Engine braking stepless adjustment method, device, equipment and medium

Abstract

The present invention relates to a method, device, equipment and medium for stepless adjustment of engine braking, belonging to the technical field of engine braking, wherein the method comprises obtaining a negative torque request and basic driving data sent when a vehicle is braking, and determining a required negative torque based on the negative torque request; determining an engine braking activation state based on the basic driving data and the required negative torque; when the engine braking activation state is on and the vehicle's engine braking does not meet the required negative torque, adjusting a pneumatic supercharger to obtain a first engine braking torque; when the first engine braking torque meets the required negative torque, completing stepless adjustment of the engine braking, and increasing the braking effect by adjusting the engine braking and the pneumatic supercharger; controlling the vehicle's engine braking torque based on the required negative torque, and performing continuously variable torque adjustment, thereby realizing stepless adjustment of the engine braking.

Description

Technical Field

[0001] The present invention relates to the technical field of engine braking, and in particular to an engine braking stepless adjustment method, device, equipment and medium. Background Art

[0002] Engine braking applies braking force to the drive wheels through the compression resistance, internal friction, and intake and exhaust resistance generated by the engine's compression stroke. When the driver gradually reduces the accelerator pedal without engaging the clutch, the engine's internal mechanisms generate resistance, helping to decelerate the vehicle. This braking method not only relies on friction braking but also effectively reduces the driver's operating burden and improves fuel economy.

[0003] Currently, stepless adjustment is typically achieved through a hydraulic retarder, a proportional exhaust brake valve, and an in-cylinder brake valve, but this is expensive. Proportional exhaust brakes alone provide insufficient torque and poor braking effectiveness. Engine brakes alone, however, have braking torque that is primarily dependent on engine speed and cannot provide continuously variable torque adjustment.

[0004] Therefore, there is an urgent need to propose a method, device, equipment and medium for stepless adjustment of engine braking to solve the technical problems in the prior art of adjusting torque solely through exhaust braking or engine braking, resulting in poor braking effect and inability to perform continuously variable torque adjustment. Summary of the Invention

[0005] In view of this, it is necessary to provide a method, device, equipment and medium for stepless adjustment of engine braking to solve the technical problems existing in the prior art of adjusting torque solely through exhaust braking or engine braking, resulting in poor braking effect and inability to perform continuously variable torque adjustment.

[0006] In order to solve the above problems, the present invention provides an engine brake stepless adjustment method, comprising:

[0007] Obtaining a negative torque request and basic driving data sent when the vehicle is braking, and determining a required negative torque based on the negative torque request;

[0008] determining an engine brake activation state according to the basic driving data and the required negative torque;

[0009] When the engine brake on state is on and the engine brake of the vehicle does not meet the required negative torque, adjusting the pneumatic supercharger to obtain a first engine brake torque;

[0010] When the first engine braking torque satisfies the required negative torque, the stepless adjustment of the engine braking is completed.

[0011] In one possible implementation, the basic driving data includes a current engine speed; the engine brake activation state includes an exhaust brake activation state and an in-cylinder brake activation state; and determining the engine brake activation state based on the basic driving data and the required negative torque includes:

[0012] determining the exhaust brake activation state according to the current engine speed and the required negative torque;

[0013] When the exhaust brake on state is on and turning on the exhaust brake does not satisfy the required negative torque, determining that the in-cylinder brake on state is on, and determining the exhaust brake on state to be off;

[0014] When the required negative torque is not satisfied by turning on the in-cylinder brake, the in-cylinder brake on state and the exhaust brake on state are determined to be on.

[0015] In one possible implementation, the basic driving data includes an intake air temperature of the pneumatic supercharger, an actual boost pressure error, and an altitude; and adjusting the pneumatic supercharger to obtain the first engine braking torque includes:

[0016] determining an initial wastegate opening feedforward term of the pneumatic supercharger according to the current engine speed and the required negative torque, and correcting the initial wastegate opening feedforward term according to the altitude to obtain a target wastegate opening feedforward term;

[0017] determining an initial boost pressure of the pneumatic supercharger according to the current engine speed and the required negative torque, and correcting the initial boost pressure according to the altitude and the intake air temperature to obtain a target boost pressure;

[0018] Performing closed-loop control calculation based on the target boost pressure and the actual boost pressure error to obtain a closed-loop term of the wastegate opening of the pneumatic supercharger;

[0019] Obtaining the wastegate opening of the pneumatic supercharger according to the target wastegate opening feedforward term and the wastegate opening closed-loop term;

[0020] The duty cycle is adjusted according to the exhaust bypass opening to obtain a first engine braking torque.

