KR20050098681A - Parallel hybrid electric vehicles of control system and method thereof - Google Patents

Abstract

In the parallel hybrid electric vehicle, when the engine is started by the motor and the cranking is judged to be completed, the motor speed command mode is changed from the motor speed command mode to the torque command mode of the motor and the engine. By maintaining it, the SOC is always maintained in an optimal state, and when it is determined that the cranking is completed, the amount of negative torque is reduced and controlled to provide a stable riding comfort.

When the engine start request is detected by the start key, it is determined whether the start condition by the motor is satisfied.When the start condition by the motor is satisfied, the speed command mode of the motor is set to the target idle RPM of the engine, and then the motor is turned to the normal torque. When the speed of the motor controlled by the constant torque is maintained after a predetermined idle RPM of the engine, the engine is started by fuel injection and ignition to the engine, and the motor is turned into Controlling to prevent sudden increase in motor speed and charging the battery, and follow the target idle RPM of the engine with the motor speed set according to the engine start attempt. Switches to the torque command mode of the engine and motor, and reduces the negative torque to a size proportional to the size of the load. Controlling to maintain charging of the battery; determining whether the SOC of the battery has been charged to a level capable of assisting and starting the motor by the control of the negative torque; and if charging of the battery above the set level is detected. And controlling the target idle RPM of the engine by releasing the negative torque and maintaining the sum of torques equal to the load through the torque control of the motor proportional to the magnitude of the load.

Description

PARALLEL HYBRID ELECTRIC VEHICLES OF CONTROL SYSTEM AND METHOD THEREOF

The present invention relates to a parallel hybrid electric vehicle, and more particularly, the motor speed command mode is changed from the motor speed command mode to the torque command mode of the motor and the engine at a time when it is determined that the cranking is completed after the engine is started by the motor, and the motor for a predetermined time. By maintaining the driving time of the battery to maintain the charging time of the SOC to maintain the optimum state at all times, and at the time when the cranking is judged to be completed by reducing the amount of negative torque to a low slope in parallel to provide a stable ride A control device and method for a hybrid electric vehicle.

The parallel hybrid electric vehicle directly connects the electric motor to a gasoline engine and transmits power to the wheels through CVT (Continuously Variable Transmission) .When the driver drives the accelerator pedal, the throttle valve is the engine's OOL (Optimal Operating Line). According to), the power that is supported by the driving of the motor by the voltage supplied from the battery is supported for the torque that is open and short.

In a parallel hybrid electric vehicle, an idle stop function is provided, and the engine is started by a hybrid motor or a start motor according to the state of the state of charge (SOC) of the battery and the condition of the outside temperature. .

That is, if the temperature of the outside air is set to a reference temperature, for example, below 10 ° C and the SOC of the battery is determined to be normal, starting by the motor is given priority.

On the other hand, if the outside temperature is kept below the set reference temperature causing the performance of the battery or the SOC of the battery is low, starting by the motor is impossible, so start with the start motor using a 12V auxiliary battery.

The idle stop function improves fuel economy by turning off the engine when the vehicle is detected to stop by the driver's brake pedal while the vehicle is running, and starting the engine again when the brake pedal is released. .

The operation for the idle stop will be described in more detail with reference to FIG. 4 as follows.

When the start request by the start key is detected by the host controller, the HCU (Hybrid Control Unit), the HCU outputs a speed command for driving the motor, such as A1, to the MCU (Motor Control Unit).

Accordingly, the MCU controls the motor to the constant torque according to the battery discharge current amount control of the battery management system (BMS) to turn on the engine.

When the ignition occurs to start the engine by driving the motor as described above, the speed of the vehicle rapidly increases, so that the HCU operates as a generator by controlling the motor as a negative torque through the MCU, thereby improving the voltage generation of the motor. To charge the battery.

In addition, if it is detected that the motor speed reaches the idle RPM of the engine after the engine is turned on through the above operation, it is determined that the cranking is completed, and the driving of the motor is stopped and the engine enters the torque command mode. In order to maintain the idle speed, torque is applied to the engine in proportion to the magnitude of the load.

