CN109080623B

CN109080623B - Snow running control system of hybrid electric vehicle

Info

Publication number: CN109080623B
Application number: CN201710442311.7A
Authority: CN
Inventors: 张凯邦; 牛小锋; 张士亮; 孔凡茂; 周申光; 贾具宾; 刘天培; 周铁; 马龙兴; 郝兴
Original assignee: Great Wall Motor Co Ltd
Current assignee: Great Wall Motor Co Ltd
Priority date: 2017-06-13
Filing date: 2017-06-13
Publication date: 2020-09-01
Anticipated expiration: 2037-06-13
Also published as: CN109080623A

Abstract

The invention relates to the technical field of vehicles, and provides a snow running control system of a hybrid electric vehicle. The snow running control system comprises a snow mode switch, a main control unit and a sub-control unit, wherein the sub-control unit comprises a transmission control unit TCU, an electronic stability control unit ESP and an electronic air suspension control unit EAS; the main control unit receives a snow mode starting signal generated by triggering a snow mode switch, controls the automobile to enter a snow mode, and sends a snow mode request signal to the sub-control unit in the snow mode; the TCU responds to the snow mode request signal to control the gear shifting time of the automobile to be matched with the running state of the power system; the ESP responds to the snow mode request signal to control the automobile to shorten the braking distance of the automobile and initiate a torque reduction request; and the EAS decreasing the suspension height in response to the snow mode request signal. The snow-driving control system of the invention enhances the adaptability of the vehicle to the driving road condition.

Description

Snow running control system of hybrid electric vehicle

Technical Field

The invention relates to the technical field of vehicles, in particular to a snow running control system of a hybrid electric vehicle.

Background

Hybrid power provided by a current new energy Vehicle (also referred to as a hybrid Vehicle or a new energy SUV) generally includes power provided by an engine, a motor, and a battery. Generally, according to the arrangement position of the motor on the transmission system, the new energy automobile can be divided into five architectures, namely P0, P1, P2, P3 and P4. The P4 architecture is that the motor is arranged at the rear axle of the transmission system as an independent power output source to drive the vehicle to run. Since the new energy battery has a high voltage power source and a low voltage power source, the P4 model has a high voltage and a low voltage. The SUV models of new energy in the market at present are high-voltage battery models under the P4 framework, and the high-voltage battery models are sufficient in electric energy and similar in output power or even superior to ordinary traditional power engines, so that the SUV models can adapt to various severe road conditions such as snowfields, sand fields and the like. However, the overall weight of the SUV equipped with the high-voltage battery exceeds that of the SUV equipped with the traditional power engine, and the consumption of generated electric energy and fuel is still high, so that the development of a low-voltage battery power system under the P4 architecture has become a main research project of various automobile companies.

The P4 low-voltage framework can provide a part of electric energy for the rear drive axle while ensuring the emission requirement, and ensures certain dynamic property, but the power provided by the system can meet the requirements of acceleration and climbing to a certain extent on a good road, but the requirement of getting rid of difficulties under severe road conditions is not satisfied. The reason is that in a vehicle powered by a low-voltage battery as a new energy, the vehicle with the low-voltage battery power system cannot run smoothly on the ice and snow road surface because the power output of the vehicle is limited and the vehicle is not assisted by a driving system for some special road conditions (such as the ice and snow road surface).

Disclosure of Invention

In view of the above, the present invention is directed to a snow-run control system for a hybrid vehicle, so as to ensure that a low-voltage battery power system can run smoothly on an icy or snowy road.

In order to achieve the purpose, the technical scheme of the invention is realized as follows:

a snow travel control system of a hybrid vehicle, the power system of the hybrid vehicle including an engine, a motor, and a low-voltage battery, and the snow travel control system of the hybrid vehicle including a snow mode switch, a main control unit, and a sub-control unit, which in turn includes a Transmission Control Unit (TCU), an Electronic Stability control unit (ESP), and an Electronic Air Suspension control unit (EAS); wherein: the main control unit is used for receiving a snow mode starting signal generated by triggering the snow mode switch, controlling the hybrid electric vehicle to enter a snow mode according to the snow mode starting signal and sending a snow mode request signal to the sub-control unit in the snow mode; the TCU is used for enabling the gear shifting timing of the hybrid electric vehicle to be matched with the power system running state in response to the snow mode request signal; the ESP for controlling an anti-lock braking System (ABS) of the hybrid vehicle to shorten a vehicle braking distance and controlling a Torque Control System (TCS) of the hybrid vehicle to initiate a Torque down request to the main Control unit in response to the snow mode request signal; and the EAS to reduce a suspension height in response to the snow mode request signal.

