Vehicle fuel cut-off control method, engine control device and vehicle
By coordinating the vehicle's fuel cut-off requests and controlling cylinder fuel cut-off based on operating conditions and torque conditions, the problem of multiple chaotic fuel cut-off requests was solved, thereby improving fuel economy and driving safety.
Patent Information
- Application Number
- CN202511933265.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-19
- Publication Date
- 2026-02-13
AI Technical Summary
When multiple fuel cut-off requests occur simultaneously or sequentially during vehicle operation, they cannot be effectively coordinated, leading to engine control chaos and affecting fuel economy and driving safety.
By acquiring fuel cut-off requests from the vehicle controller, determining the vehicle's operating status information, coordinating torque fuel cut-off and fault fuel cut-off requests, determining the number of fuel cut-off cylinders, and controlling the fuel cut-off of cylinders or all cylinders based on the engine's current torque and required torque, the system achieves coordinated control of different fuel cut-off requests.
It improves fuel economy, reduces fuel consumption, increases vehicle thermal efficiency, and balances driving safety and stability, thus optimizing the overall performance of the vehicle.
Smart Images
Figure CN121520079A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the field of engine control, in particular to a vehicle fuel cut control method, an engine control device and a vehicle. BACKGROUND
[0002] Gasoline is the fuel of a hybrid vehicle in a hybrid mode, and whether the gasoline works normally is related to the driving safety and driving comfort of the vehicle. The fuel cut control method for part of the cylinders or all the cylinders of the engine of the vehicle is the core function of the electronic control system.
[0003] During normal driving of the vehicle, the fuel supply of low-load cylinders is cut off to make the working cylinders in a high-load state, reduce throttle loss, improve charge efficiency and reduce fuel consumption, and at the same time reduce the emission of unburned gas. After fuel cut, the total surface area of the combustion chamber is reduced, heat loss is reduced, and the cycle thermal efficiency of the working cylinder is improved.
[0004] When the electronic control unit of the vehicle detects overspeed, high temperature or serious failure, it is necessary to forcibly cut off the fuel supply of all the cylinders to avoid engine burning or mechanical damage. When the vehicle is in a collision, fuel cut control can reduce the risk of fuel leakage and fire.
[0005] When multiple fuel cut requests occur simultaneously or successively, different fuel cut requests cannot be effectively coordinated. SUMMARY
[0006] The present application provides a vehicle fuel cut control method, an engine control device and a vehicle for coordinating different fuel cut requests.
[0007] In a first aspect, the present application provides a vehicle fuel cut control method applied to a vehicle, the vehicle comprising an engine, the engine comprising a plurality of cylinders, comprising: obtaining a fuel cut request of a vehicle controller of the vehicle, the fuel cut request comprising a torque fuel cut request and a failure fuel cut request; if the fuel cut request is the torque fuel cut request, determining whether the running state information of the vehicle meets a torque fuel cut condition; if the torque fuel cut condition is met, determining a number of fuel cut cylinders according to a current torque and a required torque of the engine; controlling the fuel cut of the cylinders in the plurality of cylinders with the number of the fuel cut cylinders according to the number of the fuel cut cylinders; if the fuel cut request is the failure fuel cut request, controlling the fuel cut of all the cylinders.
[0008] Optionally, the torque fuel cut condition comprises: the vehicle is started and lasts for a first set time; The catalyst heating coefficient of the engine is greater than the set catalyst heating coefficient, and the temperature of the engine's after catalyst is greater than the first set temperature. The catalytic converter temperature of the engine is lower than the second set temperature; and The target torque of the vehicle is less than or equal to the required torque.
[0009] Optionally, determining whether the vehicle meets the torque cut-off condition includes: Obtain the start status of the vehicle; If the vehicle starts successfully and continues for the first set duration, torque fuel cut-off parameters are obtained. The torque fuel cut-off parameters include: the catalyst heating coefficient, the rear catalyst temperature, the catalyst temperature, the target torque, and the required torque. Based on the torque cut-off parameters, determine whether the vehicle meets the torque cut-off conditions.
[0010] Optionally, the target torque of the vehicle is less than or equal to the required torque, including: The vehicle is not in a torque-increasing state, which includes: The vehicle's wheels were locked and it was coasting. When the minimum requested torque value for the engine speed control is greater than the minimum load torque value for the engine, the actual crankshaft torque difference that the engine can deliver is greater than 0. When the vehicle is in an idling coasting state, the target idle speed of the vehicle increases; or The throttle opening of the vehicle is greater than the set opening, and the vehicle is in a state of increasing throttle opening.
