JPH07115707A - Generation controller of hybrid electric vehicle - Google Patents

Abstract

PURPOSE:To suppress the change of torque in normal and reverse rotating directions of a crunk chaft without charging and discharging of a battery by adjusting a field current of a generator as a load of an engine to control rolling vibration of the engine. CONSTITUTION:An average amount of power generation of a generator 26, an average number of rotations of an engine 22 and a crunk angle CA detected by a crunk angle sensor 40 are inputted to ECU 30. When a torque of the engine 22 changes, this change is detected as changes of average amount of power generation and average number of rotations and ECU 30 judges how to control a field current If with reference to a map. This map is provided with determined control contents of a field current If depending on an output torque and crunk angle CA of the engine 22. Therefore, the number of rotations of the engine 22 fluctuates depending on fluctuation in torque thereof. As a result, a moment of a balancer works in the direction to control change of combined torque to suppress vibration by rolling of the engine 22.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power generation control device for controlling a generator mounted on a hybrid electric vehicle.

[0002]

2. Description of the Related Art An electric vehicle is a vehicle driven by a motor and has a battery as a power source. For example, when an AC motor is used as the motor, the discharge power of a vehicle-mounted battery is converted into AC power by an inverter, and the AC power is supplied to the motor to drive the vehicle.

A hybrid electric vehicle in which an engine-driven generator is further mounted as a drive power source for a motor is also known. In this type of vehicle, a generator is driven by the output of the engine, and the generated power of the generator drives a motor and charges a battery. An engine composed of these engine and generator is called an engine-driven generator.

In this type of electric vehicle, it is necessary to suppress the rolling fluctuation of the engine. That is, when the engine is operated, torque fluctuations occur corresponding to the combustion cycle, and the torque fluctuations cause vibrations in the engine rotation direction, that is, rolling vibrations. If this rolling vibration is large, it is uncomfortable for the vehicle operator. In particular, when the engine is rotating at a low speed, there is a problem because the exciting force due to the combustion pressure is larger than the exciting force due to the piston. In addition, such a problem becomes remarkable when the load on the engine is large, such as when the air conditioner is operated.

As means for suppressing the rolling fluctuation,
For example, as disclosed in Japanese Patent Publication No. 63-45498, there is a method of applying a current to a feed coil of an alternator attached to an engine to generate a reverse torque on a crankshaft. That is, when the torque increases in the normal rotation direction of the crankshaft of the engine, the reverse torque generated by the alternator suppresses the fluctuation of the rotation torque.

Further, in Japanese Patent Application Laid-Open No. 61-155635, a flywheel connected to a crankshaft of an engine is provided with a power generation function and a motor function, and torque control in both forward and reverse directions of the crankshaft is provided by controlling the flywheel. A method of suppressing is disclosed. In other words, when the torque increases in the normal rotation direction of the crankshaft, the flywheel functions as a generator to generate reverse torque to cancel the torque in the normal rotation direction of the crankshaft and, conversely, in the reverse rotation direction of the crankshaft. When the torque increases, the flywheel functions as a motor, and the generated positive torque cancels the torque in the reverse rotation direction of the crankshaft.

[0007]

However, all of these methods have problems.

First, in the method disclosed in Japanese Examined Patent Publication No. 63-45498, only the torque fluctuation is suppressed by the reverse torque generated by the alternator, so that the torque that can be canceled out is in the positive rotation direction of the crankshaft. Only the torque is used, and the torque in the reverse rotation direction cannot be canceled. Further, since the torque generated by the engine acts in the direction of canceling it, the fuel efficiency is deteriorated.

Such a problem is caused by the problem of JP-A-61-155.
The method disclosed in Japanese Patent No. 635 does not occur. However, the method disclosed in this publication has a problem of poor power efficiency. That is, when the flywheel functions as a generator, the electric power obtained by the flywheel is charged in the on-vehicle battery, and conversely, when the flywheel functions as a motor, the electric power for driving the flywheel is reduced. It is supplied from the battery. Therefore, when the flywheel functions as a generator or a motor, electric power is exchanged with the battery. This leads to extra power consumption, since the charge / discharge efficiency of the battery is generally not 100%. In an electric vehicle, in particular, when the method described in the above-mentioned publication is carried out, the permissible distance per charge of the battery depends on how the power of the battery is consumed. The mileage becomes shorter.