Further, the main control unit is also used for controlling the engine and the motor to output torque under a preset snow mode accelerator pedal MAP MAP in the snow mode, wherein the snow mode accelerator pedal MAP MAP is gentler than a standard accelerator pedal MAP MAP.

Further, the main control unit is also used for detecting the electric quantity of the low-voltage battery and/or faults of the hybrid electric vehicle, and controlling the hybrid electric vehicle to exit the snow mode when the electric quantity of the low-voltage battery is insufficient and/or the hybrid electric vehicle has faults.

Further, the main control unit is further configured to memorize information of the hybrid electric vehicle when the hybrid electric vehicle is powered off from the snow mode, and control the hybrid electric vehicle to enter the snow mode according to the memorized information when the hybrid electric vehicle is powered on again.

Further, the main control unit is in communication with an instrument of the hybrid electric vehicle, and is used for sending the reminding information that the hybrid electric vehicle is in the snow mode to the instrument and controlling the instrument to display the reminding information to a driver.

Further, the matching the shift timing of the hybrid electric vehicle and the power system running state by the TCU includes: controlling the hybrid electric vehicle to shift under a preset snow mode shift curve, wherein the snow mode shift curve is configured to delay the hybrid electric vehicle to start at two gears, and to upshift in advance and downshift in delay.

Further, the ABS shortens the vehicle braking distance by changing a slip rate control threshold, and the TCS changes a torque down request trigger threshold and initiates a torque down request to the main control unit based on the changed torque down request trigger threshold.

Further, the sub-control unit is further configured to feed back status signals of the TCU, the ESP, and/or the EAS to the main control unit.

Further, the main control Unit is a Hybrid Control Unit (HCU) of the hybrid vehicle.

Further, the snow mode switch transmits the snow mode start signal to a Body Control Module (BCM) of the hybrid electric vehicle through a LIN line, and the Body Control Module (BCM) forwards the snow mode start signal to a CAN network, and then the snow mode start signal is sent to a PT-CAN bus through a gateway to be received by the HCU.

Compared with the prior art, the snow running control system of the hybrid electric vehicle disclosed by the invention is provided with a special snow mode for a low-voltage power new energy vehicle type, so that the vehicle can still keep good stability and acceleration performance on an ice and snow road surface, the adaptability of the vehicle to driving road conditions is enhanced, and the stability of the vehicle is improved.

Additional features and advantages of the invention will be set forth in the detailed description which follows.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate an embodiment of the invention and, together with the description, serve to explain the invention and not to limit the invention. In the drawings:

fig. 1 is a schematic structural view of a snow travel control system of a hybrid vehicle according to an embodiment of the present invention;

FIG. 2 is a schematic diagram of a preferred control architecture for the snow ride control system according to an embodiment of the present invention;

FIG. 3 is a graph showing the relationship between the opening of the accelerator pedal and the output torque according to the embodiment of the present invention;

FIG. 4 is a shift profile of the TCU in snow mode in an embodiment of the present invention; and

fig. 5 is a slip ratio control curve in the embodiment of the present invention.

Description of reference numerals:

10. snow travel control system 11 and snow mode switch

12. Main control unit 13, sub-control unit

131. Transmission control unit 132, electronic stability control unit

133. Electronic air suspension control unit

Detailed Description

In addition, the embodiments of the present invention and the features of the embodiments may be combined with each other without conflict.

The snow covered area according to the embodiment of the present invention includes a low-adhesion-coefficient road surface such as an ice and snow road surface.

The present invention will be described in detail below with reference to the accompanying drawings in conjunction with embodiments.

The invention provides a snow-run control system of a hybrid electric vehicle, wherein a power system of the hybrid electric vehicle comprises an engine, a motor and a low-voltage battery. In an example, the engine is disposed in a forward drive portion of the vehicle to output power to a forward drive shaft and the motor is disposed in a rear drive portion of the vehicle to output power to a rear drive shaft.

Fig. 1 shows the structure of a snow run control system in an embodiment of the present invention, and as shown in fig. 1, the snow run control system 10 of the hybrid vehicle includes a snow mode switch 11, a main control unit 12, and a sub-control unit 13, and the sub-control unit 13 includes a Transmission Control Unit (TCU)131, an electronic stability control unit (ESP)132, and an electronic air suspension control unit (EAS) 133.

The snow mode switch 12 may be disposed on an instrument panel as a driving command signal source for a driver to operate, and is triggered to generate a snow mode start signal.

Further, the main control unit 12 is configured to receive a snow mode start signal generated when the snow mode switch 11 is triggered, control the hybrid vehicle to enter a snow mode according to the snow mode start signal, and send a snow mode request signal to the sub control unit 13 in the snow mode.

The sub-control unit 13 adjusts corresponding parameters of the vehicle in response to the snow mode request signal, and may specifically include: the TCU 131 enables the gear shifting timing of the hybrid electric vehicle to be matched with the power system running state in response to the snow mode request signal; the ESP 132 controls the ABS of the hybrid vehicle to shorten a vehicle braking distance and controls the TCS of the hybrid vehicle to initiate a torque-down request to the main control unit in response to the snow mode request signal; and the EAS 133 reduces a suspension height in response to the snow mode request signal.

Preferably, the main control unit 11 according to the embodiment of the present invention may be an HCU of the hybrid vehicle, and the HCU may control and manage the engine and the motor in a unified manner, and the HCU is adopted to control the stability of the vehicle on the ice and snow road surface from a software level, so that new hardware is not required to be added, the performance is improved, and the development cost is saved.

Taking the HCU as an example, fig. 2 shows a preferred control architecture of the snow travel control system 10 according to the embodiment of the present invention. As shown in fig. 2, the control architecture mainly includes the following parts:

1) snow mode switch

When the HCU is used, the snow mode switch can communicate with the HCU using the wiring of the hybrid vehicle itself. The snow mode switch CAN transmit a snow mode starting signal to the hybrid electric vehicle through the LIN wire, the BCM forwards the snow mode starting signal to the CAN network, and the snow mode starting signal is sent to the PT-CAN bus through the gateway to be received by the HCU. Wherein, PT-CAN is a high-speed network communication line.

2)HCU

After receiving the snow mode start signal, the HCU transmits a snow mode request signal to the ESP, TCU, and EAS. In addition, the HCU is also preferably configured to control the engine and the motor to output torque at a preset snow mode accelerator pedal MAP in the snow mode. Wherein the snowy mode accelerator pedal MAP is flatter than a standard accelerator pedal MAP.

Fig. 3 is a graph showing the relationship between the opening degree of the accelerator pedal and the output torque, wherein S301 is a MAP of a standard accelerator pedal MAP, S302 is a MAP of a snow mode accelerator pedal MAP, and it is obvious that S302 is gentler than S301, thereby indicating that the HCU can reasonably control the output power of the engine to the front drive shaft and the output power of the motor to the rear drive shaft according to the MAP, and when the driver steps on the accelerator pedal, the output torques of the engine and the motor are controlled to be slowly increased so as to smoothly start and accelerate the vehicle.

In addition, a plurality of snow mode accelerator pedal MAP graphs can be configured to correspond to different snow road conditions. In this regard, the HCU may also receive signals from related sensors such as wheel speed sensors to calculate the current vehicle stability and determine an appropriate MAP of the snow mode accelerator pedal based on the calculation.

Furthermore, the functions of the battery and the motor are greatly influenced by external factors, so that the conditions of limited power output or functional failure and the like often occur, and if the snow mode is still performed or switched at the moment, the overall vehicle power system is adversely influenced. Accordingly, the HCU may be further configured to detect a charge of the low-voltage battery and/or a fault of the hybrid vehicle, and control the hybrid vehicle to exit the snow mode when the low-voltage battery is low and/or the hybrid vehicle has a fault. More preferably, when the hybrid electric vehicle is controlled to exit the snow-land mode, the hybrid electric vehicle can be controlled to switch to the normal running mode, so that the whole vehicle power system runs in a relatively safe mode. Here, a protection strategy is set from a software level for the low-voltage battery, so that a certain electric quantity of the battery can be ensured to be maintained and the fault can be prevented from further worsening.

Further, if the whole vehicle is powered off from the snow mode, the vehicle has a high probability of remaining on the snow, and the vehicle still needs to be assisted in the snow mode after being powered on again. In this regard, in an embodiment of the present invention, the HCU is further configured to memorize information when the hybrid vehicle is powered from the snow mode, and to control the hybrid vehicle to enter the snow mode according to the memorized information when the hybrid vehicle is powered again. Therefore, the HCU has a mode memory function, namely after the vehicle is powered off from the snow mode, the driving mode of the whole vehicle is still in the snow mode after the vehicle is powered on again.

More preferably, in the snow mode, the HCU may be further configured to communicate with an instrument of the hybrid vehicle, so as to send a warning message that the hybrid vehicle is in the snow mode to the instrument, and control the instrument to display the warning message to a driver. Preferably, the reminding information may be a snow mode confirmation signal generated by the HCU after controlling the entire vehicle to enter the snow mode, and after receiving the signal, the meter may give a prompt, such as a prompt: snow mode, slow down. In addition, a frequently-displaying area is arranged on the instrument, the current mode is displayed as snow, and the driver is reminded of the current mode at any time.

3)TCU

The TCU mainly controls the gear shifting time in the snowfield mode, so that the gears are matched with the running state of the power system, the power system of the whole vehicle is ensured to be flexibly connected with the transmission system, and the power performance and the smoothness of the whole vehicle are ensured.

Preferably, the TCU matching the shift timing of the hybrid vehicle with the powertrain operating state comprises: and controlling the hybrid electric vehicle to shift under a preset snow mode shift curve. Fig. 4 shows a shift curve of a TCU in snow mode, where S401 denotes a downshift curve and S402 denotes an upshift curve, and in connection with fig. 4, the shift in snow mode of the embodiment of the present invention is mainly characterized in two aspects:

a. and (3) delaying to start at the second gear: the conventional first-gear starting can cause the torque output gradient to be overlarge, so that the starting is delayed to the second-gear starting to prevent the starting slip phenomenon caused by the overlarge torque output gradient;

b. the method belongs to a convergent gear shifting curve, and comprises the steps of increasing the gear in advance as shown in S402 and delaying the gear reduction as shown in S401, so that the phenomenon of slipping caused by overlarge torque output at the output shaft end due to the fact that a driver steps on an accelerator transmission suddenly in the acceleration process can be prevented.

4)ESP

The ESP comprises an ABS and a TCS, wherein the ABS system mainly realizes the control of a brake system by changing a slip rate control threshold, and the TCS system mainly realizes the control of the power output of a vehicle by changing a torque reduction request trigger threshold value.

The ESP, upon receiving the snow mode request signal, switches to a more sensitive body stability control strategy. On one hand, the ESP controls the ABS to shorten the vehicle braking distance according to the slip rate of the hybrid vehicle, and fig. 5 shows a corresponding slip rate control curve, where the curve S501 is an asphalt pavement slip rate control curve, and the curve S502 is a snow pavement slip rate control curve, so that the asphalt pavement is more likely to achieve the optimal braking force at the same slip rate, thereby indicating that the snow pavement is less likely to brake in time relative to the asphalt pavement. On the other hand, the ESP changes a torque reduction request trigger threshold value for initiating a torque reduction request to the HCU by the TCS, so that when the vehicle starts or wheels slip during acceleration, the TCS starts immediately, transmits the torque reduction request to the HCU, and reduces power output so as to enable the vehicle to accelerate and start smoothly.

In this vehicle body stability control strategy, ESP mainly plays a role in protecting the stability and safety of the vehicle in the snow mode.

5)EAS

After the EAS receives the snow mode signal, the suspension height can be minimized by changing the current value to ensure that the vehicle is more stable when the vehicle is coasting or accelerating. In addition, the EAS may also adjust suspension stiffness.

Accordingly, the control framework jointly completes the control of snow running through the HCU, the engine, the TCU, the motor, the ESP, the suspension, the low-voltage battery and the like.