[0011] Optionally, the increased throttle opening state includes: The requested torque rise slope of the vehicle is greater than the set slope, and the actual crankshaft torque of the vehicle is less than the maximum crankshaft torque. When the vehicle exits the deceleration and fuel cut-off state, the vehicle's clutch is in a locked state. The engine's firing angle allows for torque adjustment; The vehicle's stability module stops limiting the engine's output torque; or The vehicle can switch between pure electric mode and hybrid mode or pure engine mode.
[0012] Optionally, determining the number of fuel cut-off cylinders based on the current torque and the required torque includes: The difference between the current torque and the required torque is determined as the torque difference. The number of oil-cut cylinders is obtained by rounding down the ratio of the torque difference to the unit torque provided by the cylinder.
[0013] Optionally, the step of cutting off fuel to the cylinders in the plurality of cylinders, where the number of cylinders is equal to the number of fuel-cut-off cylinders, includes: Fuel is cut off to the cylinders whose number equals the number of fuel-cut-off cylinders, according to the timing cylinder sequence of the engine.
[0014] Optionally, obtaining the fuel cut-off request from the vehicle's controller includes: The vehicle controller obtains the fault fuel cut-off request issued when the vehicle is in any fault protection state. The fault protection status includes: The indicated torque of the engine is 0; the vehicle is involved in an accident; the vehicle does not request to start; the starter motor of the vehicle changes its command and issues a fuel cut-off request; the engine pre-ignites; the engine speed is greater than the maximum engine speed; the fuel rail pressure of the engine is less than the minimum fuel rail pressure limit; the ignition key of the vehicle is not turned on and a fuel cut-off mode is requested; or the functional safety module requests a fuel cut-off.
[0015] Secondly, this application provides an engine control device for performing the vehicle fuel cut-off control method as described in the first aspect.
[0016] Thirdly, this application provides a vehicle including a vehicle controller and an engine control device as described in the second aspect, the engine control device being electrically connected to the vehicle controller and receiving the fuel cut-off request from the vehicle controller.
[0017] When a torque cut-off request is received, the system determines whether the vehicle's operating status meets the torque cut-off conditions. This coordinates the vehicle's operating status with the request to reduce the engine's output torque, thereby improving fuel economy, reducing fuel consumption, and increasing thermal efficiency while also ensuring vehicle safety and operating status, thus contributing to vehicle performance optimization. Attached Figure Description
[0018] The accompanying drawings, which are incorporated in and form a part of this specification, illustrate embodiments consistent with this disclosure and, together with the description, serve to explain the principles of this disclosure.
[0019] Figure 1 The diagram shown is a schematic representation of an embodiment of the vehicle fuel cut-off control method of this application.
[0020] Figure 2 The diagram shown is a detailed representation of the vehicle fuel cut-off control method of this application.
[0021] Figure 3 The diagram shown is a detailed representation of the vehicle fuel cut-off control method of this application. Detailed Implementation
[0022] The technical solutions in the embodiments (or "implementations") of this application will be clearly and completely described herein with reference to the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements.
[0023] If the embodiments of this application contain terms relating to directional indications or positional relationships (such as up, down, left, right, front, back, inside, outside, top, bottom, center, vertical, horizontal, longitudinal, transverse, length, width, counterclockwise, clockwise, axial, radial, circumferential, etc.), such terms are only used to explain the relative positional relationships and movement of the components in a specific posture (as shown in the attached figures); if the specific posture changes, the directional indications or positional relationships will also change accordingly. Furthermore, the terms "first" and "second" used in the embodiments of this application are only for descriptive convenience and should not be construed as indicating or implying relative importance.
[0024] This application provides a vehicle fuel cut-off control method, an engine control device, and a vehicle. The vehicle fuel cut-off control method, engine control device, and vehicle of this application will be described in detail below with reference to the accompanying drawings. Unless otherwise specified, the features in the following embodiments and implementations can be combined with each other.
[0025] This application provides a vehicle. The vehicle includes an engine and an engine control unit. The engine includes multiple cylinders, and the engine control unit is used to control the multiple cylinders of the engine to cut off fuel and resume fuel supply according to a vehicle fuel cut-off control method.
[0026] See Figure 1 As shown, the vehicle fuel cut-off control method includes steps S10, S20, S30, S40 and S50.