The present invention has been made to solve the above problems, and it is an object of the present invention to suppress torque fluctuations in both forward and reverse rotation directions of a crankshaft without charging and discharging the battery. To aim.

[0011]

In order to achieve such an object, a power generation control device for a hybrid electric vehicle according to the present invention has a tendency to increase as the engine speed increases and to suppress engine rolling. Means for generating a moment, means for detecting the output torque of the engine,
Means for decreasing the field current of the generator when the detected output torque is higher than the average value, and increasing it when the output torque is decreasing, and the field of the generator that is the load of the engine. The rolling vibration of the engine is suppressed by adjusting the magnetic current.

[0012]

In the present invention, the output torque of the engine is detected. When the detected output torque is higher than the average value, the field current of the generator is reduced, and as a result, the engine speed is increased. When the engine speed increases, the moment in the direction of suppressing the rolling of the engine increases accordingly, and the fluctuation of the output torque that appears as an increase with respect to the average value is suppressed. On the contrary, when the detected output torque is smaller than the average value, the field current of the generator is increased, and as a result, the engine speed is reduced. Then, the moment in the direction of suppressing the rolling of the engine becomes small, and as a result, the fluctuation of the output torque that appears as a decrease from the average value is suppressed. Therefore, according to the present invention, even if the output torque of the engine fluctuates in the increasing direction or in the decreasing direction with respect to the average value, it becomes possible to suppress the output torque fluctuation, and At that time, since the on-vehicle battery is not charged or discharged, the power efficiency is improved.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows the configuration of a series hybrid electric vehicle according to an embodiment of the present invention.

The vehicle shown in this figure uses a three-phase AC motor 10 as a drive source. The output of the motor 10 is connected to the drive wheels 14 via the transmission (TM) 12 and the like, so that when the motor 10 is rotationally driven, the vehicle runs.

A battery 1 is used as a power source for driving the motor 10.
6 and an engine-driven generator 18 are mounted. First, the battery 16 is configured as a chargeable / dischargeable battery such as a lead battery, and its terminal is connected to the input side of the inverter 20. The engine-driven generator 18 includes an engine 22 with an offset balancer, a speed increaser 24, and a generator 2.
6, and the power generation output of the generator 26 is also connected to the input side of the inverter 20 via the rectifier 28.

Therefore, the discharge power of the battery 16 is converted into three-phase AC power by the inverter 20 and then the motor 1
0 to be used as drive power. When the engine 22 with the offset balancer is operated, its output is increased by the speed increaser 24 to a rotation speed suitable for the generator 26, and then supplied to the generator 26.
When the field current _If is supplied to the generator 6, a power generation output is obtained from the generator 26. The generated output is rectified by the rectifier 28 and then supplied to the motor 10 as driving power via the inverter 20 or used as charging power for the battery 16.

The operation of the vehicle shown in this figure is controlled by an electronic control unit (ECU) 30. ECU3
0 inputs a signal indicating an accelerator operation, a brake operation, etc. of the vehicle operator, and in addition to this signal, the motor rotation speed detected by the rotation speed sensor 32 attached to the motor 10 is used to perform pulse width modulation (PWM). ) Generate a signal and supply it to the inverter 20. Each switching element that supplies the inverter 20 is controlled by this PWM signal,
As a result, a current corresponding to the output torque required for the motor 10 is supplied to the motor 10. EC
U30 controls the output of the motor 10 in this way.

The ECU 30 further controls the engine-driven generator 18. That is, the ECU 30 controls the engine-driven generator 18 such as when the state of charge (SOC) of the battery 16 is low or when the drive power of the motor 10 is insufficient.
When power generation by the generator is required, the throttle opening of the engine 22 with an offset balancer is controlled, and the generator 2
By controlling the field current I _f of No. 6, the engine-driven generator 18 is controlled so that the required power generation can be obtained.
Therefore, the ECU 30 uses the SOC attached to the battery 16.
The sensor 34 detects the SOC of the battery 16, and the voltage sensor 36 and the current sensor 38 provided at the subsequent stage of the rectifier 28 detect the generated voltage and the generated current and input them. Further, the ECU 30 controls the engine 22 with the offset balancer to perform the control according to the features of the present embodiment.
A crank angle CA of the engine 22 is detected by a crank angle sensor 40 attached to the engine.

