Vehicle VVT expected value calculation method, vehicle control method and vehicle engine system

Abstract

The invention relates to a vehicle VVT expected value calculation method, a vehicle control method and a vehicle engine system. Whether an engine of a vehicle is in a fuel cut-off state or not is judged; when it is judged that the engine is not in the fuel cut-off state, whether the rotating speed of the engine is smaller than a rotating speed threshold value or not is judged; and under the condition that the rotating speed of the engine is judged to be smaller than the rotating speed threshold value, VVT expected values of the engine under the idling working condition and the non-idling working condition are calculated correspondingly, the VVT expected values are corrected according to VVT expected value compensation coefficients of the engine under the cold machine mode, the catalytic heating mode and the scavenging mode correspondingly, effective adjustment of the VVT is facilitated, and the service life of the engine is prolonged. Therefore, the engine obtains high inflation efficiency, the dynamic property of the engine is improved, and emission is effectively controlled.

Description

Technical Field

[0001] The present application relates to the field of vehicle control, and particularly to a method for calculating the VVT expected value of a vehicle, a vehicle control method, and a vehicle engine system. Background Art

[0002] VVT (Variable Valve Timing) is a key technology used to optimize valve operation in an engine management system. It adjusts the opening and closing times of the intake valve or exhaust valve to adapt to different engine operating conditions, thereby improving fuel efficiency, increasing power output, and reducing emissions.

[0003] Currently, most VVT systems in related technologies adopt hydraulic or electronic control methods. They monitor the engine state through sensors, calculate the actual VVT value of the engine and the required VVT expected value, and adjust the valve timing in real time by comparing the magnitudes of the two.

[0004] However, when calculating the VVT expected value in related technologies, the recognition of different engine operating conditions is lacking, resulting in an unreasonable calculated VVT expected value, and ultimately leading to insufficient power output or increased emissions of the engine. Summary of the Invention

[0005] Based on this, in view of the above technical problems, it is necessary to provide a method for calculating the VVT expected value of a vehicle, a vehicle control method, and a vehicle engine system that can set the VVT expected value according to different engine operating conditions.

[0006] In a first aspect, the present application provides a method for calculating the VVT expected value of a vehicle. The method includes:

[0007] Determine whether the engine of the vehicle is in a fuel cut-off state;

[0008] In the case where it is determined that the engine is not in a fuel cut-off state, determine whether the engine speed is less than a speed threshold;

[0009] In the case where it is determined that the engine speed is less than the speed threshold, calculate the VVT expected values of the engine in the idle and non-idle operating conditions respectively, and correct the VVT expected value according to the VVT expected value compensation coefficients of the engine in the cold engine mode, catalytic heating mode, and scavenging mode respectively.

[0010] In one embodiment, in the case where it is determined that the engine speed is less than the speed threshold, the method further includes:

[0011] Determine whether the engine triggers the idle operating condition;

[0012] When it is determined that the engine triggers the idle condition, calculate the VVT expected value of the engine, and the VVT expected value respectively includes a catalytic heating VVT expected value, a cold engine VVT expected value, and a warm-up idle VVT expected value; according to each of the VVT expected value compensation coefficients, correct the VVT expected value, including:

[0013] Subtract the catalytic heating VVT expected value from the warm-up idle VVT expected value, multiply the obtained difference by the catalytic heating compensation coefficient, and add the obtained product to the warm-up idle VVT expected value to obtain the catalytic heating idle VVT expected value;

[0014] Subtract the cold engine VVT expected value from the warm-up idle VVT expected value, multiply the obtained difference by the cold engine compensation coefficient, and add the obtained product to the warm-up idle VVT expected value to obtain the cold engine idle VVT expected value;

[0015] Compare the catalytic heating idle VVT expected value with the cold engine idle VVT expected value, and use the smaller one as the corrected idle VVT expected value.

[0016] In one embodiment, after comparing the catalytic heating idle VVT expected value with the cold engine idle VVT expected value and using the smaller one as the corrected idle VVT expected value, the method further includes:

[0017] Add the previous moment idle VVT expected value and the VVT expected value increase rate to obtain the VVT expected upper limit value;

[0018] Subtract the VVT expected value decrease rate from the previous moment idle VVT expected value to obtain the VVT expected lower limit value;

[0019] When the current moment idle VVT expected value is greater than the VVT expected upper limit value, update the current moment idle VVT expected value according to the VVT expected upper limit value; or, when the current moment idle VVT expected value is less than the VVT expected lower limit value, update the current moment idle VVT expected value according to the VVT expected lower limit value.