[0021] In a possible implementation, the method further includes:

[0022] When the first engine braking torque does not meet the required negative torque, determining a throttle opening term according to the current engine speed and the required negative torque;

[0023] adjusting the intake air amount according to the throttle opening term to obtain a second engine braking torque;

[0024] When the second engine braking torque satisfies the required negative torque, the stepless adjustment of the engine braking is completed.

[0025] In a possible implementation, when the second engine braking torque satisfies the required negative torque, after the stepless adjustment of the engine braking is completed, the method further includes:

[0026] when the second engine braking torque does not meet the required negative torque, determining an exhaust gas recirculation valve opening term according to the current engine speed and the required negative torque;

[0027] adjusting the exhaust gas volume according to the exhaust gas recirculation valve opening term to obtain a third engine braking torque;

[0028] The engine brake is continuously adjusted according to the third engine brake torque.

[0029] In one possible implementation, determining the exhaust brake activation state according to the current engine speed and the required negative torque includes:

[0030] determining whether the current engine speed is greater than a preset speed, and whether the required negative torque is greater than a preset negative torque;

[0031] If so, determining that the exhaust brake opening state is on;

[0032] If not, it is determined that the exhaust brake opening state is closed.

[0033] In one possible implementation, the correcting the initial exhaust gas bypass opening feedforward term according to the altitude to obtain a target exhaust gas bypass opening feedforward term includes:

[0034] Correcting the initial exhaust gas bypass opening feedforward term according to the altitude to obtain a corrected exhaust gas bypass opening feedforward term;

[0035] A target exhaust gas bypass opening feedforward term is obtained according to the initial exhaust gas bypass opening feedforward term and the corrected exhaust gas bypass opening feedforward term.

[0036] On the other hand, the present invention also provides an engine brake stepless adjustment device, comprising:

[0037] a data acquisition module, configured to acquire a negative torque request and basic driving data sent when the vehicle is braking, and determine a required negative torque based on the negative torque request;

[0038] a state determination module, configured to determine an engine brake activation state based on the basic driving data and the required negative torque;

[0039] a torque determination module, configured to adjust a pneumatic supercharger to obtain a first engine braking torque when the engine braking activation state is on and the engine braking of the vehicle does not meet the required negative torque;

[0040] The stepless adjustment module is configured to complete the stepless adjustment of the engine braking when the first engine braking torque meets the required negative torque.

[0041] On the other hand, an embodiment of the present invention discloses a vehicle, comprising: a processor, a memory, and a computer program stored in the memory and capable of running on the processor, wherein the computer program, when executed by the processor, implements the various steps of the above-mentioned engine brake stepless adjustment method embodiment.

[0042] On the other hand, an embodiment of the present invention discloses a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the various steps of the above-mentioned embodiment of the engine brake stepless adjustment method are implemented.

[0043] The beneficial effects of the present invention are as follows: a negative torque request and basic driving data sent when the vehicle is braking are obtained, and a required negative torque is determined according to the negative torque request; an engine brake on state is determined according to the basic driving data and the required negative torque; when the engine brake on state is on and the engine braking of the vehicle does not meet the required negative torque, the pneumatic supercharger is adjusted to obtain a first engine braking torque; when the first engine braking torque meets the required negative torque, stepless adjustment of the engine braking is completed, and the braking effect can be increased by adjusting the engine braking and the pneumatic supercharger; the engine braking torque of the vehicle is controlled according to the required negative torque, and continuously variable torque adjustment can be performed, thereby realizing stepless adjustment of the engine braking. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 A schematic flow chart of an embodiment of the engine brake stepless adjustment method provided by the present invention;

[0045] Figure 2 A schematic structural diagram of an embodiment of a process for determining a required negative torque provided by the present invention;

[0046] Figure 3 For the present invention Figure 1 A schematic flow chart of an embodiment of step S102;

[0047] Figure 4 For the present invention Figure 1A schematic flow chart of an embodiment of step S103;

[0048] Figure 5 A schematic flow chart of one embodiment of the engine brake stepless adjustment method provided by the present invention;

[0049] Figure 6 A schematic flow chart of another embodiment of the engine brake stepless adjustment method provided by the present invention;

[0050] Figure 7 A schematic structural diagram of an embodiment of the engine brake stepless adjustment device provided by the present invention;

[0051] Figure 8 This is a schematic structural diagram of an embodiment of a vehicle provided by the present invention. DETAILED DESCRIPTION

[0052] The preferred embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings, wherein the accompanying drawings constitute a part of this application and are used together with the embodiments of the present invention to illustrate the principles of the present invention, and are not used to limit the scope of the present invention.

