Fuel cut control method for vehicle

Abstract

The application provides a fuel cut control method of a vehicle, which is suitable for a power assembly system of the vehicle, and comprises the following steps: obtaining a state parameter of the vehicle, and judging whether the vehicle enters a gear shifting operation according to the state parameter of the vehicle; if yes, obtaining a state parameter of the power assembly system, and judging whether a clutch satisfies a preset clutch pedal state acquisition condition according to the state parameter of the power assembly system; if yes, obtaining pedal state information of the clutch, and determining a fuel cut delay time of an engine according to the pedal state information of the clutch. According to the scheme, the fuel cut delay time is prolonged when the clutch pedal is combined, so that the fuel is fully combusted, and the emission requirement is met. Moreover, the speed difference between the engine speed and the input shaft speed of the gearbox is small, so that the impact and noise problems caused when the clutch is combined can be inhibited. When the clutch pedal is stepped on, the fuel cut delay time is shortened, so that the engine can enter the fuel cut state early, the speed of the engine can be rapidly reduced, and the driving smoothness and the response speed of the vehicle are improved.

Description

Technical Field

[0001] This invention relates to the field of engine control technology, and in particular to a fuel cut-off control method for vehicles. Background Technology

[0002] When a vehicle suddenly releases the accelerator pedal to decelerate, the engine continues to rotate at high speed due to the vehicle's inertia. Because the throttle is closed, very little air-fuel mixture enters the cylinders, resulting in incomplete combustion at high speeds and increased harmful emissions. Fuel cut-off control automatically interrupts fuel injection when the engine suddenly decelerates from high speed, resuming injection only when the engine speed drops to a set low level. Its purpose is to control harmful emissions, reduce fuel consumption, and promote a rapid decrease in engine speed, thus aiding in vehicle deceleration.

[0003] In existing technologies, to ensure engine emissions performance, the fuel cut-off time is typically set to a delayed cut-off to allow for more complete combustion of gases in the cylinder, making it easier for the exhaust gases to meet national emission standards. However, extensive experimental research has revealed that during the clutch engagement process after upshifting in a transmission, due to the delayed fuel cut-off, the engine's drag torque is relatively small, and the engine speed drops more slowly. This results in a significant speed difference between the engine and the transmission input shaft at engagement, leading to severe impact and noise during clutch engagement. Therefore, control and optimization are needed for this specific operating condition. Summary of the Invention

[0004] The purpose of this invention is to solve the problem in the prior art where the speed difference between the engine and the transmission input shaft is too large when the clutch is engaged, resulting in severe impact and noise during clutch engagement.

[0005] To address the aforementioned problems, embodiments of the present invention disclose a fuel cut-off control method for a vehicle, applicable to the vehicle's powertrain system. The powertrain system includes an engine, a clutch, and a transmission. The clutch is disposed between the engine and the transmission to control the power transmission between the engine and the transmission. Furthermore, the fuel cut-off control method includes the following steps:

[0006] S1: Obtain the vehicle's status parameters and determine whether the vehicle has entered a gear shifting operation based on the vehicle's status parameters;

[0007] If so, proceed to step S2;

[0008] If not, continue to determine whether the vehicle has entered a gear shifting operation;

[0009] S2: Obtain the state parameters of the powertrain system and determine whether the clutch meets the preset clutch pedal state acquisition conditions based on the state parameters of the powertrain system.

[0010] If so, proceed to step S3;

[0011] If not, continue to determine whether the clutch meets the conditions for collecting clutch pedal status.

[0012] S3: Obtain the clutch pedal status information and determine the engine fuel cut-off delay time based on the clutch pedal status information.

[0013] By adopting the above solution, extending the fuel cut-off delay time when the clutch pedal is engaged allows for more complete fuel combustion, meeting emission requirements. Furthermore, the smaller speed difference between the engine speed and the transmission input shaft speed helps suppress shock and noise issues caused by clutch engagement. Conversely, shortening the fuel cut-off delay time when the clutch pedal is depressed allows the engine to enter the fuel cut-off state earlier, resulting in a rapid decrease in engine speed and improved driving smoothness and vehicle responsiveness.

[0014] According to another specific embodiment of the present invention, the fuel cut-off control method for a vehicle disclosed in this embodiment includes, in step S1, the vehicle's state parameters include the opening degree of the accelerator pedal and the vehicle's speed change rate; and, judging whether the vehicle has entered a gear shift operation based on the vehicle's state parameters includes: judging whether the opening degree of the accelerator pedal is greater than a preset opening degree threshold and whether the vehicle's speed change rate is greater than a preset speed change rate threshold.

