CN112918476B

CN112918476B - Vehicle control method and vehicle

Info

Publication number: CN112918476B
Application number: CN202110297555.7A
Authority: CN
Inventors: 陈彦波; 李丹; 王晓云; 周海磊; 李振祥
Original assignee: Weichai Power Co Ltd
Current assignee: Weichai Power Co Ltd
Priority date: 2021-03-19
Filing date: 2021-03-19
Publication date: 2022-08-05
Anticipated expiration: 2041-03-19
Also published as: CN112918476A

Abstract

The invention relates to the field of vehicles, and discloses a vehicle control method and a vehicle. After the engine is restarted in a short time, the temperature in the aftertreatment system can be quickly restored to the aftertreatment required temperature so that the vehicle maintains efficient exhaust gas treatment capability.

Description

Vehicle control method and vehicle

Technical Field

The invention relates to the field of vehicles, in particular to a vehicle control method and a vehicle.

Background

In order to ensure the conversion efficiency of the aftertreatment system to reduce harmful gases in the exhaust of the engine, it is necessary to ensure that the temperature of the exhaust gas entering the aftertreatment system is not lower than the temperature required for aftertreatment.

For a conventional internal combustion engine powered vehicle, during braking deceleration conditions or coasting conditions, a small load may be maintained by shutting off the engine fuel supply system to spin up from the driveline or by providing a small amount of fuel, at which time the engine exhaust temperature may drop significantly such that the exhaust temperature is well below the aftertreatment demand temperature, resulting in poor aftertreatment system conversion efficiency. And when the engine is restarted to run, it takes a while for the engine exhaust gas temperature to rise to the aftertreatment required temperature, so that the vehicle emission level cannot be effectively controlled.

Disclosure of Invention

The invention aims to provide a vehicle control method and a vehicle, which can control an engine to stop running under a braking and decelerating working condition or a sliding working condition and do not influence the running state of the vehicle.

In order to achieve the purpose, the invention adopts the following technical scheme:

a vehicle control method, under the condition of sliding or braking deceleration, if an engine flameout condition which allows the engine to be flameout is met, the engine is controlled to be flameout, and an output shaft of the engine stops rotating;

the engine stall conditions are as follows: the vehicle speed is less than a first preset vehicle speed and greater than a second preset vehicle speed, the gradient of the current position of the vehicle is less than the preset gradient, the temperature of cooling liquid in the engine is higher than a preset temperature, the vehicle is in a non-emergency braking state, the altitude of the current position of the vehicle is lower than the preset altitude, the engine is not in an aftertreatment regeneration mode and an SCR heating mode, and the engine has no torque demand.

As a preferable technical solution of the vehicle control method, a powertrain of a vehicle includes an engine, a transmission, a planetary gear train including a sun gear, a planetary gear, a ring gear, and a carrier, the planetary gear being rotatably supported on the carrier, the planetary gear being located between the sun gear and the ring gear and meshing with the sun gear and the ring gear, the engine being connected to the carrier, the ring gear being connected to an input shaft of the transmission, and a brake being connected to the sun gear;

under the condition of sliding or braking deceleration, if an engine flameout condition allowing the engine to be flameout is met, the brake releases the brake on the sun gear, and the engine is flameout.

As a preferable aspect of the vehicle control method, when the engine is in a stall state and the engine stall condition is not satisfied and the torque demand is satisfied, the brake is locked to brake the sun gear and the engine is ignited.

As a preferable technical solution of the above vehicle control method, a powertrain of a vehicle includes an engine, a clutch, and a transmission, an output shaft of the engine being connected to an input shaft of the transmission through the clutch;

under the condition of sliding or braking deceleration, if an engine flameout condition allowing the engine to be flameout is met, the clutch is controlled to be disconnected, and the engine is flameout.

As a preferable technical solution of the vehicle control method, if a brake pedal of the vehicle is depressed and a rate of change of the brake pedal is greater than a preset rate of change, or an opening degree of the depressed brake pedal is greater than a preset opening degree, the vehicle is in an emergency braking state; otherwise, the vehicle is in a non-emergency braking state.