[0020] In one embodiment, the method further includes:

[0021] When it is determined that the engine does not trigger the idle condition, calculate the VVT expected value of the engine, and the VVT expected value respectively includes a catalytic heating VVT expected value, a cold engine VVT expected value, and a scavenging VVT expected value; according to each of the VVT expected value compensation coefficients, correct the VVT expected value, including:

[0022] Subtract the catalytic heating VVT expected value from the scavenging VVT expected value, multiply the obtained difference by the catalytic heating compensation coefficient, and add the obtained product to the scavenging VVT base expected value to obtain the catalytic heating non-idle VVT expected value;

[0023] Subtract the cold engine VVT expected value from the scavenging VVT expected value, multiply the obtained difference by the cold engine compensation coefficient, and add the obtained product to the scavenging VVT expected value to obtain the cold engine non-idle VVT expected value;

[0024] Compare the catalytic heating non-idle VVT expected value with the cold engine non-idle VVT expected value, and take the smaller one as the corrected non-idle VVT expected value.

[0025] In one embodiment, when it is determined that the engine does not trigger the idle condition, calculating the scavenging VVT expected value includes:

[0026] Obtain the warm-up VVT expected value and the VVT expected value when the valve overlap is restricted;

[0027] Subtract the VVT expected value when the valve overlap is restricted from the warm-up VVT expected value, multiply the obtained difference by the scavenging compensation coefficient, and add the obtained product to the VVT expected value when the valve overlap is restricted to obtain the scavenging VVT expected value.

[0028] In one embodiment, the method further includes:

[0029] When it is determined that the engine is in the fuel cut-off state, determine whether the engine speed is less than the speed threshold;

[0030] When it is determined that the engine speed is less than the speed threshold, determine whether the engine triggers the idle condition;

[0031] When it is determined that the engine triggers the idle condition, calculate the corrected idle VVT expected value;

[0032] Determine the VVT limit angle according to the engine speed and the engine oil temperature;

[0033] Compare the corrected idle VVT expected value with the VVT limit angle, and take the smaller one as the final fuel cut-off idle VVT expected value.

[0034] In one embodiment, when it is determined that the engine speed is less than the speed threshold, the method further includes:

[0035] When it is determined that the engine does not trigger the idle condition, calculate the corrected non-idle VVT expected value;

[0036] Determine the VVT limit angle according to the engine speed and the engine oil temperature;

[0037] Compare the corrected non-idle VVT expected value with the VVT limit angle, and take the smaller one as the final fuel cut-off non-idle VVT expected value.

[0038] In one embodiment, before correcting the VVT expected value according to the VVT expected value compensation coefficients of the engine in the cold engine mode, the catalytic heating mode, and the scavenging mode respectively, the method further includes:

[0039] Generate a cold engine compensation coefficient table according to the engine start completion time and the heater's compensation for the coolant temperature;

[0040] Determine a temperature compensation characteristic curve according to the oil temperature and the heater's compensation for the coolant temperature, and determine a catalytic heating coefficient compensation characteristic curve according to the catalytic heating coefficient. Generate a catalytic heating compensation coefficient table according to the temperature compensation characteristic curve and the catalytic heating coefficient compensation characteristic curve;

[0041] Determine a scavenging temperature compensation characteristic curve according to the compensation of the VVT expected value when the exhaust temperature is too high and the emission protection overheat coefficient, and determine a pressure ratio coefficient compensation characteristic curve according to the pressure ratio coefficient and the engine speed. Generate a scavenging compensation coefficient table according to the scavenging temperature compensation characteristic curve and the pressure ratio coefficient compensation characteristic curve.

[0042] In a second aspect, the present application provides a vehicle control method, including:

[0043] Receive the first sensing data collected by the first sensing module in the vehicle, and calculate the actual VVT position of the engine according to the first sensing data;

[0044] Receive the second sensing data collected by the second sensing module in the vehicle, and execute the method described in the first aspect above based on the second sensing data to obtain the VVT expected value of the engine;

[0045] Compare the actual VVT position with the VVT expected value, and control the position of the oil control valve in the vehicle according to the comparison result.

[0046] In a third aspect, the present application provides a vehicle engine system, including: a control system, a sensing system, and an oil control valve. The control system is respectively connected to the sensing system and the oil control valve; wherein,

[0047] The control system is used to execute the methods described in the above first aspect and second aspect, obtain the actual VVT position of the engine and the desired VVT value required by the engine, compare the actual VVT position with the desired VVT value, and generate a control signal according to the comparison result;

[0048] The control system is further used to send the control signal to the oil control valve to control the position of the oil control valve.

