JP2987859B2 - Control device for turbocharger with rotating electric machine - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a control device for a turbocharger with a rotating electric machine that attempts to reduce engine exhaust pressure at the time of flying boost of an engine having the turbocharger with the rotating electric machine.

(Prior Art) In recent years, a turbocharger has been put to practical use in which a turbine is driven by exhaust energy from an engine, a compressor is actuated by this turbine torque to feed supercharged air to the engine, and increase the engine output.

Japanese Patent Application Laid-Open No. Sho 60-195329 proposes to attach a rotating electric machine to be a motor-generator to this kind of turbocharger and to operate this rotating electric machine as a motor or a generator according to the operating state of the engine. It is disclosed in a gazette as a turbocharger for an internal combustion engine.

(Problems to be Solved by the Invention) In a vehicle equipped with an engine equipped with a turbocharger, the engine speed does not immediately rise immediately after the accelerator pedal is depressed when starting, so that the amount of exhaust gas is small and the turbocharger causes excessive engine speed. Due to the low charging pressure, it is not possible to expect a rapid increase in engine speed.

For this reason, in the proposal in the above-mentioned publication, the rotating electric machine is operated in advance by the electric motor before the vehicle starts, and the boosting pressure is increased by energizing the pneumatic operation of the compressor. Although the pressure is increased, since the exhaust gas flow rate is constant and the turbine speed is increased, the engine exhaust pressure (turbine inlet pressure) increases as is apparent from the turbine characteristics in FIG. Therefore, in such a state, fuel efficiency may be degraded at the time of flying boost up, and in the worst case, engine stall may occur.

The present invention has been made in view of such a problem, and an object of the present invention is to provide a control device for a turbocharger with a rotating electric machine which aims to suppress an increase in engine exhaust pressure at the time of a flying booth and eliminate the conventional disadvantage. It is in.

(Means for Solving the Problems) According to the present invention, in a control device for a turbocharger with a rotating electric machine, which electrically drives a rotating electric machine arranged in a turbocharger and increases a supercharging pressure before the vehicle starts moving, Detecting means for detecting depression of an accelerator pedal, an exhaust bypass pipe for directly discharging exhaust gas from the engine to the outside air, switching means for switching between the exhaust bypass pipe and an exhaust flow path to a turbocharger, and the rotating electric machine. A controller for a turbocharger with a rotating electric machine, comprising: control means for controlling the switching means so as to flow exhaust gas to the exhaust bypass pipe in response to a signal from the detection means when electrically driven.

(Operation) In the present invention, when the boosting of the engine is detected based on the depression state of the accelerator pedal, the switching valve is switched to the exhaust bypass pipe by the switching means provided in the exhaust flow path, and the exhaust gas is directly discharged to the outside air. Therefore, even if the rotational speed of the turbine increases due to the electric drive of the rotating electric machine, the exhaust pressure of the engine is suppressed.

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

FIG. 1 is a configuration block diagram showing one embodiment of the present invention.

In FIG. 1, reference numeral 1 denotes an engine, and a turbocharger 2 is connected to an exhaust pipe 11 and an intake pipe 12 of the engine. The turbocharger 2 includes a turbine 21 driven by exhaust gas energy of the engine 1 and a turbine 21. A compressor 22 driven by torque is provided, and compressed air generated by the operation of the compressor 22 is supplied to the engine 1 as supercharged air via the intake pipe 12.

Reference numeral 14 denotes an exhaust bypass pipe which is provided in the middle of the exhaust pipe 11 to the turbocharger 2 and is provided to branch the exhaust gas directly to the outside air. A switching valve 15 is disposed at the branch.

Reference numeral 16 denotes a valve actuator for switching the switching valve 15, and a command line from a controller described later is connected to the valve actuator 16.

Reference numeral 3 denotes a rotating electric machine serving as a motor-generator, and its rotor is directly connected to a rotating shaft of the turbine 21. When the exhaust gas energy from the engine 1 is large, the compressor 22 is driven by the turbine torque to increase the boost pressure, the rotor is also driven to operate the rotating electric machine 3 as a generator, and the exhaust energy is converted into electric energy. It is to be collected. Further, when the engine 1 starts suddenly or when the engine 1 is at a low speed and a high load, the rotating electric machine 3 is operated by supplying electric power to operate as an electric motor.
To supply. A boost pressure sensor 13 detects the pressure of the supercharged air to the engine 1 and transmits it to the controller 4.