[0015] If so, the vehicle will enter gear shifting mode;

[0016] If not, continue to determine whether the accelerator pedal opening is greater than the preset opening threshold and whether the vehicle speed change rate is greater than the preset vehicle speed change rate threshold.

[0017] By employing the above scheme, determining whether the vehicle has entered a shift operation before acquiring the clutch pedal status information prevents incorrect engine fuel cut-off delay times from being determined based on erroneous clutch pedal status information due to driver accidental clutch pedal contact, thus improving the accuracy of the determined fuel cut-off delay time. Furthermore, comprehensively judging whether the vehicle has entered a shift operation based on factors such as accelerator pedal opening and vehicle speed change rate also improves judgment efficiency, as accelerator pedal opening and vehicle speed information are relatively easy to collect and can be acquired in real time.

[0018] According to another specific embodiment of the present invention, the fuel cut-off control method for vehicles disclosed in this embodiment has an opening degree threshold ranging from 95% to 98% and a vehicle speed change rate threshold ranging from 4 km / s. 2 Up to 5km / s 2 .

[0019] According to another specific embodiment of the present invention, in the vehicle fuel cut-off control method disclosed in this embodiment, in step S2, the state parameters of the powertrain system include drivability filtering parameters and fuel cut-off delay parameters; the preset clutch pedal state acquisition conditions include drivability filtering conditions and fuel cut-off delay conditions; and determining whether the clutch meets the preset clutch pedal state acquisition conditions based on the state parameters of the powertrain system includes: determining whether the clutch meets the drivability filtering conditions based on the drivability filtering parameters, and determining whether the clutch meets the fuel cut-off delay conditions based on the fuel cut-off delay conditions; determining whether the drivability filtering conditions and the fuel cut-off delay conditions are simultaneously met.

[0020] If so, the clutch meets the preset clutch pedal state acquisition conditions;

[0021] If not, the clutch does not meet the preset clutch pedal state acquisition conditions.

[0022] By adopting the above scheme, after determining that the vehicle has entered a gear shift operation and before acquiring the clutch pedal status information, it is also determined whether the clutch pedal status acquisition conditions are met. Only when these conditions are met can the clutch pedal status be acquired. This fully considers the driving conditions of the engine, transmission, and vehicle, as well as the impact on the environment. If the driving conditions of the engine, transmission, and vehicle are not up to standard, or if the combustion emissions have an impact on the environment, the clutch pedal status will not be acquired, and the fuel cut-off delay time will not be changed. This protects the environment and allows the vehicle to maintain a better driving condition.

[0023] According to another specific embodiment of the present invention, the vehicle fuel cut-off control method disclosed in this embodiment includes drivability filtering parameters such as engine coolant temperature, engine speed, transmission gear, vehicle accelerator pedal state, and engine speed decrease rate; and drivability filtering conditions include: engine coolant temperature greater than a preset temperature threshold; engine speed greater than a preset speed threshold; transmission gear in neutral or third gear or higher; vehicle accelerator pedal in a released state; and engine speed decrease rate less than a preset rate threshold; and all of the above conditions must be met simultaneously.

[0024] By adopting the above scheme, the effects of engine coolant temperature, engine speed, gearbox gear, vehicle accelerator pedal status, and engine speed drop rate are considered before collecting the clutch pedal signal. When these parameters are abnormal, the clutch pedal status is not collected, and the fuel cut-off delay time is not changed, which can maintain the vehicle in a better driving state.

[0025] According to another specific embodiment of the present invention, the fuel cut-off control method for a vehicle disclosed in this embodiment has a temperature threshold range of 60°C to 70°C; a speed threshold range of 1500 r / min to 2500 r / min; and a rate threshold range of 90 rpm / ms to 110 rpm / ms.

[0026] According to another specific embodiment of the present invention, the fuel cut-off control method for a vehicle disclosed in this embodiment includes fuel cut-off delay parameters including the diagnostic results of the vehicle's on-board diagnostic system, the crankcase ventilation status of the engine, and the engine's emissions; and the fuel cut-off delay conditions include: the diagnostic results of the vehicle's on-board diagnostic system are normal; the crankcase ventilation status of the engine is such that the crankcase airflow is greater than a preset airflow threshold; and the engine's emissions meet preset emission standards; and all of the above conditions must be met simultaneously.

