JPH0968052A - Vibration suppresser of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress engine vibration after ignition off effectively by providing an electric motor connected to the output shaft of an internal combustion engine and making this motor actuate for a specific period of time after ignition off so as to apply a reverse torque to its output shaft. SOLUTION: A motor/generator M/G2 is connected to the output shaft of an engine 1 and a transmission 3 is connected to its output shaft. And an inverter is actuated to form a rotary magnetic field on the basis of an instruction from an engine computer 4 in a control circuit 5 including the inverter so as to make the M/G2 function as a motor or generator. Also, in the case of ignition off, the power supply of the control circuit 5 is maintained in its ON state for a specific period of time or unit engine number of revolution drops below the specific revolution so as to make the M/G2 function as a motor. Thereby, the engine rotation is stopped quickly by applying a torque whose direction is reverse to that of the output torque of the engine to the output shaft of the engine.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibration suppressing device for an internal combustion engine, and more particularly to a device for preventing vibration generated when the engine is stopped by turning off the ignition.

[0002]

2. Description of the Related Art Even if the engine is stopped by turning off the ignition, the output shaft continues to rotate for a while, so that vibration occurs. This vibration is particularly noticeable in a diesel engine and is uncomfortable, but since it is a phenomenon after the ignition is turned off, no particular active measures have been taken so far.

On the other hand, as disclosed in Japanese Patent Laid-Open No. 6-247186, for example, a technique has been proposed in which an induction machine is connected to an engine output shaft to function as a motor or a generator to reduce torque fluctuations and uneven rotation speed of the engine. However, when the ignition is turned off, the control of the induction machine also stops,
This technique has not been used to prevent vibrations after the ignition is turned off.

[0004]

As described above, conventionally, no measures have been taken to positively remove the vibration after the ignition is turned off, and the uncomfortable vibration must be tolerated.

The present invention has been made in view of the above problems of the prior art, and an object thereof is to skillfully utilize an induction machine connected to an engine output shaft to suppress vibration of the engine after the ignition is turned off. It is in.

[0006]

In order to achieve the above object, a first aspect of the invention is to operate an electric motor connected to an output shaft of an internal combustion engine and to operate the electric motor for a predetermined time after ignition is turned off to output the electric power. And a control means for applying a reverse torque to the shaft.

In order to achieve the above object, a second aspect of the present invention operates an electric motor connected to an output shaft of an internal combustion engine, and operates the electric motor until the engine speed after ignition is off becomes a predetermined speed or less. Thus, the control means for applying a reverse torque to the output shaft is provided, and thus, even if the ignition is turned off, the power supply of the control means of the electric motor is not immediately turned off, and a predetermined time or a predetermined rotation is performed. By operating the electric motor while keeping the power source of the control means turned on until the number becomes equal to or less than a certain number, it is possible to quickly stop the rotation of the engine by the torque generated by the electric motor and suppress the vibration.

[0008]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of this embodiment. The induction machine 2 is connected to the output shaft of the engine E / G1, and the transmission T / M3 is further connected to transmit the driving force to the drive wheels. Since the induction machine functions as a motor and a generator, the induction machine will be referred to as a motor / generator M / G. The state of the engine E / G1 is monitored by the engine computer 4, and intake air temperature, engine speed, engine output value, etc. are input to the engine computer (engine ECU) 4.
Further, a vehicle speed and an accelerator pedal opening signal are also input to the engine computer 4 to determine the running state of the vehicle. Further, a signal from the ignition switch 8 is also input to the engine computer 4 and it is determined whether or not the ignition is turned off. Further, the control circuit 5 is configured to include an inverter, and operates the inverter based on a command from the engine computer 4 to form a rotating magnetic field, and M /
Make G2 function as a motor or a generator.
Specifically, when the engine is started or accelerated, the M / G 2 functions as a motor based on the accelerator operation amount (accelerator opening) signal from the engine computer 4, and also functions as a generator during braking to regenerate electric power to the battery 6. Supply and accumulate. The electric energy stored in the battery 6 supplies electric power for M / G2 and DC-D.
It is also used to power auxiliary equipment such as air conditioners via a C converter. A capacitor may be used instead of the battery 6.

The characteristic feature of this embodiment is that even when the engine computer 4 detects that the ignition is off, the operation of the control circuit 5 is not immediately stopped but a predetermined time or a predetermined engine speed. Until the number becomes less than or equal to the number, do not turn off the power of the control circuit 5,
The point is that the M / G 2 functions as a motor. Specifically, when the conventional engine computer 4 (or the system computer that controls the entire system) detects the ignition off, it outputs a power off signal to the control circuit 5 to stop the operation of the control circuit 5. In the form, the engine computer 4 does not instruct the control circuit 5 to stop the operation even when the ignition off signal is detected, and outputs only the ignition off signal. Then, the power-off signal is output and the power is turned off only when a predetermined time elapses (for example, 0.5 seconds) or the monitored engine rotation speed becomes a predetermined value (for example, 50 rpm) or less. After the ignition is turned off, until the power-off signal is input, the control circuit 5 is M
The inverter is controlled so that / G2 functions as a motor, and torque opposite to the output torque of the engine is applied to the engine output shaft. As a result, the rotation of the engine can be quickly stopped and the uncomfortable vibration after the ignition is turned off can be suppressed.

FIG. 2 shows a detailed flowchart of the vibration suppressing process of this embodiment. First, the engine computer 4 (or the main computer of the system)
It is determined whether the ignition is turned off (S10).
1). If the ignition is turned off, M / G2
The vibration suppression control is started (S102). That is, first, it is determined whether or not the fuel injection is stopped by the ignition off (S103), and if the fuel injection is stopped and the stop flag is on (S104), then the engine speed NE is below a predetermined value. It is determined whether or not there is, that is, whether or not NE is larger than 50 rpm (S10).
5). When the engine speed is 50 rpm or more, vibration occurs, so the control circuit 5 causes the M / G2 to function as a motor and applies the maximum torque Tmax at the time of output. The torque application direction is opposite to the rotation direction of the output shaft (S107). When such a large torque in the opposite direction is applied to the output shaft, the rotation speed of the rotation shaft is rapidly reduced to 50 rpm or less in a short time. Rotation speed is 50
If the torque in the opposite direction is applied even if the speed becomes lower than rpm, the engine may rotate in reverse due to this torque. Therefore, if the speed becomes lower than 50 rpm, the torque application is stopped and the power supply of the control circuit 5 is turned off. To end the operation (S1
06).

In this process, the application / stop of the torque is controlled by the engine speed, but it is judged in the process of S105 whether or not a predetermined time has elapsed, and the maximum torque is reversed in the reverse direction until the predetermined time elapses. It may be applied to.

[0013]

As described above, according to the present invention,
Unpleasant vibration after the ignition is turned off can be suppressed.

[Brief description of drawings]

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

FIG. 2 is a processing flowchart of an embodiment of the present invention.

[Explanation of symbols]

1 engine E / G, 2 induction machine M / G, 3 transmission T / M, 4 engine computer, 5 control circuit, 6 battery, 7 auxiliary machines, 8 ignition switch (IGSW).

Claims (2)

[Claims] 1. An electric motor connected to an output shaft of an internal combustion engine, and a control means for operating the electric motor for a predetermined time after the ignition is turned off to apply a reverse torque to the output shaft. A vibration suppressing device for an internal combustion engine. 2. An electric motor connected to an output shaft of an internal combustion engine, and a control for operating the electric motor to apply a reverse torque to the output shaft until the engine speed after ignition-off falls below a predetermined speed. A vibration suppressing device for an internal combustion engine, comprising: