Demand torque control method and system based on load change and vehicle

Abstract

The invention provides a demand torque control method and system based on load change and a vehicle, and the method specifically comprises the following steps: (1) when the vehicle is in a static state, reading the actual load mass of the vehicle, and calculating the load rate lambda corresponding to the current actual load mass; and (2) the demand torque MAP under the current load rate lambda is extracted, and after the vehicle is in the running state, the vehicle demand torque is determined based on the demand torque MAP under the current load rate. When the change of the load rate is detected, the demand torque MAP is adaptively adjusted, excessive acceleration or insufficient power caused by the change of the load is avoided, the energy utilization is optimized, and in addition, the power response better meeting the expectation of a driver is provided, especially when the change of the load is large (such as after sudden unloading).

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of vehicle control, and more particularly, the present application relates to a demand torque control method based on load variation, a system and a vehicle. BACKGROUND

[0002] With the gradual upgrading of emissions, engines are currently upgraded to electronic control models, and various control functions of the engine are completed by sensors, electronic control units (ECUs) and actuators. The ECU obtains the opening degree of the accelerator pedal stepped by the driver, obtains the driver's demand torque by querying the calibrated accelerator pedal MAP, and finally realizes the driver's driving intention through a series of torque conversion, limit value and coordination to obtain the torque required by the engine.

[0003] In the field of commercial vehicles, the dynamic change of vehicle load has a significant impact on vehicle power and economy. The traditional calibration uses a fixed parameter (i.e., a standard load) accelerator pedal MAP, which is designed based on the rated load condition optimization. This static calibration has the following defects:

[0004] Under light load conditions, the torque curve of the standard load results in power redundancy, causing invalid energy consumption; under heavy load conditions: the power reserve is insufficient and the accelerator needs to be stepped deeply, reducing energy efficiency and accelerating component wear. SUMMARY

[0005] In view of this, the present application provides a demand torque control method based on load variation, aiming to improve at least one of the above problems.

[0006] Specifically, the technical scheme includes the following:

[0007] On the one hand, the present application provides a demand torque control method based on load variation, which is specifically as follows:

[0008] (1) When the vehicle is in a stationary state, the actual load of the vehicle is read, and the load rate λ corresponding to the current actual load is calculated;

[0009] (2) Extract the demand torque MAP under the current load rate λ, and determine the vehicle demand torque based on the demand torque MAP under the current load rate after the vehicle is in a running state.

[0010] In some embodiments of the present application, the demand torque MAP under the current load rate λ is extracted as follows:

[0011] (21) Determine the load rate sampling points in the load rate interval, the accelerator pedal opening degree sampling points in the accelerator pedal opening degree interval, and the vehicle speed sampling points in the vehicle speed interval;

[0012] (22) Based on the load rate sampling point, accelerator pedal opening sampling point and vehicle speed sampling point, a series of sample working conditions are formed to determine the required torque of the vehicle with optimal drivability under the power requirements in each sample working condition.

[0013] (23) Construct a three-dimensional torque demand MAP for the vehicle under different load rates λ, pedal opening and vehicle speed;

[0014] (24) Obtain the two-dimensional demand torque MAP under the current load rate λ by smooth spline interpolation. The two-dimensional demand torque MAP is the two-dimensional demand torque MAP of the vehicle under different pedal opening and vehicle speed.

[0015] In some embodiments of the invention, the required torque on a ramp The specific method for obtaining it is as follows:

[0016] Determine the required torque on the flat road based on the required torque MAP. ;

[0017] Based on the slope of the ramp and the required torque Make corrections and calculate the required torque compensation value for the current ramp. Torque required on a slope .

[0018] In some embodiments of the present invention, a torque compensation value is required. The specific calculation formula is as follows:

[0019] ;

[0020] in, This is the slope condition coefficient, which is applied when the vehicle is currently uphill. When the vehicle is currently going downhill, , The tire's rolling radius; The vehicle's mass includes its load capacity; It is the acceleration due to gravity; The slope angle of the road.

[0021] In some embodiments of the present invention, the method for transitioning the required torque before and after a change in load factor is as follows:

[0022] Establish a first cache and a second cache. The first cache is used to store the initial load rate before the load rate changes. The two-dimensional demand torque MAP below, the second buffer is used to store the second load factor after the load factor changes. The following is a two-dimensional demand torque MAP;

[0023] Input the vehicle's current speed and accelerator pedal opening into the two-dimensional torque demand MAP stored in the first buffer, and calculate the torque demand under the current speed and accelerator pedal opening. ;

[0024] Input the vehicle's current speed and accelerator pedal opening into the two-dimensional torque demand MAP stored in the second buffer, and calculate the torque demand under the current speed and accelerator pedal opening. ;

[0025] During the transition period, control the torque from the demand torque. Transform to required torque .

[0026] In some embodiments of the present invention, the weight coefficient of the second cache is calculated. In the weighting coefficient At that time, the two-dimensional demand torque MAP stored in the first buffer will be cleared, and the second buffer will be used as the first buffer. The weight coefficient of the second buffer will be... The specific calculation formula is as follows:

[0027] ;

[0028] in, For the set transition period, Indicates the torque demand Start to demand torque The actual transition duration during the transition process.

[0029] In some embodiments of the present invention, the current transition duration The required torque is as follows:

[0030] .

[0031] In some embodiments of the present invention, after switching the second buffer to the first buffer, the two-dimensional demand torque MAP stored in the first buffer is locked until a change in the vehicle's load factor is detected, at which point the changed load factor is... The two-dimensional demand torque MAP is stored in the second cache area, and the two-dimensional demand torque MAP stored in the first cache area is unlocked.

[0032] On the other hand, embodiments of this application provide a demand torque control system based on load variation, the system comprising:

[0033] Data acquisition unit;

[0034] The first and second buffers connected to the data acquisition unit, and the first load rate before the load rate change. The two-dimensional demand torque MAP below, the second buffer is used to store the second load factor after the load factor changes. The following is a two-dimensional demand torque MAP;

[0035] The processing unit is connected to the data acquisition unit, the first buffer, and the second buffer;

[0036] When the vehicle is stationary, the data acquisition unit collects the current load rate of the vehicle and detects whether the current load rate has changed. If the detection result is yes, the current load rate is stored in the second buffer. At the same time, the current vehicle speed and accelerator pedal opening are read and sent to the processing unit. The processing unit determines the required torque based on the above-mentioned load-change-based torque control method.

[0037] On the other hand, this application provides a vehicle that integrates the aforementioned load-based torque control system.

[0038] When a change in load rate is detected, the present invention adaptively adjusts the required torque MAP to avoid over-acceleration or insufficient power caused by load changes, optimizes energy utilization, and provides a power response that is more in line with the driver's expectations, especially when the load changes significantly (such as after a sudden unloading). Attached Figure Description

[0039] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0040] Figure 1 A flowchart of a demand torque control method based on load variation provided in an embodiment of the present invention;

[0041] Figure 2 This is a schematic diagram of the demand torque control system based on load variation provided in an embodiment of the present invention;

[0042] The accompanying drawings illustrate specific embodiments of this application, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concept of this application to those skilled in the art through reference to particular embodiments. Detailed Implementation

[0043] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0044] Unless otherwise defined, all technical terms used in the embodiments of this application have the same meaning as commonly understood by one of ordinary skill in the art.

[0045] Figure 1 A flowchart of a demand torque control method based on load variation provided in an embodiment of the present invention is shown below.

[0046] (1) When the vehicle is stationary, read the actual load of the vehicle and calculate the load factor λ corresponding to the current actual load.

[0047] In this embodiment of the invention, when the vehicle speed is zero and the vehicle is in N or P gear, the vehicle is considered to be stationary. At this time, the actual load of the vehicle is detected by the height sensor on the air suspension (or the vehicle weighing system), and the load rate λ corresponding to the current actual load is calculated. The load rate λ = actual load / standard load. When the signal of the actual load is detected as invalid, the standard load is used as the actual load.

[0048] (2) Extract the required torque MAP under the current load rate λ. After the vehicle is in driving state, determine the required torque of the vehicle based on the required torque MAP under the current load rate.

[0049] In this embodiment of the invention, when the vehicle speed is not zero, or when the vehicle is not in N or P gear, the vehicle is considered to be in a driving state. When the vehicle is in a driving state, the method for extracting the required torque MAP under the current load rate λ is as follows:

[0050] (21) Determine the load rate sampling points within the load rate λ interval, the accelerator pedal opening sampling points within the accelerator pedal opening interval, and the vehicle speed sampling points within the vehicle speed interval;

[0051] (22) Based on the load rate sampling point, accelerator pedal opening sampling point and vehicle speed sampling point, a series of sample working conditions are formed to determine the required torque of the vehicle with optimal drivability under the power requirements in each sample working condition.

[0052] (23) Construct a three-dimensional torque demand MAP for the vehicle under different load rates λ, pedal opening and vehicle speed;

[0053] (24) Obtain the two-dimensional demand torque MAP under the current load rate λ by smooth spline interpolation. The two-dimensional demand torque MAP is the two-dimensional demand torque MAP of the vehicle under different pedal opening and vehicle speed.

[0054] In this embodiment of the invention, the load factor λ is set to a range of 0% to 200%, including: 0% (no load), 50% (half load), 100% (standard load), 150% and 200% (heavy load). A throttle pedal opening sampling point is set every 5°, and a vehicle speed sampling point is set every 5 km / h. A load factor sampling point, a throttle pedal opening sampling point, and a vehicle speed sampling point constitute a sample working condition. These sampling points are combined to form a series of sample working conditions, determining the vehicle's required torque under each sample working condition. Using load factor λ as the x-axis, throttle pedal opening as the y-axis, and vehicle speed as the Z-axis, the output is the required torque, constructing a three-dimensional required torque MAP for the vehicle under different load factors λ, pedal openings, and vehicle speeds.

[0055] When the vehicle is stationary, the current load factor is determined. If the load factor does not fall within the load factor sampling point, sliding spline interpolation is performed on the three-dimensional demand torque MAP to form a two-dimensional demand torque MAP under different pedal openings and vehicle speeds at the current load factor. After the vehicle is in motion, the current vehicle speed and accelerator pedal opening are collected. Based on the current vehicle speed and accelerator pedal opening, the corresponding demand torque is read from the two-dimensional demand torque MAP, and torque is output based on the demand torque.

[0056] In this embodiment of the invention, the demand torque determined based on the demand torque MAP is the basic demand torque. It is primarily designed for flat roads with no slope. Therefore, when a vehicle is currently on a slope, in order to more accurately predict the vehicle's required torque, the basic required torque is corrected based on the slope, and the required torque compensation value for the road slope is calculated. The specific calculation formula is as follows:

[0057] (1)

[0058] in, This is the slope condition coefficient, which is applied when the vehicle is currently uphill. When the vehicle is currently going downhill, , The tire's rolling radius; The vehicle's mass includes its load capacity; It is the acceleration due to gravity; Let be the slope angle of the road. Therefore, the required torque after slope compensation is... Specifically as follows:

[0059] (2)

[0060] This invention determines the required torque based on the vehicle's direction of travel (uphill / downhill) and the slope angle. Real-time, continuous compensation is performed to generate the final wheel-end torque requirement.

[0061] In this embodiment of the invention, when the actual load of the vehicle changes, its corresponding load factor also changes. At this time, the vehicle determines its current basic torque demand based on the two-dimensional torque demand MAP under the changed load factor. Since the torque demand under the load factor before and after the load factor change is different, in order to more smoothly realize the switching from the torque demand under the load factor before the load factor change to the torque demand under the load factor after the load factor change, the buffering mechanism proposed in this invention is as follows:

[0062] (25) Establish two buffers, a first buffer and a second buffer, wherein the first buffer is used to store the first load rate before the load rate changes. The two-dimensional demand torque MAP below, the second buffer is used to store the second load factor after the load factor changes. The following is a two-dimensional demand torque MAP;

[0063] (26) Input the current vehicle speed and accelerator pedal opening into the two-dimensional demand torque MAP stored in the first buffer area, and calculate the demand torque under the current vehicle speed and accelerator pedal opening. That is, the first load factor The required torque corresponding to the current vehicle speed and accelerator pedal opening;

[0064] (27) Input the current vehicle speed and accelerator pedal opening into the two-dimensional torque demand MAP stored in the second buffer area, and calculate the torque demand under the current vehicle speed and accelerator pedal opening. That is, the second load factor The required torque corresponding to the current vehicle speed and accelerator pedal opening;

[0065] (28) Control torque during the transition period from the required torque Transform to required torque .

[0066] In this embodiment of the invention, the weight coefficient of the second cache area is calculated. In the weighting coefficient At that time, the two-dimensional demand torque MAP stored in the first buffer will be cleared, and the second buffer will be used as the first buffer.

[0067] In this embodiment of the invention, the weighting coefficient of the second cache area The specific calculation formula is as follows:

[0068] (3)

[0069] in, For the set transition period, Indicates the torque demand Start to demand torque The actual transition duration during the transition process.

[0070] In this embodiment of the invention, the current transition duration is... The required torque is as follows:

[0071] (4)

[0072] In this embodiment of the invention, after a successful switch, i.e., after switching the second buffer to the first buffer, the two-dimensional demand torque MAP stored in the first buffer is locked until a change in the vehicle's load factor is detected, at which point the changed load factor is... The two-dimensional demand torque MAP is stored in the second cache area. The two-dimensional demand torque MAP stored in the first cache area is unlocked. Only after the first cache area is unlocked can it be switched to the second cache area.

[0073] When a change in load rate is detected, the present invention adaptively adjusts the required torque MAP to avoid over-acceleration or insufficient power caused by load changes, optimizes energy utilization, and provides a power response that is more in line with the driver's expectations, especially when the load changes significantly (such as after a sudden unloading).

[0074] Figure 2 This is a schematic diagram of a demand torque control system based on load variation provided in an embodiment of the present invention. For ease of explanation, only the parts relevant to the embodiment of the present invention are shown. The system includes:

[0075] Data acquisition unit;

[0076] The first and second buffers connected to the data acquisition unit, and the first load rate before the load rate change. The two-dimensional demand torque MAP below, the second buffer is used to store the second load factor after the load factor changes. The following is a two-dimensional demand torque MAP;

[0077] The processing unit is connected to the data acquisition unit, the first buffer, and the second buffer;

[0078] When the vehicle is stationary, the data acquisition unit collects the current load rate of the vehicle and detects whether the current load rate has changed. If the detection result is yes, the current load rate is stored in the second buffer. At the same time, the current vehicle speed and accelerator pedal opening are read and sent to the processing unit. The processing unit determines the required torque based on the above-mentioned load-change-based torque control method.

[0079] The present invention also provides a vehicle that integrates the aforementioned load-based demand torque control system. When a change in load rate is detected, the system adaptively adjusts the demand torque MAP to avoid over-acceleration or insufficient power caused by load changes, optimizes energy utilization, and provides a power response that better meets the driver's expectations, especially when the load changes significantly. In addition, the system compensates for the basic demand torque in real time based on the vehicle's direction of travel (uphill / downhill) and slope angle to generate the final wheel-end demand torque. The vehicle can be a gasoline-powered vehicle or an electric vehicle.

[0080] Other embodiments of this application will readily occur to those skilled in the art upon consideration of the specification and practice of the application disclosed herein. This application is intended to cover any variations, uses, or adaptations of this application that follow the general principles of this application and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only.

[0081] It should be understood that this application is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this application is limited only by the appended claims.

Claims

1. A load-dependent demand torque control method, characterized by, The method is specifically as follows: (1) reading the actual load mass of the vehicle when the vehicle is in a stationary state, and calculating the load rate λ corresponding to the current actual load mass; (2) extracting the demand torque MAP under the current load rate λ, and determining the vehicle demand torque based on the demand torque MAP under the current load rate after the vehicle is in a running state.

2. The method of claim 1, wherein the demand torque is determined based on a load change. The demand torque MAP extraction method under the current load rate λ is specifically as follows: (21) determining the load rate sampling points in the load rate interval, the accelerator pedal opening sampling points in the accelerator pedal opening interval, and the vehicle speed sampling points in the vehicle speed interval; (22) forming a series of sample working conditions based on the load rate sampling points, the accelerator pedal opening sampling points, and the vehicle speed sampling points, and determining the demand torque of the vehicle in each sample working condition under the condition that the drivability is optimal for meeting the power demand; (23) constructing a three-dimensional demand torque MAP of the vehicle under different load rates λ, pedal opening degrees, and vehicle speeds; (24) obtaining a two-dimensional demand torque MAP under the current load rate λ by spline interpolation, and the two-dimensional demand torque MAP is a two-dimensional demand torque MAP of the vehicle under different pedal opening degrees and vehicle speeds.

3. The method of claim 1, wherein the demand torque is determined based on a load change. Demand torque on a ramp The acquisition method is as follows: Determining required torque on flat road based on required torque MAP ; Demand torque based on slope of ramp corrected, the demand torque compensation value required for the current ramp is calculated , the demand torque on the ramp .

4. The method of claim 3, wherein the demand torque is determined based on a load change. Demand torque compensation value The calculation formula is as follows: ； wherein is a ramp state coefficient, which is 1 when the vehicle is currently in an uphill state, is a ramp state coefficient, which is 1 when the vehicle is currently in an uphill state, , is a rolling radius of the tire; is a vehicle mass including a load; is a gravitational acceleration; is a ramp angle of the road.

5. The method of claim 1, wherein the demand torque is determined based on a load change. The demand torque transition method before and after the change of the load rate is specifically as follows: The first cache area is used for storing the first load rate before the load rate changes The second cache area is used for storing the second load rate after the load rate changes The second cache area is used for storing the second load rate after the load rate changes The current vehicle speed and the accelerator pedal opening are input into the two-dimensional demand torque MAP stored in the first buffer area to calculate the demand torque at the current vehicle speed and the accelerator pedal opening ; The current vehicle speed and the accelerator pedal opening are input into a two-dimensional demand torque MAP stored in a second buffer area to calculate the demand torque at the current vehicle speed and the accelerator pedal opening ; controlling the torque from the demanded torque in the transition period switching to the demanded torque .

6. The method of claim 5, wherein the demand torque is determined based on a load change. The weight coefficient of the second buffer area is calculated When the weight coefficient of the second buffer area is greater than 1, the two-dimensional demand torque MAP stored in the first buffer area is cleared, the second buffer area is used as the first buffer area, and the second buffer area is used as the first buffer area, wherein the weight coefficient of the second buffer area is calculated according to the following formula: ； wherein, is a set transition period, denotes a transition time length in the transition process, denotes a transition time length in the transition process, denotes a transition time length in the transition process.

7. The method of claim 6, wherein the demand torque is determined based on a load change. Current transition duration The demand torque under the current transition duration is as follows: 。 8. The method of claim 6, wherein the demand torque is determined based on a load change. After switching the second buffer to the first buffer, the two-dimensional demand torque MAP stored in the first buffer is locked until the change of the load rate of the vehicle is detected, and the two-dimensional demand torque MAP with the changed load rate is stored in the second buffer, and the two-dimensional demand torque MAP stored in the first buffer is unlocked. After switching the second buffer to the first buffer, the two-dimensional demand torque MAP stored in the first buffer is locked until the change of the load rate of the vehicle is detected, and the two-dimensional demand torque MAP with the changed load rate is stored in the second buffer, and the two-dimensional demand torque MAP stored in the first buffer is unlocked.

9. A load-dependent demand torque control system, characterized by The system comprises: a data acquisition unit; The first cache area and the second cache area connected with the data acquisition unit, the first load rate before the load rate changes The second cache area is used for storing the second load rate after the load rate changes The two-dimensional demand torque MAP under the second load rate a processing unit connected with the data acquisition unit, the first cache area, and the second cache area; In a stationary state of the vehicle, the data acquisition unit acquires the current load rate of the vehicle, detects whether the current load rate changes, and if the detection result is yes, stores the current load rate to the second cache area, reads the current vehicle speed and accelerator pedal opening degree, and sends them to the processing unit, which determines the demand torque based on the load change vehicle torque output control method according to any one of claims 1 to 8.

10. A vehicle characterized by comprising: The vehicle is integrated with the demand torque control system based on the load change according to claim 9.

Images