JP3094859B2 - Vibration suppression device for internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for suppressing vibration of an internal combustion engine, and more particularly to a device for preventing vibration generated when an engine is stopped by turning off an 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 diesel engines and unpleasant, but since it is a phenomenon after the ignition has been turned off, no aggressive measures have been taken so far.

On the other hand, as disclosed in Japanese Patent Application Laid-Open No. Hei 6-247186, a technique has been proposed in which an induction machine is connected to an engine output shaft so as 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 vibration after ignition is turned off.

[0004]

As described above, in the prior art, no measures have been taken to actively remove the vibration after the ignition has been turned off, and unpleasant vibration must be tolerated.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and has as its object to suppress engine vibration after ignition is turned off by skillfully utilizing an induction machine connected to an engine output shaft. It is in.

[0006]

In order to achieve the above object, the present invention provides an electric motor connected to an output shaft of an internal combustion engine, and a method of operating the electric motor after ignition is turned off so as to reverse a torque to the output shaft. And a control means for stopping the torque application when the output shaft reaches a predetermined engine speed at which the output shaft starts reverse rotation by the reverse torque.

[0007]

[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. An induction machine 2 is connected to an output shaft of the engine E / G1, and a transmission T / M3 is further connected to transmit driving force to driving 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 the intake air temperature, engine speed, engine output value, and the like 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 to determine whether or not the ignition has been turned off. The control circuit 5 includes an inverter, and operates the inverter based on a command from the engine computer 4 to form a rotating magnetic field.
G2 functions as a motor or a generator.
Specifically, at the time of engine start or acceleration, the M / G 2 functions as a motor based on an accelerator operation amount (accelerator opening) signal from the engine computer 4, and at the time of braking, the M / G 2 functions as a generator to supply regenerative power to the battery 6. Supply and accumulate. The electric energy stored in the battery 6 supplies power for the M / G2 and DC-D
It is also used to power auxiliary equipment such as air conditioners via a C converter. Further, a capacitor can be used instead of the battery 6.

A characteristic of the present embodiment is that, even when the engine computer 4 detects that the ignition has been turned off, the operation of the control circuit 5 is not stopped immediately, but is performed for a predetermined time or at a predetermined engine speed. The power of the control circuit 5 is not turned off until
The point is that the M / G2 functions as a motor. Specifically, when the conventional engine computer 4 (or the system computer controlling 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 embodiment, even when the engine computer 4 detects the ignition off signal, it does not instruct the control circuit 5 to stop the operation, and outputs only the ignition off signal. Then, a power-off signal is output and the power is turned off only when a predetermined time elapses (for example, 0.5 seconds) or when the monitored engine speed becomes a predetermined value (for example, 50 rpm) or less. From the time the ignition is turned off until the power-off signal is input, the control circuit 5
The inverter is controlled so that / G2 functions as a motor, and a 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 stopped immediately, and unpleasant vibration after the ignition is turned off can be suppressed.

FIG. 2 shows a detailed flowchart of the vibration suppression processing of the present embodiment. First, the engine computer 4 (or the main computer of the system)
Is determined whether the ignition has been turned off (S10).
1). When the ignition is turned off, M / G2
Starts vibration suppression control (S102). That is, first, it is determined whether or not the fuel injection has been stopped by the ignition off (S103). If the fuel injection has been stopped and the stop flag is on (S104), then if the engine speed NE is equal to or less than the predetermined value, It is determined whether or not there is, that is, whether or not NE is greater than 50 rpm (S10).
5). When the engine speed is 50 rpm or more, vibration occurs. Therefore, 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 reverse torque is applied to the output shaft, the rotation speed of the rotation shaft rapidly decreases, and becomes 50 rpm or less in a short time. 50 rpm
If the reverse torque is applied even when the rotation speed is less than rpm, the engine may rotate in the reverse direction due to this torque. Therefore, when the rotation speed becomes lower than 50 rpm, the application of the torque 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. In the process of S105, it is determined whether or not a predetermined time has elapsed, and the maximum torque is reversed until the predetermined time has elapsed. May be applied.

[0013]

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

[Brief description of the drawings]

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

FIG. 2 is a processing flowchart according to the 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 equipment, 8 ignition switch (IGSW).

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) F02B 77/00 B60K 6/02 B60L 11/00-11/14 F02B 61/00 F02D 29/00-29 / 06 F02N 11/04

Claims (1)

(57) [Claims] A motor connected to an output shaft of an internal combustion engine, the motor being operated after ignition is turned off to apply a reverse torque to the output shaft, and the output shaft being reversely driven by the reverse torque. Control means for stopping the application of the torque when a predetermined engine speed at which rotation is started is reached, and a vibration suppression device for an internal combustion engine.