CN114013422A

CN114013422A - Auxiliary braking system and method for vehicle-mounted engine and vehicle

Info

Publication number: CN114013422A
Application number: CN202111278972.3A
Authority: CN
Inventors: 刘少军; 邹畅; 关孟樵; 黄喆
Original assignee: Dongfeng Commercial Vehicle Co Ltd
Current assignee: Dongfeng Commercial Vehicle Co Ltd
Priority date: 2021-10-31
Filing date: 2021-10-31
Publication date: 2022-02-08
Anticipated expiration: 2041-10-31
Also published as: CN114013422B

Abstract

The application discloses an auxiliary braking system and method of a vehicle-mounted engine and a vehicle, and relates to the technical field of vehicle engine braking, wherein the auxiliary braking system comprises a constant-speed switch, a vehicle control unit VECU and an engine control unit EECU; the constant-speed gear switch is used for sending out a constant-speed gear switch signal; the vehicle control unit VECU is used for determining a corresponding braking demand according to a current downhill driving vehicle speed signal after receiving a constant-speed gear switching signal, wherein the braking demand is a ratio of braking power and calibration power; the engine control unit EECU is adapted to simultaneously control engine braking and exhaust braking in accordance with the determined braking demand. The method and the device determine the only corresponding braking requirement according to the vehicle speed running on the downhill, correspondingly and automatically control the engine braking and the exhaust braking according to the braking requirement so as to keep the vehicle speed, do not need frequent gear shifting operation of a driver, have the braking requirement of the ratio of the braking power and the calibration power, and are applicable to vehicles with different calibration powers.

Description

Auxiliary braking system and method for vehicle-mounted engine and vehicle

Technical Field

The application relates to the technical field of vehicle brake control, in particular to an auxiliary brake system and method of a vehicle-mounted engine and a vehicle.

Background

During downhill running of a vehicle, a driver needs to frequently step on a brake pedal in order to maintain the vehicle speed, so that the friction frequency of a brake drum of a brake shoe is increased, and abrasion is caused. If the brake drum of the brake shoe is seriously abraded, the probability of brake failure of a vehicle brake system is easily increased, and further more traffic accidents are caused. Therefore, when the vehicle descends a slope, auxiliary braking is often needed to ensure that the vehicle safely descends the slope.

In the auxiliary braking technology of a vehicle engine, engine braking and exhaust braking are mainly included, and the current engine braking and exhaust braking only have a fixed auxiliary braking gear, for example, the engine braking is generally divided into two stages, and the exhaust braking is generally only one stage.

Specifically, in the first-stage exhaust brake, an electromagnetic valve drives an exhaust brake valve to control exhaust pressure so as to change brake power, and the exhaust brake valve is only in an open state and a closed state, so that the air pressure on the exhaust brake valve is only in two air pressure states, namely no air pressure state and maximum air pressure state, and even some engines are not provided with the exhaust brake valve.

The two-stage engine brake is mainly characterized in that a rocker arm is driven by an electromagnetic valve to control the air inlet and exhaust of an engine to realize the work of three cylinders and six cylinders, the gear of a gearbox and the gear of the engine brake need to be changed frequently in the process of driving on a road, and service brake needs to be matched simultaneously when needed, so that a driver is required to have higher driving experience, and the gear is shifted back and forth and the service brake is matched, so that the labor intensity of the driver is increased, and the driver can feel fatigue during driving easily.

Disclosure of Invention

The embodiment of the application provides an auxiliary braking system and method of a vehicle-mounted engine and a vehicle, and aims to solve the technical problem that a driver needs to shift gears frequently in a downhill braking process in the related art.

In a first aspect, an auxiliary braking system of a vehicle-mounted engine is provided, and comprises a constant speed switch, a vehicle control unit VECU and an engine control unit EECU;

the constant-speed gear switch is used for sending out a constant-speed gear switch signal;

the vehicle control unit VECU is used for determining a corresponding braking demand according to a current downhill driving vehicle speed signal after receiving a constant-speed gear switching signal, wherein the braking demand is a ratio of braking power and calibration power;

the engine control unit EECU is adapted to simultaneously control the engine brake and the exhaust brake in accordance with the determined braking demand such that the vehicle speed is maintained.

In some embodiments, a proportional solenoid valve and an exhaust brake valve are further included; the engine control unit EECU is specifically used for controlling the operation of the corresponding number of cylinders of the engine according to the determined braking requirement; meanwhile, a corresponding duty ratio is calculated according to the braking requirement, and the opening degree of the exhaust braking valve is controlled through a proportional solenoid valve based on the duty ratio.

In some embodiments, the constant-speed switch is connected with the vehicle control unit VECU through a wire, and the vehicle control unit VECU is connected with the engine control unit EECU through a CAN bus.

In a second aspect, an auxiliary braking method for a vehicle-mounted engine is further provided, and includes the following steps:

after a constant-speed gear switch signal is received, determining a corresponding braking demand according to a current downhill driving vehicle speed signal, wherein the braking demand is a ratio of braking power to calibration power;

in accordance with the determined braking demand, engine braking and exhaust braking are simultaneously controlled such that vehicle speed is maintained.

In some embodiments, the specific step of simultaneously controlling engine braking and exhaust braking based on the determined braking demand comprises:

controlling the corresponding number of cylinders of the engine to operate according to the determined braking demand;

meanwhile, according to the braking requirement, calculating to obtain a corresponding duty ratio, and controlling the opening degree of the exhaust braking valve through a proportional solenoid valve based on the duty ratio.

In some embodiments, the specific steps of simultaneously controlling engine braking and exhaust braking based on the determined braking demand further comprise:

the opening degree of the EGR valve is controlled according to the determined braking demand.

In some embodiments, the ratio is divided into a first state, a second state, a third state, a fourth state and a fifth state by 0-100%,

if the braking demand corresponds to a first state, controlling a cylinder of an engine not to operate and controlling an exhaust brake valve to close;

if the braking demand corresponds to a second state, controlling the cylinder of the engine not to run and controlling the opening degree of an exhaust braking valve;

if the brake requirement corresponds to a third state, controlling the three cylinders of the transmitter to operate, and controlling the opening of an exhaust brake valve;

if the braking requirement corresponds to a fourth state, controlling the six cylinders of the transmitter to operate, and controlling the opening degree of an exhaust braking valve;

and if the fifth state corresponds to the braking demand, controlling the six cylinders of the transmitter to operate, controlling the exhaust braking valve to be fully opened, and controlling the opening degree of the EGR valve.

In some embodiments, the ratio corresponding to the first state is zero, the ratio corresponding to the second state ranges from 0% to 40%, the ratio corresponding to the third state ranges from 40% to 65%, the ratio corresponding to the fourth state ranges from 65% to 90%, and the ratio corresponding to the fifth state ranges from 90% to 100%.

meanwhile, according to the braking requirement, calculating to obtain a corresponding duty ratio, and controlling the opening degree of the VGT valve based on the duty ratio.

In a second aspect, a vehicle is provided, wherein the gears comprise a first gear and a second gear, and further comprise a constant speed gear, and the function of the constant speed gear is realized by the steps of the auxiliary braking method of the vehicle-mounted engine.

The beneficial effect that technical scheme that this application provided brought includes: the brake system of the vehicle engine is improved, the only corresponding brake requirement is determined according to the vehicle speed running on the downhill, the engine brake and the exhaust brake are correspondingly and automatically controlled according to the brake requirement to keep the vehicle speed, the driver does not need to frequently shift gears, the brake requirement is the ratio of the brake power and the calibration power, and the brake system is also applicable to vehicles with different calibration powers.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

FIG. 1 is a first block diagram of an auxiliary braking system of an on-vehicle engine according to an embodiment of the present disclosure;

FIG. 2 is a second block diagram illustrating an auxiliary braking system of an on-vehicle engine according to an embodiment of the present disclosure;

FIG. 3 is a block flow diagram illustrating a method for assisting braking of an on-board engine according to an embodiment of the present disclosure;

FIG. 4 is a detailed flowchart of an auxiliary braking method for a vehicle-mounted engine according to an embodiment of the present disclosure.

The implementation, functional features and advantages of the objectives of the present application will be further explained with reference to the accompanying drawings.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are some embodiments of the present application, but not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

The flow diagrams depicted in the figures are merely illustrative and do not necessarily include all of the elements and operations/steps, nor do they necessarily have to be performed in the order depicted. For example, some operations/steps may be decomposed, combined or partially combined, so that the actual execution sequence may be changed according to the actual situation.

The embodiment of the application provides an auxiliary braking system of a vehicle-mounted engine, which is used for improving a braking system of the vehicle engine, determining a unique corresponding braking demand according to the speed of downhill driving, correspondingly and automatically controlling engine braking and exhaust braking according to the braking demand to keep the vehicle speed, avoiding frequent gear shifting operation of a driver, and aiming at vehicles with different calibration powers, wherein the braking demand is the ratio of braking power to calibration power.

Some embodiments of the present application will be described in detail below with reference to the accompanying drawings. The embodiments described below and the features of the embodiments can be combined with each other without conflict.

As shown in fig. 1, an auxiliary braking system of a vehicle-mounted engine according to an embodiment of the present application includes a constant speed switch, a vehicle controller VECU, and an engine control unit EECU;

the engine control unit EECU is adapted to simultaneously control engine braking and exhaust braking in accordance with the determined braking demand such that the vehicle speed is maintained.

In the downhill process of the vehicle, a driver starts a constant gear, namely a constant gear switch is turned on, the constant gear switch generates a constant gear switch signal and sends the constant gear switch signal to a vehicle control unit VECU, the vehicle control unit VECU determines a corresponding braking demand according to a current downhill driving vehicle speed signal after receiving the constant gear switch signal and sends the braking demand to an engine control unit EECU, and the engine control unit EECU controls engine braking and exhaust braking simultaneously according to the determined braking demand, so that the vehicle speed is kept. Therefore, the vehicle can keep the speed by starting the constant-speed gear in the downhill process of the vehicle, the driver does not need to shift gears in a reciprocating manner, the labor intensity of the driver is reduced, the experience feeling of the driver is improved, and the requirement on the operation level of the driver is reduced.

It is noted that the braking demand is a ratio of a braking power, which is a power required to maintain a vehicle speed, to a calibration power, which is a maximum braking power calibrated in advance.

Further, the system also comprises a proportional electromagnetic valve and an exhaust brake valve; the engine control unit EECU is specifically used for controlling the operation of the corresponding number of cylinders of the engine according to the determined braking requirement; meanwhile, a corresponding duty ratio is calculated according to the braking requirement, and the opening degree of the exhaust braking valve is controlled through a proportional solenoid valve based on the duty ratio.

As shown in fig. 1, in the present embodiment, the constant-speed switch is connected to a vehicle controller VECU, the vehicle controller VECU is connected to an engine control unit EECU, the engine control unit EECU is connected to an exhaust brake valve through a proportional solenoid valve, and the engine control unit is further connected to a rocker arm through a solenoid valve.

The method comprises the steps that a driver opens a constant-speed switch, the constant-speed switch generates a constant-speed switch signal and sends the constant-speed switch signal to a vehicle control unit VECU, the vehicle control unit VECU determines a corresponding braking requirement according to a current downhill driving vehicle speed signal after receiving the constant-speed switch signal and sends the braking requirement to an engine control unit EECU, the engine control unit EECU outputs a corresponding duty ratio to a proportional solenoid valve to adjust the opening degree of an exhaust braking valve on the opening degree of 0-100%, different opening degrees on the exhaust braking valve correspond to different air pressures, in the process that the exhaust braking valve is gradually opened, the exhaust braking backpressure is gradually increased, corresponding braking power is also gradually increased, exhaust braking is further achieved, meanwhile, the determined braking requirement controls the movement of a rocker arm through the solenoid valve, so that a corresponding number of cylinders can operate, and engine braking is further achieved.

If the proportional solenoid valve and the exhaust brake valve are entirely replaced with the VGT valve, exhaust brake can be achieved.

As shown, an EGR valve is also included and is connected to the engine control unit EECU.

The ratio is in the range of 0-100%, the ratio is 0-100% and is divided into a first state, a second state, a third state, a fourth state and a fifth state in sequence from small to large, and if the braking demand corresponds to the first state, the cylinder of the engine is controlled not to operate, and the exhaust brake valve is controlled to be closed; if the braking demand corresponds to a second state, controlling the cylinder of the engine not to run and controlling the opening degree of an exhaust braking valve; if the brake requirement corresponds to a third state, controlling the three cylinders of the transmitter to operate, and controlling the opening of an exhaust brake valve; if the braking requirement corresponds to a fourth state, controlling the six cylinders of the transmitter to operate, and controlling the opening degree of an exhaust braking valve; if the fifth state corresponding to the braking requirement controls the six cylinders of the transmitter to operate, controls the exhaust brake valve to be fully opened, and also controls the opening degree of the EGR valve, wherein different braking requirements correspond to different opening degrees of the EGR valve, and in the process of controlling the exhaust brake valve, different braking requirements also correspond to different opening degrees of the exhaust valve from 0-100%.

