JP3807603B2 - Vehicle power generation device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a vehicular power generation device, and more particularly to a vehicular power generation device capable of reducing a shift shock.
[0002]
[Prior art]
Usually, in an automotive alternator called an alternator and a vehicular generator / motor used in an idle stop vehicle, after the engine is started, power is supplied to the on-vehicle electric load, and the on-vehicle equipment is driven during engine start or engine stop. The power generation state is always maintained during traveling to recover the battery stored power.
[0003]
Japanese Patent Laid-Open No. 2000-204995 describes a level at which the battery cannot sufficiently accept power during deceleration of the vehicle by increasing the generated current when the battery is at a level that can sufficiently accept power during deceleration of the vehicle. In this case, it is proposed to avoid an increase in generated current. Thereby, regenerative braking can be performed without causing battery abnormality.
[0004]
[Problems to be solved by the invention]
The engine of a vehicle is usually coupled to an axle through a transmission. However, if the transmission is shifted on the reduction side (low side), that is, the large reduction ratio while the vehicle is running, the engine speed increases. The pumping resistance and frictional resistance of the engine increase, which functions as an increase in braking force against the axle. Such a situation continues until the rotational speed ratio between the wheel and the engine reaches a value that matches the new gear ratio. Further, the increase in the engine speed described above is only for a period of time until the suppression by the feedback control is effective, but it also causes an increase in the generated current due to an increase in the generated voltage during power generation and a temporary increase in the braking force.
[0005]
As a result, vehicle stability and driving comfort may be impaired due to a temporary increase in braking force immediately after the shift.
[0006]
The present invention has been made in view of the above-described problems, and an object thereof is to improve vehicle stability and driving comfort by reducing a shock at the time of shifting with a simple configuration.
[0007]
[Means for Solving the Problems]
The vehicular power generation device according to claim 1, comprising: a power generator that is driven by an engine that drives wheels through a transmission to generate power; and a power generation control unit that controls a power generation amount of the power generator.
The power generation control means is in a state where no vehicle braking operation is performed when the transmission ratio is changed from a small reduction ratio to a large reduction ratio based on the input transmission ratio change information and vehicle braking operation information. The power generation control unit is instructed only to reduce the power generation amount.
[0008]
This makes it possible to compensate partially or completely for the phenomenon in which the change in vehicle inertia energy immediately after the shift of the engine accelerates and the braking force suddenly increases when viewed from the axle side by reducing the power generation load of the generator. It is possible to improve vehicle stability and driving comfort.
[0009]
Here, “reducing the amount of power generation” includes shifting from the state of power generation amount 0 to the state of electric output.
[0010]
According to the configuration of claim 2, in the vehicle power generation device according to claim 1, the power generation control unit further performs the shift at a predetermined vehicle speed or higher based on the gear ratio change information , vehicle speed information, and vehicle braking operation information. When the ratio is changed from the small reduction ratio to the large reduction ratio, the power generation control unit is instructed to reduce the power generation amount only when the vehicle braking operation is not performed .
[0011]
As a result, it is possible to prevent an increase in battery discharge due to a decrease in power generation capacity when the shift occurs at low vehicle speeds and the shift shock is small.
[0012]
The configuration according to claim 1 will be further described. The power generation control means is configured such that the gear ratio is changed from a small gear ratio to a large gear ratio only when a vehicle braking operation is not performed based on the gear ratio change information and the vehicle braking operation information. The power generation control unit is instructed to reduce the power generation amount when the power generation control unit is changed.
[0013]
As a result, when the vehicle braking operation is performed, the reduction in the power generation amount is stopped or weakened, so that a sufficient vehicle braking force can be obtained when the vehicle braking operation is performed.
[0014]
According to a preferred aspect, the power generator includes an inverter interposed between the generator that is an AC generator and the battery, and the power generation control means controls the power generation by phase control of the power generator under the control of the inverter. Reduce the amount .
[0015]
Although the shift shock occurs suddenly immediately after the shift, the shift shock cannot be reduced with good response if the field current decreases due to the reduction of the field current of the generator. On the other hand, in this configuration, since the amount of power generation is reduced by the phase control of the armature current of the synchronous machine, shift shock suppression can be realized with good response.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Preferred embodiments of the invention are illustrated by the following examples.
[0017]
(overall structure)
FIG. 1 is a block diagram showing an embodiment of a vehicular power generator of the present invention.
[0018]
Reference numeral 1 denotes a field winding synchronous machine connected to the crankshaft of the engine 7 to form a generator referred to in the present invention, 2 a current control circuit, 3 a controller (power generation control means referred to in the present invention), and 4 a high voltage battery Reference numeral 5 denotes a low-voltage battery, 6 denotes an engine control ECU, and 8 denotes a step-down DC-DC converter.
[0019]
A field winding type synchronous machine 1 includes a three-phase armature winding 11 wound around a stator core, a field winding 12 wound around a rotor core, a magnetic pole position sensor 13 for detecting a rotor angular position, a field winding. Although the flywheel diode 14 is connected in antiparallel with the line 11, the configuration itself is a normal field winding type synchronous machine, and therefore further detailed description is omitted.
[0020]
The current control circuit 2 includes a three-phase inverter 21 composed of six power MOS transistors (switching elements) 211 to 216, a field current switch 22 having a high-side switch configuration, and a current sensor 23 that detects an armature current. Although the smoothing capacitor 24 is connected in parallel with the high voltage battery 4, the circuit configuration itself is already well known, and further detailed description is omitted.
[0021]
The controller 3 converts the command value of the field current and the armature current from the control device 31 with a built-in microcomputer into the PWM voltages G1 to G7 of each duty to convert the power MOS transistors 211 to 216 and the field magnets. However, since the circuit configuration itself is already well known, further detailed description is omitted. G1 to G6 are PWM control voltages applied to the gate terminals of the power MOS transistors 211 to 216 of the inverter 21, and G7 is a PWM control voltage applied to the gate terminal of the field current switch 22. . Further, the control of the three-phase armature current by the control of the inverter 21 performed by the controller 3 and the field current control by the control of the field current switch 22 are essentially the same as those of the conventional field winding type synchronous machine. Since it is well known, the description is omitted. In addition, the controller 3 communicates with the engine control ECU 6 and exchanges necessary information from the outside. Based on this information, the controller 3 operates in accordance with a rotating electrical machine control mode such as engine start control, power generation control, torque assist control, regenerative braking control, or the like. A magnetic winding type synchronous machine (generator referred to in the present invention) is controlled. Since these controls themselves are well known, only the portions related to the present invention will be described in detail later.
[0022]
After the engine is started, the engine control ECU 6 calculates a required value of the engine output as a sum of the required power received from the controller 3 and the vehicle required output received from others, and corresponds to the required value of the engine output. The engine 7 is controlled so as to generate an engine output. The engine control ECU 6 reads shift information of the transmission, vehicle speed information, braking operation information (brake pedal depression amount information and brake booster pressure information), engine speed information, and the like from a detection sensor group (not shown), and based on these information Thus, engine control such as engine output control, engine automatic stop control, and subsequent engine restart control is performed. Since these controls are well known and are not related to the present invention, detailed description thereof is omitted.
[0023]
The step-down DC-DC converter 8 transmits power from the high voltage battery 4 to the low voltage battery 5. The controller 3 controls the operation of the step-down DC-DC converter 8 based on the received voltage of the low-voltage battery 5 to feedback control the power transmission from the high-voltage battery 4 to the low-voltage battery 5 so that the voltage of the low-voltage battery 5 is kept within a certain range. maintain.
[0024]
(Power generation control)
Next, of the power generation control, the part of the power generation amount reduction control during shifting that characterizes this embodiment will be described below with reference to the flowchart of FIG. Note that the routine shown in FIG. 2 is repeatedly executed at short time intervals during which the power generation is performed (in other words, the engine 7 is operating) without causing any trouble in operation.
