JP3994904B2 - Control device for hybrid vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make an occupant not feel a sense of discomfort caused by the variation of the number of revolutions of an engine. <P>SOLUTION: This control device determines whether a vehicle is in a coast state or not (S1), and when the coast state is determined, the control device determines whether the vehicle is in a lockup state or not (S2). When it is determined that the vehicle is not in the lockup state, the control device determines whether there is a power generation request or not (S3). When there is the request, the control device operates the charging state of a battery. Next, it is determined whether the number of revolutions of the engine is the number of idle revolutions or not (S4), and when it is not the number of idle revolutions, it is determined whether the engine is cut in fuel supply or not (S5). When the fuel cut is conducted based on the determination, and when a prescribed time has elapsed (S7), a difference between the number of revolutions of the engine after the cut of the fuel and the number of revolutions the engine after the lapse of the prescribed time is operated (S8). A road gradient is estimated according to the difference (S9), the target number of revolutions is set by the estimated road gradient (S10), and torque that corresponds to a generation amount is operated by the target number of revolutions, thus suppressing the variation of the number of revolutions. <P>COPYRIGHT: (C)2005,JPO&amp;NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a control device for a hybrid vehicle including an engine and a motor.
[0002]
[Prior art]
In a conventional hybrid vehicle equipped with an engine and a motor, when the state of charge SOC of the battery is below a predetermined value, the engine is operated as a generator to generate power, and the battery is charged with the generated power. Like to do. At this time, the engine outputs a torque obtained by adding the torque for driving the vehicle corresponding to the accelerator operation amount operated by the driver and the torque for generating the motor.
[0003]
[Patent Document 1]
Japanese Patent Laid-Open No. 2000-115908
[Problems to be solved by the invention]
However, in the prior art, the load torque resulting from the road surface condition is transmitted to the engine via the torque converter. However, when the torque converter is not locked up, the load torque transmitted from the road surface is not uniformly transmitted to the engine depending on the slipping condition of the torque converter at that time. Therefore, the rotational speed of the engine fluctuates from time to time, and this fluctuation in the rotational speed may give the passenger a sense of incongruity.
[0005]
The present invention has been made in view of such a problem, and a main object thereof is not to give an uncomfortable feeling to the occupant due to fluctuations in engine speed.
[0006]
[Means for Solving the Problems]
The present invention is characterized by setting a target rotational speed based on the estimated road gradient and adjusting the power generation amount based on the target rotational speed when the vehicle is in a deceleration state when not locked up. And
[0007]
【The invention's effect】
The present invention can prevent the passenger from feeling uncomfortable due to the rotational speed fluctuation without causing the rotational speed fluctuation.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
[0009]
FIG. 1 is a configuration diagram showing the configuration of the present embodiment.
[0010]
An engine 1 that is a vehicle drive source is connected at one end to a motor / generator (hereinafter referred to as a motor) 2 via a clutch 11 by a belt and a crank pulley. A continuously variable transmission (CVT) 9 having a torque converter 20 is connected to the other end of the engine 1.
[0011]
A three-phase AC motor is used as the motor 2, and the motor 2 is charged and discharged with the battery 5 through the inverter 4. When the driving force of the vehicle is generated by the engine 1 and the motor 2 or when the engine 1 is started by the motor 2, the electric power charged in the battery 5 is supplied to the motor 2 via the inverter 4. The motor 2 operates as an electric motor and performs powering. The motor 2 generates electric power by rotating with the driving force of the engine 1, and charges the generated electric power to the battery 5 through the inverter 4.
[0012]
The motor 2 is provided with a resolver 8 that detects the rotational speed of the motor 2, and the rotational speed of the motor 2 detected by the resolver 8 is input to the controller 3. In the present embodiment, the rotational speed of the engine 1 and the rotational speed of the motor 2 are the same. Therefore, when the engine rotational speed is described later, the rotational speed detected by the resolver 8 is used.