As a preferable technical solution of the vehicle control method, the first preset vehicle speed is 80Km/h to 100Km/h, and the second preset vehicle speed is 0Km/h to 30Km/h and does not include 0 Km/h.

As a preferable aspect of the vehicle control method, the preset gradient is 2 ° to 10 °.

As a preferable technical scheme of the vehicle control method, the preset temperature is-60 ℃ to 60 ℃.

As a preferable technical solution of the above vehicle control method, the preset altitude is 2.5Km to 5 Km.

The invention also provides a vehicle and a vehicle control method adopting the vehicle control method.

The invention has the beneficial effects that: under the working condition of sliding or braking deceleration, the engine is controlled to be flamed out, the output shaft of the engine stops rotating, the output shaft of the engine cannot be dragged to rotate when the vehicle continues to run, no waste gas is generated in an exhaust system of the engine, the temperature of an aftertreatment system cannot be reduced, the aftertreatment system naturally cools, the temperature required by aftertreatment can be maintained in a short time, and the high conversion rate of the aftertreatment system is ensured. After the engine is restarted in a short time, the temperature in the aftertreatment system can be quickly restored to the aftertreatment required temperature so that the vehicle maintains efficient exhaust gas treatment capability.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments of the present invention will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the contents of the embodiments of the present invention and the drawings without creative efforts.

FIG. 1 is a schematic illustration of a vehicle powertrain system provided by an embodiment of the present invention;

fig. 2 is a flowchart of a vehicle control method according to an embodiment of the present invention.

In the figure:

1. an engine; 2. a clutch; 31. a sun gear; 32. a planet wheel; 33. a planet carrier; 34. a ring gear; 4. a brake; 5. a transmission; 6. a drive shaft; 7. a main speed reducer; 8. and (7) wheels.

Detailed Description

In order to make the technical problems solved, the technical solutions adopted and the technical effects achieved by the present invention clearer, the technical solutions of the present invention are further described below by way of specific embodiments with reference to the accompanying drawings. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting of the invention. It should be further noted that, for the convenience of description, only some but not all of the elements associated with the present invention are shown in the drawings.

As shown in fig. 1 and 2, the present embodiment provides a vehicle control method for controlling the engine 1 to stall and stopping rotation of the output shaft of the engine 1 if an engine stall condition that allows the engine 1 to stall is satisfied under a coasting or braking deceleration condition.

Under the working condition of sliding or braking deceleration, the engine 1 is controlled to be shut down, the output shaft of the engine 1 stops rotating, the vehicle continues to run, the output shaft of the engine 1 cannot be dragged and rotate, no waste gas is generated in an exhaust system of the engine 1, the temperature of an aftertreatment system cannot be reduced, the aftertreatment system naturally cools, the temperature required by aftertreatment can be maintained in a short time, and the high conversion rate of the aftertreatment system is ensured. After the engine is restarted in a short time, the temperature in the aftertreatment system can be quickly restored to the aftertreatment required temperature so that the vehicle maintains efficient exhaust gas treatment capability.

Specifically, the engine stall condition is: the vehicle speed is less than a first preset vehicle speed and greater than a second preset vehicle speed, the gradient of the current position of the vehicle is less than the preset gradient, the temperature of the cooling liquid in the engine 1 is higher than a preset temperature, the vehicle is in a non-emergency braking state, the altitude of the current position of the vehicle is lower than a preset altitude, the engine 1 is not in an aftertreatment regeneration mode and an SCR heating mode, and the engine 1 has no torque demand.