As described above, in the case of the conventional parallel hybrid electric vehicle, at the time when it is determined that the cranking is completed, the motor stops driving and enters the torque command mode of the engine, and the size of the load on the engine to maintain the idle speed. As the torque is proportional to, the speed of the engine increases rapidly due to the rapid decrease of the motor load, and then the riding comfort decreases as the stability stabilizes after a certain time.

In addition, in the case of a hybrid electric vehicle, conditions for charging / discharging for each SOC are set as shown in Table 1 below to ensure efficient use, durability, and protection of a battery.

Item SOC (%) Control Contents One 0 to 17.9 Do not use motor to protect battery 2 18 to 54.9 Use of motor at start, prohibit motor power support, regenerative braking charge 3 55-79.9 Motor use at start-up, motor power support, regenerative braking charge 4 80-100 Use motor at start, support motor power, prohibit regenerative braking charge

Therefore, it is impossible to perform power support of the motor until the SOC is charged to a certain amount, about 55 to 79.9% or more by regenerative braking while driving after starting the motor in a state where the SOC of the battery is low (18 to 54.9%). Problems that result in degradation occur.

In addition, when repeatedly starting while maintaining the idle state to turn on the heater or air conditioner while not driving, there is a problem that the start of the phenomenon due to the motor as the SOC of the battery is gradually lowered.

In addition, since the driving of the motor is stopped immediately after the ignition of the engine and the engine torque command is entered, the engine and the motor maintain a constant speed, thereby causing a problem in reducing fuel efficiency.

The present invention has been invented to solve the above problems, the object of which is the torque command mode of the motor and the engine in the motor speed command mode if it is determined that the cranking completion of the motor speed reaches the idle RPM when starting by the motor In this case, the SOC of the battery is optimally maintained at all times by maintaining the driving time and maintaining the generation time through the negative torque control (generation control) for a predetermined time.

In addition, the present invention is to provide a stable ride comfort and improved fuel economy by reducing the control to a low inclination in applying a torque proportional to the size of the load to maintain the idle speed at the time when the cranking completion is determined.

In addition, as the torque of the motor is reduced, the engine torque is controlled in proportion to the motor torque, so that the sum of the torques is always the same as the size of the load so as to provide a stable ride without rumbling of the speed.

According to an aspect of the present invention, there is provided a parallel hybrid electric vehicle equipped with a motor and an engine, comprising: a driving request detection unit detecting a starting request and a driving request signal of an engine; An ECU controlling general operation of driving of the engine; A TCU for controlling the output torque according to the current vehicle speed, gear ratio and clutch state information; A battery which supplies a starting voltage when the engine starts, supports the power of the motor while driving, and recovers and regenerates the regenerative braking energy of the motor operating as a generator during engine mode and braking control; A BMS for comprehensively detecting voltage, current, and temperature information of the battery to manage and control the SOC state, and to control the power of the motor and the amount of output current when the engine is started; Integrated control of the above controllers controls the overall behavior of the vehicle, outputs a speed command to the motor at start-up to follow the target idle RPM of the engine with the constant torque, and prevents the vehicle's speed from increasing rapidly during engine ignition. In order to control the motor as a negative torque to provide a control device for a parallel hybrid electric vehicle comprising a HCU / MCU to operate by a generator to charge the battery.

In addition, the present invention comprises the steps of determining whether the start condition by the motor is satisfied when the engine start request by the start key is detected; Setting a speed command mode of the motor to a target idle RPM of the engine when the starting condition by the motor is satisfied, and then controlling the motor to a constant torque; When the speed of the motor controlled by the constant torque is maintained for a predetermined time following the target idle RPM of the set engine, the engine is attempted to start by fuel injection and ignition to the engine, and the motor is controlled as a negative torque at the time of ignition. Preventing rapid rise in speed and performing battery charging; When following the engine idling attempt to follow the target idle RPM of the set engine speed, if it is determined that the cranking is completed and the idle RPM of the engine is maintained, the motor speed command mode is switched to the engine and motor torque command mode. Maintaining a charge of the battery by controlling the negative torque to a size proportional to the size; Determining whether the SOC of the battery is charged to a level capable of power assistance and start-up of the motor by controlling the negative torque; When the SOC of the battery is detected to be charged above the set level, the torque is controlled by the motor which is proportional to the size of the load at the same time as the negative torque is released, thereby maintaining the target idle RPM of the engine by maintaining the sum of the torque equal to the load. It provides a control method of a parallel hybrid electric vehicle, comprising the process.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

As can be seen in Figure 1, the control device for a parallel hybrid electric vehicle according to the present invention is the driving request detection unit 10 and ECU 20, TCU 30, battery 40, BMS (50), HCU / MCU 60, engine 70, motor 80, CVT 90, and drive wheel 100.