Reference numeral 5 denotes an accelerator pedal, which is provided with a depression amount sensor 51 as detection means for detecting the depression amount of the pedal, and is connected so that a signal from the depression amount sensor 51 is input to the controller 4.

Reference numeral 6 denotes a battery, which stores electric power generated by the rotating electric machine 3 at the time of power generation operation via the power converter 61, and rotates by the electric power from the battery 6 when the engine 1 starts suddenly or at a low speed and a high load. The electric motor 3 is electrically driven to supercharge the compressed air from the compressor 22 to the engine 1. Note that a frequency signal corresponding to the back electromotive force of the stator is input from the rotating electric machine 3 to the controller 4, and the rotation speed of the turbocharger 2 can be detected based on this signal.

The power converter 61 includes an AC / DC converter having an inverter and a converter. The AC converter 61 receives an AC output of the rotating electric machine 3 during a power generation operation and converts the AC output into DC power for charging the battery 6 or rotates the power of the battery 6. When supplied to the electric machine 3, the DC power is converted into predetermined AC power by a signal from the controller 4.

The controller 4 is composed of a microcomputer and includes a central controller for performing arithmetic processing, various memories for storing arithmetic processing procedures and control procedures, input / output circuits, and the like. A line is connected, and a command line to the power converter 61 is connected to the output circuit. When signals from the depression amount sensor 51, the boost pressure sensor 13, and the like are input, the power converter 61
And a command signal is issued to the valve actuator 16 to supply electric power to the rotary electric machine 3 and to perform switching control of the switching valve 15.

Next, the operation of the present embodiment thus configured will be described.

When the driver depresses the accelerator pedal 5 when the vehicle starts, a signal from the depression amount sensor 51 is transmitted to the controller 4.
Is input to

Here, when the controller 4 determines that the flying boost-up is to be performed based on the signal from the depression amount sensor 51, the controller 4 instructs the power converter 61 to convert the power from the battery 6 into predetermined AC power and supply it to the rotating electric machine. At the same time, a command is issued to the valve actuator 16 to operate the switching valve 15 to instruct the exhaust gas from the engine 1 to pass through the exhaust bypass pipe 14.

For this reason, the rotating electric machine 3 which is electrically operated by the electric power from the battery 6 drives the compressor 22 at high speed to pump the intake air to the engine 1 before the rotation speed increases, thereby increasing the boost pressure, and increasing the engine torque at the time of starting. On the other hand, on the turbine 21 side, even if the exhaust gas energy from the engine 1 is released to the outside air by the exhaust bypass pipe 14 and the rotation speed of the turbine 21 is increased by the electric drive of the rotary electric machine 3, The increase in the engine exhaust pressure is suppressed.

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

(Effects of the Invention) According to the present invention, an exhaust bypass pipe that directly guides exhaust gas to the outside air is provided in the middle of an exhaust pipe connecting an engine and a turbocharger, and a switching valve is disposed in the branched portion. The exhaust gas is guided to the outside air when the engine's flying boost is increased, so even if the rotation speed of the turbine is increased by the electric drive of the rotating electric machine, the increase in the exhaust pressure of the engine is suppressed, and the fuel efficiency of the engine deteriorates and the engine stalls. Is obtained.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG.
The figure is a curve diagram showing the related characteristics between the pressure ratio and the corrected flow rate in the turbine. 1 ... Engine 2 ... Turbocharger 3 ... Rotating electric machine 4 ... Controller 5 ... Accelerator pedal 11
... exhaust pipe, 14 ... exhaust bypass pipe, 15 ... switching valve, 51 ... stepping amount sensor.

Claims (1)

(57) [Claims] 1. A control device for a turbocharger with a rotating electric machine for electrically driving a rotating electric machine disposed on a turbocharger and increasing a supercharged pressure before the vehicle starts, detecting means for detecting depression of an accelerator pedal, An exhaust bypass pipe that directly discharges exhaust gas from the engine to the outside air, a switching unit that switches between the exhaust bypass pipe and an exhaust flow path to a turbocharger, and an electric motor that drives the rotating electric machine. Control means for controlling the switching means so that exhaust gas flows through the exhaust bypass pipe in response to a signal.