[0027] By adopting the above approach, considering the diagnostic results of the on-board diagnostic system related to emissions and pollution, the crankcase ventilation status of the engine, and the engine's emissions before collecting the clutch pedal signal, the fuel burned by the engine can meet emission standards, preventing environmental pollution caused by exhaust gases emitted due to incomplete combustion.

[0028] According to another specific embodiment of the present invention, the fuel cut-off control method for vehicles disclosed in this embodiment has an airflow threshold of 0.1 m³ / s. 3 / s to 0.3m 3 / s.

[0029] According to another specific embodiment of the present invention, the fuel cut-off control method for a vehicle disclosed in this embodiment includes clutch pedal state information including: clutch pedal depressed and clutch pedal released; and, when the clutch pedal state information is clutch pedal depressed, determining the engine fuel cut-off delay time based on the clutch pedal state information includes: determining the engine fuel cut-off delay time as a first time; when the clutch pedal state information is clutch pedal released, determining the engine fuel cut-off delay time based on the clutch pedal state information includes: determining the engine fuel cut-off delay time as a second time; wherein, the first time is less than the second time.

[0030] According to another specific embodiment of the present invention, the fuel cut-off control method for a vehicle disclosed in this embodiment has a first time range of 0.1s to 0.3s and a second time range of 0.7s to 0.9s.

[0031] Using the above solution, the fuel cut-off delay time is about 0.2 seconds, which can achieve a good balance between emission requirements and the elimination of noise and jerking sensation.

[0032] The beneficial effects of this invention are:

[0033] The fuel cut-off control method for vehicles provided by this invention, when detecting a user's gear shifting operation, diagnoses the conditions based on the clutch pedal state acquisition. When the conditions are met, a fuel cut-off signal is sent to the engine along with a fuel cut-off delay time based on the clutch pedal state information. This allows for setting different fuel cut-off delay times according to different clutch pedal states. If the clutch pedal is in the released state, the normal fuel cut-off delay time is maintained; if the clutch pedal is in the depressed state, indicating a gear shifting operation, the fuel cut-off delay time is shortened. In this way, when the clutch pedal is engaged, extending the fuel cut-off delay time allows for more complete fuel combustion, meeting emission requirements, and reduces the speed difference between the engine speed and the transmission input shaft speed, suppressing the impact and noise problems caused by clutch engagement. When the clutch pedal is depressed, shortening the fuel cut-off delay time allows the engine to enter the fuel cut-off state earlier, causing the engine speed to drop rapidly, improving driving smoothness and vehicle responsiveness. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the clutch pedal provided in an embodiment of the present invention;

[0035] Figure 2 This is a schematic diagram illustrating the analysis of influencing factors of impact sensing problems provided in an embodiment of the present invention;

[0036] Figure 3 This is a schematic flowchart of the fuel cut-off control method for vehicles provided in an embodiment of the present invention;

[0037] Figure 4 This is a schematic diagram illustrating the implementation of the vehicle fuel cut-off control method provided in this embodiment of the invention.

[0038] Explanation of reference numerals in the attached figures:

[0039] 1. Flywheel; 2. Pressure plate; 3. Clutch pedal; 4. Driven plate; 5. Gearbox input shaft. Detailed Implementation

[0040] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. Although the description of the present invention is presented in conjunction with preferred embodiments, this does not mean that the features of the invention are limited to these embodiments. On the contrary, the purpose of describing the invention in conjunction with embodiments is to cover other options or modifications that may be derived based on the claims of the present invention. To provide a deep understanding of the invention, many specific details will be included in the following description. The invention may also be implemented without using these details. Furthermore, to avoid confusion or obscuring the focus of the invention, some specific details will be omitted in the description. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of the present invention can be combined with each other.

[0041] It should be noted that in this specification, similar reference numerals and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0042] In the description of this embodiment, it should be noted that the terms "upper", "lower", "inner", "bottom", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship that the product of the invention is usually placed in during use. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the present invention.

[0043] The terms “first”, “second”, etc., are used only to distinguish descriptions and should not be interpreted as indicating or implying relative importance.

[0044] In the description of this embodiment, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set up," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this embodiment based on the specific circumstances.