FIG. 2 shows the engine 2 in this embodiment.
The structure of the balancer attached to No. 2 is shown. In the balancer shown in this figure, the weight 106 is vertically arranged in the cylinder direction (Y direction) of the crankshaft 100 of the engine 22.
Since it is offset by L along the line, it will be referred to as an offset balancer hereinafter.

As shown in this figure, it is assumed that the crank of the engine 22 rotates clockwise at an angular velocity ω in the figure, and the piston 102 moves up and down in the cylinder 104 in the Y direction accordingly. The offset balancer in this embodiment has the two weights 106 offsetly arranged as described above. One of these weights 106 rotates in the direction of rotation of the crank and the other rotates in the direction opposite to the direction of rotation of the crank at angular velocity ω. Therefore, the reciprocating inertial force due to the vertical movement of the piston 102 is canceled by the Y-direction component F _y of the centrifugal force F generated by the weight 106, and a part of the torque fluctuation related to rolling is X of the centrifugal force F of the two weights 106. It is canceled by the moment F _x · L due to the direction component F _x and the offset L.

FIG. 3 shows the ECU 30 in this embodiment.
The flow of the operation of is shown.

As shown in this figure, the ECU 30 is
First, the average power generation amount P _t of the generator 26 is input (20
0). This average power generation amount P _t is calculated, for example, by the voltage sensor 36.
And the product of the generated voltage and the current detected by the current sensor 38 are time-averaged. ECU3
0 further inputs the average engine speed N _e (2
02). That is, the control target value of the rotation speed of the engine 22 is determined according to the amount of power generation required for charging the battery 16 or driving the motor 10, and the determined rotation speed is time-averaged to obtain the control target value. The average rotation speed N _e is ECU3
At 0, it is used for the operation described later. The ECU 30 further detects the crank angle CA by the crank angle sensor 40 and inputs the detected crank angle CA (20
4).

The ECU 30 receives the input average power generation amount P _t ,
Based on the average rotation speed N _e and the crank angle CA, it is determined by referring to the map how to control the field current I _f (206). As shown in FIG. 4, the map used at that time controls the field current on a plane constituted by the average rotational speed N _e of the engine 22 and the average generated power P _{t of the} generator 26. Is a map in which the plane is mapped to the crank angle CA (CA _{0 to} CA _n ).

Here, the output of the engine 22 can be expressed as the product of its torque and the number of revolutions. Engine 22
Since the output of the engine 22 is supplied to the generator 26, the output of the engine 22 can be represented by the power generation amount of the generator 26. Therefore, the power generation amount of the generator 26 (average power generation amount P _{t in} this embodiment) and the rotation speed of the engine 22 (average rotation speed N _{e in} this embodiment) are quantities representing the output torque of the engine 22. Can be said. Therefore, in the map shown in FIG. 4, the control content of the field current _If is determined according to the output torque of the engine 22 and the crank angle CA. In the figure, it is turned on / off as the control content of the field current _If
Off is shown, which indicates whether to increase or decrease the duty of the field current _If .

Further, by determining the control content of the field current I _f Such maps, the power generation amount of the generator 26 can be controlled to a power generation amount of the target. That is, when the ECU 30 controls the field current I _f based on the control content determined in step 206 (20
8), whereby torque fluctuations associated with rolling vibration of the engine 22 are suitably suppressed, and the generator 26
From this, the amount of power generation required for charging the battery 16 and driving the motor 10 can be obtained.

FIG. 5 shows in more detail the control contents realized by the flow of FIG. 3 and characterizing the present embodiment, taking the case of using a two-cylinder engine as the engine 22 as an example.

