JP6585875B2 - Hybrid vehicle operation control method - Google Patents

Description

  The present invention relates to a driving control method for a hybrid vehicle, and more specifically, driving a hybrid vehicle in which the energy utilization capability of the vehicle is actively made intelligent and the fuel consumption of the vehicle is further improved by the efficient use of energy. It relates to a control method.

  The concept of the parallel hybrid is that the engine clutch is located between the engine and the drive motor, so that it is easy to control the transmission of the engine power to the wheel. By releasing the clutch, there is a great feature in entering a regenerative braking mode in which braking energy is purely absorbed by the motor.

  SOC (State Of Charge) means a high voltage battery charge state, that is, a charge amount. At this time, the high voltage battery serves as a damper by charging and discharging the motor in order to make the engine have an optimum operating efficiency.

  However, if the engine is started and stopped a number of times, it will act as a reduction in fuel consumption and load on the system. Therefore, the engine will be turned on and off stably, reflecting the driver's will to the maximum with appropriate control inputs and results. Need to achieve off.

In recent years, there has been a growing demand for environmentally friendly automobiles in accordance with the continuous demand for improving fuel economy of automobiles and the tightening of emission regulations in each country. Hybrid vehicles are attracting attention as a realistic alternative to this.
In such a hybrid vehicle, in addition to an engine that is an internal combustion engine, a motor that uses electric energy is used as a power source, and therefore, SOC management of a battery that is a storage device for electric energy has an important meaning. .

  Therefore, hybrid vehicles strive to apply driving strategies that can achieve optimal fuel economy levels while taking into account the high and low SOC conditions. Therefore, a hybrid vehicle operation control method that manages the SOC and efficiently uses energy has been proposed [see Patent Document 1]. According to this method, the SOC that is the state of charge of the battery is divided into a series of a plurality of regions, and a separate power distribution strategy is applied to each SOC region, and a power distribution strategy such as a separate operation map provided for each region. To select the torque that must be generated from the engine and the torque that must be generated from the motor, etc., determine which SOC area the current SOC belongs to, and according to the corresponding power distribution strategy, It is intended to be run.

  This power allocation strategy basically reduces the torque generated by the motor in the low SOC region to suppress the additional decrease in SOC, and allows the vehicle to run and the battery to be charged with the power generated from the engine to allow the SOC to rise. If the SOC is low, the engine power is used to perform idle charging. If the SOC is lower, the battery is disconnected from the electronic equipment. Also, in the high SOC region, the specific gravity of torque generated from the motor is increased by allowing or inducing a decrease in SOC, and the use of the engine is suppressed as much as possible to improve the fuel consumption of the vehicle.

  In addition, there is a proposal of a hybrid vehicle that can increase the operating efficiency of the engine while suppressing a decrease in the charging efficiency of the battery, and can improve the energy efficiency of the entire vehicle [see Patent Document 2].

  On the other hand, in recent years, due to the rapid development of information technology (IT) related to vehicles, the vehicle can relatively easily obtain various information about the road on which the vehicle travels. It is possible to improve fuel efficiency by improving the driving strategy. For example, information on road conditions, current vehicle conditions, and past operation conditions is acquired, and it is predicted whether or not fuel efficiency of the vehicle will be deteriorated based on these information, resulting in deterioration of fuel efficiency. There is a proposal of a driving assistance device that, when predicted, notifies a vehicle occupant in advance of an operation for improving fuel consumption [see, for example, Patent Document 3].

Korean Patent Publication No. 10-2013-0024413 Specification JP 2011-240757 A JP 2012-013021 A

  An object of the present invention is to provide an operation control method for a hybrid vehicle in which the energy utilization capability of the vehicle is actively made intelligent to use the energy efficiently and improve the fuel efficiency of the vehicle.

The present invention is an operation control method for a hybrid vehicle having an SOC target in which a state of charge (SOC) is divided into a high region, a middle region, and a low region, and an engine target torque preset for each SOC region,
The engine target torque is calculated from the SOC region to which the current state of charge (SOC) belongs, and when the current SOC is larger than the maximum value within a certain range , the corrected engine target torque is obtained by reducing the magnitude of the calculated engine target torque. When the engine is controlled and the SOC is smaller than the minimum value in the certain range, the engine is controlled to the corrected engine target torque obtained by increasing the magnitude of the calculated engine target torque, and the current SOC is within the certain range. If the engine is controlled to the calculated engine target torque if there is an inertial running in which neither the accelerator pedal nor the brake pedal is depressed, the clutch between the engine and the motor is turned off at a certain SOC or more, and the vehicle speed is The SOC is gradually lowered as the clutch-off criterion increases as the value increases.

When the SOC traveling road is uphill is higher than a certain value, the engine is controlled to the corrected target engine torque reduced the size of the target engine torque the calculated were the calculated higher slope increases engine It is characterized in that the degree of reduction in the magnitude of the target torque is increased.

  In inertial driving where neither the accelerator pedal nor the brake pedal is depressed, the creep torque of the motor is increased in a negative direction as the vehicle speed increases. When the road is downhill, make it suddenly larger than on flat ground.

A driving control method for a hybrid vehicle having an SOC target in which a state of charge (SOC) is divided into a high region, a middle region, and a low region and an engine target torque preset for each SOC region,
The engine target torque is calculated from the SOC range to which the current state of charge (SOC) belongs, and the engine is controlled to the corrected engine target torque that is reduced when the current SOC is above a certain range. The engine is controlled to the corrected engine target torque obtained by increasing the calculated engine target torque when the SOC is below a certain range. If the current SOC is within the certain range, the engine is adjusted to the calculated engine target torque. Control
When the inertial running without the accelerator pedal or the brake pedal is performed, the clutch between the engine and the motor is turned off at a certain SOC or more, and the SOC that becomes the reference for clutch-off is determined based on the slope of the running road. Compared to the case of flat ground, it is characterized in that it is highest when the road is uphill and lowest when it is downhill.

Wherein in a range above about the current SOC is higher lowers greater the magnitude of the target engine torque, the current SOC is higher up greater the magnitude of the target engine torque lower below the predetermined range, the travel path There when uphill, characterized in that to lower the said engine target torque than the flat or downhill.

According to the traveling mode control method for a hybrid vehicle of the present invention, frequent start / stop of the engine is prevented, and the fuel consumption is thereby reduced.
Further, the engine and the clutch can be protected, and the battery charge amount can be effectively ensured. Since power control is performed with different maps depending on the vehicle speed and the inclination, it is possible to simultaneously improve fuel consumption, improve driving texture, and stabilize vehicle durability.

1 is a block diagram showing an embodiment of a driving control method for a hybrid vehicle according to the present invention. It is a figure which shows the driving mode of the driving | running control method of a hybrid vehicle. It is another block diagram of the driving control method of a hybrid vehicle. It is a graph which shows the effect of the driving control method of the hybrid vehicle by the present invention. It is a graph which shows the effect of the driving control method of the hybrid vehicle by the present invention. It is a graph which shows the effect of the driving control method of the hybrid vehicle by the present invention. It is a graph which shows the effect of the driving control method of the hybrid vehicle by the present invention.

Hereinafter, a hybrid vehicle operation control method according to the present invention will be described in detail with reference to the accompanying drawings by way of preferred embodiments.
FIG. 1 is a block diagram of a driving control method for a hybrid vehicle, FIG. 2 is a diagram showing a driving mode, and FIG. 3 is a block diagram in another embodiment of a driving control method for a hybrid vehicle.

  The hybrid vehicle operation control method of the present invention is a hybrid vehicle operation control method having a high region / medium region / low region SOC region, and an engine target torque corresponding to each SOC region, which is a current SOC. The engine target torque is calculated from the above, and when the current SOC is above a certain range, the engine target torque is decreased, and when the SOC is below the certain range, the engine target torque is increased.

  In the hybrid vehicle operation control method of the present invention, the SOC region is divided into a high region / medium region / low region, and the SOC region of the high region / medium region / low region is further divided into detailed regions subdivided according to the vehicle speed, The engine target torque can be set for each detail area. FIG. 1 is a block diagram of a hybrid vehicle operation control method, in which an engine target torque map is divided into a high region / middle region / low region SOC region, and these are further divided into a high region (VERY HIGH) / high region (HIGH). ) / Medium-high region (NORMAL HIGH) / Medium-low region (NORMAL LOW) / Low region (LOW) / Low-low region (VERY LOW). Each area is further subdivided (general, high speed, city center, etc.) depending on the vehicle speed.

  That is, the engine target torque is calculated by taking into account both the current SOC and the vehicle speed, and the optimum engine in the current situation is determined by a data map in which the SOC and the vehicle speed are input and the engine target torque corresponding to each detail area is output. Output torque.

  Thus, even if the target torque of the engine is calculated using the engine target torque map in consideration of the current SOC and vehicle speed, fine adjustment is required. When the current SOC is above a certain range, the engine target torque is decreased, and when the SOC is below a certain range, the engine target torque is increased.

  In other words, when the engine target torque is made uniform regardless of the variation in the SOC, if the SOC is high, it is output with the target engine torque optimized in advance, but the vehicle durability, driver deviation, driver boarding There is a possibility that the traveling load may change depending on the personnel, and it may proceed to a higher SOC region. If the SOC is low, the vehicle's durability, driver deviation, and excessive traveling load due to the driver's occupant under high load conditions There is a possibility that the SOC is greatly reduced by excessive use compared to the target engine torque.

  Therefore, by confirming the driving load condition based on the average vehicle speed and the inclination angle and performing variable control for compensating the engine torque according to the SOC state, the engine torque is lowered by the driving load when the current SOC is a high SOC exceeding a certain range. The SOC is variably controlled so that the SOC is not charged to improve fuel efficiency. On the other hand, when the current SOC is a low SOC below a certain range, when the SOC enters the SOC region where the SOC is low due to the traveling load, first, a control for compensating the engine torque is performed to prevent a sudden drop in the SOC. FIG. 4 shows such engine target torque control. When the SOC is 45 to 70% or more, which is below a certain range, the engine target torque is gradually decreased, and when the SOC is below, the engine target torque is gradually increased. .

  When the travel path is uphill and the SOC is equal to or higher than a certain value, the engine target torque is decreased, but the degree of decrease in the engine target torque is increased as the inclination increases. When the road is downhill, the stop point of the engine is advanced as the inclination increases.

  Such an uphill or downhill situation can be reflected with reference to a travel mode according to travel load provided in advance. Specifically, FIG. 2 is a diagram showing a driving mode of the driving control method for a hybrid vehicle according to the present invention. A plurality of fine driving modes are provided in consideration of the vehicle speed and the inclination of the driving path, and each priority order is determined. It is possible to keep.

  In other words, the travel mode includes a mode that is classified according to the vehicle speed and a mode that is classified according to the inclination of the travel path. A data map that inputs the vehicle speed and the slope of the road and outputs the driving mode is provided. The data map includes a mode that is classified by the vehicle speed or a mode that is classified by the slope for each case that matches the vehicle speed and the slope. Either one can be prioritized and saved as a result.

  In the example shown in the figure, the driving mode is controlled by selecting the driving mode according to the vehicle speed when the vehicle speed is very slow and the slope is general flat, and the driving mode is determined by the inclination in other cases. Is to select and operate.

  By referring to the driving mode, the degree of inclination can be found, and considering this, when the road is uphill and the SOC is above a certain value, the engine target torque is reduced, but the degree of decrease in the engine target torque increases as the inclination increases. Increase FIG. 5 shows such a control situation. In a situation where the SOC is 55% or more, the engine target torque is gradually decreased on the uphill, and the engine target torque increases as the slope increases, that is, as the slope of the uphill increases. Try to lower the torque.

  This may cause SOC charging when the vehicle load is small during uphill traveling, and SOC charging may occur when traveling downhill after uphill, resulting in a deterioration in fuel consumption. However, depending on the average vehicle speed and inclination angle By checking the driving load condition and variably controlling the engine torque according to the SOC state, the engine torque is variably controlled according to the SOC state during the uphill driving, and the SOC is prepared in preparation for the charging situation that occurs during the subsequent downhill driving. It can be controlled to maintain an appropriate level (55%).