[0045] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0046] To better illustrate the fuel cut-off control method provided by this invention, first refer to... Figure 1This section describes the basic structure of a clutch. The clutch mainly consists of a flywheel 1, a pressure plate 2, a clutch pedal 3, and a driven plate 4. When engaged, the flywheel 1, driven plate 4, and pressure plate 2 are pressed tightly together. The engine torque is transmitted to the driven plate 4 via the friction between the two friction surfaces of the flywheel 1 and pressure plate 2, and then input to the transmission via the gearbox input shaft 5. When disengaging the clutch, the driver depresses the clutch pedal 3, separating the flywheel 1, driven plate 4, and pressure plate 2, and the engine torque transmission to the transmission stops. During engagement, the driver slowly releases the clutch pedal 3, and the pressure plate 2 gradually presses against the driven plate 4, gradually increasing the pressure between the contact surfaces and the frictional torque. When the engagement between the flywheel 1, pressure plate 2, and driven plate 4 is not yet tight, the transmitted frictional torque is relatively small, and there is a speed difference between the flywheel 1, pressure plate 2, and driven plate 4, resulting in clutch slippage. As the person gradually lifts the clutch pedal 3, the pressure between the flywheel 1, pressure plate 2, and driven plate 4 gradually tightens, and the rotational speeds of the clutch flywheel 1, pressure plate 2, and driven plate 4 gradually become equal until the clutch is fully engaged and slippage stops, thus ending the engagement process.

[0047] Further, refer to Figure 2 The factors influencing the perception of impact after upshifting are explained. The perception of impact after upshifting refers to the severe impact that occurs when releasing the clutch after upshifting. During clutch engagement, due to delayed oil cut-off, lower engine torque, and slower engine speed drop, the speed difference between the engine and the transmission input shaft is too large, resulting in a significant impact accompanied by noise. This impact primarily occurs when shifting from first to second gear and from second to third gear. After releasing the accelerator and depressing the clutch pedal, followed by releasing the clutch pedal after upshifting, a significant impact accompanied by noise occurs during clutch engagement.

[0048] Impact perception mainly utilizes Figure 2 The system analysis shown is complete. This impact sensing analysis system includes the engine, flywheel, clutch, transmission, engine mount, transmission mount, tire, and lower tie rod. The engine mount is connected to the engine, and the transmission mount and lower tie rod are both connected to the transmission. The engine, flywheel, clutch, and transmission are connected sequentially. The tire is connected to the transmission via a half-shaft. Extensive analysis and verification revealed that the main cause of the impact sensing problem is an excessively large difference between the engine speed and the transmission input shaft speed when the clutch engages. The main factors contributing to this excessive speed difference include: first, the user releases the clutch too quickly after shifting gears; second, the speed ratio difference between the two gears in the transmission is too large; and third, the engine speed decreases too slowly during gear shifting and clutch engagement. For the first two reasons, due to user habits and the existing hardware, further optimization is not possible; only the third reason can be optimized.

[0049] After extensive analysis and verification, the main factors affecting the third factor are as follows: First, insufficient engine internal resistance; second, engine filtering time; third, engine fuel cut-off delay time; and fourth, engine and flywheel inertia. Engine internal resistance and inertia are already fixed, and reducing engine internal resistance helps improve efficiency, which is the current development direction. Therefore, there is no possibility of optimizing the first factor. Engine filtering time is a necessary part of drivability filtering, preventing severe dragging and nose-diving problems after releasing the accelerator. Therefore, the second factor cannot be optimized either. Thus, optimization can only be done on the engine fuel cut-off delay time strategy. Current fuel cut-off delay strategies, considering emission performance and ensuring that vehicle exhaust gases more easily meet national emission standards, typically set the fuel cut-off delay time to a fixed time, generally around 0.8 seconds.

[0050] To address the problem in existing technologies where the excessive speed difference between the engine and transmission input shafts during clutch engagement leads to severe impact and noise, the present invention provides a fuel cut-off control method for vehicles.

[0051] The fuel cut-off control method for vehicles provided by this invention is applicable to the powertrain system of a vehicle. The powertrain system includes an engine, a clutch, and a transmission. The clutch is located between the engine and the transmission to control the power transmission between them. Specific structures and connection methods can be found in existing technologies, and this specific embodiment does not limit these aspects.

[0052] Furthermore, in the fuel cut-off control method for a vehicle according to the present invention, reference is made to... Figure 3 The fuel cut-off control method includes the following steps:

[0053] S1: Obtain the vehicle's status parameters and determine whether the vehicle has entered a gear shifting operation based on the vehicle's status parameters;

[0054] If so, proceed to step S2;

[0055] If not, continue to determine whether the vehicle has entered a gear shifting operation;

[0056] S2: Obtain the state parameters of the powertrain system and determine whether the clutch meets the preset clutch pedal state acquisition conditions based on the state parameters of the powertrain system.