[0053] like Figure 1 As shown, a specific embodiment of the present invention discloses a method for stepless adjustment of engine braking, comprising:

[0054] S101, obtaining a negative torque request and basic driving data sent when the vehicle is braking, and determining a required negative torque based on the negative torque request;

[0055] S102: Determine the engine brake on state based on basic driving data and required negative torque;

[0056] S103: When the engine brake on state is on and the engine brake of the vehicle does not meet the required negative torque, adjust the pneumatic supercharger to obtain a first engine brake torque;

[0057] S104: When the first engine braking torque meets the required negative torque, the stepless adjustment of the engine braking is completed.

[0058] It should be understood that when the vehicle is driven downhill at a constant speed, the auxiliary brake needs to be continuously adjustable to provide the required negative torque according to the change in vehicle speed. The stepless adjustment of vehicle engine braking refers to the continuous and smooth adjustment of the engine speed and torque to achieve stepless changes in the braking effect. This adjustment method is different from the traditional fixed gear adjustment. It can be adjusted arbitrarily and smoothly within a range, rather than in a jumpy manner. Figure 2 As shown, Figure 2The process for determining the required negative torque includes requests from the auxiliary brake handle, retarder controller, transmission controller, and EBS controller. The retarder, transmission, and EBS controllers directly request a torque percentage. When the auxiliary brake handle is not in constant gear, different handle positions correspond to fixed torque percentages. When the auxiliary brake handle is in constant gear, the vehicle speed at the time of accelerator release is used as the target speed, and closed-loop control is performed based on the difference between the target speed and the actual vehicle speed. The calculated torque percentage is multiplied by a fixed reference torque value to determine the negative torque request source. The required negative torque is then determined through TSC1 arbitration.

[0059] In a specific embodiment of the present invention, based on the vehicle's arbitrated demanded negative torque, actuators such as the engine brake (including the in-cylinder brake valve or on / off exhaust brake valve), throttle, exhaust gas recirculation valve, and pneumatic supercharger participate in controlling the amount of air in the engine cylinder, thereby expanding the range of engine brake torque adjustment. When the EECU receives a negative torque request from the vehicle, it determines the demanded negative torque based on the negative torque request and obtains basic driving data from various modules on the vehicle. This basic driving data may include current engine speed, altitude, and other data. It then performs a table lookup based on the basic driving data and the demanded negative torque to determine the engine brake activation state. For example, a mapping table is searched based on the current engine speed and the demanded negative torque, and the table value determines whether the engine brake is activated. For example, if the current engine speed or the demanded negative torque is low, the engine brake activation state is disabled; if the current engine speed is greater than a preset speed (e.g., 800 rpm) and the demanded negative torque is greater than a preset negative torque (e.g., -200 Nm), the engine brake activation state is enabled; otherwise, the exhaust brake activation state is determined to be disabled. The engine brake activation state can then be determined. If the engine brake activation state is off, the process ends and the next negative torque request is received. If the engine brake activation state is on, it is determined whether the required negative torque can be maintained by activating the engine brake alone. If so, the engine brake is determined to be on and the engine brake torque is adjusted by the engine brake to achieve stepless adjustment of the engine brake. If not, the pneumatic booster is adjusted while the engine brake activation state is on. The duty cycle is adjusted by adjusting the opening of the pneumatic booster, thereby adjusting the engine brake torque to obtain a first adjusted engine brake torque. It is then determined whether the first engine brake torque meets the required negative torque (i.e., whether activating the engine brake and the pneumatic booster is sufficient to maintain the required negative torque of the vehicle). If so, the engine brake and the pneumatic booster are activated to meet the engine brake torque condition, thereby achieving stepless adjustment of the engine brake. If not, the engine brake torque can be adjusted by other devices, and the process returns to S101. The specific process can be set according to actual conditions and is not limited in this embodiment of the present invention.

[0060] Compared with the prior art, the present embodiment provides a method for obtaining a negative torque request and basic driving data sent when a vehicle is braking, and determining a required negative torque based on the negative torque request; determining an engine braking on-state based on the basic driving data and the required negative torque; when the engine braking on-state is on and the vehicle's engine braking does not meet the required negative torque, adjusting the pneumatic supercharger to obtain a first engine braking torque; when the first engine braking torque meets the required negative torque, completing stepless adjustment of the engine braking, and adjusting the engine braking and the pneumatic supercharger to increase the braking effect; controlling the vehicle's engine braking torque based on the required negative torque, and performing continuously variable torque adjustment, thereby achieving stepless adjustment of the engine braking.

[0061] In some embodiments of the present invention, before step S102, the method further includes:

[0062] The throttle opening is set to fully open, the exhaust gas recirculation valve opening is set to fully closed, and the duty cycle of the pneumatic supercharger is set to a preset value.

[0063] In a specific embodiment of the present invention, when the EECU receives a negative torque request from the vehicle, the engine brake is controlled not to be turned on, the throttle opening is fully opened, the exhaust gas recirculation valve opening (EGR) is fully closed, and the pneumatic supercharger duty cycle is a preset value, which can be 0.

[0064] In some embodiments of the present invention, the basic driving data includes the current engine speed; the engine brake opening state includes the exhaust brake opening state and the cylinder brake opening state; Figure 3 As shown, step S102 includes:

[0065] S301: Determine the exhaust brake activation state based on the current engine speed and required negative torque;

[0066] S302: when the exhaust brake on state is on and the exhaust brake on state does not satisfy the required negative torque, determining that the in-cylinder brake on state is on and setting the exhaust brake on state to off;

[0067] S303: When the in-cylinder brake is turned on but the required negative torque is not satisfied, the in-cylinder brake turn-on state and the exhaust brake turn-on state are determined to be turned on.

[0068] In a specific embodiment of the present invention, the engine brake on state may include the exhaust brake on state and the in-cylinder brake on state. When the EECU receives a negative torque request from the entire vehicle, the required negative torque is used as a target and the exhaust brake on state is calculated according to the current engine speed and the required negative torque. When the exhaust brake on state is on, and turning on the exhaust brake alone is sufficient to maintain the required negative torque of the entire vehicle (when turning on the exhaust brake meets the required negative torque), only the exhaust brake is used; when turning on the exhaust brake alone is insufficient to maintain the required negative torque of the entire vehicle (when turning on the exhaust brake does not meet the required negative torque), the in-cylinder brake on state is set to on, and the exhaust brake on state is determined to be off; when turning on the in-cylinder brake alone is sufficient to maintain the required negative torque of the entire vehicle (when turning on the in-cylinder brake meets the required negative torque), only the in-cylinder brake is used; when turning on the in-cylinder brake alone is insufficient to maintain the required negative torque of the entire vehicle (when turning on the in-cylinder brake does not meet the required negative torque), the in-cylinder brake on state and the exhaust brake on state are determined to be on, that is, the in-cylinder brake and the exhaust brake are used at the same time.

[0069] In some embodiments of the present invention, step S301 includes:

[0070] Determining whether the current engine speed is greater than a preset speed and whether the required negative torque is greater than a preset negative torque;

[0071] If so, determining that the exhaust brake activation state is on;

[0072] If not, it is determined that the exhaust brake opening state is closed.

[0073] In a specific embodiment of the present invention, a mapping table is consulted based on the current engine speed and required negative torque, and the table value determines whether the engine brake is enabled. For example, when the current engine speed or required negative torque is low, the exhaust brake is disabled; when the current engine speed is greater than a preset speed (e.g., 800 rpm) and the required negative torque is greater than a preset negative torque (e.g., -200 Nm), the exhaust brake is enabled; otherwise, the exhaust brake is disabled.

[0074] In some embodiments of the present invention, the basic driving data includes the air intake temperature of the pneumatic supercharger, the actual boost pressure error and the altitude; Figure 4 As shown, step S103 includes:

[0075] S401: determining an initial wastegate opening feedforward term of the pneumatic supercharger based on the current engine speed and the required negative torque, and correcting the initial wastegate opening feedforward term based on the altitude to obtain a target wastegate opening feedforward term;

[0076] S402: Determine an initial boost pressure of the pneumatic supercharger based on the current engine speed and the required negative torque, and correct the initial boost pressure based on the altitude and intake air temperature to obtain a target boost pressure;

[0077] S403, performing closed-loop control calculation based on the target boost pressure and the actual boost pressure error to obtain a closed-loop term of the wastegate opening of the pneumatic supercharger;

[0078] S404, obtaining the wastegate opening of the pneumatic supercharger according to the target wastegate opening feedforward term and the wastegate opening closed-loop term;

[0079] S405 : Adjust the duty cycle according to the exhaust bypass opening to obtain a first engine braking torque.

[0080] In some embodiments of the present invention, step S401 includes:

[0081] Correcting the initial exhaust gas bypass opening feedforward term according to the altitude to obtain a corrected exhaust gas bypass opening feedforward term;

[0082] A target exhaust gas bypass opening feedforward term is obtained according to the initial exhaust gas bypass opening feedforward term and the corrected exhaust gas bypass opening feedforward term.

[0083] In a specific embodiment of the present invention, the basic driving data may also include the intake temperature of the pneumatic supercharger, the actual boost pressure error and the altitude. When the engine braking alone is not sufficient to maintain the required negative torque, the engine braking torque is adjusted by adjusting the duty cycle of the pneumatic supercharger to obtain the adjusted first engine braking torque. Specifically, the initial exhaust bypass opening feedforward item of the pneumatic supercharger under the engine braking condition is calculated according to the engine speed and the negative torque demand, and then the initial exhaust bypass opening feedforward item is corrected by the altitude to obtain the corrected initial exhaust bypass opening feedforward item, and then the initial exhaust bypass opening feedforward item is added to the corrected initial exhaust bypass opening feedforward item to obtain the target exhaust bypass opening feedforward item; the exhaust bypass opening closed-loop item of the pneumatic supercharger under the engine braking condition is calculated according to the engine speed and the negative torque demand. The initial boost pressure / exhaust manifold demand pressure is calculated based on the speed and negative torque demand (the boost pressure closed loop is preferred, and the exhaust manifold pressure sensor is used when there is no boost pressure sensor). The initial boost pressure is corrected according to the altitude and intake temperature to obtain the corrected boost pressure. The initial boost pressure is then added to the corrected boost pressure to obtain the target boost pressure. A closed-loop control calculation is then performed based on the error between the target boost pressure and the actual boost pressure to obtain the closed-loop item of the exhaust gas bypass opening of the pneumatic supercharger. The exhaust gas bypass opening of the pneumatic supercharger is calculated based on the feedforward item and closed-loop item of the exhaust gas bypass opening of the pneumatic supercharger under engine braking conditions, and the duty cycle is adjusted according to the exhaust gas bypass opening to obtain the first engine braking torque. When there is no boost pressure sensor or exhaust manifold pressure sensor, only the feedforward item is considered.

[0084] In some embodiments of the present invention, the method further comprises:

[0085] When the first engine braking torque does not meet the required negative torque, determining a throttle opening term according to the current engine speed and the required negative torque;

[0086] Adjusting the intake air volume according to the throttle opening term to obtain a second engine braking torque;

[0087] When the second engine braking torque satisfies the required negative torque, the stepless adjustment of the engine braking is completed.

[0088] In a specific embodiment of the present invention, when engine braking and the pneumatic supercharger are insufficient to maintain the required negative torque (when the first engine braking torque does not meet the required negative torque), a throttle opening term is determined based on the current engine speed and the required negative torque. Altitude correction is then performed, and the engine braking torque is adjusted by adjusting the intake air volume using the throttle opening term to obtain a second engine braking torque. When engine braking, the pneumatic supercharger, and the throttle are sufficient to maintain the required negative torque (when the second engine braking torque meets the required negative torque), stepless engine braking adjustment is completed.

[0089] In some embodiments of the present invention, when the second engine braking torque satisfies the required negative torque, after the stepless adjustment of the engine braking is completed, the method further includes:

[0090] When the second engine braking torque does not meet the required negative torque, determining an exhaust gas recirculation valve opening term according to the current engine speed and the required negative torque;

[0091] The exhaust gas volume is adjusted according to the exhaust gas recirculation valve opening term to obtain a third engine braking torque;

[0092] The engine brake is continuously adjusted according to the third engine brake torque.

[0093] In a specific embodiment of the present invention, when turning on the engine brake, the pneumatic supercharger, and the throttle is insufficient to maintain the required negative torque (when the second engine braking torque does not meet the required negative torque), the exhaust gas recirculation valve opening item under the engine braking condition is calculated based on the engine speed and the negative torque requirement to determine the exhaust gas recirculation valve opening item, and then an altitude correction is performed. The exhaust gas volume is adjusted by adjusting the exhaust gas opening item to adjust the engine braking torque to a third engine braking torque, and then the engine braking is continuously variable adjusted according to the third engine braking torque.

[0094] A specific embodiment of the present invention, as Figure 5As shown in the figure, when the EECU receives a negative torque request from the vehicle, it takes the required negative torque as the target, controls the throttle to be fully open, EGR to be fully closed, and the duty cycle of the pneumatic supercharger to be 0, and calculates the engine brake opening state according to the current engine speed and negative torque demand.

[0095] When engine braking alone is insufficient to maintain the required negative torque, the engine braking torque is adjusted by adjusting the duty cycle of the pneumatic supercharger. Under engine braking conditions, the pneumatic supercharger wastegate opening feedforward term is calculated based on the engine speed and negative torque demand, and then corrected for altitude. Under engine braking conditions, the pneumatic supercharger wastegate opening closed-loop term calculates the target boost pressure / exhaust manifold demand pressure based on the engine speed and negative torque demand (prioritizing the boost pressure closed-loop; the exhaust manifold pressure sensor is used when no boost pressure sensor is available). The target boost pressure is corrected based on altitude and intake air temperature, and closed-loop control calculations are performed based on the error between the target boost pressure and the actual boost pressure. The pneumatic supercharger wastegate opening is calculated based on the pneumatic supercharger wastegate opening feedforward term and closed-loop term under engine braking conditions. When there is no boost pressure sensor or exhaust manifold pressure sensor, only the feedforward term is considered.

[0096] When engine braking and the pneumatic booster are insufficient to maintain the required negative torque, the engine braking torque is adjusted by adjusting the intake air volume through the throttle. The throttle opening term under engine braking conditions is calculated based on engine speed and negative torque demand, and then corrected for altitude.