[0049] The above vehicle VVT desired value calculation method, vehicle control method and vehicle engine system detect the fuel supply state and rotational speed of the vehicle engine, and trigger the calculation of the desired VVT value under different working conditions when it is detected that the engine is not out of fuel and the rotational speed of the engine is less than the rotational speed threshold, including the calculation of the desired VVT value under the idle condition and the calculation of the desired VVT value under the non-idle condition. Further, according to the VVT desired value compensation coefficients of the engine in the cold engine mode, catalytic heating mode and scavenging mode respectively, the desired VVT values under different working conditions are corrected, which is beneficial to the effective adjustment of VVT, so that the engine can obtain a higher charging efficiency, improve the power performance of the engine, and effectively control emissions. Description of the Drawings

[0050] Figure 1 It is a hardware structure block diagram of the terminal in an embodiment;

[0051] Figure 2 It is a schematic diagram of the key angles of the intake / exhaust VVT control in an embodiment;

[0052] Figure 3 It is a schematic diagram of the structure of the intake / exhaust system in an embodiment;

[0053] Figure 4 It is a schematic diagram of the valve timing in an embodiment;

[0054] Figure 5 It is a flowchart of the vehicle VVT desired value calculation method in an embodiment;

[0055] Figure 6 It is a schematic diagram of the change of the catalytic heating state in an embodiment;

[0056] Figure 7 It is a schematic diagram of the engine scavenging in an embodiment;

[0057] Figure 8 It is a schematic diagram of the calculation process of the intake VVT desired value in an embodiment;

[0058] Figure 9 It is a schematic diagram of the calculation process of the exhaust VVT desired value in an embodiment;

[0059] Figure 10 It is a schematic structural diagram of a vehicle engine system in an embodiment;

[0060] Figure 11 It is a flowchart of a vehicle control method in an embodiment;

[0061] Figure 12 It is a schematic structural diagram of a VVT system in an embodiment. Detailed implementation manners

[0062] In order to make the objectives, technical solutions and advantages of the present application clearer and more understandable, the present application will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0063] Unless otherwise defined, the technical terms or scientific terms involved in the present application shall have the general meanings understood by those with ordinary skills in the technical field to which the present application belongs. In the present application, words such as "a", "one", "a kind of", "the", "these" and the like do not represent a limitation in quantity, and they can be singular or plural. The terms "including", "comprising", "having" and any variants thereof involved in the present application are intended to cover non-exclusive inclusion; for example, a process, method, system, product or device including a series of steps or modules (units) is not limited to the listed steps or modules (units), but may include unlisted steps or modules (units), or may include other steps or modules (units) inherent in these processes, methods, products or devices. The terms "connected", "coupled" and the like involved in the present application are not limited to physical or mechanical connections, but may include electrical connections, whether directly or indirectly. The term "plurality" involved in the present application means two or more. "And / or" describes the association relationship of associated objects and indicates that three relationships may exist. For example, "A and / or B" may represent: A exists alone, A and B exist simultaneously, and B exists alone. Usually, the character " / " indicates that the objects associated before and after are in an "or" relationship. The terms "first", "second", "third" and the like involved in the present application are only used to distinguish similar objects and do not represent a specific sorting of the objects.

[0064] The method embodiments provided in this embodiment can be executed on a terminal, a computer or a similar computing device. For example, running on a terminal, Figure 1 is a hardware structure block diagram of a terminal in an embodiment of the present application, which can execute the vehicle VVT expected value calculation method and / or the vehicle control method. As Figure 1 shown, the terminal may include one or more ( Figure 1Only one processor 101 and a memory 102 for storing data are shown, where the processor 101 may include, but is not limited to, a processing device such as a microprocessor MCU or a programmable logic device FPGA. The above terminal may further include a transmission device 103 for communication functions and an input / output device 104. Those of ordinary skill in the art can understand that Figure 1 The structure shown is only illustrative and does not limit the structure of the above terminal. For example, the terminal may further include more or fewer components than Figure 1 shown therein, or have a different configuration from Figure 1 that shown.

[0065] The memory 102 can be used to store computer programs, for example, software programs and modules of application software, such as the computer programs corresponding to the vehicle VVT expected value calculation method or the vehicle control method in this embodiment. The processor 101 executes various functional applications and data processing by running the computer programs stored in the memory 102, that is, implements the above methods. The memory 102 may include a high-speed random access memory and may also include a non-volatile memory, such as one or more magnetic storage devices, flash memories, or other non-volatile solid-state memories. In some instances, the memory 102 may further include a memory remotely set relative to the processor 101, and these remote memories can be connected to the terminal through a network. Examples of the above network include, but are not limited to, the Internet, an enterprise intranet, a local area network, a mobile communication network, and combinations thereof.

[0066] The transmission device 103 is used to receive or send data via a network. The above network includes a wireless network provided by the communication provider of the terminal. In one instance, the transmission device 103 includes a network adapter (Network Interface Controller, abbreviated as NIC), which can be connected to other network devices through a base station and thus can communicate with the Internet. In one instance, the transmission device 103 may be a radio frequency (RF) module, which is used to communicate with the Internet wirelessly.

[0067] In one embodiment, Figure 2 a schematic diagram of the key angles for intake / exhaust VVT control is provided, as Figure 2 shown, where the horizontal axis (X-axis) represents the crank angle (Crank Angle in Degrees), and the unit is degrees (°KW). The vertical axis (Y-axis) represents the valve lift (Valve Lifting [mm]), and the unit is millimeters (mm). The red curve represents the lift curve of the intake valve, and the blue curve represents the lift curve of the exhaust valve. The dashed line indicates the changes in the advance angle and the retard angle. Explanation of key terms:

[0068] Top Dead Centre(TDC): The highest position of the piston in the cylinder, i.e., the top dead centre.

[0069] Inlet: Intake valve.

[0070] Outlet: Exhaust valve.

[0071] Advance: Advance angle, indicating the angle by which the valve opening time is advanced compared to the normal situation.

[0072] Retard: Retard angle, indicating the angle by which the valve opening time is retarded compared to the normal situation.

[0073] Different angular ranges are marked in the figure, and these ranges correspond to the advance and retard angles of the valves. For example, wnwsmna_w and wnwsme_w represent the advance and retard angles of the intake and exhaust valves respectively.

[0074] The arrows and boxes in the figure are used to indicate specific angular ranges and the corresponding valve actions. For example, WNW RAS and WNW RBO represent specific valve actions or states.

[0075] The reference point for intake / exhaust VVT selection is the exhaust top dead centre (TDC). The corresponding crankshaft angle at the exhaust top dead centre is 0 degrees. Before the exhaust top dead centre, the angle is negative, and after the exhaust top dead centre, the angle is positive. During the engine variable valve timing adjustment process, to ensure the charging efficiency and improve various engine performances, the intake valve can only open earlier and the exhaust valve can only close later. In the SPM system, the calculation reference point for the intake valve advance angle calculation is the maximum mechanical dead centre when the intake valve opens to 1 mm, i.e., Figure 2 wnwsmxe_w in it; the calculation reference point for the exhaust valve late closing angle calculation is the minimum mechanical dead centre when the exhaust valve closes to 1 mm, i.e., Figure 2 wnwsmn a_w in it.

[0076] The expected value of the intake VVT is the calculated angle relative to the exhaust top dead centre. To calculate the accurate intake valve advance angle, it needs to be converted based on the calculation reference point when the intake valve opens to 1 mm. The expected value GEVCtl_agSpExtIntk of the intake valve advance angle is:

[0077] GEVCtl_agSpExtIntk = wnwsmxe_w - sVcVVTiTar_an_Tar

[0078] The exhaust VVT expected value r is the calculated angle relative to the exhaust top dead center. Entering the underlying layer, in order to calculate the accurate intake valve advance angle, it needs to be converted based on the calculation reference point when the exhaust valve closes to 1 mm. The expected value of the exhaust valve late closing angle GEVCtl_agSpExtOutl is as follows:

[0079] GEVCtl_agSpExtOutl = wnwsmn a_w + sVcVVTeTar_an_Tar

[0080] Figure 3 A structural schematic diagram of the intake / exhaust system is provided. Figure 4 A valve timing schematic diagram is provided, as Figure 3 、 Figure 4 shown. When the engine is in the high-speed range, a working stroke of the engine only takes a few thousandths of a second. Such a short time often causes insufficient intake and incomplete exhaust of the engine, affecting the efficiency of the engine. Therefore, it is necessary to make up for the deficiencies of insufficient intake and incomplete exhaust by opening the valve early and closing it late. In this case, there will inevitably be a moment when the intake valve and the exhaust valve are both open, which is called the "valve overlap angle" in the valve timing. Combining Figure 3 and Figure 4 , the formula for calculating the valve overlap angle wnwvu_w formed by VVT is as follows:

[0081] wnwvu_w = wnwuea_w + wnwuee_w

[0082] In the formula, wnwuea_w - available exhaust valve late closing angle;

[0083] wnwuee_w - intake valve advance angle.

[0084] Based on the selected VVT characteristics, Figure 2 the description of the key angle values in

[0085] is shown in the following table.

[0086] Angle Name Description Value (CA) wnwsmna_w Expected minimum closing angle of exhaust camshaft (1mm) -11.2969 wnwsmxa_w Expected maximum closing angle of exhaust camshaft (1mm) 18.7031 wnwsmne_w Expected minimum opening angle of intake camshaft (1mm) -12.7031 wnwsmxe_w Expected maximum opening angle of intake camshaft (1mm) 37.2969

[0087] Among them, "CA" represents the angle of the camshaft (Cam Angle), and the same applies hereinafter.