  In the case of a downhill, the electric vehicle mode (EV mode) starts earlier by making the engine stop point earlier as the inclination increases. Conventionally, when traveling downhill, if the vehicle does not enter the EV even if it can travel on EV, the fuel consumption deteriorates when the engine torque is controlled with the engine optimum operating point as the target (optimal operation on the engine). However, although the target torque is high and the amount of fuel consumption is large), by such variable control, entry into the EV can be advanced quickly to prevent unnecessary fuel consumption deterioration.

  When determining modes such as extreme traffic jam, city center, and general according to the vehicle speed, more accurate mode determination can be made by considering not only the vehicle speed but also the number of times the vehicle has stopped. In other words, even if the vehicle speed is very fast, if the number of stops is more than a certain standard prepared in advance, it is considered as “city center” mode when traveling in the city, and if the vehicle does not stop even if the vehicle speed is very slow It is determined that the vehicle is traveling on a highway and is in “high speed” mode. Thus, by determining the mode in consideration of the vehicle speed and the number of stops, it is possible to determine a more accurate mode classified by the vehicle speed.

  FIG. 3 is another block diagram of the driving control method for a hybrid vehicle according to the present invention. In the case of inertia traveling where neither the accelerator pedal nor the brake pedal is depressed, the creep torque of the motor increases in the negative direction as the vehicle speed increases. To do. That is, when neither the accelerator pedal nor the brake pedal is depressed, inertial traveling is performed at the vehicle speed at which the vehicle travels. In this case, the creep torque of the motor is increased in the negative direction as the vehicle speed is higher. Making the motor creep torque negative means that the motor is decelerated by regenerative braking.The higher the vehicle speed and the higher the inertia, the more the creep torque is increased in the negative direction and the more the regenerative braking and deceleration are. Make it happen smoothly.

  As shown in FIG. 6, when the inertial running is performed at a higher vehicle speed, the creep torque of the motor is gradually increased in the negative direction. In particular, when the traveling road is uphill, the road is gradually increased as compared with the case of flat ground, and when the traveling road is downhill, the road is suddenly increased as compared with the case of flat ground. As a result, the creep torque of the motor is relatively small on the uphill, resulting in insufficient deceleration and regeneration, and the creep torque of the motor is relatively large on the downhill, which reduces the braking operation and is advantageous for vehicle durability. It is possible to regenerate and decelerate. As a result, it is possible to obtain an effect of eliminating the uncomfortable feeling of deceleration on the uphill and downhill that the driver has.

  In inertial driving in which neither the accelerator pedal nor the brake pedal is depressed, the clutch between the engine and the motor is turned off at a certain SOC or higher, and the constant SOC that is the reference for clutch-off is gradually lowered as the vehicle speed increases. be able to. That is, in the case of a general hybrid vehicle, the engine is connected to a motor via a clutch, and the motor is directly connected to the drive shaft. The engine is provided with a start motor / generator (HSG) on the side opposite to the clutch. When the inertial running is performed without turning off the clutch, the motor and the HSG simultaneously charge the battery by regeneration by the minimum driving of the engine.

Therefore, in the case of inertial running where neither the accelerator pedal nor the brake pedal is depressed, the clutch between the engine and the motor is turned off at a certain SOC or more to prevent drive loss due to frequent on / off of the clutch. The higher the speed, the lower the SOC, which is the reference for clutch-off, and the longer the time during which the clutch is turned off when the vehicle speed is high.

  In inertial running where neither the accelerator pedal nor the brake pedal is depressed, the clutch between the engine and the motor is turned off at a certain SOC or higher, and the SOC that is the reference for clutch-off is high when the road is uphill. The downhill case can be lowered.

  As shown in the graph of FIG. 7, it can be said that the clutch is turned off when the inertial travel in which neither the accelerator pedal nor the brake pedal is depressed exceeds a certain SOC, that is, when the SOC boundary is exceeded in the graph. However, such a reference SOC line is high when going uphill and low when going downhill, and the SOC line is lowered as the vehicle speed increases.

  As a result, on / off of the clutch and frequent on / off of the engine are prevented, and the SOC is increased by further charging with HSG.

