JP3178353B2 - Hybrid electric vehicle - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hybrid electric vehicle in which a motor is used as a driving source, and relates to a generator operated by a prime mover, in which power generation of the prime mover is prevented from being reduced and the condition of the prime mover is maintained in a good condition. It is something that can be done.

[0002]

2. Description of the Related Art A hybrid electric vehicle using a motor as a driving source is driven by a motor using a battery (battery) as a power source, and the battery is charged by a generator operated by a prime mover (engine). As a result, the output of the electric motor is secured. In general, a hybrid electric vehicle travels while driving an electric motor only with a battery, or traveling while supplying electricity from a generator to an electric motor while operating a generator by an engine to charge the battery. . Usually, the vehicle is driven by driving the electric motor only with the battery, and when the charging rate of the battery becomes equal to or less than a preset value, the generator is operated to charge the battery. This allows the hybrid electric vehicle to maintain a predetermined power performance.

[0003]

In a conventional power generation control device for a hybrid electric vehicle, a battery is charged by a generator based on a charging rate so that the output of the motor maintains a predetermined power performance. . However, when the temperature of the battery is low or the battery is deteriorated, the output of the battery is reduced even if the charging rate exceeds a preset value, and the output of the electric motor is reduced, and power performance such as acceleration and speed is reduced. There is a possibility that it will decrease.

[0004] The engine that operates the generator includes:
A catalyst purifying device for purifying the exhaust gas is provided, and it is desirable to heat the catalyst temperature of the catalyst purifying device to a predetermined temperature in advance in order to maintain good exhaust gas performance. Also,
In order to maintain good exhaust gas performance, it is desirable that the engine be driven at idle speed for a predetermined time to perform a warm-up operation. However, in the conventional power generation control device for a hybrid electric vehicle, power generation is started immediately when the charge rate of the battery falls below a predetermined value. It was not considered.

The present invention has been made in view of the above circumstances, and provides a hybrid electric vehicle capable of performing power generation while keeping the state of the prime mover in a state where the output of the motor does not decrease. With the goal.

[0006]

According to the present invention, there is provided a motor for driving a driving wheel of a vehicle by supplying electric power from a power supply, and supplying electric power to the power supply and the electric motor. In a hybrid electric vehicle including a generator to be supplied and a motor device for driving the generator, operating state detecting means for detecting an operating state of the vehicle, and actual output detection for detecting an actual output generated by the electric motor Means, a decrease limit setting means for setting a decrease limit of the output of the electric motor, and a driving state of the vehicle detected by the driving state detecting means and an actual output of the electric motor detected by the actual output detecting means. Time limit calculating means for calculating a time limit for the actual output to reach the lower limit, and the motor device drives the generator based on a state of the motor device. Start time calculating means for calculating a time until the function becomes active, and control for operating the prime mover device when the limit time calculated by the limit time calculating means is equal to or less than the start time calculated by the start time calculating means. And a means for calculating the time when the actual output reaches the lower limit when a difference occurs between the actual output and the instruction output that is the driving state of the vehicle. When the time becomes equal to or less than the start time at which the generator can be driven, the generator is driven by the prime mover to secure the output of the motor.

In the hybrid electric vehicle according to the present invention that achieves the above object, the control means drives the generator by the motor device when the motor device can drive the generator. There is a feature. In the hybrid electric vehicle according to the present invention, the limit time calculating means is configured such that a ratio between an instruction output to be output to the electric motor and the actual output based on information obtained from the operating state detecting means is a predetermined value. When the distance is smaller, the calculation of the limit time is performed. The hybrid electric vehicle according to the present invention is characterized in that the time limit calculating means approximates a quadratic expression of a plurality of stored actual output values by a least square method. In the hybrid electric vehicle according to the present invention, the motor device has a catalyst for purifying exhaust gas of the motor, and the start time is a heating time for heating the catalyst to a predetermined temperature and a warm-up time for warming the motor. It is characterized by consisting of.

Further, the hybrid electric vehicle according to the present invention provides a hybrid electric vehicle in which a difference occurs between an actual output and an instruction output that is a driving state of the vehicle even when the remaining capacity of electricity of the power supply device is equal to or more than a predetermined value. According to a feature of the present invention, the power generator is driven by driving the generator by the motor unit based on the comparison between the limit time and the start time.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a schematic configuration of a hybrid electric vehicle having a power generation control device according to an embodiment of the present invention, FIG. 2 is a block configuration of the control device, and FIG. FIG. 4 is a flowchart of the power generation preparation routine, and FIG. 5 is a graph showing the state of the output of the motor with respect to the elapsed time. The condition of the output of the motor is such that a parameter that minimizes the sum of squares of the error of the detection point is obtained (least square method), and the position of the white point is interpolated. FIG. 6 shows a flowchart of a power generation preparation routine according to another embodiment.