[0097] When engine braking, the pneumatic booster, and the throttle are insufficient to maintain the required negative torque, exhaust gas recirculation (EGR) is used to adjust the exhaust gas volume to regulate engine braking torque. The EGR valve opening term for engine braking is calculated based on engine speed and the required negative torque, and then corrected for altitude.

[0098] A specific embodiment of the present invention, as Figure 6 As shown, when there are both a switch-type engine brake valve and a switch-type exhaust brake valve:

[0099] When the EECU receives a negative torque request from the vehicle, it uses the required negative torque as the target. At this time, the engine brake is controlled not to be turned on, the throttle is fully open, the EGR is fully closed, and the duty cycle of the pneumatic supercharger is 0. The exhaust brake opening state is calculated based on the current engine speed and negative torque demand.

[0100] When the exhaust brake alone is sufficient to maintain the required negative torque, only the exhaust brake is used; when the exhaust brake alone is insufficient to maintain the required negative torque, the in-cylinder brake is turned on; when the in-cylinder brake alone is sufficient to maintain the required negative torque, only the in-cylinder brake is used; when the engine brake alone is insufficient to maintain the required negative torque, both the in-cylinder brake and the exhaust brake are used;

[0101] The engine braking torque is adjusted by adjusting the duty cycle of the pneumatic supercharger. Under engine braking conditions, the pneumatic supercharger wastegate opening feedforward term is calculated based on engine speed and negative torque demand, and then corrected for altitude. Under engine braking conditions, the pneumatic supercharger wastegate opening closed-loop term calculates the target boost pressure / exhaust manifold demand pressure based on engine speed and negative torque demand (preferably based on the boost pressure closed-loop; if a boost pressure sensor is not available, the exhaust manifold pressure sensor is used). The target boost pressure is corrected based on altitude and intake air temperature, and closed-loop control calculations are performed based on the error between the target boost pressure and the actual boost pressure. The pneumatic supercharger wastegate opening is calculated based on the pneumatic supercharger wastegate opening feedforward term and closed-loop term under engine braking conditions. If a boost pressure sensor or exhaust manifold pressure sensor is not available, only the feedforward term is considered.

[0102] When engine braking and the pneumatic booster are insufficient to maintain the required negative torque, the engine braking torque is adjusted by adjusting the intake air volume through the throttle. The throttle opening term under engine braking conditions is calculated based on engine speed and negative torque demand, and then corrected for altitude.

[0103] When engine braking, the pneumatic booster, and the throttle are insufficient to maintain the required negative torque, exhaust gas recirculation (EGR) is used to adjust the exhaust gas volume to regulate engine braking torque. The EGR valve opening term for engine braking is calculated based on engine speed and the required negative torque, and then corrected for altitude.

[0104] The embodiment of the present invention has good compatibility, determines the priority action sequence of each actuator, and is compatible with different configurations; the principle of adjusting the intake boost pressure by a pneumatic supercharger is utilized, and the duty cycle of the pneumatic supercharger is closed-loop regulated according to the boost pressure or the exhaust manifold pressure; the throttle and the exhaust gas recirculation valve are used to assist in open-loop regulation to avoid mutual interference among the actuators of the pneumatic supercharger, the throttle and the exhaust gas recirculation valve. The pneumatic supercharger, the throttle and the exhaust gas recirculation valve are used in combination to achieve stepless regulation of the engine braking torque from 0 to the maximum capacity range.

[0105] In order to better implement the engine brake stepless adjustment method in the embodiment of the present invention, based on the engine brake stepless adjustment method, the embodiment of the present invention also provides an engine brake stepless adjustment device, such as Figure 7 As shown, the engine brake stepless adjustment device 700 includes:

[0106] The data acquisition module 701 is used to acquire the negative torque request and basic driving data sent by the vehicle when braking, and determine the required negative torque according to the negative torque request;

[0107] A state determination module 702 is configured to determine an engine brake on state based on basic driving data and required negative torque;

[0108] a torque determination module 703 for adjusting the pneumatic supercharger to obtain a first engine braking torque when the engine braking state is on and the engine braking of the vehicle does not meet the required negative torque;

[0109] The stepless adjustment module 704 is configured to complete stepless adjustment of the engine brake when the first engine brake torque meets the required negative torque.

[0110] The engine brake stepless adjustment device 700 provided in the above embodiment can implement the technical solution described in the above engine brake stepless adjustment method embodiment. The specific implementation principles of the above modules or units can refer to the corresponding contents in the above engine brake stepless adjustment method embodiment, which will not be repeated here.