[0027] In step S10, the fuel cut-off request from the vehicle's overall controller is obtained. The fuel cut-off request includes torque fuel cut-off request and fault fuel cut-off request.
[0028] In step S20, if the fuel cut-off request is a torque fuel cut-off request, it is determined whether the vehicle's operating status information meets the torque fuel cut-off conditions.
[0029] In step S30, if the torque cutoff condition is met, the number of cylinders to be cut off is determined based on the engine's current torque and required torque.
[0030] In step S40, based on the number of oil-cut-off cylinders, the number of cylinders among the multiple cylinders that is equal to the number of oil-cut-off cylinders is controlled to cut off the oil supply.
[0031] In step S50, if the fuel cut-off request is a fault fuel cut-off request, control all cylinders to cut off fuel.
[0032] When a torque cut-off request is received, the system determines whether the vehicle's operating status meets the torque cut-off conditions. This coordinates the vehicle's operating status with the request to reduce the engine's output torque, thereby improving fuel economy, reducing fuel consumption, and increasing thermal efficiency while also ensuring vehicle safety and operating status, thus contributing to vehicle performance optimization.
[0033] In an optional embodiment, the torque cut-off condition includes: The vehicle has started and will continue for the first set duration; The engine's catalytic converter heating coefficient is greater than the set catalytic converter heating coefficient, and the engine's post-catalytic converter temperature is greater than the first set temperature. The engine's catalytic converter temperature is lower than the second set temperature; and The vehicle's target torque is less than or equal to the required torque.
[0034] Specifically, after the vehicle starts, the start-up continues for a first set duration. To avoid engine speed fluctuations caused by fuel cut-off in the cylinders after starting, the engine must not cut off fuel for a period of time after starting; that is, the start-up continues for the first set duration. In this embodiment, the first set duration can be set to 0.2 seconds. In other embodiments, the first set duration can be set within the range of 0.1-0.5 seconds, depending on the type of vehicle.
[0035] The engine's catalytic converter heating coefficient is greater than the set catalytic converter heating coefficient, and the engine's post-catalytic converter temperature is greater than the first set temperature. After the vehicle has started and remained running for the first set duration, the engine's catalytic converter heating coefficient is calculated. Specifically, during vehicle startup, the initial value of the catalytic converter heating coefficient is obtained by dividing the temperature calculated according to the model by the set ignition temperature (325℃). After the vehicle has started and remained running for the first set duration, the initial value of the catalytic converter heating coefficient at the last moment of vehicle startup is added to the product of the intake air flow rate and the coolant temperature compensation value to obtain the final catalytic converter heating coefficient. The coolant temperature compensation value is positively correlated with the engine coolant temperature.
[0036] The engine's catalytic converter temperature is lower than the second set temperature, which is 960°C in this embodiment. During cylinder fuel cut-off recovery, the fuel concentration in the catalytic converter increases, causing the oxygen released by cerium to react with unburned gas, generating exothermic reactions that further raise the catalytic converter temperature. Therefore, when the catalytic converter temperature is greater than or equal to the second set temperature, cylinder fuel cut-off is prohibited.
[0037] The vehicle's target torque is less than or equal to the required torque, thus avoiding a situation where the engine output torque needs to be increased in a short time to restore the fuel cut-off after the engine cylinders are cut off, which is conducive to the stable operation of the vehicle's engine.
[0038] In an optional embodiment, see Figure 2 As shown, step S20 determines whether the vehicle meets the torque cut-off condition, including steps S21, S22 and S23.
[0039] In step S21, the vehicle's start status is obtained.
[0040] In step S22, if the vehicle has started successfully and continues for a first set duration, the torque cut-off parameters are acquired. These parameters include: catalyst heating coefficient, after-catalyst temperature, catalyst temperature, target torque, and required torque.
[0041] In step S23, the vehicle is determined to meet the torque cut-off condition based on the torque cut-off parameters.
[0042] In this way, coordinating the vehicle's operating state with the request to reduce the engine's output torque, while avoiding a situation where the engine needs to increase its output torque briefly after the fuel cut-off is applied to the engine cylinders, thus promoting stable engine operation. This improves fuel economy, reduces fuel consumption, and enhances thermal efficiency while also considering the vehicle's driving conditions, further contributing to performance optimization.
[0043] In an optional embodiment, the target torque of the vehicle is less than or equal to the required torque, including when the vehicle is not in a torque-increasing state.