As shown in FIG. 1, a battery 1 as a power supply is mounted on a hybrid electric vehicle, and the battery 1 is electrically connected to a motor 3 as a motor via a motor controller 2. The motor 3 is connected to a drive wheel side of a vehicle (not shown), and the hybrid electric vehicle runs by driving the motor 3. On the other hand, a motor device is mounted on a hybrid electric vehicle. This prime mover device includes an engine 4 as a prime mover, a radiator, and a catalyst device 23. A generator 5 that supplies power to the battery 1 and the motor 3 is connected to an output side of the engine 4. When the generator 5 is driven by the driving of the engine 4, the battery 1 is charged. The operations of the engine 4 and the generator 5 are controlled based on a command from the control device 6.

On the other hand, the accelerator pedal 7 is provided with an accelerator opening sensor 8 as operating state detecting means, and an output corresponding to the amount of depression of the accelerator pedal 7 by the driver is input to the motor controller 2 and the control device 6. . An instruction output to the motor 3 is set in the motor controller 2 by the output signal of the accelerator opening sensor 8, and the motor 3
The motor 3 is driven in response to the instruction output to. Further, an actual output detecting means 9 for detecting the number of rotations of the motor 3 and the current value supplied from the motor controller 2 to the motor 3 and calculating an actual output from the number of rotations and the current value is provided. , A motor instruction output is input and an actual output of the motor 3 detected by the actual output detection means 9 is input.
Further, a remaining capacity meter 10 is provided in the battery 1, and the remaining capacity of the battery 1 is detected by the remaining capacity meter 10.
The detection information of the remaining capacity meter 10 is input to the control device 6.

Further, the engine 4 is provided with a water temperature sensor 22 for detecting the temperature of the cooling water in the water jacket 21. Further, the engine 4 as a motor device
A catalyst device 23 is provided in the exhaust system, and the catalyst of the catalyst device 23 is heated by a heating device (such as an electric heater) 24 and the heating temperature is detected by a temperature sensor 25. The water temperature information from the water temperature sensor 22 and the catalyst heating information from the temperature sensor 25 are input to the control device 6, and the temperature of the catalyst, which is the state of the engine, and the warm-up state are determined.

As shown in FIG. 2, the control device 6 is provided with a calculation means 11, a judgment means 12, and an instruction means 13. The detection information of the actual output detection means 9 and the output signal of the accelerator opening sensor 8 are input to the calculation means 11.
The arithmetic means 11 receives the coolant temperature information from the coolant temperature sensor 22 and the catalyst heating information from the temperature sensor 25. The detection information of the remaining capacity meter 10 and the calculation result information of the calculation means 11 are input to the determination means 12. Further, the control device 6 includes a storage unit 14, and the storage unit 14 stores various preset values and information calculated by the calculation unit 11. Judgment means 1
The information stored in the storage unit 14 is input to 2, the operation result information and the storage information are compared and determined, and the determination result information is input to the instruction unit 13. The instruction unit 13 outputs an operation instruction to the engine 4 and the generator 5 based on the input determination result information.

That is, the determination means 12 includes the remaining capacity meter 10
, The charging rate A of the battery 1 is input.
The storage means 14 previously stores a lower limit value (predetermined value) a of the remaining capacity of electricity of the battery 1, and the determination means 12 compares the predetermined value a stored in the storage means 14 with the charging rate A, and Is determined whether or not the remaining capacity is sufficient.

A driving force required for the vehicle is calculated based on the information of the output signal of the accelerator opening sensor 8, and the driving force value is sent to the motor controller 2, and the motor controller 2 outputs the output value of the motor 3, that is, An instruction output P is calculated. Then, electric power is supplied to the motor 3 based on the instruction output. This instruction output P is sent to the calculating means 11. The actual output D of the motor 3 is input to the calculating means 11 based on the detection information of the actual output detecting means 9. The calculating means 11 calculates a ratio B (actual output D / instruction output P) between the actual output D and the instruction output P. Storage means 1
4 stores a set value (set ratio b) of the ratio B between the actual output D and the instruction output P of the motor 3 in advance, and the determination unit 12 compares the ratio B with the set ratio b. Ratio B and set ratio b
Are compared, it is determined whether or not an output corresponding to the amount of depression of the accelerator pedal 7 by the driver is obtained by the motor 3.