[0025]
In FIG. 2, first, the required power P, which is the power to be generated by the field winding type synchronous machine 1, is calculated based on the voltage (or estimated capacity) of the high-voltage battery 4 and the operating state of the in-vehicle electric load (S101). This required power is essentially the sum of the battery charge / discharge power for maintaining the battery at a predetermined capacity level and the power consumption of the in-vehicle electric load, but the voltage or remaining capacity of the high-voltage battery 4 is simply fixed. The electric power to be generated by the field winding type synchronous machine 1 in order to maintain the range may be used.
[0026]
Next, based on a detection signal from a brake pedal depression amount sensor (or brake booster pressure detection sensor) (not shown), it is determined whether the brake pedal has been depressed (that is, whether a vehicle braking operation has been performed) (S102). When the vehicle is stepped on, it is not preferable to reduce the vehicle braking force by reducing the power generation amount, which will be described later. Thus, the steps described below are bypassed and the process returns to the main routine (not shown).
[0027]
Next, based on a detection signal from a vehicle speed sensor (not shown), it is determined whether the vehicle speed is equal to or higher than a predetermined threshold value Vth (S103). This is because if the vehicle speed is equal to or higher than the predetermined threshold value Vth, a shift shock due to a low-speed shift (shift from a small reduction ratio to a large reduction ratio) is large. If the vehicle speed is less than the predetermined threshold value Vth, the shift shock is small and it is not necessary to reduce the amount of power generation, which will be described later, and the process returns to the main routine.
[0028]
In S104, a shift from the shift position of the small reduction ratio to the shift position of the large reduction ratio (hereinafter also referred to as a low speed shift) is performed based on a detection signal from a shift position sensor (not shown) that detects the shift position of the transmission. If it is determined that the shift has been made, the shift flag F is set to 1 (S105), and the process proceeds to step S107 for power generation amount reduction control. If it is determined that the shift has not been performed, it is determined whether or not the shift flag F is 1 (S106). If the shift flag F is 1, the process proceeds to step S107 because the power generation amount reduction control is still necessary. If the flag F is 0, the shift is not performed and the power generation amount reduction control is unnecessary, and the process returns to the main routine.
[0029]
In step S107, since a sufficient time has elapsed since the shift, it is determined whether the power generation amount reduction control described later is no longer necessary. If it is no longer necessary, the shift flag F is reset to 0 and the process returns to the main routine. However, if not much time has passed since the shift and the power generation amount reduction control is necessary, the process proceeds to step S109.
[0030]
In this embodiment, the determination in step S107 is performed based on whether or not the temporary increase in the braking force applied to the axle or the wheel by the engine can be regarded as substantially 0 (below a predetermined small value). More specifically, immediately after the above shift is performed (in the manual clutch, the clutch is then engaged), the engine is strongly accelerated by the axle (vehicle body), and the large engine is greatly controlled by the axle in proportion to the acceleration rate. Power is applied, and then the engine speed converges to a steady value determined by the vehicle speed and the reduction ratio after shifting, and after this convergence, the braking force applied to the axle by the engine corresponds to this steady value. It converges to the value of braking force corresponding to engine pumping loss and friction loss. Therefore, the engine speed is increased between the shift time and the convergence time, and the braking force applied to the axle by the engine temporarily increases in this increased speed state.
[0031]
In this embodiment, the determination in S107 is made based on whether or not the differential value of the engine speed is greater than or equal to a predetermined positive value, but it may be determined simply by a timer or the like.
[0032]
In step S10 9, to reduce the required power to engine speed increasing in which the above is to reduce the amount of power generation to cancel the temporary increase ΔFe of the braking force applied to the axle.