The driving request detection unit 10 detects a driver's vehicle driving request, an acceleration position sensor (APS) signal for a driver's starting request, a start and an acceleration request, a brake pedal signal for controlling braking, and an inverter for selecting a shift stage. Detect the traffic light of the switch and output electrical information about it.

The ECU 20 controls overall operations of the engine according to the vehicle driving request signal of the driver from the driving request detection unit 10 and engine state information such as coolant temperature and engine torque.

The TCU 30 controls the overall operation of the output torque adjustment of the CVT 90 by detecting information such as the current vehicle speed, gear ratio, and clutch status.

The battery 40 supports the output power of the motor by supplying a voltage to the motor 80 in the hybrid driving mode, and supplies a voltage at the start of the engine by the motor 80, and operates as a generator during engine mode and braking control. The regenerative braking energy of 80 is recovered and charged.

The BMS 50 manages and controls the SOC state of the battery 40 by comprehensively detecting information such as voltage, current, and temperature of the battery 40, and supports the power of the motor 80 and at the start of the engine 70. Control the amount of current output to

The HCU / MCU 60 controls the overall behavior of the vehicle by controlling each controller according to the driver's oscillation control request, controls the output torque and speed of the motor 80, and converts the motor 80 into an electric motor or a generator. Control to operate.

In addition, by outputting a speed command to the motor 80 at start-up, the motor 80 follows the speed command with a constant torque, and the motor 80 is prevented from being rapidly increased during engine ignition. By controlling the negative torque to operate as a generator to maintain the charge of the battery 40.

In addition, when the speed of the motor 80 reaches the idle RPM after ignition of the engine, it is determined that the cranking is completed, and the motor speed command mode is switched to the torque command mode of the motor and the engine, and the load size is maintained to maintain the idle speed. In applying proportional torque, the negative torque is applied at a set decreasing slope to provide stability of the engine and provide a stable ride.

In addition, the HCU / MCU 60 sets the driving time of the motor 80 so that the SOC of the battery 40 can charge 55-80% of the motor 80 and can support normal driving and power support. It extends as much as possible, and when the set driving time elapses, the negative torque is applied at a constant slope to keep the SOC of the battery 40 stable.

In addition, as the torque of the motor 80 is reduced, the engine torque is controlled so that the sum of torque is always proportional to the magnitude of the load so that a stable ride comfort and reliability can be provided by a control in which a deviation of speed does not occur.

The output of the engine 70 is controlled by the control of the ECU 20 under the control of the HCU, which is the host controller, and the amount of intake air is adjusted through the electric throttle control (ETC).

The motor 80 is typically applied to a BLDC motor, and when the initial driving request is detected, the motor 80 is driven by the voltage of the battery 40 to start the engine 70, and to turn on the power when driving by the output of the engine 70. It supports and operates as a generator to charge the battery 40.

The CVT 90 adjusts the speed ratio under the control of the TCU 30 to transmit the power transmitted from the motor 80 to the driving wheel 100 through the differential gear so that the vehicle can be driven.

Referring to Figures 2 and 3 with respect to the control operation of the parallel hybrid electric vehicle according to the present invention including the function as described above are as follows.

When the on of the start key is detected, the HCU / MCU 60 analyzes the general state information of the vehicle to determine whether the starting condition by the motor 80 is satisfied (S101).

The starting condition by the motor 80 is a reference temperature at which the outside air temperature is set, approximately minus 10 degrees Celsius or more, and the SOC of the battery 40 is startable as in the conditions shown in Table 1 above, for example, at least 18 It is a condition that keeps more than%.

If the start state by the motor 80 is not possible in S101, the engine is started by the starter motor according to the voltage supply of the auxiliary battery (not shown) (S200).

However, if it is determined that the condition that satisfies the starting condition by the motor 80, that is, the outside temperature is maintained above the set reference temperature and the SOC of the battery 40 is maintained in the startable state, the motor 80 speed command mode. Set (S102).