Further, the storage means 14 stores a lower limit set value c which is a lower limit value of the actual output D of the motor 3.
(Lower limit setting means) . On the other hand, the ratio B
(Actual output D / instruction output P) is smaller than set ratio b
If it is determined , the ratio B (actual output D /
The value of the actual output D used in the calculation of the instruction output P) is stored in the storage unit 14, the value of the most recent actual output D in the storage unit 14 a plurality (3 or more, D _1, D _2, D ₃ ... D _n ) Stored while being updated. The updated plurality of actual outputs D (D
₁ , D ₂ , D ₃ ... D _n ) are input to the calculating means 11, and the calculating means 11 calculates a parameter approximated by a quadratic expression that minimizes the sum of squares of errors of the values of the plurality of real outputs D. At the same time, the time Δt (limit time) until the actual output D reaches the lower limit set value c is calculated based on this parameter. That is, as shown in FIG. The time Δt from when D _n is detected to when it reaches the lower limit set value c is predicted based on the parameter approximated by the quadratic expression.

The calculating means 11 includes a temperature sensor 2
The catalyst temperature detected at 5 and the water temperature of the radiator 21 detected by the water temperature sensor 22 are input, and the start time d ₃ is a time until the engine 4 can drive the generator 5 based on the catalyst temperature and the water temperature. Is calculated. That is, from the viewpoint of the exhaust gas performance of the engine 4, it is desirable that the catalyst be heated in advance before the operation of the engine 4 starts, and that the engine 4 be warmed up before the generator 5 is driven. Therefore, the heating time d ₁ required until the catalyst device 23 acts effectively is calculated based on the current catalyst temperature, the time required to warm up the engine 4 based on the current temperature of the radiator 21 d ₂ is calculated. The heating time d ₁ and time required for warm-up d ₂ start time d ₃ by adding the (warm-up time) of the catalytic converter 23 is determined.

Although the accelerator position sensor 8 which directly reflects the driver's intention has been described as an example of the driving state detecting means, the output control of the motor 3 is performed regardless of the depression of the accelerator pedal 7 when traveling uphill. In the case of a vehicle or the like that is controlled so as to keep the output of the vehicle constant, the driving is performed based on information instructed to the motor 3, that is, based on information of running state detecting means for detecting the running state of the vehicle. It is also possible to determine the state. Also, the means for detecting the operating state of the engine 4 is not limited to the water temperature of the radiator 21 and the catalyst temperature of the catalyst device 23, but may be a means for counting time from engine start or for directly detecting the state of exhaust gas. It is also possible to use means.

Next, the content of the power generation start processing in the hybrid electric vehicle described above will be described with reference to FIGS.

As shown in FIG. 3, first, in step S1, the battery 1
It is determined whether or not the charging rate A exceeds a predetermined value a.
When it is determined that the charging rate A of the battery 1 is equal to or less than the predetermined value a, the process proceeds to step S2. In step S2, an operation command is output to the engine 4 and the generator 5 based on various conditions, power generation is started by controlling the exciting current, and the battery 1 is charged.

If it is determined in step S1 that the charging rate A of the battery 1 exceeds the predetermined value a, the process proceeds to step S1.
Proceeding to 3, the ratio B is compared with the set ratio b. That is, it is determined whether or not the ratio B (actual output D / instruction output P) between the actual output D and the instruction output P computed by the computing means 11 is smaller than the set ratio b stored in the storage means 14 in advance. It is judged. If it is determined that the ratio B is smaller than the set ratio b, the output of the motor 3 is insufficient for the driver's required output, and the process proceeds to step S4 and shifts to the process leading to the start of power generation (limit Time calculation). If it is determined in step S3 that the ratio B is greater than the set ratio b, it means that the output of the motor 3 substantially matches the output required by the driver, and therefore does not shift to the process leading to the start of power generation. It returns to step S1.

In step S4, a plurality of actual outputs D (D ₁ , D ₂ , D) when the ratio B stored in the storage means 14 is calculated.
₃ ... D _n ) is updated. In step S5, based on the data of a plurality of actual output D updating determined parameters approximated quadratic equation by the least square method (see FIG. 5), from the present time it detects a latest actual output D _n of the motor 3, The actual output D of the motor 3 is set to the lower limit set value c based on the parameter approximated by the quadratic expression by the least square method (see FIG. 5).
Is calculated (limit time calculation means).