[0111] like Figure 8 As shown, the present invention also provides a vehicle 800. The vehicle 800 includes a processor 801, a memory 802 and a display 803. Figure 8 Only some of the components of vehicle 800 are shown, but it should be understood that implementing all of the shown components is not a requirement, and more or fewer components may alternatively be implemented.

[0112] In some embodiments, the memory 802 may be an internal storage unit of the vehicle 800, such as a hard drive or memory of the vehicle 800. In other embodiments, the memory 802 may be an external storage device of the vehicle 800, such as a plug-in hard drive, a Smart Media Card (SMC), a Secure Digital (SD) card, a flash card, etc., equipped in the vehicle 800.

[0113] Furthermore, the memory 802 may include both an internal storage unit of the vehicle 800 and an external storage device. The memory 802 is used to store application software installed in the vehicle 800 and various data.

[0114] In some embodiments, the processor 801 may be a central processing unit (CPU), a microprocessor, or other data processing chip, configured to execute program codes or process data stored in the memory 802 , such as the engine brake stepless adjustment method of the present invention.

[0115] In some embodiments, display 803 can be an LED display, a liquid crystal display, a touch-sensitive liquid crystal display, or an OLED (Organic Light-Emitting Diode) touchscreen. Display 803 is used to display information about vehicle 800 and to present a visual user interface. Components 801-803 of vehicle 800 communicate with each other via a system bus.

[0116] In some embodiments of the present invention, when the processor 801 executes the engine brake stepless adjustment program in the memory 802, the following steps may be implemented:

[0117] Obtaining a negative torque request and basic driving data sent by the vehicle during braking, and determining a required negative torque based on the negative torque request;

[0118] Determine the engine brake activation state based on basic driving data and required negative torque;

[0119] When the engine brake on state is on and the engine brake of the vehicle does not meet the required negative torque, the pneumatic supercharger is adjusted to obtain a first engine brake torque;

[0120] When the first engine braking torque satisfies the required negative torque, the stepless adjustment of the engine braking is completed.

[0121] It should be understood that, when the processor 801 executes the engine brake stepless adjustment program in the memory 802 , in addition to the above functions, it can also implement other functions. For details, please refer to the description of the corresponding method embodiment above.

[0122] Furthermore, the embodiment of the present invention does not specifically limit the type of the vehicle 800 mentioned, and the vehicle 800 may be a commercial vehicle, an off-road vehicle, or other vehicles.

[0123] Accordingly, an embodiment of the present application also provides a computer-readable storage medium, which is used to store computer-readable programs or instructions. When the program or instructions are executed by a processor, the engine braking stepless adjustment method steps or functions provided in the above-mentioned method embodiments can be implemented.

[0124] Those skilled in the art will appreciate that all or part of the process flow of the above-described method embodiment can be implemented by instructing related hardware (such as a processor, controller, etc.) through a computer program, and the computer program can be stored in a computer-readable storage medium. The computer-readable storage medium may be a magnetic disk, an optical disk, a read-only memory, or a random access memory.

[0125] The above is a detailed introduction to the engine brake stepless adjustment method, device, equipment and medium provided by the present invention. Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. At the same time, for those skilled in the art, based on the ideas of the present invention, there will be changes in the specific implementation methods and application scope. In summary, the contents of this specification should not be understood as limiting the present invention.

Claims

1. A method for stepless adjustment of engine braking, characterized in that: include: Obtaining a negative torque request and basic driving data sent when the vehicle is braking, and determining a required negative torque based on the negative torque request; determining an engine brake activation state according to the basic driving data and the required negative torque; When the engine brake on state is on and the engine brake of the vehicle does not meet the required negative torque, adjusting the pneumatic supercharger to obtain a first engine brake torque; When the first engine braking torque satisfies the required negative torque, the stepless adjustment of the engine braking is completed; The basic driving data includes the current engine speed; the engine brake activation state includes the exhaust brake activation state and the cylinder brake activation state; The determining the engine brake activation state according to the basic driving data and the required negative torque includes: determining the exhaust brake activation state according to the current engine speed and the required negative torque; When the exhaust brake on state is on and turning on the exhaust brake does not satisfy the required negative torque, determining that the in-cylinder brake on state is on, and determining the exhaust brake on state to be off; When the in-cylinder brake is turned on but the required negative torque is not satisfied, determining the in-cylinder brake turn-on state and the exhaust brake turn-on state to be turned on; The basic driving data includes an intake air temperature of the pneumatic supercharger, an actual boost pressure error, and an altitude; and adjusting the pneumatic supercharger to obtain a first engine braking torque includes: determining an initial wastegate opening feedforward term of the pneumatic supercharger according to the current engine speed and the required negative torque, and correcting the initial wastegate opening feedforward term according to the altitude to obtain a target wastegate opening feedforward term; determining an initial boost pressure of the pneumatic supercharger according to the current engine speed and the required negative torque, and correcting the initial boost pressure according to the altitude and the intake air temperature to obtain a target boost pressure; Performing closed-loop control calculation based on the target boost pressure and the actual boost pressure error to obtain a closed-loop term of the wastegate opening of the pneumatic supercharger; Obtaining the wastegate opening of the pneumatic supercharger according to the target wastegate opening feedforward term and the wastegate opening closed-loop term; The duty cycle is adjusted according to the exhaust bypass opening to obtain a first engine braking torque.

2. The engine brake stepless adjustment method according to claim 1, characterized in that: The method further comprises: When the first engine braking torque does not meet the required negative torque, determining a throttle opening term according to the current engine speed and the required negative torque; adjusting the intake air amount according to the throttle opening term to obtain a second engine braking torque; When the second engine braking torque satisfies the required negative torque, the stepless adjustment of the engine braking is completed.

3. The engine brake stepless adjustment method according to claim 2, characterized in that: After the stepless adjustment of the engine brake is completed when the second engine brake torque satisfies the required negative torque, the method further includes: when the second engine braking torque does not meet the required negative torque, determining an exhaust gas recirculation valve opening term according to the current engine speed and the required negative torque; adjusting the exhaust gas volume according to the exhaust gas recirculation valve opening term to obtain a third engine braking torque; The engine brake is continuously adjusted according to the third engine brake torque.

4. The engine brake stepless adjustment method according to claim 1, characterized in that: The step of determining the exhaust brake activation state according to the current engine speed and the required negative torque includes: determining whether the current engine speed is greater than a preset speed, and whether the required negative torque is greater than a preset negative torque; If so, determining that the exhaust brake opening state is on; If not, it is determined that the exhaust brake opening state is closed.

5. The engine brake stepless adjustment method according to claim 1, characterized in that: The step of correcting the initial exhaust gas bypass opening feedforward term according to the altitude to obtain a target exhaust gas bypass opening feedforward term includes: Correcting the initial exhaust gas bypass opening feedforward term according to the altitude to obtain a corrected exhaust gas bypass opening feedforward term; A target exhaust gas bypass opening feedforward term is obtained according to the initial exhaust gas bypass opening feedforward term and the corrected exhaust gas bypass opening feedforward term.

6. An engine brake stepless adjustment device, characterized in that: include: a data acquisition module, configured to acquire a negative torque request and basic driving data sent when the vehicle is braking, and determine a required negative torque based on the negative torque request; a state determination module, configured to determine an engine brake activation state based on the basic driving data and the required negative torque; a torque determination module, configured to adjust a pneumatic supercharger to obtain a first engine braking torque when the engine braking activation state is on and the engine braking of the vehicle does not meet the required negative torque; a stepless adjustment module, configured to complete stepless adjustment of the engine braking when the first engine braking torque satisfies the required negative torque; The basic driving data includes the current engine speed; the engine brake activation state includes the exhaust brake activation state and the cylinder brake activation state; The determining the engine brake activation state according to the basic driving data and the required negative torque includes: determining the exhaust brake activation state according to the current engine speed and the required negative torque; When the exhaust brake on state is on and turning on the exhaust brake does not satisfy the required negative torque, determining that the in-cylinder brake on state is on, and determining the exhaust brake on state to be off; When the in-cylinder brake is turned on but the required negative torque is not satisfied, determining the in-cylinder brake turn-on state and the exhaust brake turn-on state to be turned on; The basic driving data includes an intake air temperature of the pneumatic supercharger, an actual boost pressure error, and an altitude; and adjusting the pneumatic supercharger to obtain a first engine braking torque includes: determining an initial wastegate opening feedforward term of the pneumatic supercharger according to the current engine speed and the required negative torque, and correcting the initial wastegate opening feedforward term according to the altitude to obtain a target wastegate opening feedforward term; determining an initial boost pressure of the pneumatic supercharger according to the current engine speed and the required negative torque, and correcting the initial boost pressure according to the altitude and the intake air temperature to obtain a target boost pressure; Performing closed-loop control calculation based on the target boost pressure and the actual boost pressure error to obtain a closed-loop term of the wastegate opening of the pneumatic supercharger; Obtaining the wastegate opening of the pneumatic supercharger according to the target wastegate opening feedforward term and the wastegate opening closed-loop term; The duty cycle is adjusted according to the exhaust bypass opening to obtain a first engine braking torque.

7. A vehicle, characterized in that: include: A processor, a memory, and a computer program stored in the memory and capable of running on the processor, wherein when the computer program is executed by the processor, the steps of the engine brake stepless adjustment method according to any one of claims 1 to 5 are implemented.

8. A computer-readable storage medium, characterized in that The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the engine brake stepless adjustment method according to any one of claims 1 to 5 are implemented.

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