The speed command value of the motor 80 set above is set to a target idle RPM of the engine 70, that is, approximately 700 RPM as shown in the table of FIG.

Thereafter, as shown in FIG. 3, the speed command is applied to the motor 80 through the MCU to control the motor 80 to the constant torque according to the discharge current amount control of the BMS 50, and the speed of the motor 80 is set to the engine ( The target idle RPM of 70) is followed (target idle RPM ± ΔRPM of the engine 70), and it is determined whether to maintain a predetermined time (S103).

If the speed of the motor 80 does not follow the target idle RPM of the engine 70 for a predetermined time or more in step S103, the process returns to step S102, and the speed of the motor 80 is the target idle of the engine 70 for a predetermined time or more. If it is determined that the RPM is to be followed, fuel is injected into the combustion chamber of the engine 70 through the ECU 20 and then ignition is performed to attempt to start on the engine 70 (S104).

Since the speed of the vehicle is rapidly increased when the ignition for starting the engine 70 is turned on as described above, as shown in FIG. 3, the HCU / MCU 60 controls the motor 80 as a negative torque generator. By operating as, the battery 40 is charged through voltage generation of the motor.

At this time, the negative torque of the motor 80 to be controlled is reduced and controlled to the slope corresponding to the RPM change of the engine 70.

After the start of the engine 70 is turned on by the above operation, it is determined whether the speed of the motor 80 and the target idle RPM ± ΔRPM of the engine 70 are followed (S105).

When it is determined that the speed of the motor 80 and the target idle RPM ± ΔRPM of the engine 70 are being followed, it is determined that the cranking is completed and the idle RPM of the engine 70 is maintained (S106).

When the crank is completed and the idle RPM is maintained after starting the engine 70, the speed command mode of the motor 80 is reset and the torque command mode of the motor 80 and the engine 70 is set. As shown in the drawing, the driving of the motor 80 is continuously maintained so that the charging of the battery 40 is continuously maintained by the negative torque of the motor 80, and to prevent the speed of the vehicle from increasing rapidly. The torque command value of the motor 80 adds a predetermined value, for example, 3 Nm, to the current motor 80 torque, and maintains the engine torque command value at '0' (S107).

It is determined whether the torque of the motor 80 is maintained larger than the current load in the state in which the control as described above (S108), and if it is determined that the large state is maintained, the SOC of the battery 40 It is determined whether the power of the motor 80 and the start-up are sufficient, for example, the SOC is charged at 70% or more (S109).

If the SOC of the battery 40 is not charged in a state sufficient to support and start the power of the motor 80, the torque command of the motor 80 is maintained under the load condition to continuously charge the battery 40. Keep it as (S110).

When it is determined that the SOC of the battery 40 is sufficiently charged to enable power support and start-up of the motor 80, the motor 80 is added by adding a predetermined value, for example, 3 Nm, to the current motor 80 torque. The command torque of the motor 70 is controlled upward to terminate the drive of the motor 70, and the torque command of the engine 70 is reduced and controlled by the torque command value of the motor 80 at the current load to reduce the torque of the motor 80. As much as the engine 70 torque is reduced, the sum of the torques is always maintained at the same value as the magnitude of the load (S111).

Thereafter, it is determined whether the command torque of the motor 80 is continuously output, and if the output is maintained, the command torque of the motor 80 is terminated and the engine command torque follows the current load. Allow the engine 70 to follow the idle target RPM (S112) (S113).

As described above, in the parallel hybrid electric vehicle, the battery is charged and controlled in an optimal SOC state only by maintaining the idle RPM for a while even when the SOC of the battery is not driven after being started by the motor in a state where the SOC of the battery is low. The power of the motor can be supported to maximize the efficiency of hybrid electric vehicles.

In addition, when repeatedly attempting to start the idle RPM while driving the heater or air conditioner while the vehicle is stopped, the SOC of the battery maintains the optimal state, which prevents starting by the motor, thereby improving stability and reliability in the operation of the vehicle. to provide.

By maintaining the speed of the engine and the motor constant for a certain time after the engine is ignited, fuel efficiency improvement is provided and the SOC state of the battery is stabilized.