[0023] After calculating the time Δt in step S5, the heating time d ₁ required until the catalyst device 23 acts effectively on the basis of the current catalyst temperature is calculated in step S6, the current cooling water in step S7 Engine 4 based on temperature
The time required to warm up d ₂ of is calculated. Thereafter, the heating time d ₁ and time required for warm-up d ₂ of the engine 4 of the catalytic converter 23 is added in step S8, the start time d ₃ until the engine 4 starts to operate effectively, i.e., the generator 5 The operation time of the engine 4 until driving is calculated (start time calculation means).

After calculating the start time d ₃ , the time Δt (the limit time calculated by the limit time calculation means) until the actual output D reaches the lower limit set value c in step S 9 and the engine 4
And a start time d ₃ until the start of effective operation are compared. Result of the comparison, when it is determined that the time Δt becomes the start time d ₃ below, the catalyst was heated to warm up the engine 4 (actuating the prime mover device) performs the power generation preparation routine in step S10, in step S2 Power generation is started, and the battery 1 is charged (control means). Step S
Longer than the time Delta] t is the start time d ₃ 9, i.e., if there is a state output of the motor 3 to the required output of the driver is insufficient, it is determined that there is sufficient margin in time Delta] t, the step S1 Return to the processing of.

That is, the time until the actual output D of the motor 3 reaches the lower limit set value c (the time Δt which is the limit time) is equal to the operation start time (start time) of the engine 4 until the generator 5 can be driven. d ₃ ) When the temperature falls below, preheat the catalyst,
Further, the process proceeds to a power generation preparation routine for warming up the engine 4 (step S10), and thereafter, the battery 1 is charged.

The processing content of the power generation preparation routine will be described with reference to FIG. First, in step S11, the heating of the catalyst of the catalyst device 23 is started by a power generation preparation command from the control device 6. The catalyst device 23 is provided with an electric heating device 24 that operates independently of the operation of the engine 4, and the catalyst is heated by the heating device 24. Next, in step S12, it is determined whether or not the temperature of the catalyst is equal to or higher than a predetermined temperature.
The temperature of the catalyst is detected until the temperature of the catalyst exceeds a predetermined temperature,
If it is determined that the temperature of the catalyst has reached a predetermined temperature or higher, the temperature of the cooling water is detected in step S13.

In step S14, a warm-up time is set according to the detected temperature of the cooling water. That is, a plurality of warm-up times of the engine 4 according to the temperature of the cooling water are set, and are stored in the control device 6 as a table.
The warm-up time of the engine 4 is set longer as the water temperature is lower. After setting the warm-up time, the engine 4 is started in step S15, and it is determined in step S16 whether the set warm-up time has elapsed. The warm-up time is detected until the set warm-up time has elapsed, and when it is determined that the set warm-up time has elapsed, the process proceeds to the main process (FIG. 3) and power generation is started in step S2. You.

Another embodiment of the power generation start routine will be described with reference to FIG. As in the embodiment shown in FIG. 4, heating of the catalyst of the catalyst device 23 is started in step S11,
It is determined in step S12 whether or not the temperature of the catalyst is equal to or higher than a predetermined temperature. If it is determined that the temperature of the catalyst is equal to or higher than the predetermined temperature, the temperature of the cooling water is detected in step S13. afterwards,
In step S21, the engine 4 is started, and in step S2
At 2, the temperature of the cooling water is detected again. The coolant temperature is detected in step S23 until the coolant temperature becomes equal to or higher than the predetermined temperature, and when the water temperature becomes equal to or higher than the predetermined temperature, it is determined that the engine 4 has been warmed up. When the engine 4 is warmed up,
After shifting to the main process (FIG. 3), power generation is started in step S2. That is, in the present embodiment, the warm-up of the engine 4 is determined based on the temperature of the cooling water, and the setting of the warm-up time is unnecessary.

Therefore, according to the above-described power generation control device,
When the charging rate A of the battery 1 becomes equal to or less than the predetermined value a, power generation is started immediately and charging is performed.
A decrease in the output of the motor 3 can be prevented.

In the hybrid electric vehicle according to the above-described embodiment, the time required for the actual output D of the motor 3 to reach the lower limit set value c is determined when the time Δt, which is the limit time, becomes equal to or less than the start time d _3. Since the catalyst device 23 is heated and the engine 4 is warmed up, the catalyst is preliminarily heated, and the engine 4 is warmed up before being charged, the battery 1 can be charged efficiently. It is possible to prevent the output of the motor 3 from decreasing without deteriorating the exhaust gas performance. As a result, the power generation can be performed in a state where the output of the motor 3 does not decrease without deteriorating the exhaust gas performance, and the power performance of the hybrid electric vehicle does not decrease.