[0013]
The battery 5 is provided with a current sensor 6 that detects a charging / discharging current (hereinafter referred to as battery current) flowing through the battery 5, and a voltage sensor 7 that detects a voltage between terminals of the battery 5 (hereinafter referred to as battery voltage). ing. The battery current detected by the current sensor 6 and the battery voltage detected by the voltage sensor 7 are output to the controller 3, and the controller 3 uses the battery current and battery voltage to charge the state of charge SOC (State Of) of the battery 5. Charge) is calculated.
[0014]
Various control signals are input to the controller 3, and the hydraulic pressure is controlled after determining whether the torque converter 20 of the CVT 9 is locked up or unlocked based on the control signal and the engine speed. Then, the state of the torque converter 20 is controlled.
[0015]
The controller 3 is connected to an accelerator sensor 12 that detects an operation amount of an accelerator pedal operated by a driver, a brake sensor 10 that detects on / off of the brake pedal, and a vehicle speed sensor 13 that detects a vehicle speed.
[0016]
Further, the controller 3 calculates a torque corresponding to the driving force for driving the vehicle based on the accelerator pedal operation amount detected by the accelerator sensor 12 and the vehicle speed detected by the vehicle speed sensor 13, while the calculated battery 5 Based on the state of charge SOC and the rotation speed of the motor 2 detected by the resolver 8, a power generation torque is calculated, and the engine 1 outputs a torque obtained by adding the driving power torque and the power generation torque. A fuel injection device and an ignition device (not shown) of the engine 1 are controlled. In other words, among the torque output by the engine 1, the driving force torque is transmitted to the wheels via the CVT 9 to drive the vehicle, and the motor 1 generates the generated torque out of the torque output by the engine 1. 2 is generating electricity.
[0017]
The controller 3 includes a CPU, a ROM, a RAM, an input / output interface, and the like.
[0018]
In the present embodiment, the vehicle in which the engine 1 and the motor 2 are connected via a belt and a crank / pulley has been described as an example. However, the drive shaft of the engine 1 and the drive shaft of the motor 2 are directly connected. In other words, any vehicle can be applied as long as the motor 2 can generate electric power with the torque generated by the engine 1.
[0019]
Next, the control block of the controller 3 will be described with reference to FIG.
[0020]
FIG. 2 is a block diagram showing a control function calculated by the controller 3. In FIG. 2, the first deviation unit 21 is a rotation speed deviation egne−egnez (hereinafter referred to as a first rotation speed deviation) between the current engine speed egne detected by the reso lever 8 and the previously calculated engine speed egnez. And input to the coast target rotational speed calculation unit 22.
[0021]
The coast determination unit 23 receives the accelerator operation amount detected by the accelerator sensor 12, the on / off state of the brake pedal detected by the brake sensor 10, and the vehicle speed detected by the vehicle speed sensor 13, and the vehicle is decelerating ( (Coast state) is determined, and a flag fcoast indicating whether it is a coast state or not is output to the coast target rotation speed calculation unit 22.
[0022]
The target rotation speed calculation unit 22 at the time of coasting includes a first rotation speed deviation output from the first deviation unit 21, an engine rotation speed egne detected by the resolver 8, a flag fcoast output from the coast determination unit 23, A fuel cut signal indicating whether or not the fuel is cut, a lockup signal indicating whether or not the vehicle is in the lockup state, and the presence / absence of a power generation request output from the power generation calculation unit 26, which will be described later, are input. / The prohibition is calculated, a signal is output to the fuel injection device of the engine 1, and the target rotation speed tagne is calculated and output to the second deviation unit 24.
[0023]
The second deviation unit 24 calculates a target rotational speed tagne output from the coast target rotational speed calculation unit 22 and a rotational speed deviation tagne-egne (hereinafter referred to as a second rotational speed deviation) between the current engine egne, It outputs to the power generation amount correction value calculation unit 25.
[0024]
The power generation amount correction value calculation unit 25 calculates the power generation amount hosei by comparing the input second rotational speed deviation with the map shown in FIG. 8, and outputs it to the power generation amount calculation unit 26.