In addition, by reducing the motor load after the ignition of the engine to the set slope to eliminate the sudden deviation between the engine speed and the motor speed to provide a stable ride without engine rumble.

1 is a schematic configuration block diagram of a control device for a parallel hybrid electric vehicle according to the present invention.

2 is a flowchart of an embodiment of the control execution of a parallel hybrid electric vehicle according to the present invention;

3 is a timing diagram for control execution of a parallel hybrid electric vehicle according to the present invention;

4 is a timing diagram for control execution of a conventional parallel hybrid electric vehicle.

Claims (9)

In a parallel hybrid electric vehicle equipped with a motor and an engine, A driving request detector for detecting a starting request and a driving request signal of the engine; An ECU controlling general operation of driving of the engine; A TCU for controlling the output torque according to the current vehicle speed, gear ratio and clutch state information; A battery which supplies a starting voltage when the engine starts, supports the power of the motor while driving, and recovers and regenerates the regenerative braking energy of the motor operating as a generator during engine mode and braking control; A BMS for comprehensively detecting voltage, current, and temperature information of the battery to manage and control the SOC state, and to control the power of the motor and the amount of output current when the engine is started; Integrated control of the above controllers controls the overall behavior of the vehicle, outputs a speed command to the motor at start-up to follow the target idle RPM of the engine with the constant torque, and prevents the vehicle's speed from increasing rapidly during engine ignition. In order to control the motor as a negative torque to operate the generator to control the parallel hybrid electric vehicle, characterized in that it comprises a HCU / MCU to charge the battery. The method of claim 1, When the HCU / MCU determines that the cranking is completed after the engine is ignited, the motor speed command mode is switched to the torque command mode of the motor and the engine, and the target idle RPM is maintained by applying torque proportional to the magnitude of the load. Control device for parallel hybrid electric vehicle. The method of claim 2, The control unit of the parallel hybrid electric vehicle, characterized in that the HCU / MCU prevents a sudden increase in the speed of the engine by controlling the set slope in applying torque proportional to the magnitude of the load as the cranking of the engine is completed. . The method of claim 1, The HCU / MCU controls the negative torque of the motor to a set slope until the SOC of the battery is charged to a level at which the normal operation of the motor and the power can be supported after the cranking of the engine is completed. Control device. The method of claim 1, The control unit of the parallel hybrid electric vehicle, characterized in that the HCU / MCU is controlled so that the sum of the torque is always proportional to the magnitude of the load through the engine torque control as the torque of the motor is reduced. In a parallel hybrid electric vehicle, Determining whether a start condition by a motor is satisfied when an engine start request is detected by a start key; Setting a speed command mode of the motor to a target idle RPM of the engine when the starting condition by the motor is satisfied, and then controlling the motor to a constant torque; When the speed of the motor controlled by the constant torque is maintained for a predetermined time following the target idle RPM of the set engine, the engine is attempted to start by fuel injection and ignition to the engine, and the motor is controlled as a negative torque at the time of ignition. Preventing rapid rise in speed and performing battery charging; When following the engine idling attempt to follow the target idle RPM of the set engine speed, if it is determined that the cranking is completed and the idle RPM of the engine is maintained, the motor speed command mode is switched to the engine and motor torque command mode. Maintaining a charge of the battery by controlling the negative torque to a size proportional to the size; Determining whether the SOC of the battery is charged to a level capable of power assistance and start-up of the motor by controlling the negative torque; When the SOC of the battery is detected to be charged above the set level, the torque is controlled by the motor which is proportional to the size of the load at the same time as the negative torque is released, thereby maintaining the target idle RPM of the engine by maintaining the sum of the torque equal to the load. Control method of a parallel hybrid electric vehicle, characterized in that it comprises a process. The method of claim 6, The starting condition by the motor is a control method of a parallel hybrid electric vehicle, characterized in that the outside temperature is above the set temperature, the SOC of the battery is more than the level that can supply the starting voltage. The method of claim 6, And when the start condition by the motor is not satisfied, attempting to start the engine by starting the starter motor by the voltage of the auxiliary battery. The method of claim 6, The control method of the parallel hybrid electric vehicle, characterized in that for extending the control of the negative torque controlled for battery charging at the time of starting the engine to the time when the SOC of the battery is charged to the level capable of power assistance.