In addition, in this control architecture, the sub-control unit 13 may also feed back a subsystem status signal, i.e., a status signal of the TCU, the ESP, and/or the EAS, to the main control unit 12, and the main control unit 12 may determine whether each subsystem normally starts the control strategy in the snow mode according to the subsystem status signal.

In summary, the snow-run control system of the embodiment of the invention configures a special snow mode for a low-voltage power new energy vehicle type, so that the vehicle can still keep good stability and acceleration performance on an ice and snow road surface, the adaptability of the vehicle to driving road conditions is enhanced, and the stability of the vehicle is improved. Moreover, a plurality of chassis systems such as TCU, ESP, EAS and the like participate in the control of the stability of the vehicle together, and the comprehensive performance of the chassis is greatly improved.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.

Claims

1. The snow running control system of the hybrid electric vehicle is characterized by comprising an engine, a motor and a low-voltage battery, and comprises a snow mode switch, a main control unit and a sub-control unit, wherein the sub-control unit comprises a transmission control unit TCU, an electronic stability control unit ESP and an electronic air suspension control unit EAS; wherein:

the main control unit is used for receiving a snow mode starting signal generated by triggering the snow mode switch, controlling the hybrid electric vehicle to enter a snow mode according to the snow mode starting signal and sending a snow mode request signal to the sub-control unit in the snow mode;

the TCU, which is used for matching the gear shifting timing of the hybrid electric vehicle with the power system running state in response to the snow mode request signal, comprises the steps of controlling the hybrid electric vehicle to shift under a preset snow mode gear shifting curve, wherein the snow mode gear shifting curve is configured to delay the hybrid electric vehicle to start at two gears and to upshift in advance and downshift in delay;

the ESP for controlling an anti-lock braking system ABS of the hybrid vehicle to shorten a vehicle braking distance and controlling a torque control system TCS of the hybrid vehicle to initiate a torque-off request to the main control unit in response to the snow mode request signal; and

the EAS to reduce suspension height in response to the snow mode request signal.

2. The snow travel control system of a hybrid vehicle according to claim 1, wherein the main control unit is further configured to control the engine and the motor to output torque under a preset snow mode accelerator pedal MAP in the snow mode, wherein the snow mode accelerator pedal MAP is gentler than a standard accelerator pedal MAP.

3. The snow travel control system of a hybrid vehicle according to claim 1, wherein the main control unit is further configured to detect a charge level of the low-voltage battery and/or a failure of the hybrid vehicle, and to control the hybrid vehicle to exit the snow mode when the charge level of the low-voltage battery is insufficient and/or the hybrid vehicle has a failure.

4. The snow travel control system of a hybrid vehicle according to claim 1, wherein the main control unit is further configured to memorize information when the hybrid vehicle is powered off from the snow mode, and to control the hybrid vehicle to enter the snow mode according to the memorized information when the hybrid vehicle is powered on again.

5. The snow running control system of the hybrid electric vehicle according to claim 1, wherein the main control unit communicates with an instrument of the hybrid electric vehicle, and is configured to send a warning message that the hybrid electric vehicle is in a snow mode to the instrument and control the instrument to present the warning message to a driver.

6. The snow travel control system of a hybrid vehicle according to claim 1, wherein the ABS shortens a vehicle braking distance by changing a slip rate control threshold, and the TCS changes a torque down request trigger threshold and initiates a torque down request to the main control unit based on the changed torque down request trigger threshold.

7. The snow drive control system of a hybrid vehicle of claim 1, wherein the sub-control unit is further configured to feed back status signals of the TCU, the ESP and/or the EAS to the main control unit.

8. The snow travel control system of a hybrid vehicle according to any one of claims 1 to 7, wherein the main control unit is a hybrid control unit HCU of the hybrid vehicle.

9. The snow travel control system of a hybrid vehicle of claim 8, wherein the snow mode switch transmits the snow mode initiation signal to a Body Control Module (BCM) of the hybrid vehicle via a LIN line, and the BCM forwards the snow mode initiation signal to a CAN network, and the snow mode initiation signal is sent to a PT-CAN bus via a gateway to be received by the HCU.