JPH08196006A - Retarder - Google Patents

Abstract

PURPOSE: To reduce the energy loss due to the self-discharge of a capacitor for supplying power to a motor generator(M/G) in a retarder in which the motor generator(M/G) is connected to an engine output shaft. CONSTITUTION: A motor generator(M/G) 2 such as an induction motor is coupled to the output shaft of an engine 1, a power capacitor 4 of a high voltage (200V or more) of a power source is electrically connected through an inverter 3 to the M/G 2, and the inverter 3 is controlled by an electronic control unit ECU 7. An auxiliary unit battery 6 and the capacitor 4 are connected by a bidirectional DC-DC converter 5 to supply power from the capacitor 4 to the battery 6 or vice versa. When the engine stops, electric energy from the capacitor 4 is transferred to the battery 6 to reduce the loss of the energy.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a retarder device, and more particularly to a self-discharge countermeasure for a capacitor that drives a motor / generator.

[0002]

2. Description of the Related Art Conventionally, for example, Japanese Unexamined Patent Publication No. 4-20790.
No. 0, etc., a motor / generator (hereinafter referred to as M / G) connected in series between an engine crankshaft and a transmission, and electrically connected to the stator side of this M / G via an inverter. When the engine is braked, the M / G functions as a generator to perform regenerative braking to convert mechanical energy into electric energy to charge the capacitor. On the other hand, when the engine is started and accelerated, the capacitor is charged with electricity. Energy is used M
/ G has been developed as a motor to provide a starter and acceleration assist to improve fuel efficiency.

The M / G of such a retarder device needs to generate a high torque in order to directly rotate the engine crankshaft at the time of starting the engine and accelerating the engine. Therefore, the voltage of the capacitor is correspondingly high voltage (200V). that's all)
What is used.

[0004]

However, if the vehicle is left for a long time after the end of traveling, the electric energy accumulated by the self-discharge of the capacitor is reduced, and the voltage between terminals is significantly reduced. Therefore, there is a problem that the engine start after leaving it for a long time and the torque assist at the time of accelerating the vehicle become impossible, and the intended purpose of improving fuel efficiency cannot be achieved.

The present invention has been made in view of the above problems of the prior art. An object of the present invention is to prevent the electric energy of the capacitor from decreasing and improve the fuel consumption even if it is left for a long time after the period is stopped. It is to provide a retarder device that can perform.

[0006]

In order to achieve the above object, a retarder device according to claim 1 is connected to an M / G connected to a mechanical drive system and to the M / G via an inverter. In a retarder device including a capacitor, a bidirectional DC-DC converter connected between the capacitor and a battery for supplying auxiliary power, and when the engine is stopped, the power held in the capacitor is supplied to the battery, And a control means for controlling the operation of the DC-DC converter so as to supply the electric power held in the battery to the capacitor at the time of starting.

Further, in order to achieve the above object, the retarder device according to a second aspect is the retarder device according to the first aspect, further comprising a monitoring means for monitoring a charge amount of the capacitor, and the control means. After supplying power from the capacitor to the battery, when the charge amount of the capacitor becomes equal to or less than a first predetermined amount, power is supplied from the battery to the capacitor and the charge amount of the capacitor is set to a second value. It is characterized in that the operation of the DC-DC converter is controlled so as to maintain a fixed amount or more.

[0008]

In the retarder device according to the first aspect of the present invention, the electric energy stored in the capacitor when the engine is stopped is converted into the bidirectional DC-
The DC converter transfers to the auxiliary battery to prevent energy loss due to self-discharge of the capacitor. The electric energy transferred to the auxiliary battery is transferred again to the capacitor when the engine is started and supplied to the M / G.

In the retarder device according to the second aspect of the invention, when the electric energy stored in the capacitor is transferred to the auxiliary battery, the charge amount of the capacitor is maintained at a certain constant value. As a result, it is possible to reduce the amount of electrical energy to be transferred from the auxiliary battery to the capacitor at the time of engine start, while suppressing the loss of electrical energy due to self-discharge of the capacitor, and to reduce the capacity of the relatively expensive DC-DC converter. .