[0057] If so, proceed to step S3;

[0058] If not, continue to determine whether the clutch meets the conditions for collecting clutch pedal status.

[0059] S3: Obtain the clutch pedal status information and determine the engine fuel cut-off delay time based on the clutch pedal status information.

[0060] Furthermore, the system includes steps to detect when a user initiates a gear shift. It diagnoses the clutch pedal status by collecting data on the condition that it meets the criteria. Then, based on the clutch pedal status information, it sends a fuel cut-off signal to the engine and specifies a fuel cut-off delay time. This allows for different fuel cut-off delay times to be set according to different clutch pedal states. If the clutch pedal is raised, the normal fuel cut-off delay time is maintained; if the clutch pedal is depressed, indicating a gear shift, the fuel cut-off delay time is shortened. In this way, when the clutch pedal is engaged, extending the fuel cut-off delay time allows for more complete fuel combustion, meeting emission requirements, and a smaller speed difference between the engine speed and the transmission input shaft speed, suppressing shock and noise issues caused by clutch engagement. When the clutch pedal is depressed, shortening the fuel cut-off delay time allows the engine to enter the fuel cut-off state earlier, causing the engine speed to drop rapidly, improving driving smoothness and vehicle responsiveness.

[0061] Furthermore, in this specific embodiment, it is first determined whether the vehicle has entered a gear shifting operation, and then it is determined whether the clutch meets the preset clutch pedal state acquisition conditions. Instead of directly judging the pedal state acquisition conditions, the gear shifting operation is confirmed first. This prevents the problem of the driver accidentally pressing the clutch pedal, which would cause the determined fuel cut-off delay time to be inaccurate. It also avoids the operation process and time required to obtain the powertrain system state parameters and perform the judgment process every time, and improves the efficiency of fuel cut-off control.

[0062] Furthermore, in the vehicle fuel cut-off control method according to the present invention, in step S1, the vehicle's state parameters include the opening degree of the accelerator pedal and the vehicle speed change rate. The accelerator pedal opening degree can be measured by an accelerator pedal sensor, and the vehicle speed change rate can be calculated based on the change in vehicle speed and the time interval of the speed change. Furthermore, determining whether the vehicle has entered a gear shift operation based on the vehicle's state parameters includes:

[0063] Determine whether the accelerator pedal opening is greater than a preset opening threshold and whether the vehicle speed change rate is greater than a preset vehicle speed change rate threshold.

[0064] If so, the vehicle will enter gear shifting mode;

[0065] If not, continue to determine whether the accelerator pedal opening is greater than the preset opening threshold and whether the vehicle speed change rate is greater than the preset vehicle speed change rate threshold.

[0066] Specifically, if the user releases the accelerator, it indicates that the vehicle may be entering a gear shift. Before upshifting, the vehicle needs to be accelerated to match the engine speed and current vehicle speed with the gear to be shifted. Therefore, the shift operation can also be determined based on the rate of change of vehicle speed. More specifically, the opening threshold ranges from 95% to 98%, for example, it could be 95%, 96%, 97%, or 98%, which can be arbitrarily selected by those skilled in the art depending on the vehicle model. The vehicle speed change rate threshold ranges from 4 km / s. 2 Up to 5km / s 2 For example, it could be 4km / s 2 4.5km / s 2 5km / s 2 Or other values ​​within that range.

[0067] Furthermore, in the fuel cut-off control method for a vehicle according to the present invention, since it is determined whether the vehicle has entered a shift operation before acquiring the clutch pedal state information, it is possible to prevent the driver from accidentally pressing the clutch pedal and determining an incorrect engine fuel cut-off delay time based on incorrect clutch pedal state information, thereby improving the accuracy of the determined fuel cut-off delay time. Moreover, by comprehensively judging whether the vehicle has entered a shift operation based on factors such as the accelerator pedal opening and the rate of change of vehicle speed, and since information such as the accelerator pedal opening and vehicle speed is relatively easy to collect and can be collected in real time, the judgment efficiency is also improved.

