CN108357489A - A kind of post-processing temperature control system and method - Google Patents

Abstract

The present invention provides an aftertreatment temperature control system and method. Compared with the original hybrid electric vehicle, an electric heater arranged on the exhaust pipe of the engine and a first relay arranged between the electric heater and the ISG motor are added. and a second relay arranged between the electric heater and the power battery, and both the first relay and the second relay are connected to the vehicle controller. The energy generated by the ISG motor when the vehicle is coasting or braking can be used by the electric heater to increase the aftertreatment temperature, which improves the problem of engine emission deterioration under low operating conditions without sacrificing vehicle power or economy.

Description

A post-processing temperature control system and method

technical field

The invention relates to the technical field of hybrid electric vehicles, and more specifically, to an aftertreatment temperature control system and method.

Background technique

Vehicles running on urban roads, such as public transport and municipal vehicles, often operate in low-speed and low-load areas, resulting in low post-processing temperature and low post-processing efficiency of the engine post-processing system. After the hybrid power system is adopted, due to the work of the battery motor, the intermittent operation frequency of the engine is higher, which makes the post-processing temperature lower, which leads to the ineffective treatment of engine exhaust and causes environmental pollution.

At present, the measures commonly used to increase the aftertreatment temperature include fuel injection, electric heating, air intake throttling and exhaust throttling, etc., but the above measures will reduce economy or sacrifice vehicle power.

In view of this, how to increase the aftertreatment temperature of the engine with minimum energy consumption is an urgent problem to be solved by those skilled in the art.

Contents of the invention

In view of this, the present invention provides an aftertreatment temperature control system and method to solve how to increase the aftertreatment temperature of the engine with minimum energy consumption. The technical solution is as follows:

An aftertreatment temperature control system, including a hybrid power unit of a hybrid electric vehicle, the hybrid power unit includes an engine, an ISG vehicle starter generator motor, a power battery and a vehicle controller, and the aftertreatment temperature control system also includes: an electric heater, a first relay and a second relay;

The electric heater is arranged on the exhaust pipe of the engine, connected with the ISG motor through the first relay, and connected with the power battery through the second relay; the first relay and the second relay are connected;

The vehicle controller is configured to determine whether the first aftertreatment temperature of the engine aftertreatment system is lower than a preset maximum aftertreatment temperature when the engine is detected to be on; if the first aftertreatment temperature is less than the preset post-processing maximum temperature, judge whether the hybrid electric vehicle is in a coasting state or braking state; if the hybrid electric vehicle is in a coasting state or braking state, according to the speed of the hybrid electric vehicle, the The SOC remaining power of the power battery and the first post-processing temperature determine the target recovery torque of the ISG motor; control the ISG motor to run according to the target recovery torque, and turn on the first relay and disconnect the second relay.

Preferably, the vehicle controller is also used for:

If the first after-treatment temperature is not less than the preset maximum after-treatment temperature, simultaneously disconnect the first relay and the second relay.

Preferably, the vehicle controller is also used for:

If the hybrid electric vehicle is not in a coasting state or a braking state, it is judged whether the first after-treatment temperature is lower than a preset minimum after-treatment temperature; if the first after-treatment temperature is lower than the preset minimum after-treatment temperature, Turn off the first relay and turn on the second relay; if the first post-treatment temperature is not less than the preset minimum post-treatment temperature, turn off the first relay and the second relay at the same time.

Preferably, the vehicle controller is also used for:

Judging whether the recovery torque of the ISG motor is greater than zero;

If the recovery torque is greater than zero, judge whether the second aftertreatment temperature of the engine aftertreatment system is lower than the preset minimum aftertreatment temperature; if the second aftertreatment temperature is lower than the preset minimum aftertreatment temperature, disconnect The first relay turns on the second relay.

A post-processing temperature control method, applied to the vehicle controller in the post-processing temperature control system described in any one of the above technical solutions, comprising:

When it is detected that the engine is in the on state, it is judged whether the first aftertreatment temperature of the engine aftertreatment system is lower than the preset maximum aftertreatment temperature;

If the first after-treatment temperature is lower than the preset maximum after-treatment temperature, it is judged whether the hybrid electric vehicle is in a coasting state or a braking state;

If the hybrid electric vehicle is in a coasting state or a braking state, determine the target recovery torque of the ISG motor according to the vehicle speed of the hybrid electric vehicle, the SOC remaining power of the power battery, and the first post-processing temperature;

The ISG motor is controlled to run according to the target recovery torque, the first relay is turned on, and the second relay is turned off.

Preferably, it also includes:

If the first after-treatment temperature is not less than the preset maximum after-treatment temperature, simultaneously disconnect the first relay and the second relay.

Preferably, it also includes:

If the hybrid electric vehicle is not in a coasting state or a braking state, judging whether the first after-treatment temperature is lower than a preset minimum after-treatment temperature;

If the first after-treatment temperature is lower than the preset minimum after-treatment temperature, turn off the first relay and turn on the second relay;

If the first after-treatment temperature is not less than the preset minimum after-treatment temperature, simultaneously disconnect the first relay and the second relay.

Preferably, it also includes:

Judging whether the recovery torque of the ISG motor is greater than zero;

If the recovery torque is greater than zero, judging whether the second aftertreatment temperature of the engine aftertreatment system is lower than a preset minimum aftertreatment temperature;

If the second after-treatment temperature is lower than the preset minimum after-treatment temperature, the first relay is turned off and the second relay is turned on.

Compared with the prior art, the beneficial effects realized by the present invention are:

The post-processing temperature control system and method provided by the present invention above, compared with the original hybrid electric vehicle, have increased the electric heater arranged on the engine exhaust pipe, the first relay arranged between the electric heater and the ISG motor, and The second relay is arranged between the electric heater and the power battery, and both the first relay and the second relay are connected to the vehicle controller. The energy generated by the ISG motor when the vehicle is coasting or braking can be used by the electric heater to increase the aftertreatment temperature, which improves the problem of engine emission deterioration under low operating conditions without sacrificing vehicle power or economy.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only It is an embodiment of the present invention, and those skilled in the art can also obtain other drawings according to the provided drawings without creative work.

Fig. 1 is the structural representation of the aftertreatment temperature control system provided by the embodiment of the present invention;

Fig. 2 is the method flowchart of the post-processing temperature control method provided by the embodiment of the present invention;

Fig. 3 is another method flowchart of the post-processing temperature control method provided by the embodiment of the present invention;

Fig. 4 is a flow chart of another method of the post-processing temperature control method provided by the embodiment of the present invention.

Detailed ways

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

ISG (Integrated Starter and Generator, automobile starter and generator integrated motor): It is directly integrated on the main shaft of the engine, that is, it directly replaces the traditional starter motor with a motor with high transient power, and replaces the engine to drive the car for a short time in the starting stage, and At the same time, it plays the role of starting the engine, reducing the idling loss and pollution of the engine.

Fig. 1 shows a kind of aftertreatment temperature control system, and this system comprises the hybrid power unit of hybrid electric vehicle, and hybrid power unit comprises engine 1, ISG motor 2, power battery 3 and vehicle controller 4, and aftertreatment temperature control system also Including an electric heater 5, a first relay 6 and a second relay 7;

The electric heater 5 is arranged on the exhaust pipe of the engine 1, connected with the ISG motor 2 through the first relay 6, and connected with the power battery 3 through the second relay 7; the vehicle controller 4 is connected with the first relay 6 and the second relay respectively. Relay 7 is connected;

The vehicle controller 4 is used to determine whether the first after-treatment temperature of the engine after-treatment system is lower than the preset maximum after-treatment temperature when the engine is detected to be on; if the first after-treatment temperature is lower than the preset after-treatment temperature The highest temperature, to determine whether the hybrid electric vehicle is in a coasting or braking state; if the hybrid electric vehicle is in a coasting or braking state, determine the ISG according to the speed of the hybrid electric vehicle, the SOC remaining power of the power battery and the first post-processing temperature The target regenerative torque of the motor; control the ISG motor to run according to the target regenerative torque, and turn on the first relay and turn off the second relay.

In this embodiment, if the engine speed is greater than the preset idle speed, it can be determined that the engine is in the on state, otherwise, the engine is in the off state. In addition, the preset post-processing temperature is the highest temperature that can ensure post-processing.

If the throttle depth value of the hybrid vehicle is not higher than the preset throttle depth value used to characterize vehicle coasting, that is, the driver does not step on the gas pedal, then it is determined that the hybrid vehicle is in a coasting state. In addition, if the braking depth value of the hybrid electric vehicle is not higher than the preset braking depth value used to characterize vehicle braking, that is, the driver does not step on the brake, it is determined that the hybrid electric vehicle is in a braking state.

The corresponding relationship between the vehicle speed, the SOC remaining power of the power battery, the first post-processing temperature and the target recovery torque is preset, and the form stored in the vehicle controller can be a MAP table. The principle of setting the target recovery torque is that the higher the vehicle speed, the lower the SOC remaining power of the power battery, and the lower the first after-treatment temperature, the greater the target recovery torque.

In some other embodiments, in order to avoid the aftertreatment temperature being too high, the vehicle controller 4 is also used for:

If the first after-treatment temperature is not less than the preset maximum after-treatment temperature, simultaneously disconnect the first relay and the second relay.

In this embodiment, when the aftertreatment temperature is very high, the energy supply of the electric heater is cut off.

In some other embodiments, in order to realize that the aftertreatment temperature can be increased when the motor is not generating electricity, the vehicle controller 4 is also used for:

If the hybrid electric vehicle is not in the coasting state or the braking state, it is judged whether the first after-treatment temperature is lower than the preset minimum after-treatment temperature; if the first after-treatment temperature is lower than the preset minimum after-treatment temperature, disconnect the first relay and turn on Two relays; if the first post-processing temperature is not less than the preset minimum post-processing temperature, simultaneously disconnect the first relay and the second relay.

In some other embodiments, in order to avoid the problem that the recovery of energy by the motor cannot raise the aftertreatment temperature, the vehicle controller 4 is also used for:

Determine whether the recovery torque of the ISG motor is greater than zero; if the recovery torque is greater than zero, determine whether the second aftertreatment temperature of the engine aftertreatment system is lower than the preset minimum aftertreatment temperature; if the second aftertreatment temperature is lower than the preset minimum aftertreatment temperature, Turn off the first relay and turn on the second relay.

In this embodiment, if the recovery torque of the ISG motor is greater than zero, it means that the energy recovery of the motor is completed and the electric heater cannot be powered. At this time, if the second after-treatment temperature is lower than the minimum preset after-treatment temperature, the power battery is used to supply power to the electric heater.

Conversely, if the recovery torque of the ISG motor is not greater than zero, it means that the motor is recovering energy, and no operation is performed. And if the second after-treatment temperature is not less than the preset after-treatment temperature, the electric heater can continue to use energy recovered from the motor to supply power to the electric heater, so as to further increase the after-treatment temperature.

Compared with the original hybrid electric vehicle, the post-processing temperature control system provided by the embodiment of the present invention adds an electric heater arranged on the exhaust pipe of the engine, a first relay arranged between the electric heater and the ISG motor, and a setting The second relay is between the electric heater and the power battery, and both the first relay and the second relay are connected to the vehicle controller. The energy generated by the ISG motor when the vehicle is coasting or braking can be used by the electric heater to increase the aftertreatment temperature, which improves the problem of engine emission deterioration under low operating conditions without sacrificing vehicle power or economy.

Based on the post-processing temperature control system provided by the above-mentioned embodiments, FIG. 2 shows a post-processing temperature control method, which is applied to the vehicle controller 4 in FIG. 1 and includes the following steps:

S10, when it is detected that the engine is turned on, it is judged whether the first aftertreatment temperature of the engine aftertreatment system is lower than the preset maximum temperature of aftertreatment; if the first aftertreatment temperature is lower than the preset maximum temperature of aftertreatment, the step is executed S20;

In this embodiment, if the engine speed is greater than the preset idle speed, it can be determined that the engine is in the on state, otherwise, the engine is in the off state.

In addition, the preset post-processing temperature is the highest temperature that can ensure post-processing.

S20, judging whether the hybrid electric vehicle is in a sliding state or a braking state; if the hybrid electric vehicle is in a sliding state or a braking state, then perform step 30;

In this embodiment, if the accelerator depth value of the hybrid electric vehicle is not higher than the preset accelerator depth value used to characterize the vehicle coasting, that is, the driver does not step on the accelerator, it is determined that the hybrid electric vehicle is in a coasting state.

In addition, if the braking depth value of the hybrid electric vehicle is not higher than the preset braking depth value used to characterize vehicle braking, that is, the driver does not step on the brake, it is determined that the hybrid electric vehicle is in a braking state.

S30. Determine the target recovery torque of the ISG motor according to the vehicle speed of the hybrid electric vehicle, the SOC remaining power of the power battery, and the first post-processing temperature;

In this embodiment, the correspondence between the vehicle speed, the SOC remaining power of the power battery, the first post-processing temperature, and the target recovery torque is preset, and the form stored in the vehicle controller can be a MAP table. The principle of setting the target recovery torque is that the higher the vehicle speed, the lower the SOC remaining power of the power battery, and the lower the first after-treatment temperature, the greater the target recovery torque.

S40. Control the ISG motor to run according to the target recovery torque, and turn on the first relay and turn off the second relay.

In some other embodiments, in order to avoid the post-processing temperature being too high, on the basis of the post-processing temperature control method shown in Figure 2, the following steps are also included, and the method flow chart is shown in Figure 3:

S50, if the first after-treatment temperature is not less than the preset maximum after-treatment temperature, simultaneously disconnect the first relay and the second relay.

In this embodiment, when the aftertreatment temperature is very high, the energy supply of the electric heater is cut off.

In some other embodiments, in order to realize that the aftertreatment temperature can also be increased when the motor is not generating electricity, on the basis of the aftertreatment temperature control method shown in Figure 2, the following steps are also included, and the method flow chart is shown in Figure 4:

S60, if the hybrid electric vehicle is not in the coasting state or the braking state, determine whether the first after-treatment temperature is lower than the preset minimum temperature of after-treatment; if the first after-treatment temperature is lower than the preset minimum temperature of after-treatment, execute step S70; if If the first post-processing temperature is not less than the preset minimum post-processing temperature, step S80 is executed;

S70, disconnecting the first relay and turning on the second relay;

S80, disconnecting the first relay and the second relay at the same time.

In some other embodiments, in order to avoid the problem that the aftertreatment temperature cannot be increased after the motor recovers energy, on the basis of the aftertreatment temperature control method shown in Figure 2, the following steps are further included:

Determine whether the recovery torque of the ISG motor is greater than zero;

If the recovery torque is greater than zero, it is judged whether the second aftertreatment temperature of the engine aftertreatment system is lower than a preset minimum aftertreatment temperature;

If the second post-treatment temperature is lower than the preset minimum post-treatment temperature, the first relay is turned off and the second relay is turned on.

In this embodiment, if the recovery torque of the ISG motor is greater than zero, it means that the energy recovery of the motor is completed and the electric heater cannot be powered. At this time, if the second after-treatment temperature is lower than the minimum preset after-treatment temperature, the power battery is used to supply power to the electric heater.

Conversely, if the recovery torque of the ISG motor is not greater than zero, it means that the motor is recovering energy, and no operation is performed. And if the second after-treatment temperature is not less than the preset after-treatment temperature, the electric heater can continue to use energy recovered from the motor to supply power to the electric heater, so as to further increase the after-treatment temperature.

The aftertreatment temperature control method provided by the embodiment of the present invention can use the energy generated by the ISG motor when the vehicle is coasting or braking for the electric heater to increase the aftertreatment temperature, which improves the problem of engine emission deterioration under low operating conditions , and without sacrificing vehicle power or economy.

The post-processing temperature control system and method provided by the present invention have been introduced in detail above. In this paper, specific examples have been used to illustrate the principle and implementation of the present invention. The descriptions of the above examples are only used to help understand the method of the present invention. and its core idea; at the same time, for those of ordinary skill in the art, according to the idea of the present invention, there will be changes in the specific implementation and scope of application. limits.

It should be noted that each embodiment in this specification is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. For the same and similar parts in each embodiment, refer to each other, that is, Can. As for the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and for the related information, please refer to the description of the method part.

It should also be noted that in this article, relational terms such as first and second etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that these entities or operations Any such actual relationship or order exists between. Furthermore, the term "comprises", "comprises" or any other variation thereof is intended to cover a non-exclusive inclusion such that elements inherent in a process, method, article, or apparatus comprising a set of elements are included, or are also included as such , method, article or device inherent in the elements. Without further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of additional identical elements in the process, method, article or apparatus comprising said element.