According to the traveling mode control method for a hybrid vehicle having the above-described structure, frequent start / stop of the engine can be prevented, and the fuel consumption can be reduced accordingly.
Further, the engine and the clutch can be protected, and the amount of charge of the battery can be effectively ensured. Then, power control is performed with different maps depending on the vehicle speed and the degree of inclination, so that improvement in fuel consumption, improvement in driving texture, and stabilization of vehicle durability can be achieved simultaneously.

  The hybrid vehicle operation control method of the present invention has been illustrated and described with reference to specific embodiments. However, the present invention is within the scope of the technical idea of the present invention provided by the claims. It will be apparent to those skilled in the art that various modifications and changes can be made.

  The present invention variably embodies the hybrid vehicle SOC management method using the vehicle speed and the inclination, thereby making the vehicle's energy utilization more active and intelligent, and more efficient use of the vehicle to improve the fuel efficiency of the vehicle. The present invention can be applied to a hybrid vehicle that is improved.

Claims (7)

A driving control method for a hybrid vehicle having an SOC target in which a state of charge (SOC) is divided into a high region, a middle region, and a low region and an engine target torque preset for each SOC region,
The engine target torque is calculated from the SOC region to which the current state of charge (SOC) belongs, and when the current SOC is larger than the maximum value within a certain range , the corrected engine target torque is obtained by reducing the magnitude of the calculated engine target torque. When the engine is controlled and the SOC is smaller than the minimum value in the certain range, the engine is controlled to the corrected engine target torque obtained by increasing the magnitude of the calculated engine target torque, and the current SOC is within the certain range. If the engine is controlled to the calculated engine target torque if there is an inertial running in which neither the accelerator pedal nor the brake pedal is depressed, the clutch between the engine and the motor is turned off at a certain SOC or more, and the vehicle speed is Driving control of a hybrid vehicle, characterized by gradually decreasing the SOC, which is a reference for clutch-off, as it increases Law. When the SOC traveling road is uphill is higher than a certain value, the engine is controlled to the corrected target engine torque reduced the size of the target engine torque the calculated were the calculated higher slope increases engine 2. The hybrid vehicle operation control method according to claim 1, wherein the degree of decrease in the magnitude of the target torque is increased. The method for controlling driving of a hybrid vehicle according to claim 1, wherein when the travel path is a downhill, the engine stop point becomes earlier as the inclination increases. Wherein when coasting without depressed any of the accelerator pedal and the brake pedal, the operation control method for a hybrid vehicle according to claim 1, characterized in that to increase the creep torque of the motor as the vehicle speed increases in the negative direction . When the inertial travel is performed without the accelerator pedal and the brake pedal being depressed, the creep torque of the motor is increased in the negative direction as the vehicle speed is increased. The method for controlling driving of a hybrid vehicle according to claim 1, wherein when the travel path is a downhill, the travel path is made larger suddenly than in the case of flat ground. This is an operation control method for a hybrid vehicle having a SOC range in which the state of charge (SOC) is divided into a high range, a middle range, and a low range, and an engine target torque that is preset for each SOC range. The engine target torque is calculated from the SOC region to which the SOC) belongs, and the engine is controlled to the corrected engine target torque in which the magnitude of the engine target torque calculated when the current SOC is larger than the maximum value in a certain range , The engine is controlled to a corrected engine target torque that is obtained by increasing the magnitude of the engine target torque that is calculated when the SOC is smaller than the minimum value within a certain range. If the current SOC is within the certain range, the calculated engine target More than a certain SOC during inertial driving where the engine is controlled by torque and neither the accelerator pedal nor the brake pedal is depressed The SOC between the engine and the motor is turned off, and the SOC, which is the reference for clutch-off, is the highest when the road is uphill compared to when the road is flat, due to the slope of the road. A driving control method for a hybrid vehicle, characterized in that it is lowest in the case of a downhill. When the current SOC is higher than the maximum value of the certain range, the engine target torque is further decreased as the current SOC is higher. When the current SOC is lower than the minimum value of the certain range, the engine target torque is decreased. The method for controlling the operation of a hybrid vehicle according to claim 1, characterized in that the engine target torque is made lower when the vehicle travels uphill and the road is uphill than when the road is flat or downhill.

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