[0068] Furthermore, in the fuel cut-off control method for a vehicle according to the present invention, reference is made to... Figure 4 In step S2, the powertrain system's state parameters include drivability filtering parameters and fuel cut-off delay parameters; the preset clutch pedal state acquisition conditions include drivability filtering conditions and fuel cut-off delay conditions. Furthermore, determining whether the clutch meets the preset clutch pedal state acquisition conditions based on the powertrain system's state parameters includes:

[0069] Determine whether the clutch meets the drivability filtering conditions based on the drivability filtering parameters, and determine whether the clutch meets the fuel cut-off delay conditions based on the fuel cut-off delay conditions.

[0070] Determine whether the drivability filtering condition and the fuel cut-off delay condition are simultaneously met;

[0071] If so, the clutch meets the preset clutch pedal state acquisition conditions;

[0072] If not, the clutch does not meet the preset clutch pedal state acquisition conditions.

[0073] Furthermore, in the fuel cut-off control method for a vehicle according to the present invention, after determining that the vehicle has entered a shift operation and before acquiring the clutch pedal state information, it is also determined whether the clutch pedal state acquisition conditions are met. Only when the conditions are met can the clutch pedal state be acquired. This fully considers the driving state of the engine, transmission, and vehicle, as well as the impact on the environment. When the driving state of the engine, transmission, and vehicle is not up to standard, or when combustion emissions have an impact on the environment, the clutch pedal state is not acquired, and the fuel cut-off delay time is not changed. This protects the environment and allows the vehicle to maintain a better driving state.

[0074] Furthermore, in the fuel cut-off control method for a vehicle according to the present invention, reference is made to... Figure 4 The driving performance filtering parameters include engine coolant temperature, engine speed, transmission gear position, accelerator pedal position, and engine speed drop rate. Engine coolant temperature can be measured using an in-engine coolant temperature sensor; engine speed can be measured using an engine speed sensor; transmission gear position can be measured using a gear position sensor; accelerator pedal position can be measured using a pedal opening sensor; and engine speed drop rate can be calculated based on changes in engine speed and the time intervals between these changes. The measurement methods for these parameters are existing technology and will not be elaborated upon in this specific embodiment. Furthermore, the system includes a step that considers the influence of engine coolant temperature, engine speed, transmission gear position, accelerator pedal position, and engine speed drop rate before acquiring the clutch pedal signal. When these parameters are abnormal, the clutch pedal position is not acquired, and the fuel cut-off delay time is not changed, thus maintaining the vehicle in an optimal driving condition.

[0075] Furthermore, in the fuel cut-off control method for a vehicle according to the present invention, the drivability filtering conditions include: the engine coolant temperature is greater than a preset temperature threshold; the engine speed is greater than a preset speed threshold; the gearbox is in neutral or in third gear or higher; the accelerator pedal is released; and the rate of decrease in engine speed is less than a preset rate threshold; and all of the above conditions must be met simultaneously. More specifically, the temperature threshold ranges from 60°C to 70°C, for example, it can be 60°C, 65.5°C, 70°C, or other values ​​within this range. Those skilled in the art can determine this range based on different engine types and actual needs, and this specific embodiment will not elaborate further. The speed threshold ranges from 1500 r / min to 2500 r / min, for example, it can be 1500 r / min, 1850 r / min, 2000 r / min, 2500 r / min, or other values ​​within this range. The rate threshold ranges from 90 rpm / ms to 110 rpm / ms, for example, it can be 90 rpm / ms, 98 rpm / ms, 104 rpm / ms, 110 rpm / ms, or other values.

[0076] Furthermore, in the fuel cut-off control method for a vehicle according to the present invention, the fuel cut-off delay parameters include the diagnostic results of the vehicle's on-board diagnostic system, the crankcase ventilation status of the engine, and the engine's emissions. More specifically, the on-board diagnostic system (OBD) can monitor the vehicle's exhaust emissions at any time based on the engine's operating status, and will immediately issue a warning if emissions exceed the limits. Engine crankcase ventilation can prevent oil deterioration, crankshaft oil seal and crankcase gasket leaks, and also prevent oil vapor pollution of the atmosphere. Excessive engine emissions indicate incomplete fuel combustion, and the vehicle will emit gases harmful to the environment. Moreover, by considering the diagnostic results of the on-board diagnostic system, the engine's crankcase ventilation status, and the engine's emissions related to emissions and pollution before acquiring the clutch pedal signal, the method ensures that the fuel burned by the engine meets emission standards, preventing environmental pollution caused by exhaust gases emitted due to incomplete combustion.