[0088] Regarding the calculation of the VVT expected value, in one embodiment, as Figure 5 shown, a method for calculating the vehicle VVT expected value is provided. Taking the application of this method to the Figure 1 terminal as an example for illustration, it includes the following steps:

[0089] Step S101, determine whether the engine of the vehicle is in the fuel cut-off state.

[0090] Step S102: When it is determined that the engine is not in the fuel cut-off state, determine whether the engine speed is less than the speed threshold value.

[0091] Step S103: When it is determined that the engine speed is less than the speed threshold value, calculate the VVT expected values of the engine under the idle condition and the non-idle condition respectively, and correct the VVT expected values according to the VVT expected value compensation coefficients of the engine under the cold engine mode, the catalytic heating mode, and the scavenging mode respectively.

[0092] In this step, the VVT expected value can be the intake VVT expected value (including the idle intake VVT expected value and the non-idle intake VVT expected value), or the exhaust VVT expected value (including the idle exhaust VVT expected value and the non-idle exhaust VVT expected value). The VVT expected value compensation coefficients of the engine under the cold engine mode, the catalytic heating mode, and the scavenging mode can be determined based on the look-up table method, and then the VVT expected values are corrected according to the respective VVT expected value compensation coefficients. The calculation of the VVT expected value compensation coefficients is triggered by the engine speed and the engine speed threshold value. When the engine speed is less than the engine speed threshold value, the calculation of the VVT expected value compensation coefficient function will be activated. Among them, the calculation methods of the respective VVT expected value compensation coefficients are as follows:

[0093] (1) Cold engine mode: Generate a cold engine compensation coefficient table according to the engine start completion time and the heater's compensation for the coolant temperature.

[0094] The cold engine compensation coefficient includes the cold engine intake VVT expected value compensation coefficient and the cold engine exhaust VVT expected value compensation coefficient. The cold engine compensation coefficient can be obtained by calculating the characteristic curve z_COLDWGHT, and this characteristic curve is related to the engine start completion time and the heater's compensation for the coolant temperature. For the cold engine intake VVT expected value compensation coefficient, the data for constructing the characteristic curve z_COLDWGHT1 is shown in Table 1-1, where x represents the engine start completion time and y represents the heater's compensation for the coolant temperature.

[0095] Table 1-1

[0096] y\x 0.0000 5.0000 30.0000 90.0000 150.0000 300.0000 -20.0000 1.0000 1.0000 1.0000 1.0000 1.0000 0.0000 -10.0000 1.0000 1.0000 1.0000 1.0000 0.0000 0.0000 10.0000 1.0000 1.0000 1.0000 0.0000 0.0000 0.0000 40.0000 1.0000 1.0000 0.0000 0.0000 0.0000 0.0000 50.0000 1.0000 0.0000 0.0000 0.0000 0.0000 0.0000 100.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000

[0097] For the cold engine exhaust VVT expected value compensation coefficient, the data for constructing the characteristic curve z_COLDWGHT2 is shown in Table 1-2, where x represents the engine start completion time and y represents the heater's compensation for the coolant temperature.

[0098] Table 1-2

[0099] y\x 0.0000 5.0000 30.0000 60.0000 90.0000 120.0000 -20.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 -10.0000 0.5000 0.5000 0.5000 0.5000 0.0000 0.0000 10.0000 1.0000 1.0000 1.0000 1.0000 0.0000 0.0000 40.0000 1.0000 1.0000 1.0000 1.0000 0.0000 0.0000 50.0000 1.0000 1.0000 0.0000 0.0000 0.0000 0.0000 100.0000 1.0000 1.0000 0.0000 0.0000 0.0000 0.0000

[0100] (2) Catalytic heating mode: Determine the temperature compensation characteristic curve based on the engine oil temperature and the compensation of the coolant temperature by the heater, and determine the catalytic heating coefficient compensation characteristic curve based on the catalytic heating coefficient. Generate a catalytic heating compensation coefficient table according to the temperature compensation characteristic curve and the catalytic heating coefficient compensation characteristic curve.

[0101] The catalytic heating compensation coefficient includes the catalytic heating intake VVT expected value compensation coefficient and the catalytic heating exhaust VVT expected value compensation coefficient. The calculation formula for the catalytic heating compensation coefficient (fac_ColdWght1) is as follows:

[0102] fac_ColdWght = z_TCMP × z_CATWGHT

[0103] In the formula:

[0104] z_TCMP - The temperature compensation characteristic curve, which depends on the engine oil temperature and the coolant temperature compensation;

[0105] z_CATWGHT - The catalytic heating coefficient compensation characteristic curve, which depends on the catalytic heating coefficient (Z_CatHeatIdx).

[0106] The data for constructing the temperature compensation characteristic curve z_TCMP is shown in Table 2-1, where x represents the engine oil temperature and y represents the coolant temperature compensation.