[0044] Increased torque states include: The vehicle's wheels are locked and it is coasting. When the minimum requested torque value for engine speed control is greater than the minimum load torque value of the engine, the difference between the actual crankshaft torque that the engine can deliver is greater than 0. When a vehicle is idling, the target idle speed increases; or The vehicle's throttle opening is greater than the set opening, and the vehicle is in a state of increasing throttle opening.
[0045] When a vehicle is in a locked-up, coasting state, the torque required by the wheels calculated through the crankshaft torque path is lower than the minimum front axle torque required for stability control. At this point, the engine slip adjustment function is activated, requiring an increase in engine output torque to prevent wheel slippage. When the wheels slip due to engine torque being lower than road friction, the engine output torque is increased.
[0046] When the minimum requested torque value for engine speed control is greater than the minimum load torque value of the engine, and the difference between the actual crankshaft torque that the engine can produce and the torque is greater than 0, the clutch needs to be disengaged and the oil cut-off restored.
[0047] When the vehicle is idling and the target idle speed increases, the driver performs a gear shift. During the shift, the torque converter unlocks, the transmission disengages from the engine flywheel, the engine speed decreases, while the transmission input shaft speed is higher. This brings the engine's target idle speed close to the transmission input shaft speed, making it easier for the torque converter to lock up after the shift.
[0048] If the engine speed deviates too much from the input shaft speed, there will be a longer slip process, which will cause mechanical damage and prolong the lock-up process of the torque converter, thus having a certain negative impact on the torque transmission efficiency of the vehicle.
[0049] The conditions for adjusting the target idle speed during gear shifts are as follows: When the clutch is open, the target idle speed can be set to increase during upshifts or downshifts, depending on the needs. There is a time delay in detecting gear shifts, so sufficient time must be allowed to correctly determine whether a shift is in progress. When the clutch is in neutral, no adjustment to the target idle speed after a gear shift is required. When the vehicle is in economy mode, no target idle speed adjustment is needed to save fuel. If the driver depresses the brake pedal during a gear shift, the torque converter is open, and the transmission input shaft speed will decrease due to braking; therefore, there is no need to increase the target idle speed to approach the transmission input shaft speed. When the torque demanded by the wheels is greater than or equal to the maximum front axle torque limit, a reduction in torque demand is required, and thus, there is no need to increase the target idle speed.
[0050] When the torque demanded by the wheels is lower than the minimum front axle torque limit, and more torque is needed, the anti-slip system is activated. At this time, the vehicle will exit idling coasting, and the torque demand will be provided by other paths.
[0051] When the conditions for unlocking the torque converter and increasing the target idle speed are met, the transmission input shaft speed is used as the engine's basic target idle speed. This shortens the torque converter engagement process and improves transmission efficiency. During this process, the frictional torque generated by braking uses the transmission input shaft speed minus a portion of the friction compensation as the basic target idle speed. Fuel consumption is reduced by lowering the engine's target idle speed. By using the engine's basic target idle speed as a minimum constraint, the target idle speed is increased to minimize the speed deviation between the flywheel and transmission at the moment of gear engagement. This target speed increases or decreases in a certain gradient.
[0052] When the accelerator pedal opening is greater than the set opening and the vehicle is in a state of increasing accelerator pedal opening, it indicates to the driver that the accelerator pedal has been pressed. In this application, the set opening is 10%.
[0053] In an optional embodiment, the throttle opening increase state includes: The vehicle's requested torque rise rate is greater than the set rise rate, and the vehicle's actual crankshaft torque is less than the maximum crankshaft torque. When the vehicle exits deceleration and fuel cut-off, the vehicle's clutch is locked. The engine's ignition timing allows for torque adjustment; The vehicle's stability module stops limiting the engine's output torque; or The vehicle can switch between pure electric mode and hybrid mode or pure engine mode.
[0054] The reduced throttle opening states include: the actual crankshaft torque is close to the maximum crankshaft torque at the current speed, and the required torque of the circuit after the slope limit of the increased throttle opening is greater than 90% of the required crankshaft torque; or, the required torque of the circuit after the slope limit of the increased throttle opening is basically equal to the required crankshaft torque.
[0055] In an optional embodiment, see Figure 3 As shown, step S30 determines the number of oil cut-off cylinders based on the current torque and the required torque, including steps S31 and S32.
[0056] In step S31, the difference between the current torque and the required torque is determined as the torque difference.
[0057] In step S32, the ratio of the torque difference to the unit torque provided by the cylinder is rounded down to obtain the number of oil cut-off cylinders.