[0033]
The required power can be reduced by various methods. For example, in most cases, the increase amount ΔFe is larger than the braking force applied to the axle by the generator during power generation, and therefore the braking force applied to the axle by the generator during the engine acceleration period is set to 0 as the friction loss and wind. Only the braking force corresponding to the loss may be used. Alternatively, since the increase amount ΔFe has a maximum value immediately after the shift and then gradually decreases, the power generation amount (required power) of the generator is set to 0 immediately after the shift, and then gradually (for example, a constant increase rate). ) It may be increased to the original required power value. In addition, the increase amount ΔFe may be further compensated by setting the power generation amount (required power) of the generator to 0 immediately after the shift to a predetermined electric output. Furthermore, as advanced control, the engine speed and current shift pattern are substituted into the map of the engine speed and current shift pattern stored in advance and the above-mentioned ΔFe, and the current ΔFe is estimated. It is possible to reduce the amount of power generation that can be commensurate and increase the electric output. Further, ΔFe may be calculated from the differential value of the engine speed, and the amount of power generation or the increase in electric output capable of compensating this ΔFe to the maximum may be performed.
[0034]
Note that in the main routine (not shown), control of the inverter 21 (or control of the field current) is preferably performed so that power generation corresponding to the required output determined in step S101 or S109 is performed.
[0035]
With the above control, it is possible to reduce or eliminate a shift shock when a low-speed shift is performed during high-speed traveling and a braking operation is not performed. The engine braking force (braking force that the engine gives to the axle) and the generator braking force (braking force that the generator gives to the axle) when the shift for low speed is performed at the time of high speed traveling in one example and the brake braking operation is not performed FIG. 3 shows changes with time of these and their total braking force.
[0036]
In addition, the engine braking force (braking force applied to the axle by the engine) and the generator braking force (braking force applied to the axle by the generator) when a low-speed shift is performed during high-speed traveling and then a brake braking operation is performed. FIG. 4 shows changes with time in the braking force and the total braking force.
[0037]
3 and 4, it is assumed that the accelerator pedal is not depressed before the shift, and the engine gives a braking force corresponding to the friction loss and the pumping loss to the axle. The broken lines in FIGS. 3 and 4 show changes in the rotating machine braking force and the total braking force when the shift power generation amount reduction control of the above embodiment is not performed. In FIG. 3 and FIG. 4, the rotating machine braking force increases stepwise due to the shift because the rotating speed of the rotating machine increases because the engine speed increases, and the generated voltage increases and the generated output increases. It is.
[0038]
(Modification)
In the above embodiment, the field winding type synchronous machine is used as the generator, but the case where a conventional generator dedicated to power generation is used as the generator is substantially the same.
[Brief description of the drawings]
FIG. 1 is a block circuit diagram showing a circuit configuration of a vehicular power generator of the present invention.
FIG. 2 is a flowchart showing shift-time power generation amount reduction control in FIG. 1;
FIG. 3 is a timing chart showing changes in each braking force when brake braking is not performed.
FIG. 4 is a timing chart showing changes in each braking force when brake braking is performed.
[Explanation of symbols]
1 Field winding type synchronous machine (generator)
3 Controller (Power generation control means)
7 Engine 21 Inverter 22 Field current switch

Claims (2)

A generator that generates power by being driven by an engine that drives wheels through a transmission;
Power generation control means for controlling the power generation amount of the generator;
In a vehicle power generation device comprising:
The power generation control means includes
The power generation control unit only when the vehicle braking operation is not performed when the gear ratio is changed from a small reduction ratio to a large reduction ratio based on the input transmission ratio change information and vehicle braking operation information. The vehicle power generation device is characterized by instructing the power generation amount to be reduced. The vehicular power generator according to claim 1,
The power generation control means includes
The power generation is performed only when the vehicle braking operation is not performed when the gear ratio is changed from a small reduction ratio to a large reduction ratio at a predetermined vehicle speed or higher based on the transmission ratio change information , vehicle speed information, and vehicle braking operation information. A vehicular power generation device that commands a control unit to reduce the power generation amount .

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