Further, in the hybrid electric vehicle according to the above-described embodiment, even if the charging rate A of the battery 1 exceeds the predetermined value a, it is determined according to the actual output D of the motor 3 and the depression amount of the accelerator pedal 7. When the ratio B to the required instruction output P is smaller than the set ratio b, that is, when the output of the motor 3 is insufficient for the driver's required output, power generation is started and charging is performed. Like that.
For this reason, even if the charging rate A of the battery 1 is sufficient, when the temperature of the battery 1 is low or when the battery 1 is deteriorated, power generation is started and charging is performed. Can be prevented. As a result, power can be generated in a state where the output of the motor 3 does not decrease, and the power performance of the hybrid electric vehicle does not decrease.

In the above-described embodiment, the comparison between the actual output of the motor 3 with respect to the output required by the driver is performed by determining the ratio B (actual output D / instruction output P) of the actual output D and the instruction output P to the set ratio b. However, the actual output D and the instruction output P may be directly compared by calculation.

[0033]

According to the hybrid electric vehicle of the present invention, the time when the limit time until the actual output of the motor reaches the lower limit is equal to the time (start time) for driving the prime mover device in a good state. (When the limit time becomes equal to or less than the start time), that is, in a state where there is a margin to keep the state of the prime mover device good, the driving of the generator by the operation of the prime mover device is started after the state of the prime mover device is kept good. As a result, power can be efficiently generated, and the prime mover device can be operated in a good state without deteriorating the exhaust gas performance and the like. As a result, a decrease in the output of the electric motor does not occur in a state where the state of the prime mover device is maintained in a good state, and it is possible to prevent a decrease in the power performance of the hybrid electric vehicle.

Further, since the driving of the generator is controlled based on the driving state of the vehicle and the actual output of the motor, it is possible to start the power generation when the actual output of the motor is insufficient for the driving state. it can. Further, when the actual output of the electric motor becomes insufficient with respect to the operation state, power generation can be started to charge the power supply device. For this reason, even when the temperature of the power supply device is low or the power supply device is deteriorated, charging can be performed before the charging rate of the power supply device decreases.

[Brief description of the drawings]

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

FIG. 2 is a block diagram of a control device in the hybrid electric vehicle according to one embodiment of the present invention.

FIG. 3 is a flowchart of a power generation start process by a control device shown in FIG. 2;

FIG. 4 is a flowchart of a power generation preparation routine in FIG. 3;

FIG. 5 is a graph showing a predicted state of an output of a motor with respect to an elapsed time.

FIG. 6 is a flowchart of a power generation preparation routine.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Battery 2 Motor controller 3 Motor 4 Engine 5 Generator 6 Control device 7 Accelerator pedal 8 Accelerator opening sensor 9 Actual output detecting means 10 Remaining capacity meter 11 Computing means 12 Judging means 13 Instruction means 14 Storage means 21 Water jacket 22 Water temperature sensor 23 Catalyst device 24 Heating device 25 Temperature sensor

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B60L ⁷ /00-13/00 B60K 6/02 F02D 29/06 H02J 7/00

Claims (5)

(57) [Claims] An electric motor for driving a driving wheel of a vehicle by supplying electric power from a power supply device, a generator for supplying electric power to the power supply device and the electric motor, and a motor device for driving the generator. Hybrid electric vehicle
Operating state detecting means for detecting an operating state of the vehicle; actual output detecting means for detecting an actual output generated by the electric motor; lowering limit setting means for setting a lowering limit of the output of the electric motor; Limit time calculating means for calculating a limit time until the actual output reaches the reduction limit based on the driving state of the vehicle detected by the means and the actual output of the electric motor detected by the actual output detecting means; A start time calculating means for calculating a time until the prime mover device can drive the generator based on a state of the prime mover device, and the limit time calculated by the limit time calculating means by the start time calculating means. Control means for operating the motor device when the calculated start time is equal to or shorter than the start time. 2. The hybrid electric vehicle according to claim 1, wherein said control means drives said generator by said motor device when said motor device is ready to drive said generator. 3. The method according to claim 2, wherein the limit time calculating means determines that a ratio between an instruction output output to the motor and the actual output based on the information obtained from the operating state detecting means is smaller than a predetermined value. The hybrid electric vehicle according to claim 1, wherein the calculation of the limit time is performed. 4. The hybrid electric vehicle according to claim 1, wherein said limit time calculation means approximates a quadratic expression of a plurality of stored actual output values by a least squares method. 5. The motor device has a catalyst for purifying exhaust gas of the motor, and the start time includes a heating time for heating the catalyst to a predetermined temperature and a warm-up time for warming up the motor. The hybrid electric vehicle according to claim 1, wherein: