A vehicle torque optimization control method and system

Abstract

The application discloses a kind of vehicle torque optimization control method and system, including: vehicle acceleration process, judge whether engine is off-cylinder, if yes, according to the speed signal at this time to determine air-fuel ratio, as target air-fuel ratio;Otherwise, directly set value to target air-fuel ratio, the set value is equal to or close to the value of optimum air-fuel ratio.The application in vehicle acceleration process, when engine off-cylinder, according to the speed signal measured at this time, off-cylinder air-fuel ratio calibration under different speeds is carried out, control air-fuel ratio is around 1, reduce the performance of mis-addition, optimize the acceleration time per 100 kilometers to improve, air-fuel ratio is no longer thickened, torque performance is smooth, reach the goal of acceleration time per 100 kilometers.

Description

Technical Field

[0001] The present invention relates to the technical field of vehicle system control, and in particular to a vehicle torque optimization control method and system. Background Art

[0002] The statements in this section merely provide background information related to the present invention and do not necessarily constitute prior art.

[0003] During the vehicle's 0-100km / h acceleration process, the engine is prone to cylinder cut-off requests, and oxygen purification and enrichment are performed at a speed of 70km / h. The purpose is to prevent excessive HC organic gas from entering the catalyst and protect the catalyst. However, at this time, the model temperature at the exhaust end is still lower than the component enrichment threshold, which is a misidentification phenomenon. Therefore, the enrichment of the air-fuel ratio leads to incomplete combustion, glitches and uneven torque performance, a long 0-100km / h acceleration time, poor response, and easy to cause setbacks and impacts. It is also easy to cause clutch jitter due to excessive speed regulation time or inaccurate speed regulation. This process will last for about 3 seconds, accounting for more than 50% of the 0-100km / h acceleration time, seriously affecting the user's driving experience. Summary of the Invention

[0004] In order to solve the above problems, the present invention proposes a vehicle torque optimization control method and system to optimize the air-fuel ratio performance of the vehicle when the cylinder is cut off, reduce the enrichment recognition of the air-fuel ratio under cylinder cut-off, solve the problem of uneven acceleration from 0 to 100 km / h, and improve the robustness of the strategy.

[0005] In some embodiments, the following technical solutions are adopted:

[0006] A vehicle torque optimization control method, comprising:

[0007] During vehicle acceleration, it is determined whether the engine is cylinder-decoupled. If so, the air-fuel ratio is determined based on the speed signal at that time and used as the target air-fuel ratio. Otherwise, a set value is directly assigned to the target air-fuel ratio, and the set value is equal to or close to the optimal air-fuel ratio.

[0008] As a further solution, the method further includes:

[0009] The vehicle is powered on and initialized to determine whether the engine water tank temperature reaches the set temperature. If so, the vehicle enters the starting state and uses the starting air-fuel ratio as the target air-fuel ratio; otherwise, it enters the warm-up state and uses the warm-up air-fuel ratio as the target air-fuel ratio.

[0010] As a further solution, the method further includes:

[0011] During vehicle operation, determine whether the vehicle has entered the catalyst light-off phase. If so, reduce the air-fuel ratio and assign it to the target air-fuel ratio.

[0012] At the same time, it is determined whether the model temperature at the exhaust end reaches the component protection threshold. If so, the air-fuel ratio is enriched and assigned to the target air-fuel ratio.

[0013] In other embodiments, the following technical solutions are adopted:

[0014] A vehicle torque optimization control system, comprising:

[0015] The air-fuel ratio control module is used to determine whether the engine is cylinder-decoupled during vehicle acceleration. If so, the air-fuel ratio is determined based on the speed signal at that time as the target air-fuel ratio; otherwise, a set value is directly assigned to the target air-fuel ratio, and the set value is a value close to the optimal air-fuel ratio.

[0016] As a further solution, the air-fuel ratio control module is also used to: when the vehicle is powered on and initialized, determine whether the engine water tank temperature reaches the set temperature. If so, the vehicle enters the starting state and uses the starting air-fuel ratio as the target air-fuel ratio; otherwise, it enters the warm-up state and uses the warm-up air-fuel ratio as the target air-fuel ratio.

[0017] As a further solution, the air-fuel ratio control module is also used to: during vehicle operation, determine whether the vehicle has entered the catalyst ignition stage. If so, reduce the air-fuel ratio and assign it to the target air-fuel ratio; at the same time, determine whether the model temperature at the exhaust end has reached the component protection threshold. If so, enrich the air-fuel ratio and assign it to the target air-fuel ratio.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] (1) During the acceleration of the vehicle, the present invention calibrates the cylinder-off air-fuel ratio at different speeds based on the speed signal measured at this time when the engine is cut off, controls the air-fuel ratio to be near 1, and reduces the performance of false enrichment. After optimization, the acceleration time from 0 to 100 km / h is improved, the air-fuel ratio is no longer enriched, and the torque performance is smooth, thereby achieving the target acceleration time from 0 to 100 km / h.

[0020] Other features and advantages of additional aspects of the present invention will be given in part in the following description and in part will become obvious from the following description or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a flow chart of the vehicle torque optimization control method in an embodiment of the present invention. DETAILED DESCRIPTION

[0022] It should be noted that the following detailed description is illustrative and is intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meaning as commonly understood by those skilled in the art to which the present application belongs.

[0023] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0024] Example 1

[0025] In one or more embodiments, a vehicle torque optimization control method is disclosed, combining Figure 1 , specifically including the following process:

[0026] (1) First, power on and initialize to determine whether the engine water tank temperature reaches the set temperature (e.g. 40°C). If so, the vehicle enters the starting state and uses the starting air-fuel ratio as the target air-fuel ratio; if not, it enters the warm-up phase and assigns the warm-up air-fuel ratio to the target air-fuel ratio;

[0027] In this embodiment, the starting air-fuel ratio and the warm-up air-fuel ratio are corrections to the target air-fuel ratio at different engine water tank temperatures. Those skilled in the art are able to know the values ​​of the starting air-fuel ratio and the warm-up air-fuel ratio.

[0028] (2) During vehicle operation, determine whether the ambient temperature is within a set temperature range, which in this embodiment is 0-60°C; if so, enter the catalyst ignition stage, reduce the air-fuel ratio, and assign it to the target air-fuel ratio; otherwise, determine the target air-fuel ratio based on the current vehicle operating conditions.

[0029] At the same time, determine whether the temperature of the exhaust end model (for example, the exhaust manifold or turbine pre-turbine temperature) reaches the component protection threshold (for example, 930°C). If so, enrich the air-fuel ratio and assign it to the target air-fuel ratio; otherwise, determine the target air-fuel ratio based on the current vehicle operating conditions.

[0030] In this embodiment, when the air-fuel ratio is leaned, the maximum value of the air-fuel ratio leaning is determined on the premise that no vibration occurs on the engine end and the vehicle end; then, based on the current speed, the air-fuel ratio value after leaning is determined according to the MAP table that represents the relationship between speed and load; generally, to ensure rapid ignition of the catalyst, the empirical standard will lean the air-fuel ratio to around 1.05.

[0031] The principles for enriching and enforcing the air-fuel ratio are the same. The minimum air-fuel ratio enrichment value is determined, preserving the normal operating temperature of vehicle components. The air-fuel ratio is then determined based on the current speed, using a map chart that represents the relationship between speed and load. When the vehicle is operating at high speeds and high loads, such as when climbing a hill, exhaust temperatures can reach extremely high levels. To protect components, the air-fuel ratio is enriched within the high-load, high-speed region of the two-dimensional map chart, determined by speed and load. The specific value is less than 1, with a typical minimum of 0.7.