[0077] Furthermore, in the fuel cut-off control method for a vehicle according to the present invention, reference is made to... Figure 4 The fuel cut-off delay conditions include: the vehicle's on-board diagnostic system showing no abnormalities; the engine's crankcase ventilation status indicating that the crankcase airflow exceeds a preset airflow threshold; and the engine's emissions meeting preset emission standards. Furthermore, all of the above conditions must be met simultaneously. The airflow threshold is 0.1m³ / s. 3 / s to 0.3m 3 / s, for example 0.1m 3 / s, 0.15m 3 / s, 0.3m 3 / s, or other values ​​within that range. More specifically, steps that incorporate environmentally impactful factors such as on-board diagnostic system results, crankcase ventilation status, and engine emissions as fuel cut-off delay conditions enable the determined fuel cut-off delay time to meet environmental requirements and improve vehicle performance.

[0078] Furthermore, in the fuel cut-off control method for a vehicle according to the present invention, reference is made to... Figure 4 The clutch pedal status information includes: clutch pedal depressed and clutch pedal released. The depressing or releasing of the clutch pedal can be determined based on the clutch pedal opening. For example, a clutch pedal opening greater than 95% is considered as clutch pedal released, and a clutch pedal opening less than 30% is considered as clutch pedal depressed. Of course, this specific embodiment is merely illustrative, using 95% and 30% as threshold values ​​for judgment. In fact, those skilled in the art can comprehensively determine the clutch pedal opening value based on different vehicle models, pedal sensitivity, and actual needs. Determining the clutch pedal status based on the opening value is relatively simple to collect and can be achieved in real time, thus resulting in high accuracy and efficiency. It should be understood that this specific embodiment is merely illustrative, using pedal opening as the basis for judging the pedal status. In fact, those skilled in the art can choose other methods to judge the clutch pedal status.

[0079] Furthermore, in the fuel cut-off control method for a vehicle according to the present invention, when the clutch pedal state information indicates that the clutch pedal is depressed, determining the engine fuel cut-off delay time based on the clutch pedal state information includes: determining the engine fuel cut-off delay time as a first time. When the clutch pedal state information indicates that the clutch pedal is released, determining the engine fuel cut-off delay time based on the clutch pedal state information includes: determining the engine fuel cut-off delay time as a second time. It should be noted that the first time is shorter than the second time. With these steps, when the clutch pedal is engaged, extending the fuel cut-off delay time allows for more complete fuel combustion, meeting emission requirements, and reduces the speed difference between the engine speed and the transmission input shaft speed, thus suppressing shock and noise problems caused by clutch engagement. When the clutch pedal is depressed, shortening the fuel cut-off delay time allows the engine to enter the fuel cut-off state earlier, causing the engine speed to drop rapidly, improving driving smoothness and vehicle responsiveness.

[0080] Furthermore, in the fuel cut-off control method for a vehicle according to the present invention, reference is made to... Figure 4The first time interval is between 0.1s and 0.3s, for example, it can be 0.1s, 0.15s, 0.2s, 0.3s, or other times within this range. The second time interval is between 0.7s and 0.9s, for example, it can be 0.7s, 0.85s, 0.9s, or other times within this range.

[0081] Extensive experimental research and analysis have shown that when the clutch pedal is depressed, if the fuel cut-off delay is too short, fuel combustion is incomplete, failing to meet emission requirements. Conversely, if the fuel cut-off delay is too long, it fails to rapidly reduce engine speed, resulting in a strong jerk and noise upon clutch engagement. A delay of around 0.2 seconds, ideally 0.2 seconds, achieves a good balance between meeting emission requirements and eliminating noise and jerkiness.

[0082] While the present invention has been illustrated and described with reference to certain preferred embodiments, those skilled in the art should understand that the above description is a further detailed explanation of the invention in conjunction with specific embodiments, and should not be construed as limiting the specific implementation of the invention to these descriptions. Various changes in form and detail can be made by those skilled in the art, including several simple deductions or substitutions, without departing from the spirit and scope of the invention.