[0107] Table 2-1

[0108] y\x -20.000 -10.000 10.000 40.000 50.000 100.000 -20.000 0.0000 0.2998 0.2998 0.2998 0.2998 0.2998 -10.000 0.0000 0.5000 0.5000 0.5000 0.5000 0.5000 10.000 0.0000 0.5039 1.0000 1.0000 1.0000 1.0000 40.000 0.0000 0.5000 1.0000 1.0000 1.0000 1.0000 50.000 0.0000 0.5000 1.0000 1.0000 1.0000 1.0000 100.000 0.0000 0.5000 1.0000 1.0000 1.0000 1.0000

[0109] The data for constructing the catalytic heating coefficient compensation characteristic curve z_CATWGHT is shown in Table 2-2, where x represents the catalytic heating coefficient and z represents the catalytic heating coefficient compensation characteristic curve.

[0110] Table 2-2

[0111] x 0.0000 0.1250 0.2250 1.0000 1.4000 1.9900 z 1.0000 1.0000 1.0000 1.0000 1.0000 1.0000

[0112] Among them, the catalytic heating coefficient Z_CatHeatIdx characterizes the catalytic heating process. Figure 6 A schematic diagram of the change in the catalytic heating state is provided, as Figure 6As shown, the catalytic heating process (CatHeat Process) has three states. Status0 represents the cold state, i.e., the catalyst is not heated and the catalyst temperature is 0°C; Status1 represents catalytic ignition, i.e., the catalyst reaches the combustion critical temperature and the catalyst temperature is around 300°C; Status 2 represents the completion of catalytic heating, i.e., the catalyst is working normally and the catalyst temperature is around 500°C. The compensation coefficient corresponding to the MAP table z_CATWGHT can be set according to the change of the catalytic heating state. Figure 6 Explanation of related terms is as follows:

[0113] catalyst supported on a ceramic bloc—catalyst used on a ceramic block;

[0114] OUT--Output;

[0115] IN--Input;

[0116] No Heat(0℃)--No heating (0 degrees Celsius);

[0117] Light Off(300℃)--Ignition (300 degrees Celsius);

[0118] CatHeat Process--Catalytic heat process;

[0119] Heat Done(500℃)--Heating completed (500 degrees Celsius);

[0120] H2O--Water

[0121] CO2--Carbon dioxide;

[0122] N2--Nitrogen;

[0123] CO--Carbon monoxide;

[0124] C x H y --Hydrocarbon;

[0125] NOx--Nitrogen oxides.

[0126] (3) Scavenging mode: Determine the scavenging temperature compensation characteristic curve according to the compensation of the expected value of VVT and the overheat coefficient for emission protection when the exhaust temperature is too high, and determine the pressure ratio coefficient compensation characteristic curve according to the pressure ratio coefficient and the engine speed. Generate the scavenging compensation coefficient table according to the scavenging temperature compensation characteristic curve and the pressure ratio coefficient compensation characteristic curve.

[0127] Figure 7 A schematic diagram of engine scavenging is provided, as Figure 7As shown, this figure illustrates the working principle of Variable Valve Timing (VVT) in an engine. The term explanations are as follows:

[0128] VVT Work: Variable Valve Timing operation; scavenging: scavenging; Mass flow through inlet valve: mass flow through the intake valve; Exhaust air mass flow: exhaust air mass flow. Among them, the green arrows indicate the opening directions of the intake and exhaust valves, and the red arrows indicate the gas flow directions during the scavenging process.

[0129] The so-called scavenging refers to using a specific valve overlap angle. During the valve opening overlap period, due to the pressure difference between the intake and exhaust, fresh air directly flows from the intake manifold to the exhaust manifold. Therefore, the necessary conditions for scavenging are: (1) The engine has a valve overlap angle; (2) The intake pressure is greater than the exhaust pressure. The valve overlap angle during scavenging is achieved by advancing the opening of the intake valve and delaying the closing of the exhaust valve. During the valve opening overlap period, the intake, exhaust, and in-cylinder pressure states will have different effects on the engine's gas exchange method. During the valve overlap duration, if the pressures in the intake and exhaust manifolds are comparable, while fresh air enters the cylinder, part of the exhaust gas may flow back into the cylinder from the exhaust port, forming internal EGR; if at this time the pressure in the intake manifold is lower than that in the exhaust manifold, the exhaust gas may flow back into the intake manifold, and due to the cooling effect of the intake air, carbon deposits may form at the intake valve and other places. When there is a positive pressure difference between the intake and exhaust manifolds, scavenging can be achieved, using fresh air to discharge the residual exhaust gas in the cylinder and reducing the amount of residual exhaust gas in the cylinder. At low loads, affected by the throttling at the throttle valve, the intake pressure is usually less than the exhaust pressure, not meeting the scavenging conditions. At high loads, as the engine speed increases, the increased flow resistance causes the exhaust pressure to rise, becoming greater than the intake pressure, also not meeting the scavenging conditions. Only in the high-load and low-speed range, the pressure difference between the intake and exhaust may be positive, which is suitable as the scavenging operating condition.

[0130] In this embodiment, the scavenging compensation coefficient (fac_ScavWght) includes the scavenging intake VVT expected value compensation coefficient and the scavenging exhaust VVT expected value compensation coefficient. The scavenging compensation coefficient can be calculated according to the characteristic curve z_ScavTempCmp and the characteristic curve z_PWght. Among them, the characteristic curve z_ScavTempCmp is used to compensate the expected angle of the intake VVT when the exhaust temperature is too high, and this characteristic curve is related to the emission protection overheat coefficient rt_EnrTx. The value of rt_EnrTx is used to limit the temperatures of the exhaust and catalytic heating. If this overheat coefficient exceeds the given threshold, the torque will be reduced accordingly to ensure the combustion stability. The characteristic curve z_PWght is related to the pressure ratio coefficient rt_InExPres and the engine speed, where the pressure ratio coefficient rt_InExPres is the ratio between the intake manifold pressure and the modeled pressure of the exhaust manifold.

[0131] The data for constructing the characteristic curve z_PWght is shown in Table 3-1, where x represents the engine speed and y represents the pressure ratio coefficient.

[0132] Table 3-1

[0133] y\x 1000.0 1300.0 1600.0 1800.0 2000.0 2500.0 0.5000 0.099 0.099 0.099 0.099 0.099 0.099 0.8000 0.099 0.099 0.099 0.099 0.099 0.099 0.9000 0.099 0.099 0.099 0.099 0.099 0.099 1.0000 0.099 0.099 0.099 0.099 0.099 0.099 1.1000 0.099 0.099 0.099 0.099 0.099 0.099 1.3000 0.099 0.099 0.099 0.099 0.099 0.099

[0134] For the scavenging intake VVT expected value compensation coefficient, the data for constructing the characteristic curve z_ScavTempCmp1 is shown in Table 3-2, where x represents the emission protection overheat coefficient and z represents the scavenging intake VVT expected value compensation coefficient.

[0135] Table 3-2

[0136] x 0.0000 0.1000 0.2000 0.3000 0.4000 0.5000 1.0000 2.0000 z 0.299 0.400 0.500 0.599 0.700 0.799 0.900 1.000

[0137] For the scavenging exhaust VVT expected value compensation coefficient, the data for constructing the characteristic curve z_ScavTempCmp2 is shown in Table 3-3, where x represents the scavenging intake VVT expected value compensation coefficient and y represents the scavenging exhaust VVT expected value compensation coefficient.

[0138] Table 3-3

[0139] x 0.0000 0.1000 0.2000 0.3000 0.4000 0.5000 1.0000 2.0000 z 0.099 0.299 0.400 0.500 0.599 0.700 0.799 1.000

[0140] Among them, the calculation formula for the scavenging compensation coefficient fac_ScavWght is as follows:

[0141] fac_ScavWght = z_ScavTempCmp × z_PWght

[0142] The calculation of the triggered scavenging compensation coefficient fac_ScavWght depends on the following conditions:

[0143] (1) No VVT fault occurs;

[0144] (2) The driving mode request is not equal to 1, that is, the ECO-plus mode is not selected or there is no scavenging for the ECO mode request. The calculation of the scavenging compensation coefficient fac_ScavWght needs to meet the above conditions at the same time, otherwise the scavenging compensation coefficient fac_ScavWght = 0.

[0145] In the above steps S101 to S103, by detecting the fuel supply state and rotational speed of the vehicle engine, when it is detected that the engine is not fuel cut off and the rotational speed of the engine is less than the rotational speed threshold, the calculation of the VVT expected value for different working conditions is triggered, including the calculation of the VVT expected value under the idle condition and the calculation of the VVT expected value under the non-idle condition. Further, according to the VVT expected value compensation coefficients of the engine in the cold engine mode, catalytic heating mode, and scavenging mode respectively, the VVT expected values under different working conditions are corrected, which is beneficial to effectively adjust the VVT, so that the engine obtains a higher charging efficiency, improves the power performance of the engine, and effectively controls emissions.

[0146] In the following some embodiments, the calculation processes of the intake VVT expected value and the exhaust VVT expected value of the engine are introduced respectively for the working conditions of whether the engine is fuel cut off and whether idle is triggered.