[0058] In this way, while improving the vehicle's fuel economy, reducing fuel consumption, and improving the vehicle's thermal efficiency, it is also possible to take into account the vehicle's driving conditions. By cutting off fuel to some cylinders of the engine, the frequency of adjusting the number of cylinders that are cut off fuel is reduced, which is more conducive to optimizing the vehicle's performance.
[0059] In an optional embodiment, step S40, which cuts off the fuel supply to the cylinders in the plurality of cylinders whose number is equal to the number of fuel-cut-off cylinders, includes step S41.
[0060] In step S41, fuel is cut off to the number of cylinders whose timing cylinders are in sequence, according to the engine's synchronized timing cylinder number sequence. The synchronized timing cylinder number is determined by the engine electronic control unit using crankshaft and camshaft position sensor signals to precisely identify the top dead center of the first cylinder's compression stroke, thus establishing a timing reference for sequential fuel injection and precise ignition. By controlling the engine cylinders to cut off fuel in a specific sequence, the engine control unit can accurately control the number of cylinders whose fuel is cut off.
[0061] In an optional embodiment, when the fuel cut-off is restored, it is restored according to the engine's timing cylinder number sequence.
[0062] In an optional embodiment, step S10, obtaining the fuel cut-off request from the vehicle's overall controller, includes step S11.
[0063] In step S11, the fault fuel cut-off request issued by the vehicle controller when the vehicle is in any fault protection state is obtained.
[0064] Fault protection states include: engine indicated torque is 0; vehicle accident occurs; vehicle does not request to start; vehicle starter motor changes command and issues fuel cut-off request; engine pre-ignition occurs; engine speed exceeds maximum engine speed; engine fuel rail pressure is below minimum fuel rail pressure limit; fuel cut-off mode is requested when vehicle ignition key is not turned on; or, functional safety module requests fuel cut-off. When any of the above conditions are met, the vehicle controller issues a fault fuel cut-off request, and fuel is cut off to all cylinders of the engine. When the driver releases the accelerator, if the engine idle speed closed-loop control is not enabled, and the engine speed is higher than a certain limit, and no other module prohibits fuel cut-off, deceleration fuel cut-off can be enabled. In this case, the engine's indicated torque is 0. Specific situations where deceleration fuel cut-off occurs when the engine speed exceeds the limit include: the driver has not pressed the accelerator or requested engine braking; idle speed closed-loop control is not activated; coasting mode is not activated; the vehicle wheels are not locked and coasting, requiring no ABS system to reduce brake disc pressure or engine torque increase; engine speed control does not require prohibition of fuel cut-off; coasting shift closed-loop control of engine speed is not activated; fuel cut-off is not prohibited when pressing the accelerator; fuel cut-off requests from the vehicle's automatic transmission control unit are not prohibited; the motor charging fuel cut-off prohibition flag is not set; the clutch is locked; the catalytic converter ignition module and exhaust temperature protection module fuel cut-off flags are combined, and closed-loop idle speed control is not enabled; fuel cut-off is enabled when the accelerator is released.
[0065] When any of the above conditions are not met, or when the engine speed drops below the limit, the deceleration fuel cut-off flag is reset, and the engine's indicated torque is not 0.
[0066] When engine speed suddenly increases, the vehicle's starter motor may attempt fuel recovery. In situations where the engine is stopped, engine speed increases, or the starter motor is not running, controlling the starter motor to not change commands to perform fuel recovery operations avoids interfering with and activating the starter motor, thus preventing starter motor reversal.
[0067] When the engine speed exceeds the limit by a significant margin, reducing the engine's output torque is insufficient to meet the requirements. In this case, the engine speed is reduced directly by cutting off the fuel supply. Since the engine speed increases during the recovery process after fuel cut-off compared to the initial fuel cut-off speed, the recovery speed must be set to be lower than the maximum speed limit to prevent the engine speed from exceeding the limit after fuel cut-off recovery.
[0068] Before starting the engine, if the pressure in the fuel rail is lower than the minimum fuel pressure limit, the engine enters the start-up fuel cut-off mode. When the engine requests to start, and the difference between the actual engine speed and the target idle speed is less than the calibrated value, and the integrated starter is selected, start-up fuel cut-off can be performed.
[0069] It should be noted that the technical solutions or features described in the above embodiments can be combined or complemented by each other without conflict. The scope of protection of this application is not limited to the precise structures described in the above embodiments and shown in the accompanying drawings; all modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application.