[0025]
The power generation amount calculation unit 26 outputs the SOC (State Of Charge) of the battery 5 calculated based on the battery current detected by the current sensor 6, the battery voltage detected by the voltage sensor 7, and the power generation amount correction value calculation unit 25. Based on the correction coefficient hosei, the power generation torque is calculated, and the engine 1 and the motor 2 are controlled so that this torque becomes the power generation torque. Further, when it is determined that power generation is to be performed, the power generation amount calculation unit 26 outputs to the coast target rotation speed calculation unit 22 that there is a power generation request.
[0026]
Further, the gradient change monitoring unit 27 calculates the change in gradient against the map shown in FIG. 4 on the basis of the first rotational speed deviation, calculates the execution / prohibition of fuel cut based on this gradient, and the engine 1 A signal is output to the fuel injection device.
[0027]
FIG. 3 is a flowchart showing a control program executed by the controller 3. Hereinafter, the control program will be described with reference to this flowchart.
[0028]
The flowchart shown in FIG. 3 starts processing when an unillustrated ignition switch is turned on.
[0029]
First, in step S1, it is determined whether or not the coast state is set. Specifically, the accelerator operation amount detected by the accelerator sensor 12 is 0, the brake pedal state detected by the brake sensor 10 is OFF, and the vehicle speed detected by the vehicle speed sensor 13 is equal to or higher than a predetermined vehicle speed (for example, 10 km) When all the conditions of / h) are satisfied, it is determined that the state is the coast state. If it is determined that the state is the coast state, the process proceeds to step S2, and if it is determined that the state is not the coast state, the process proceeds to step S17. . If it is determined in step S1 that the vehicle is in the coast state, fuel cut is started.
[0030]
In step S2, it is determined whether the torque converter 20 of the CVT 9 is in the lock-up state. If it is determined that the torque converter 20 is not in the lock-up state, the process proceeds to step S3, and if it is determined in the lock-up state, step S17 is performed. Proceed to
[0031]
In step S3, it is determined whether there is a power generation request. If there is a power generation request, the process proceeds to step S4, and if there is no power generation request, the process proceeds to step S17. Specifically, the presence / absence of a power generation request is calculated by calculating the state of charge SOC of the battery 5 based on the battery current detected by the current sensor 6 and the voltage across the terminals detected by the voltage sensor 7. The power generation amount tpgn is calculated by comparing with the map shown in FIG. 7. If the power generation amount tpgn is not 0, it is determined that there is a power generation request, and if the power generation amount tpgn is 0, it is determined that there is no power generation request.
[0032]
The map shown in FIG. 7 shows a constant power generation amount (for example, 20 kw) when the state of charge SOC is 0 to 60%, and the above-described constant power generation when the state of charge SOC is 60% to 100%. The power generation amount is gradually reduced from the amount (20 kw), and the power generation amount is set to 0 in the state of charge SOC 100%.
[0033]
In step S4, it is determined whether the engine speed detected by the resolver 8 is a predetermined idle speed. If the engine speed is the idle speed, the process proceeds to step S17, where If it is not the rotational speed, the process proceeds to step S5.
[0034]
In step S5, it is determined whether the engine 1 is fuel cut. If the fuel is cut, the process proceeds to step S6. If the fuel is not cut, the process proceeds to step S12. If it is determined in step S1 that the vehicle is in the coast state, the fuel cut is performed. Therefore, this determination is made from the non-coast state to the coast state, and it is determined whether the fuel cut is started. It will be.
[0035]
In step S6, the engine speed detected by the resolver 8 is detected, and the current engine speed is stored as the previous speed.
[0036]
In step S7, it is determined whether or not a predetermined time (for example, 100 msec) has elapsed since the fuel cut was started. If it has elapsed, the process proceeds to step S8, and if not, the process returns to step S1. That is, if the determination of step S1 affirmation, step S2 negation, step S3 affirmation, step S4 negation, and step S5 affirmation does not change, steps S1 to S7 are repeated until a predetermined time elapses after the fuel cut is started. Will be.
[0037]
In step S8, a rotational speed deviation between the detected current engine speed and the stored previous engine speed is calculated.
[0038]
Referring to FIG. 4A, when it is determined that the coast is in the state at time t1, the fuel cut is started at time t1, the engine speed at time t1 is stored, and a predetermined time ( For example, the rotational speed deviation from the engine rotational speed at time t2 when 100 msec) has elapsed is calculated.
[0039]
Next, in step S9, the inclination α for correcting the target rotational speed is calculated by comparing the rotational speed deviation calculated in step S8 with the table shown in FIG. 4B.
[0040]
As shown in FIG. 4B, when the rotational speed deviation is small (rotational speed deviation a), it is determined that the road gradient is a downhill, the slope α is reduced, and the rotational speed deviation is medium (rotational speed deviation). In b), the road slope is judged to be flat, the slope α is moderate, and when the rotational speed deviation is large (rotational speed deviation c), the road slope is judged to be uphill and the slope α is increased. (See FIG. 5).
[0041]
When this is a downhill, since the running resistance is small, the inclination α for correction with respect to the target rotational speed is reduced in order to reduce the deceleration of the vehicle. However, as shown in FIG. 4B, when the slope of the downhill is large, the lower limit is set and the lower limit is set so as to prevent the vehicle from accelerating.
[0042]
In addition, when it is an uphill, the running resistance is large, so that the inclination for correction with respect to the target rotational speed is increased in order to increase the deceleration of the vehicle. In order to prevent this from happening, an upper limit is set on the slope, and the upper limit is kept to this limit. In this way, by setting the inclination α based on the gradient, it is possible to obtain the same deceleration (deceleration feeling) as that of a normal vehicle that is not a hybrid vehicle, and to prevent discomfort when switching to a normal vehicle. ing.
[0043]
In step S10, the current engine speed is set to the target speed.
[0044]
In step S11, fuel cut recovery (prohibition of fuel cut, that is, resupply of fuel) is performed, and power generation by the motor 2 is started.
[0045]
When the fuel cut is performed in step S11, the process returns to step S1, the coast state continues (step S1 is affirmative), is not in the lockup state (step S2 is negative), and there is a power generation request (step S3 is affirmative). If it is not the idling speed (No at Step S4), Step S5 is denied and the process proceeds to Step S12.
[0046]
In step S12, the inclination α calculated in step S9 is subtracted from the target rotational speed set in step S10, and this rotational speed is set as a new target rotational speed. Note that the target rotational speed set in step S10 is used in the initial calculation in step S12, but the target rotational speed set in step S12 is used in the next calculation, that is, the target rotational speed is shown in FIG. As shown in Fig. 3, it gradually decreases until the idling speed is reached.
[0047]
Next, in step S13, it is determined whether or not the deviation between the target rotational speed set in step S12 and the current rotational speed is equal to or smaller than a predetermined threshold value. The process proceeds to step S14, and if the rotational speed deviation is larger than the threshold value, the process proceeds to step S16.
[0048]
In step S14, the correction coefficient hosei is calculated by comparing the deviation between the target rotational speed set in step S12 and the current rotational speed against the map shown in FIG.
[0049]
In step S15, the power generation amount based on the state of charge SOC calculated in step S3 is corrected by multiplying by the correction coefficient hosei calculated in step S14, and a power generation torque is calculated.
[0050]
In other words, when the deviation between the set target speed and the actual speed is small, the engine speed is equal to the target value, so torque for controlling the speed is not required, All of the torque calculated as the minute torque can be used for power generation, but when the deviation between the set target speed and the actual speed increases, the actual speed matches the target speed. Therefore, in order to bring out the torque for performing the rotation speed control from the torque originally calculated as the power generation torque, the power generation torque is corrected. The power generation torque calculated in this way is output to the motor 2 and the inverter 4.
[0051]
If it is determined in step S13 that the deviation between the target rotational speed and the actual rotational speed is larger than the threshold value, that is, if there is a difference between the estimated road gradient and the actual gradient, the process again in step S16. In order to perform the calculation, fuel cut is performed, power generation is temporarily stopped, and the process returns to step S4.
[0052]
As shown in FIG. 7, the normal control in step S17 calculates the power generation torque so that the power generation amount calculated in step S3 is obtained, and controls the engine 1, the motor 2, and the inverter 4.
[0053]
As described above, in the present embodiment, in the coast state, not in the lockup state, and when the fuel cut is performed, the target rotational speed is set based on the estimated road gradient, Since the power generation torque is calculated based on the target rotational speed, it is possible to prevent the passenger from feeling uncomfortable due to the rotational speed fluctuation without causing the rotational speed fluctuation.
[0054]
In this embodiment, since the gradient is estimated based on the deviation between the rotation speed at the time when the fuel cut is started and the rotation speed after a predetermined time has elapsed, the dedicated gradient estimation is performed. Without using any parts, the gradient can be estimated and can be configured at low cost.
[0055]
In the present embodiment, when the deviation between the set target rotational speed and the actual rotational speed exceeds a predetermined value, the estimation of the gradient is performed again, so that an estimation error occurs. However, the correction can be made, smooth deceleration can be performed, and the passenger does not feel strange.
[0056]
The correspondence relationship between the constituent elements of the claims and the configuration of the present embodiment is as follows.
[0057]
The engine 1 is an engine, the motor 2 is a generator, the torque converter 20 is a torque converter, the battery 5 is a battery, the controller 3 is a lock-up state determination means, a deceleration state determination means, a fuel supply stop means, a target rotational speed setting. Means, power generation amount calculation means, and generator control means.
[Brief description of the drawings]
FIG. 1 is a configuration diagram showing a configuration of an embodiment.
FIG. 2 is a block diagram illustrating a control function calculated by a controller.
FIG. 3 is a flowchart showing a control program executed by a controller.
FIG. 4A is a diagram for explaining the transition of engine speed at the start of deceleration, and B is a table for calculating a target speed gradient α from a speed deviation.
FIG. 5 is a diagram for explaining a relationship between a road gradient and a slope α.
FIG. 6 is a characteristic diagram showing a time transition of the target rotational speed.
FIG. 7 is a diagram showing a relationship between a state of charge SOC and a power generation amount.
FIG. 8 is a diagram showing a relationship of a power generation amount correction coefficient with respect to a rotational speed deviation between a target rotational speed and an actual engine rotational speed.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Engine 2 ... Motor / generator 3 ... Controller 4 ... Inverter 5 ... Battery 6 ... Current sensor 7 ... Voltage sensor 8 ... Speed sensor 9 ... CVT
DESCRIPTION OF SYMBOLS 10 ... Foot brake sensor 11 ... Clutch 12 ... Accelerator sensor 20 ... Torque converter 22 ... Coast target rotational speed calculating part 23 ... Coast judging part 25 ... Power generation amount correction value calculating part 26 ... Power generation amount calculating part 27 ... Gradient change monitoring part

Claims (3)

An engine that drives the vehicle;
A generator generated by this engine;
A transmission having a torque converter for transmitting the driving force of the engine to wheels;
Lockup state determination means for determining whether the torque converter is not locked up;
Deceleration state determination means for determining whether or not the vehicle is in a deceleration state;
Fuel supply stopping means for stopping supply of fuel to the engine when it is determined that the vehicle is in the deceleration state;
A target speed setting means for setting a target speed corresponding to the estimated road gradient when the fuel supply is stopped by the fuel supply stop means;
Based on the target rotational speed set based on the target rotational speed setting means, the power generation amount calculating means for calculating the power generation amount by the generator,
Generator control means for controlling the generator so as to generate the power generation amount calculated by the power generation amount calculation means;
The deceleration state determining means determines whether or not a deceleration state has been started, and the target rotational speed setting means is an engine rotational speed when deceleration is started by the deceleration state determination, and a deceleration A control apparatus for a hybrid vehicle, characterized in that a target rotational speed is set based on a deviation from an engine rotational speed when a predetermined time has elapsed since the start of the engine . 2. The hybrid according to claim 1, wherein the target rotational speed setting stage sets the target rotational speed again when a deviation between the set target rotational speed and the actual engine rotational speed is greater than or equal to a predetermined value. Vehicle control device. A battery for charging power generated by the generator;
The power generation amount calculated by the power generation amount calculation means is corrected based on the target rotation speed set by the target rotation speed setting means with respect to the power generation amount set based on the state of charge of the battery. control apparatus for a hybrid vehicle according to claim 1 or 2, characterized.

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