JPS59158330A - Device for smoothing engine torque - Google Patents

Abstract

PURPOSE:To improve an effect of smoothing torque and responsive property by connecting a motor generator to a crankshaft of an engine, connecting a capacitor in parallel to an armature of said generator and providing a field current controlling circuit for increasing and decreasing the field current. CONSTITUTION:A motor generator 2 is connected directly to a crankshaft 1a of an engine 1. A coil of an armature 2a is connected to a capacitor 4 through a commutator 2b and a brush 2c. A field current controlling circuit 5 increases the field current of the motor generator 2 when the rotational speed of the engine is low, and decrease the field current when same is high. Thus, an effect of smoothing the engine torque is improved and vibration is reduced to improve a responsive property to acceleration and deceleration.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for smoothing torque fluctuations in, for example, a single cylinder or 2 to 3 cylinder internal combustion engine.

Conventional torque smoothing devices of this type include, for example, those in which a large flywheel is attached to the rear end of the crankshaft of an internal combustion engine (hereinafter referred to as the "engine"), and those described in "Machine Research," Vol. 25, No. 1. As described on page 116 of No. (1973), there are those using a no<ranthwaite.

However, such conventional torque smoothing devices use the moment of inertia of the flywheel or balance weight to smooth the torque using the stored energy), so the smoothing effect cannot be greatly improved. In order to do this, the moment of inertia must be increased, which causes problems such as an increase in the weight of the device and a worsening of responsiveness to acceleration and deceleration of the engine.

Note that although balance weights are highly effective in reducing vibrations, they are no more effective than flywheels in absorbing I-lux fluctuations).

This invention was made by focusing on these conventional problems, and uses an so-called active flywheel that absorbs and releases energy using electromagnetic force. An object of the present invention is to provide a torque smoothing device for an internal combustion engine that eliminates the problem.

Therefore, in the engine torque smoothing device according to the present invention, a motor generator that operates as an electric motor and a generator is connected to the engine crankshaft, and a capacitor is connected in parallel to the armature of the motor generator, and the rotational speed of the engine is increased. Accordingly, a field current control circuit is provided to reduce the field current of the motor generator.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a schematic diagram showing an embodiment of the present invention.

In this embodiment, a motor generator 2 that can operate as an electric motor and a generator is directly connected to a crankshaft 1a of an engine 1 at a position where a flywheel would normally be attached.

That is, the crankshaft 1a of the engine 1 and the output shaft 3 of the motor generator 2 rotate together. A coil of an armature 2a of this motor generator 2 is connected to a capacitor 4 via a commutator 2b and a brush 2c.

On the other hand, the field coil 2d is connected to the field current control circuit 5. The field current control circuit 5 receives a crank angle signal from a crank angle sensor 6 that detects the rotation angle of the crankshaft 1a.

For example, as shown in FIG. 2, the field current control circuit 5 includes a rotation speed calculation circuit 512, a division circuit 52, and a power transistor 56. Note that 7 is a diode connected in parallel to the field coil 2d of the motor generator 2, and 8 is a battery as a power source.

Next, the operation of this embodiment will be explained.

In FIG. 2, the crank angle signal CA is input, for example, as a pulse signal every 1° of crank angle.

The rotation speed calculation circuit 51 calculates the engine rotation speed N, and the division circuit 52 drives the power transistor 53 with an output that is inversely proportional to the square of the rotation speed N.

Therefore, the current If flowing through the field coil 2d of the motor generator 2 is inversely proportional to the square of the number of rotations N, and the field strength φ is I fOC1/N2.

The armature electromotive force Ec is Ec = KφN, (K: constant) Therefore, Ec = 1. /N.

By charging and discharging capacitor 4, the armature voltage is smoothed and plays the role of a flywheel, but the smoothing ability is Ec
It is proportional to the square of

For example, when an iron flywheel with a diameter of 40 cm and a thickness of 3 cm (mometer of inertia, / 0.06 kgm52) rotates at 60 rpm, the capacitor that corresponds to the inertial energy has an Ec of 50 V and 0. ], F, but when the engine speed increases to 1200rpm, Ec is controlled to 25V and the inertial energy is 600rpm.
It is 1/4 of the time at pm.

Therefore, the higher the rotational speed of the engine, the smaller the inertial energy becomes, and the responsiveness during acceleration and deceleration is improved.

In addition, 0. IF level capacitors are electrolytic capacitors,
This can be easily achieved using electric double layer capacitors, etc., and compared to conventional flywheels, it is possible to significantly increase inertial energy with a slight increase in weight. In addition, the charging and discharging efficiency is higher than that of batteries, close to 100%.

Further, here, an example has been described in which the inertia energy is controlled to be inversely proportional to the square of the engine speed N, but the characteristics can be arbitrarily set by changing the calculation method of the control circuit.

As explained above, according to the present invention, a motor generator is connected to the engine crankshaft, a capacitor is connected in parallel to the armature of the motor generator, and the field current is decreased as the engine rotation speed increases. With this configuration, the following effects can be obtained.

■ Great engine torque smoothing effect, reducing vibration.

■ At high engine speeds, the torque smoothing effect is reduced, so responsiveness to acceleration and deceleration does not deteriorate.

[Brief explanation of drawings]

FIG. 1 is a schematic block diagram showing an embodiment of the present invention, and FIG. 2 is a circuit diagram showing the same circuit structure. 1... Engine 2 Motor generator 2a...
・Armature 2b... Commutator 2c... Brush
2d...Field coil 4...Capacitor 5
...Field current control circuit 6...Crank angle sensor Fig. 1

Claims (1)

[Claims] 1 An electric motor connected to the crankshaft of the engine and a motor generator capable of operating as a generator, a capacitor connected in parallel to the armature of this motor generator, and a field current of the motor generator when the rotational speed of the engine is low. 1. An engine torque smoothing device comprising a field current control circuit that increases the field current and decreases the field current when the engine rotational speed is high.