Claims
1. A vehicle fuel cut-off control method, the vehicle comprising an engine, the engine comprising a plurality of cylinders, characterized in that, include: Obtain the fuel cut-off request from the vehicle controller, the fuel cut-off request including torque fuel cut-off request and fault fuel cut-off request; If the fuel cut-off request is the torque fuel cut-off request, determine whether the vehicle's operating status information meets the torque fuel cut-off conditions; If the torque-based fuel cut-off condition is met, the number of fuel-cut-off cylinders is determined based on the engine's current torque and required torque. Based on the number of oil cut-off cylinders, control the oil cut-off of the cylinders in the plurality of cylinders whose number is equal to the number of oil cut-off cylinders; If the fuel cut-off request is a fault fuel cut-off request, control all cylinders to cut off fuel.
2. The vehicle fuel cut-off control method according to claim 1, characterized in that, The torque cutoff conditions include: The vehicle has started and continues to start for a first set duration; The catalyst heating coefficient of the engine is greater than the set catalyst heating coefficient, and the temperature of the engine's after catalyst is greater than the first set temperature. The catalytic converter temperature of the engine is lower than the second set temperature; and The target torque of the vehicle is less than or equal to the required torque.
3. The vehicle fuel cut-off control method according to claim 2, characterized in that, The determination of whether the vehicle meets the torque cut-off condition includes: Obtain the start status of the vehicle; If the vehicle starts successfully and continues for the first set duration, torque fuel cut-off parameters are obtained. The torque fuel cut-off parameters include: the catalyst heating coefficient, the rear catalyst temperature, the catalyst temperature, the target torque, and the required torque. Based on the torque cut-off parameters, determine whether the vehicle meets the torque cut-off conditions.
4. The vehicle fuel cut-off control method according to claim 2, characterized in that, The target torque of the vehicle is less than or equal to the required torque, including: The vehicle is not in a torque-increasing state, which includes: The vehicle's wheels were locked and it was coasting. When the minimum requested torque value for the engine speed control is greater than the minimum load torque value for the engine, the actual crankshaft torque difference that the engine can deliver is greater than 0. When the vehicle is in an idling coasting state, the target idle speed of the vehicle increases; or The throttle opening of the vehicle is greater than the set opening, and the vehicle is in a state of increasing throttle opening.
5. The vehicle fuel cut-off control method according to claim 4, characterized in that, The increased throttle opening states include: The requested torque rise slope of the vehicle is greater than the set slope, and the actual crankshaft torque of the vehicle is less than the maximum crankshaft torque. When the vehicle exits the deceleration and fuel cut-off state, the vehicle's clutch is in a locked state. The engine's firing angle allows for torque adjustment; The vehicle's stability module stops limiting the engine's output torque; or The vehicle can switch between pure electric mode and hybrid mode or pure engine mode.
6. The vehicle fuel cut-off control method according to claim 1, characterized in that, The step of determining the number of fuel cut-off cylinders based on the current torque and the required torque includes: The difference between the current torque and the required torque is determined as the torque difference. The number of oil-cut cylinders is obtained by rounding down the ratio of the torque difference to the unit torque provided by the cylinder.
7. The vehicle fuel cut-off control method according to claim 1, characterized in that, The step of cutting off fuel to cylinders in a number equal to the number of fuel-cut-off cylinders among the plurality of cylinders includes: Fuel is cut off to the cylinders whose number equals the number of fuel-cut-off cylinders, according to the timing cylinder sequence of the engine.
8. The vehicle fuel cut-off control method according to claim 1, characterized in that, The step of obtaining the fuel cut-off request from the vehicle's overall controller includes: The vehicle controller obtains the fault fuel cut-off request issued when the vehicle is in any fault protection state. The fault protection status includes: The indicated torque of the engine is 0; the vehicle is involved in an accident; the vehicle does not request to start; the starter motor of the vehicle changes its command and issues a fuel cut-off request; the engine pre-ignites; the engine speed is greater than the maximum engine speed; the fuel rail pressure of the engine is less than the minimum fuel rail pressure limit; the ignition key of the vehicle is not turned on and a fuel cut-off mode is requested; or the functional safety module requests a fuel cut-off.
9. An engine control device, characterized in that, The engine control unit is used to execute the vehicle fuel cut-off control method as described in any one of claims 1-8.
10. A vehicle, characterized in that, The vehicle includes a vehicle controller and an engine control unit as described in claim 9, the engine control unit being electrically connected to the vehicle controller, and the engine control unit receiving the fuel cut-off request from the vehicle controller.