargers that can be freely connected in series/parallel are provided in the air supply flow path of the engine, and the superchargers are driven by electric power recovered from exhaust energy. The turbochargers are connected in series to increase boost pressure, while in high-speed ranges the turbochargers are connected in parallel to increase air flow, supporting a wide range of engine operation.

(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
Fixed advance volume of 2! The output from 23 is led to power converter 41. Note that 24 is a silencer provided at the gas exhaust port of the turbine generator 2.

Reference numeral 12 denotes an intake pipe of the engine 1, and upstream of the intake pipe, a first compressor 31 and a second compressor are connected via an intercooler 13.
A two-stage supercharger 3 coaxially equipped with a compressor 32 is attached.

Here, the bypass intake pipe 14 connected between the intercooler 13 and the intake pipe 12 is connected to the one-stage supercharger of the first compressor 31 without going through the second compressor 32 of the two-stage supercharger 3, as described later. This is an intake pipe in which supercharging to the engine 1 is performed only by supplying air.

Note that a first compressor 31 is attached to the rotating shaft of the two-stage supercharger 3.
An electric motor 33 is arranged to drive the second compressor 32 and the second compressor 32, and is configured to be efficiently driven at high speed by the power generation output of the turbine generator 2 described above.

34 is an air cleaner, 35 is an intercooler, which is connected to the input and output of the first compressor 31, and 42, 43, and 44 are switching valves, which are turned on and off by commands from the controller 4, and are connected to the input and output of the first compressor 31, respectively. It controls the opening and closing of the flow path connected to the switching valve.

For example, when the switching valves 42 and 44 are controlled to close and the switching valve 43 is controlled to open, the pressurized air from the first compressor 31 of the two-stage supercharger 3 is sent to the second compressor 32 and becomes high pressure, which increases the engine pressure. On the other hand, when the switching valves 42 and 44 are opened and the switching valve 43 is closed, the pressurized air from the first compressor 31 is directly sent to the engine 1 via the bypass intake pipe 14. At the same time, the air from the air cleaner 36 is compressed by the second compressor 32 and supplied to the engine 1.

The controller 4 is composed of a microcomputer, and is equipped with a central control unit, various memories, input/output circuits, etc. When a predetermined signal such as engine speed or engine load is input, the controller 4 switches the respective switching valves and electric power. A command is issued to the converter 41 to convert the output from the turbine generator 2 into electric power that drives the electric motor 33 at high speed, and to change the supercharging operation of the two-stage supercharger 3 to one-stage or two-stage supercharging. It is something to control.

Next, the operation of this embodiment configured as described above will be explained.

When it is determined from the signal input to the controller 4 that the engine 1 is in a predetermined high speed range, the switching valve 42 .
44 and close control of the switching valve 43. Therefore, the air taken in from the air cleaner 34 is compressed by the first compressor 31, and the air taken in from the air cleaner 34 is compressed by the first compressor 31.
5, the air is sent under pressure to the engine 1 via the bypass intake pipe 14 without being sent to the second compressor 32. At the same time, the air from the air cleaner 36 is compressed by the second compressor 32, and is supplied to the engine 1 through the intercooler 13 together with the pressurized air from the bypass intake pipe 14. .

On the other hand, when it is determined that the signal to the controller 4 indicates that the engine 1 is in a low speed range, the switching valves 42 and 44 are controlled to close and the switching valve 43 is opened. Through this control, the air compressed by the first compressor 31 is transferred to the intercooler 3.
5 and the second compressor 32 via the switching valve 43.
The compressor provides even more highly compressed air, and the high-pressure air from the two-stage supercharging is supplied to the engine 1 at low speeds through the intercooler 13, increasing engine torque. It turns out.

Although the present invention has been described above with reference to the above-mentioned 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, the two-stage supercharger is electrically driven and installed in the intake flow path of the engine, and the two-stage supercharger is driven by the electric power generated from the exhaust energy of the engine. In addition, multiple switching valves are placed in the flow path of the two-stage supercharger to enable series/parallel switching control of the two compressors of the two-stage supercharger, so that the two compressors of the two-stage supercharger can be controlled to switch between series and parallel. In the low speed range, the air flow path is connected in series by controlling the switching valve to supercharge highly compressed air using two-stage supercharging, while in the high speed range, the air flow path is connected in parallel to create multiple air flow paths to increase the air flow rate. By doing so, it is possible to obtain the effect of being able to respond to a wide range of engine operating conditions.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the structure of an engine supercharging device according to the present invention, and FIG. 2 is a block diagram showing the structure of a conventional engine supercharging device. 1...Engine, 2...Turbine generator, 3...
Two-stage supercharger, 4... Controller, 11... Exhaust pipe, 12... Intake pipe, 14... Bypass flow path, 33...
...Electric motor, 42,43.44...Switching valve.

Claims (1)

[Claims] A turbine generator is arranged in the exhaust flow path of the engine and recovers exhaust energy as electric power, and a plurality of electrically driven superchargers are arranged in the intake flow path of the engine and the air flow paths can be freely connected in series/parallel. A supercharging device for an engine, characterized in that the supercharger is driven by power recovered from a turbine generator, and the supercharger is controlled to be switched between serial and parallel depending on the operation of the engine.