The vehicle speed is limited, so that the starting failure of the vehicle caused by flameout of the vehicle when the vehicle speed is too low is prevented, and the driving safety is prevented from being influenced by too high vehicle speed; the gradient of the current position of the vehicle is limited, so that the condition that the running safety of the vehicle is influenced by flameout of the engine 1 under a large gradient can be prevented; the temperature of the cooling liquid in the engine 1 is limited, so that the problem that the running efficiency of the engine is poor in the vehicle warming process due to the fact that the temperature of the cooling liquid is too low can be avoided; in a high-altitude area, the power requirement of the vehicle is preferably considered, the vehicle cannot be flamed out, the altitude is limited, and the influence of flameout of the engine 1 on the normal running of the vehicle can be prevented; if the engine 1 is shut down when the engine 1 is in the aftertreatment regeneration mode, the aftertreatment regeneration system is damaged, and therefore the engine 1 is prohibited from shutting down when the engine 1 is in the aftertreatment regeneration mode; the SCR heating mode is to raise the temperature of the aftertreatment system to ensure the aftertreatment system to work normally, and once the engine 1 is in the SCR heating mode, the engine 1 is shut down, which may result in insufficient temperature of the aftertreatment system, and the aftertreatment system may continue to cool naturally, so that the aftertreatment system cannot perform aftertreatment normally, and therefore, the engine 1 is in the SCR heating mode, and the engine 1 is prohibited from shutting down. The engine 1 is considered to have a torque demand when an accelerator pedal is depressed, or an air conditioning compressor has a work demand, a generator has a work demand, or a power take-off connected to the engine 1 has a power take-off demand.

Preferably, the first preset vehicle speed is 80-100 Km/h, the second preset vehicle speed is 0-30 Km/h and does not include 0Km/h, the preset gradient is 2-10 degrees, the preset temperature is-40-60 degrees, and the preset altitude is 2.5-5 Km. The first preset vehicle speed, the second preset vehicle speed, the preset gradient, the preset temperature and the preset altitude can be further set through actual requirements on the basis of the limited range.

It should be noted that, if the brake pedal of the vehicle is stepped on and the change rate of the brake pedal is greater than the preset change rate, or the opening degree of the brake pedal is greater than the preset opening degree, the vehicle is in an emergency braking state; otherwise, the vehicle is in a non-emergency braking state. The preset change rate and the preset opening degree can be determined through repeated tests to ensure the driving safety.

The vehicle is provided with a GPS positioning module to acquire the height of the current position of the vehicle in real time; the vehicle is provided with a gradient sensor for measuring the gradient of the current position of the vehicle. Because the existing vehicle is provided with a speed sensor for measuring the vehicle speed and a temperature sensor for measuring the temperature of the cooling liquid, the speed sensor for measuring the vehicle speed and the temperature sensor for measuring the temperature of the cooling liquid do not need to be additionally arranged, and the prior art is used for judging whether the brake pedal of the vehicle is pressed down and obtaining the change rate of the brake pedal, so that the description is omitted.

Further, the powertrain of the vehicle includes an engine 1, a transmission 5, a planetary gear train including a sun gear 31, planetary gears 32, a ring gear 34, and a carrier 33, the planetary gears 32 being rotatably supported on the carrier 33, the planetary gears 32 being located between the sun gear 31 and the ring gear 34 and meshing with the sun gear 31 and the ring gear 34, the engine 1 being connected to the carrier 33, the ring gear 34 being connected to an input shaft of the transmission 5, and the brake 4 being connected to the sun gear 31. The output shaft of the engine 1 is connected to the carrier 33 through the clutch 2.

In a vehicle equipped with the power system, when an engine stall condition that allows the engine 1 to stall is satisfied under a coasting or braking deceleration condition, the brake 4 releases the brake on the sun gear 31, and the engine 1 stalls.

In the normal driving process, the brake 4 brakes the sun gear 31, the sun gear 31 is fixed, the engine 1 drives the planet carrier 33 to rotate through the clutch 2, the planet carrier 33 drives the planet gear 32 to rotate, the planet gear 32 is meshed with the gear ring 34, the gear ring 34 drives the transmission 5 to work, and the transmission 5 drives the wheel 8 to rotate through the driving shaft 6 and the main reducer 7. How the transmission 5 rotates the wheels 8 through the driving shaft 6 and the final drive 7 is prior art in the field, and details are not described here.

When an engine stall condition that allows the engine 1 to stall is met, the brake 4 releases the brake on the sun gear 31, the engine 1 stalls, the planet carrier 33 stops rotating, the wheels 8 drag the transmission 5 to work, and the transmission 5 drives the sun gear 31 to rotate through the gear ring 34 and the planet gears 32. In the process, the output shaft of the engine 1 cannot be dragged to rotate, so that the exhaust system of the engine 1 cannot generate waste gas, and the aftertreatment system is ensured to be cooled only naturally.

Further, if the ignition condition of the engine 1 is not satisfied and there is a torque demand while the engine 1 is in a stall state, the brake 4 is locked to brake the sun gear 31, the engine 1 is ignited, the engine 1 is forcibly pulled down to start, and the engine 1 starts to operate after the fuel supply.

In other embodiments, for a vehicle without a planetary gear train, i.e. a power system including the engine 1, the clutch 2 and the transmission 5, the output shaft of the engine 1 is connected with the input shaft of the transmission 5 through the clutch 2. Under the condition of coasting or braking deceleration, if an engine stall condition that allows the engine 1 to stall is satisfied, the clutch 2 is controlled to be disconnected, and the engine 1 stalls. Although the same technical effects can be achieved, the reliability and safety of the clutch 2 are affected to some extent.

It should be understood that the above-described embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention should be included in the protection scope of the claims of the present invention.

In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance. Wherein the terms "first position" and "second position" are two different positions.

In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly and may be, for example, 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 meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

Claims

1. A vehicle control method is characterized in that under the condition of coasting or braking deceleration, if an engine flameout condition allowing an engine (1) to flameout is met, the engine (1) is controlled to flameout, and an output shaft of the engine (1) stops rotating;

the engine stall conditions are as follows: the vehicle speed is less than a first preset vehicle speed and greater than a second preset vehicle speed, the gradient of the current position of the vehicle is less than the preset gradient, the temperature of cooling liquid in the engine (1) is higher than a preset temperature, the vehicle is in a non-emergency braking state, the altitude of the current position of the vehicle is lower than a preset altitude, the engine (1) is not in an aftertreatment regeneration mode and an SCR heating mode, and the engine (1) has no torque requirement;

the first preset vehicle speed is 80-100 Km/h, and the second preset vehicle speed is 0-30 Km/h and does not include 0 Km/h; the preset gradient is 2-10 degrees, the preset temperature is-40-60 degrees, and the preset altitude is 2.5-5 Km.

2. A vehicle control method according to claim 1, a powertrain of a vehicle comprising an engine (1), a transmission (5), a planetary gear train comprising a sun gear (31), planet wheels (32), a ring gear (34) and a planet carrier (33), the planet wheels (32) being rotatably supported on the planet carrier (33), the planet wheels (32) being located between the sun gear (31) and the ring gear (34) and being in mesh with the sun gear (31) and the ring gear (34), the engine (1) being connected to the planet carrier (33), the ring gear (34) being connected to an input shaft of the transmission (5), and the brake (4) being connected to the sun gear (31);

under the condition of coasting or braking deceleration, if an engine stall condition that allows the engine (1) to stall is satisfied, the brake (4) releases the brake on the sun gear (31), and the engine (1) stalls.

3. A vehicle control method according to claim 2, characterized in that, while the engine (1) is in a stall state, if the engine stall condition is not satisfied and there is a torque demand, the brake (4) is locked to brake the sun gear (31) and the engine (1) is ignited.

4. The vehicle control method according to claim 1, characterized in that a powertrain of a vehicle includes an engine (1), a clutch (2), and a transmission (5), and an output shaft of the engine (1) is connected to an input shaft of the transmission (5) through the clutch (2);

under the condition of coasting or braking deceleration, if an engine flameout condition allowing the engine (1) to flameout is met, the clutch (2) is controlled to be disconnected, and the engine (1) is flamed out.

5. The vehicle control method according to any one of claims 1 to 4, characterized in that if a brake pedal of the vehicle is depressed and a rate of change of the brake pedal is greater than a preset rate of change, or an opening degree of the brake pedal is greater than a preset opening degree, the vehicle is in an emergency braking state; otherwise, the vehicle is in a non-emergency braking state.

6. A vehicle characterized by employing the vehicle control method according to any one of claims 1 to 5.