[0032] (3) During vehicle acceleration, for example, in third gear at 70 km / h, the vehicle is judged based on the cylinder cut-off performance. If the cylinder is cut off, the air-fuel ratio is set according to the speed signal at that time. If there is no cylinder cut-off request, the target air-fuel ratio is directly assigned.

[0033] In this embodiment, based on the current speed and load, when the gradient of releasing the throttle is greater than the set threshold, it is determined that the engine has cylinder cut-off; when the current speed is greater than the minimum engine speed setting value, the fuel supply will be resumed.

[0034] If the engine is cylinder-cut off, this embodiment determines the air-fuel ratio based on the speed signal at that time, specifically:

[0035] Based on the MAP table that characterizes the relationship between speed and load, the value of the air-fuel ratio is determined according to the current speed and load. The load is the ratio of the current charge volume to the charge volume under standard conditions, which is the charge efficiency.

[0036] At low speeds, the air-fuel ratio is determined with the goal of ensuring vehicle operation stability; at medium and high speeds, the air-fuel ratio is determined with the goal of reducing fuel consumption and emissions; at high speeds, the air-fuel ratio is determined with the goal of controlling vehicle torque.

[0037] In this embodiment, low speed refers to idling to 1500 rpm; medium and high speed refers to 1500-4500 rpm; and high speed refers to the range of 4500 to 6200 rpm.

[0038] If cylinder cutoff does not occur, the target air-fuel ratio is assigned to the optimal air-fuel ratio 1 or maintained near the optimal air-fuel ratio 1.

[0039] This embodiment reduces the identification of enrichment of the air-fuel ratio under cylinder cut-off by increasing the determination of the air-fuel ratio when the engine has and has not had cylinder cut-off, thereby solving the problem of uneven acceleration torque per 100 kilometers. The optimization strategy improves the robustness of the control method.

[0040] After experimental verification, it was found that before optimization, the torque had many glitches and obvious jitters when accelerating from 0 to 100 km / h, and the model temperature did not reach the threshold for component enrichment at this time. The air-fuel ratio was indeed enriched with oxygen to around 0.76. At this time, the acceleration time from 0 to 100 km / h was long, the response was poor, and it was easy to cause setbacks and impacts. However, after optimization using this implementation method, the torque performance was smoother, no oxygen enrichment was performed, and the torque rose faster.

[0041] Example 2

[0042] In one or more embodiments, a vehicle torque optimization control system is disclosed, comprising:

[0043] The air-fuel ratio control module is used to determine whether the engine is cylinder-decoupled during vehicle acceleration. If so, the air-fuel ratio is determined based on the speed signal at that time as the target air-fuel ratio; otherwise, a set value is directly assigned to the target air-fuel ratio, and the set value is a value close to the optimal air-fuel ratio.

[0044] As an optional solution, the air-fuel ratio control module is also used to: when the vehicle is powered on and initialized, determine whether the engine water tank temperature has reached the set temperature. If so, the vehicle enters the starting state and uses the starting air-fuel ratio as the target air-fuel ratio; otherwise, it enters the warm-up state and uses the warm-up air-fuel ratio as the target air-fuel ratio.

[0045] As an optional solution, the air-fuel ratio control module is also used to: during vehicle operation, determine whether the vehicle has entered the catalyst ignition stage. If so, reduce the air-fuel ratio and assign it to the target air-fuel ratio; at the same time, determine whether the model temperature at the exhaust end has reached the component protection threshold. If so, enrich the air-fuel ratio and assign it to the target air-fuel ratio.

[0046] The specific implementation of the above process has been described in Example 1 and will not be described in detail here.

[0047] Although the above describes the specific embodiments of the present invention in conjunction with the accompanying drawings, it is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art on the basis of the technical solution of the present invention without any creative work are still within the scope of protection of the present invention.