[0010]

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

First Embodiment FIG. 1 is a block diagram showing the configuration of this embodiment. An M / G 2 such as an induction motor is coupled to the output shaft of the engine 1 and further connected to the transmission T / M. A high-voltage (200 V or more) power capacitor 4 as a power source is electrically connected to the M / G 2 via an inverter 3, and the operation of the inverter 3 is controlled by an electronic control unit ECU 7. That is, the ECU 7
When starting or accelerating the engine, switching of the inverter 2 is controlled so that the M / G2 functions as a motor to supply electric power from the capacitor 4 to the M / G2, and when the engine is braked, the M / G2 functions as a generator. The switching is controlled to charge the capacitor 4.

In addition, an auxiliary battery (12V or 24V) such as a lead storage battery for electric components such as headlights is installed in a vehicle.
V) 6 is mounted, and the auxiliary battery 6 and the capacitor 4 are connected by a bidirectional DC-DC converter 5, and the capacitor 4 to the auxiliary battery 6 or the auxiliary battery 6 to the capacitor 4 are mutually connected. It is configured to be able to supply power to. The operation of the bidirectional DC-DC converter 5 is controlled by the ECU 7,
Determines the power transfer based on the lock / unlock signal of the ignition IG and the detection signal from the voltage sensor 8 which detects the voltage between the terminals of the capacitor. Therefore, in this embodiment, the ECU 7 constitutes the control means, and the voltage sensor 8
Constitutes the monitoring means.

The configuration of the present embodiment is as described above, and when the vehicle is decelerated, the ECU 7 causes the M / G 2 to function as a generator to store mechanical energy as electric energy in the capacitor 4 as described above, and at the next engine start. In preparation for power supply to M / G2 during acceleration, when the engine is stopped for a long period of time, electric energy is lost due to self-discharge of the capacitor 4, and the voltage between terminals is the voltage required to rotate the clan shaft. In addition to the following, torque assist cannot be performed even during acceleration.

Therefore, in the present embodiment, the electric energy stored in the capacitor 4 is transferred to the auxiliary battery 6 having a relatively small amount of self-discharge to reduce the loss of the electric energy, and when the engine is started, the transferred electric energy is transferred. Is again transferred from the auxiliary battery 6 to the capacitor 4 to supply power to the M / G 2.

FIG. 2 shows an operation flowchart of this embodiment. First, the ECU 7 determines whether the IG key is locked (engine stopped) or unlocked (engine started).
(S101). When the IG key is in the locked state, it is then determined whether the inter-terminal voltage V of the capacitor 4 detected by the voltage sensor 8 is larger than the predetermined value V1 (S102). If the voltage V between the terminals is larger than the predetermined value V1, the loss of electric energy due to self-discharge is large, and therefore the ECU 7 operates the DC-DC converter 5
Is stepped down to transfer the electric power of the capacitor 4 to the battery 6 (S103). When the inter-terminal voltage V becomes V1 or less, the loss of the electric energy of the capacitor 4 is almost eliminated, so that the step-down operation of the DC-DC converter 5 is stopped.

On the other hand, when the IG key is in the unlocked state, it is next determined whether the inter-terminal voltage V is larger than a predetermined value V2 (S104). This predetermined value V2 is a voltage sufficient for the capacitor 4 to drive the engine crankshaft. When the inter-terminal voltage V2 is equal to or lower than the predetermined value V2, the ECU 7 boosts the DC-DC converter 5 to transfer the electric energy transferred to the auxiliary battery 6 to the capacitor 4 again (S105). When the inter-terminal voltage V reaches the predetermined value V2, the step-up operation of the DC-DC converter 5 is stopped.

FIG. 3 shows the above-mentioned processing in terms of time and capacitor voltage. The broken line indicated by A in the figure shows the capacitor 4 after the IG lock is turned on (the engine is stopped).
The change in the terminal voltage of the related art that does not transfer the electric energy is as follows. The solid line indicated by B in the figure is the change in the terminal voltage of the present embodiment. After the IG lock is turned on, the electric energy is transferred to the auxiliary battery 6 side and the voltage between terminals is set to V1.
It can be seen that the energy loss thereafter is small.