Specifically, as shown in table 1, it is a correspondence table of braking demand to engine braking and exhaust braking. The braking requirement corresponding to the first state is that the ratio is zero, the ratio range corresponding to the second state is 0-40%, the ratio range corresponding to the third state is 40-65%, the ratio range corresponding to the fourth state is 65-90%, and the ratio range corresponding to the fifth state is 90-100%.

TABLE 1

Specifically, the constant-speed switch is connected with the vehicle control unit VECU through an electric wire, and the vehicle control unit VECU is connected with the engine control unit EECU through a CAN bus.

In the embodiment, the vehicle control unit VECU receives the constant-speed switch signal through the electric wire, receives the vehicle speed signal through the CAN bus, the vehicle speed signal is collected by the instrument assembly, the vehicle speed is faster and faster when the vehicle descends the slope, the vehicle speed is increased, the required braking power is also increased, the calibration power of the vehicle is fixed, the braking power is increased, the ratio of the braking power to the calibration power is increased, the ratio is defined as the braking requirement, the vehicle controller VECU CAN determine the only braking requirement according to the vehicle speed signal, the braking requirement is sent to the engine control unit EECU through the CAN bus, the larger the vehicle speed is, the larger the braking requirement is, the exhaust braking is steplessly adjusted by the engine control unit EECU according to the braking requirement, and with the assistance of different levels of engine braking, the vehicle speed can be kept substantially constant when the vehicle is descending a slope.

As shown in fig. 3, an embodiment of the present application further provides an auxiliary braking method for a vehicle-mounted engine, including the following steps:

s1: after a constant-speed gear switch signal is received, determining a corresponding braking demand according to a current downhill driving vehicle speed signal, wherein the braking demand is a ratio of braking power to calibration power;

s2: in accordance with the determined braking demand, engine braking and exhaust braking are simultaneously controlled such that vehicle speed is maintained.

As shown in fig. 4, further, the specific steps of simultaneously controlling engine braking and exhaust braking according to the determined braking demand include:

s21, controlling the operation of the cylinders with the corresponding number of the engines according to the determined braking requirement;

s22: and calculating to obtain a corresponding duty ratio according to the braking demand, and controlling the opening degree of the exhaust braking valve through the proportional solenoid valve based on the duty ratio.

In the embodiment, the engine control unit EECU controls the operation of a corresponding number of cylinders of the engine specifically according to the determined braking demand; meanwhile, a corresponding duty ratio is calculated according to the braking requirement, and the opening degree of the exhaust braking valve is controlled through a proportional solenoid valve based on the duty ratio.

Specifically, the constant-speed switch is connected with a vehicle control unit VECU, the vehicle control unit VECU is connected with an engine control unit EECU, the engine control unit EECU is connected with an exhaust brake valve through a proportional solenoid valve, and the engine control unit is further connected with a rocker arm through a solenoid valve.

If the proportional solenoid valve and the exhaust brake valve are entirely replaced with the VGT valve, exhaust brake can be achieved. Then, the specific steps of step S2 include:

In order to better ensure the braking force of the exhaust brake, the specific steps of simultaneously controlling the engine brake and the exhaust brake according to the determined braking demand further comprise:

In this embodiment, the EGR valve is connected to an engine control unit EECU, which controls the opening of the EGR valve in accordance with the determined braking demand.

Preferably, the ratio is divided into a first state, a second state, a third state, a fourth state and a fifth state according to 0-100%,

Specifically, the ratio corresponding to the first state is zero, the ratio corresponding to the second state ranges from 0% to 40%, the ratio corresponding to the third state ranges from 40% to 65%, the ratio corresponding to the fourth state ranges from 65% to 90%, and the ratio corresponding to the fifth state ranges from 90% to 100%.

In the embodiment, the ratio is in the range of 0-100%, the ratio of 0-100% is divided into a first state, a second state, a third state, a fourth state and a fifth state in order from small to small, if the braking demand corresponds to the first state, the cylinder of the engine is controlled not to operate, and the exhaust brake valve is controlled to be closed; if the braking demand corresponds to a second state, controlling the cylinder of the engine not to run and controlling the opening degree of an exhaust braking valve; if the brake requirement corresponds to a third state, controlling the three cylinders of the transmitter to operate, and controlling the opening of an exhaust brake valve; if the braking requirement corresponds to a fourth state, controlling the six cylinders of the transmitter to operate, and controlling the opening degree of an exhaust braking valve; if the fifth state corresponding to the braking requirement controls the six cylinders of the transmitter to operate, controls the exhaust brake valve to be fully opened, and also controls the opening degree of the EGR valve, wherein different braking requirements correspond to different opening degrees of the EGR valve, and in the process of controlling the exhaust brake valve, different braking requirements also correspond to different opening degrees of the exhaust valve from 0-100%.

TABLE 1

The embodiment of the application also provides a vehicle, the gears of the vehicle comprise a first gear and a second gear, and the vehicle further comprises a constant speed gear, and the function of the constant speed gear is realized by the steps of the auxiliary braking method of the vehicle-mounted engine.

As shown in fig. 3, the auxiliary braking method of the vehicle-mounted engine includes the steps of:

In the description of the present application, it should be noted that the terms "upper", "lower", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, which are only for convenience in describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed in a specific orientation, and operate, and thus, should not be construed as limiting the present application. Unless expressly stated or limited otherwise, the terms "mounted," "connected," and "connected" are intended to be inclusive and mean, for example, that they may be fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present application can be understood by those of ordinary skill in the art as appropriate.

It is noted that, in the present application, relational terms such as "first" and "second", and the like, are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.

The above description is merely exemplary of the present application and is presented to enable those skilled in the art to understand and practice the present application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the application. Thus, the present application is not intended to 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

1. An auxiliary braking system of a vehicle-mounted engine is characterized by comprising a constant-speed switch, a vehicle control unit VECU and an engine control unit EECU;

2. The auxiliary brake system of the vehicle-mounted engine according to claim 1, further comprising a proportional solenoid valve and an exhaust brake valve; the engine control unit EECU is specifically used for controlling the operation of the corresponding number of cylinders of the engine according to the determined braking requirement; meanwhile, a corresponding duty ratio is calculated according to the braking requirement, and the opening degree of the exhaust braking valve is controlled through a proportional solenoid valve based on the duty ratio.

3. The auxiliary braking system of an on-board engine according to claim 1, wherein the constant speed switch is connected to the vehicle controller VECU through a wire, and the vehicle controller VECU is connected to the engine control unit EECU through a CAN bus.

4. An auxiliary braking method for a vehicle-mounted engine is characterized by comprising the following steps:

5. The auxiliary braking method for the vehicle-mounted engine according to claim 4, wherein the specific step of simultaneously controlling the engine brake and the exhaust brake according to the determined braking demand comprises:

6. The auxiliary braking method for a vehicle-mounted engine according to claim 5, wherein the step of simultaneously controlling engine braking and exhaust braking according to the determined braking demand further comprises:

7. The auxiliary braking method of a vehicle-mounted engine according to claim 6, characterized in that the ratio is divided into a first state, a second state, a third state, a fourth state and a fifth state according to 0-100%,

8. The auxiliary braking method for the vehicle-mounted engine according to claim 7, characterized in that the ratio corresponding to the first state is zero, the ratio corresponding to the second state is in a range of 0-40%, the ratio corresponding to the third state is in a range of 40-65%, the ratio corresponding to the fourth state is in a range of 65-90%, and the ratio corresponding to the fifth state is in a range of 90-100%.

9. The auxiliary braking method for the vehicle-mounted engine according to claim 4, wherein the specific step of simultaneously controlling the engine brake and the exhaust brake according to the determined braking demand comprises:

10. A vehicle, the gears of which comprise a first gear and a second gear, and the vehicle is characterized by further comprising a constant-speed gear, wherein the function of the constant-speed gear is realized by the steps of the auxiliary braking method of the vehicle-mounted engine according to any one of claims 4-9.