Claims

1. A vehicle torque optimization control method, characterized in that: include: During vehicle acceleration, determine whether the engine is cylinder-decoupled. If so, determine the air-fuel ratio based on the speed signal at that time as the target air-fuel ratio. Otherwise, directly assigning a set value to the target air-fuel ratio, wherein the set value is equal to or close to the optimal air-fuel ratio; During vehicle acceleration, determine whether the engine is cylinder cut-off. The specific method is as follows: Based on the vehicle's current speed and load, when the gradient of releasing the accelerator is greater than the set threshold, the engine is judged to have cylinder cut-off; The air-fuel ratio is determined according to the speed signal at this time, specifically: At low speeds, the air-fuel ratio is determined with the goal of ensuring vehicle operation stability; at medium and high speeds, the air-fuel ratio is determined with the goal of reducing fuel consumption and emissions; at high speeds, the air-fuel ratio is determined with the goal of controlling vehicle torque.

2. The vehicle torque optimization control method according to claim 1, characterized in that: Also includes: The vehicle is powered on and initialized to determine whether the engine water tank temperature has reached the set temperature. If so, the vehicle enters the starting state and uses the starting air-fuel ratio as the target air-fuel ratio; Otherwise, the engine enters the warm-up state and uses the warm-up air-fuel ratio as the target air-fuel ratio.

3. The vehicle torque optimization control method according to claim 1, characterized in that: Also includes: During vehicle operation, determine whether the vehicle has entered the catalyst light-off phase. If so, reduce the air-fuel ratio and assign it to the target air-fuel ratio. At the same time, it is determined whether the model temperature at the exhaust end reaches the component protection threshold. If so, the air-fuel ratio is enriched and assigned to the target air-fuel ratio.

4. The vehicle torque optimization control method according to claim 3, characterized in that: The air-fuel ratio is reduced in size, specifically: The maximum value of the air-fuel ratio reduction is determined on the premise that no vibration occurs on the engine side and the vehicle side; then, the air-fuel ratio is determined based on the current speed according to the MAP table that represents the relationship between speed and load.

5. The vehicle torque optimization control method according to claim 3, characterized in that: The enrichment of the air-fuel ratio is specifically as follows: The minimum value of the air-fuel ratio enrichment is determined on the premise that the temperature of the vehicle components does not exceed normal operation. Then, the air-fuel ratio is determined based on the current speed according to the MAP table that characterizes the relationship between speed and load.

6. A vehicle torque optimization control system, characterized in that: include: The air-fuel ratio control module is used to determine whether the engine is cylinder-decoupled during vehicle acceleration. If so, the air-fuel ratio is determined based on the speed signal at that time as the target air-fuel ratio. Otherwise, a set value is directly assigned to the target air-fuel ratio, wherein the set value is a value close to the optimal air-fuel ratio; During vehicle acceleration, determine whether the engine is cylinder cut-off. The specific method is as follows: Based on the vehicle's current speed and load, when the gradient of releasing the accelerator is greater than the set threshold, the engine is judged to have cylinder cut-off; The air-fuel ratio is determined according to the speed signal at this time, specifically: At low speeds, the air-fuel ratio is determined with the goal of ensuring vehicle operation stability; at medium and high speeds, the air-fuel ratio is determined with the goal of reducing fuel consumption and emissions; at high speeds, the air-fuel ratio is determined with the goal of controlling vehicle torque.

7. The vehicle torque optimization control system according to claim 6, characterized in that: The air-fuel ratio control module is also used to: when the vehicle is powered on and initialized, determine whether the engine water tank temperature reaches the set temperature. If so, the vehicle enters the starting state and uses the starting air-fuel ratio as the target air-fuel ratio; otherwise, it enters the warm-up state and uses the warm-up air-fuel ratio as the target air-fuel ratio.

8. The vehicle torque optimization control system according to claim 6, characterized in that: The air-fuel ratio control module is also used to: during vehicle operation, determine whether the vehicle has entered the catalyst ignition stage. If so, reduce the air-fuel ratio and assign it to the target air-fuel ratio; at the same time, determine whether the model temperature at the exhaust end has reached the component protection threshold. If so, enrich the air-fuel ratio and assign it to the target air-fuel ratio.

Images