As described above, in this embodiment, when the engine is stopped, the electric energy of the capacitor 4 is transferred to the auxiliary battery 6 which causes less self-discharge, and when the engine is started, the electric energy is returned to the capacitor again. The internal energy loss can be suppressed, the M / G can normally function as a motor at the time of engine start and acceleration, and fuel consumption can be improved.

In this embodiment, the high-voltage winding and the low-voltage winding are provided on the stator side of the M / G 2, the capacitor 4 is connected to the high-voltage winding side, and the low-voltage winding side is connected via the second inverter. When the retarder device having the double winding structure for connecting the auxiliary battery 6 is used, the inverter 3, the second inverter, and the double winding can function as a bidirectional DC-DC converter. New DC-D
It is not necessary to provide the C converter 5.

Second Embodiment FIG. 4 shows a processing flowchart after the engine is stopped in this embodiment. The configuration of this embodiment is similar to that of the first embodiment.

In this embodiment, when the IG lock is ON, after counting a predetermined time with a timer (S201),
It is determined whether the voltage V between the capacitor terminals is larger than a predetermined value V1 '(S202). This predetermined value V1 'is the minimum voltage between terminals (V2>V1') at which the capacitor 4 can drive the engine crankshaft. When the terminal voltage V is larger than a predetermined value, the ECU 7 is operated as in the first embodiment.
Causes the DC-DC converter 5 to step down to transfer the electric power of the capacitor 4 to the battery 6 (S203). Then, when the inter-terminal voltage V becomes equal to or lower than the predetermined value, it is next determined whether or not the capacitor voltage V reaches the predetermined value V2 '(S204). This predetermined value V2 'is the predetermined value V1
It is a value slightly smaller than ´. When the terminal voltage V drops to a predetermined value V2 ', the ECU 7 boosts the DC-DC converter 5 to transfer the electric energy of the auxiliary battery 6 to the capacitor 4, and the terminal voltage V to the predetermined value V2.
It is maintained at 1 '(S205). FIG. 5 shows the above-mentioned processing as a relationship between time and terminal voltage. The terminal voltage V is maintained between V1 'and V2'.

As described above, in this embodiment, the voltage across the terminals of the capacitor 4 is maintained in the vicinity of V1 'even during the engine stop period (also in this case, the electric energy is transferred to the auxiliary battery 6 when the engine is stopped). Therefore, the energy loss due to self-discharge is less than that in the prior art). Therefore, less electric energy needs to be transferred from the auxiliary battery 6 to the capacitor 4 at the time of engine start, and DC-DC compared to the first embodiment.
The capacity of the converter 5 can be set small.

[0023]

As described above, according to the retarder device of the first or second aspect, it is possible to prevent the electric energy of the capacitor from being lost due to self-discharge during the engine stop period, and at the time of engine start and This electric energy can be supplied to the M / G during acceleration to improve the fuel efficiency of the engine.

[Brief description of drawings]

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

FIG. 2 is a processing flowchart of the embodiment.

FIG. 3 is a graph showing a change with time of a voltage across a capacitor terminal of the embodiment.

FIG. 4 is a processing flowchart of a second embodiment of the present invention.

FIG. 5 is a graph showing a change with time of a voltage between capacitor terminals of the embodiment.

[Explanation of symbols]

1 engine, 2 motor / generator M / G, 3
Inverter, 4 capacitors, 5 DC-DC converter, 6 auxiliary battery, 7 ECU.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical indication H02P 15/00 H

Claims (2)

[Claims] 1. A retarder device comprising: a motor / generator connected to a mechanical drive system; and a capacitor connected to the motor / generator via an inverter, wherein a capacitor is connected between the capacitor and a battery for supplying auxiliary power. A bidirectional DC-DC converter connected to the DC-DC converter to supply the electric power held in the capacitor to the battery when the engine is stopped and to supply the electric power held in the battery to the capacitor when the engine is started. A retarder device comprising: a control unit that controls the operation of the DC converter. 2. The retarder device according to claim 1, wherein
Furthermore, the DC-DC converter includes a monitoring unit that monitors a charge amount of the capacitor, and the control unit holds the charge amount of the capacitor near a predetermined amount after supplying power from the capacitor to the battery. Retarder device characterized by controlling the operation of.