Claims

1. A fuel cut-off control method for a vehicle, characterized in that, A powertrain system suitable for the vehicle, the powertrain system including an engine, a clutch, and a transmission, the clutch being disposed between the engine and the transmission to control power transmission between the engine and the transmission; and The fuel cut-off control method includes the following steps: S1: Obtain the status parameters of the vehicle, and determine whether the vehicle has entered a gear shifting operation based on the status parameters of the vehicle; If so, proceed to step S2; If not, continue to determine whether the vehicle has entered a gear shifting operation; S2: Obtain the state parameters of the powertrain system, and determine whether the clutch meets the preset clutch pedal state acquisition conditions based on the state parameters of the powertrain system; If so, proceed to step S3; If not, continue to determine whether the clutch meets the clutch pedal state acquisition conditions; S3: Obtain the clutch pedal state information, and determine the engine fuel cut-off delay time based on the clutch pedal state information; wherein In step S2, the state parameters of the powertrain system include drivability filter parameters and fuel cut-off delay parameters. The preset clutch pedal state acquisition conditions include drivability filtering conditions and fuel cut-off delay conditions; and Determining whether the clutch meets the preset clutch pedal state acquisition conditions based on the state parameters of the powertrain system includes: The clutch is judged to meet the drivability filtering conditions based on the drivability filtering parameters, and the clutch is judged to meet the fuel cut-off delay conditions based on the fuel cut-off delay conditions. Determine whether the drivability filtering condition and the fuel cut-off delay condition are simultaneously satisfied; If so, the clutch satisfies the preset clutch pedal state acquisition conditions; If not, then the clutch does not meet the preset clutch pedal state acquisition conditions.

2. The fuel cut-off control method for a vehicle as described in claim 1, characterized in that, In step S1, the vehicle's state parameters include the opening of the accelerator pedal and the vehicle's speed change rate. and Determining whether the vehicle has entered a gear shift operation based on the vehicle's status parameters includes: Determine whether the opening degree of the accelerator pedal is greater than a preset opening degree threshold and whether the vehicle speed change rate is greater than a preset vehicle speed change rate threshold. If so, the vehicle enters a gear shifting operation; If not, then continue to determine whether the opening of the accelerator pedal is greater than a preset opening threshold and whether the vehicle speed change rate is greater than a preset vehicle speed change rate threshold.

3. The fuel cut-off control method for a vehicle as described in claim 2, characterized in that, The range of the opening threshold is 95% to 98%; The threshold range for the vehicle speed change rate is 4 km / s. 2 Up to 5km / s 2 .

4. The fuel cut-off control method for a vehicle as described in claim 1, characterized in that, The driving performance filtering parameters include the engine coolant temperature, the engine speed, the gear position of the transmission, the state of the vehicle's accelerator pedal, and the rate of decrease in engine speed. and The drivability filtering conditions include: The engine's water temperature is greater than a preset temperature threshold. The engine speed is greater than a preset speed threshold; The gearbox has no gear or more than three gears; The accelerator pedal of the vehicle is in the released state; The rate of decrease in engine speed is less than a preset rate threshold; and All of the above conditions must be met simultaneously.

5. The fuel cut-off control method for a vehicle as described in claim 4, characterized in that, The temperature threshold ranges from 60°C to 70°C. The speed threshold ranges from 1500 r / min to 2500 r / min; The rate threshold ranges from 90 rpm / ms to 110 rpm / ms.

6. The fuel cut-off control method for a vehicle as described in claim 1, characterized in that, The fuel cut-off delay parameters include the diagnostic results of the vehicle's on-board diagnostic system, the crankcase ventilation status of the engine, and the engine's emissions. and The fuel cut-off delay conditions include: The vehicle's on-board diagnostic system reported no abnormalities. The crankcase ventilation state of the engine is that the air volume of the engine crankcase is greater than a preset air volume threshold. The engine's emissions meet preset emission standards; and All of the above conditions must be met simultaneously.

7. The fuel cut-off control method for a vehicle as described in claim 6, characterized in that, The airflow threshold is 0.1m. 3 / s to 0.3m 3 / s.

8. The fuel cut-off control method for a vehicle as described in any one of claims 1 to 7, characterized in that, The clutch pedal status information includes: clutch pedal depressed and clutch pedal released; and When the clutch pedal status information indicates that the clutch pedal is depressed, determining the engine fuel cut-off delay time based on the clutch pedal status information includes: The fuel cut-off delay time of the engine is determined as the first time. When the clutch pedal status information indicates that the clutch pedal is released, determining the engine fuel cut-off delay time based on the clutch pedal status information includes: The fuel cut-off delay time of the engine is determined to be the second time; wherein The first time is shorter than the second time.

9. The fuel cut-off control method for a vehicle as described in claim 8, characterized in that, The first time interval is from 0.1s to 0.3s; The second time ranges from 0.7s to 0.9s.

Images