As shown in this figure, in this embodiment, when the torque of the engine 22 changes in the positive direction, such as during the combustion period, this change is detected as a change in the average power generation amount P _t and the average rotation speed N _e. Then, the field current _If is controlled to be reduced. At this time, depending on the crank angle CA, the field current I _f
Change. When the field current I _f decreases, the engine 2
The load of No. 2 is reduced, and therefore, the rotation speed (angular velocity ω) of the engine 22 is increased. When the angular velocity ω increases, the X-direction component F _x of the centrifugal force F of the weight 106 increases, so the moment F _x L in the direction that suppresses rolling of the engine 22 increases. Therefore, the combined torque of the torque related to this moment and the torque fluctuation of the engine 22 has a value that suppresses the torque fluctuation of the engine 22 due to the pressure in the cylinder, as shown in FIG.

On the contrary, when the output torque of the engine 22 fluctuates in the negative direction, the ECU 30 increases the field current I _f , thereby decreasing the rotational speed of the engine 22, that is, the angular velocity ω. As a result, the balancer moment F _x L generated by the weight 106 is reduced, and the torque fluctuation of the engine 22 is appropriately canceled.

By the way, in the series hybrid vehicle,
Generally, in order to keep the fuel consumption and emission of the engine 22 at suitable values, the engine 22 is operated at a predetermined rotation speed (rotation constant control). When performing constant rotation control, the moment generated by the balancer is
And fluctuate in the opposite direction. In FIG. 5, the variation of the moment F _x L in the balancer when the constant rotation control is performed is indicated by a broken line. When the variation related to the broken line is compared with the moment F _x L in the present embodiment, a difference as shown by hatching in the figure occurs. This difference causes a difference in the combined torque of the engine 22 as shown at the bottom of FIG. This is because when the torque of the engine 22 fluctuates in the positive direction, the amount of canceling the torque fluctuation becomes smaller,
On the contrary, when it fluctuates in the negative direction, it means that the torque in the negative direction is generated.

As described above, according to the present embodiment, the torque fluctuation of the engine 22 is determined by the average power generation amount P _t and the average rotation speed N _e.
Since the field current _If is controlled in synchronism with the torque fluctuation of the engine 22, its rotational speed fluctuates according to the torque fluctuation of the engine 22, and as a result, the balancer moment F _x L is combined. This acts in the direction of suppressing the torque fluctuation, and suppresses the vibration caused by the rolling of the engine 22.

The subject of the present invention is not limited to the two-cylinder engine.

[0033]

As described above, according to the present invention,
Since the field current of the generator is controlled according to the fluctuation of the detected output torque of the engine, it is possible to suitably suppress the rolling vibration of the engine without charging / discharging the battery mounted on the vehicle, thereby improving the power efficiency. An excellent hybrid electric vehicle is obtained.

[Brief description of drawings]

FIG. 1 is a block diagram showing a system configuration of a hybrid electric vehicle according to an embodiment of the present invention.

FIG. 2 is a schematic configuration diagram showing a configuration of a balancer in this embodiment.

FIG. 3 is a flowchart showing a flow of operation of an ECU 30 in this embodiment.

FIG. 4 is a diagram showing the contents of a map used in this embodiment.

FIG. 5 is a timing chart showing the content of engine torque fluctuation suppression control, which is an effect of this embodiment.

[Explanation of symbols]

10 motor 16 battery 18 engine drive generator 22 engine with offset balancer 26 generator 30 electronic control unit (ECU) I _f field current CA crank angle ω engine angular velocity F _x component in centrifugal direction L weight generated by balancer weight L weight Offset amount between P _t Average power generation of generator N _e Average engine speed

Claims (1)

[Claims] 1. A power generator mounted on a hybrid electric vehicle including a motor that is a drive source of a vehicle, a generator that supplies drive power to the motor, and an engine that drives the generator, and that controls the power generation operation of the generator. In the control device, a means for generating a moment in the direction that suppresses rolling of the engine that increases with an increase in the engine speed, a means for detecting the output torque of the engine, and the detected output torque increase compared to the average value. If it is, the field current of the generator is decreased, and if it is decreased, it is increased, and by adjusting the field current of the generator, which is the load of the engine, the rolling of the engine is adjusted. A power generation control device characterized by suppressing vibration.