The above description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention will not be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (8)

1. An aftertreatment temperature control system, comprising a hybrid power unit of a hybrid electric vehicle, said hybrid power unit comprising an engine, an ISG automobile starter generator, a power battery and a vehicle controller, characterized in that said aftertreatment The temperature control system also includes: an electric heater, a first relay and a second relay; The electric heater is arranged on the exhaust pipe of the engine, connected with the ISG motor through the first relay, and connected with the power battery through the second relay; the first relay and the second relay are connected; The vehicle controller is configured to determine whether the first aftertreatment temperature of the engine aftertreatment system is lower than a preset maximum aftertreatment temperature when the engine is detected to be on; if the first aftertreatment temperature is less than the preset post-processing maximum temperature, judge whether the hybrid electric vehicle is in a coasting state or braking state; if the hybrid electric vehicle is in a coasting state or braking state, according to the speed of the hybrid electric vehicle, the The SOC remaining power of the power battery and the first post-processing temperature determine the target recovery torque of the ISG motor; control the ISG motor to run according to the target recovery torque, and turn on the first relay and disconnect the second relay. 2. The aftertreatment temperature control system according to claim 1, wherein the vehicle controller is further used for: If the first after-treatment temperature is not less than the preset maximum after-treatment temperature, simultaneously disconnect the first relay and the second relay. 3. The aftertreatment temperature control system according to claim 1, wherein the vehicle controller is further used for: If the hybrid electric vehicle is not in a coasting state or a braking state, it is judged whether the first after-treatment temperature is lower than a preset minimum after-treatment temperature; if the first after-treatment temperature is lower than the preset minimum after-treatment temperature, Turn off the first relay and turn on the second relay; if the first post-treatment temperature is not less than the preset minimum post-treatment temperature, turn off the first relay and the second relay at the same time. 4. The aftertreatment temperature control system according to claim 1, wherein the vehicle controller is further used for: Judging whether the recovery torque of the ISG motor is greater than zero; If the recovery torque is greater than zero, judge whether the second aftertreatment temperature of the engine aftertreatment system is lower than the preset minimum aftertreatment temperature; if the second aftertreatment temperature is lower than the preset minimum aftertreatment temperature, disconnect The first relay turns on the second relay. 5. A post-processing temperature control method, characterized in that it is applied to the vehicle controller in the post-processing temperature control system according to any one of claims 1 to 4, comprising: When it is detected that the engine is in the on state, it is judged whether the first aftertreatment temperature of the engine aftertreatment system is lower than the preset maximum aftertreatment temperature; If the first after-treatment temperature is lower than the preset maximum after-treatment temperature, it is judged whether the hybrid electric vehicle is in a coasting state or a braking state; If the hybrid electric vehicle is in a coasting state or a braking state, determine the target recovery torque of the ISG motor according to the vehicle speed of the hybrid electric vehicle, the SOC remaining power of the power battery, and the first post-processing temperature; The ISG motor is controlled to run according to the target recovery torque, the first relay is turned on, and the second relay is turned off. 6. post-processing temperature control method according to claim 5, is characterized in that, also comprises: If the first after-treatment temperature is not less than the preset maximum after-treatment temperature, simultaneously disconnect the first relay and the second relay. 7. post-processing temperature control method according to claim 5, is characterized in that, also comprises: If the hybrid electric vehicle is not in a coasting state or a braking state, judging whether the first after-treatment temperature is lower than a preset minimum after-treatment temperature; If the first after-treatment temperature is lower than the preset minimum after-treatment temperature, turn off the first relay and turn on the second relay; If the first after-treatment temperature is not less than the preset minimum after-treatment temperature, simultaneously disconnect the first relay and the second relay. 8. post-processing temperature control method according to claim 5, is characterized in that, also comprises: Judging whether the recovery torque of the ISG motor is greater than zero; If the recovery torque is greater than zero, judging whether the second aftertreatment temperature of the engine aftertreatment system is lower than a preset minimum aftertreatment temperature; If the second after-treatment temperature is lower than the preset minimum after-treatment temperature, the first relay is turned off and the second relay is turned on.