[0147] In one embodiment, Figure 8 A schematic diagram of the calculation process of the intake VVT expected value is provided, as Figure 8 shown. This process includes the following steps:

[0148] Step S201, determine whether the engine is in a fuel cut off state; if not, execute step S202; if so, execute step S212.

[0149] Step S202, determine whether the rotational speed of the engine is less than the rotational speed threshold; if so, execute step S203; if not, end the process.

[0150] Step S203, determine whether the engine triggers the idle condition; if so, execute step S204; if not, execute step S208.

[0151] Step S204, calculate the intake VVT expected value of the engine. Among them, the intake VVT expected value respectively includes the catalytic heating intake VVT expected value, the cold engine intake VVT expected value, and the warm-up idle intake VVT expected value.

[0152] Step S205, obtain each intake VVT expected value compensation coefficient and correct the intake VVT expected value. Among them, the intake VVT expected value compensation coefficient respectively includes the catalytic heating compensation coefficient and the cold engine compensation coefficient. This step includes:

[0153] Subtract the catalytic heating intake VVT expected value from the warm-up idle intake VVT expected value, multiply the obtained difference by the catalytic heating compensation coefficient, and add the obtained product to the warm-up idle intake VVT expected value to obtain the catalytic heating idle intake VVT expected value; subtract the cold engine intake VVT expected value from the warm-up idle intake VVT expected value, multiply the obtained difference by the cold engine compensation coefficient, and add the obtained product to the warm-up idle intake VVT expected value to obtain the cold engine idle intake VVT expected value; compare the catalytic heating idle intake VVT expected value with the cold engine idle intake VVT expected value, and take the smaller of them as the corrected idle intake VVT expected value.

[0154] Specifically, the calculation formula for the expected value an_IdlePreSm of the idle intake VVT is as follows:

[0155] an_IdlePreSm = min(an_IdleCatLim, an_IdleColdLim);

[0156] an_IdleCatLim = (an_CaTIdle - an_IdleWarm) × fac_CatWght + an_IdleWarm;

[0157] an_IdleColdLim = (an_ColdIdle - an_IdleWarm) × fac_ColdWght + an_IdleWarm.

[0158] In the formula:

[0159] an_CaTIdle - The characteristic curve for calculating the expected value in the catalytic heating mode (i.e., the catalytic heating intake VVT expected value), which depends on the engine speed and load;

[0160] an_ColdIdle - The characteristic curve for calculating the expected value in the cold engine mode (i.e., the cold engine intake VVT expected value), which depends on the engine speed and load;

[0161] fac_CatWght - The catalytic heating compensation coefficient;

[0162] fac_ColdWght - The cold engine compensation coefficient;

[0163] an_IdleWarm - The warm-up idle intake VVT expected value;

[0164] an_IdleCatLim - The catalytic heating idle intake VVT expected value;

[0165] an_IdleColdLim - The expected value of VVT for cold engine idle intake air.

[0166] Among them, the expected value of VVT for warm engine idle intake air, an_IdleWarm, can be calculated by looking up a MAP table. When the vehicle selects to enter the sport mode, the calculation of the expected value of intake VVT at this time depends on the characteristic curve an_IdleSptMod; otherwise, the calculation of the expected value of intake VVT depends on the characteristic curve an_BaseIdle. Among them, the characteristic curves an_BasIdle and an_IdleSptMod respectively represent the expected values of VVT for intake air during engine warm-up idle and vehicle sport mode idle, and the two characteristic curves are related to the engine speed and engine load.

[0167] The data for constructing the characteristic curve an_BasIdle is shown in Table 4-1, where x represents the engine speed and y represents the engine load.

[0168] Table 4-1

[0169] y\x 400.00 900.00 1200.00 1500.00 1800.0 2100.0 2500.0 3250.00 60.00 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 3.0000 85.00 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 3.0000 116.00 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 3.0000 165.00 0.0000 0.0000 0.0000 0.0000 0.0000 2.6269 1.9942 2.4687 200.00 0.0000 0.0000 0.0000 0.0000 0.0000 4.6914 3.4824 2.0878 301.00 0.0000 0.0000 0.0000 0.0000 0.0000 10.648 7.9402 4.7421 375.00 0.0000 0.0000 0.0000 0.0000 0.0000 15.011 11.140 6.6875

[0170] The data for constructing the characteristic curve an_IdleSptMod is shown in Table 4-2, where x represents the engine speed and y represents the engine load.

[0171] Table 4-2

[0172] y\x 400.00 900.00 1200.00 1500.00 1800.0 2100.0 2500.0 3250.00 3400.00 60.00 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 3.0000 6.0000 85.00 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 3.0000 6.0000 116.00 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 3.0000 6.0000 165.00 0.0000 0.0000 0.0000 0.0000 0.0000 2.6269 1.9942 2.4687 3.6035 200.00 0.0000 0.0000 0.0000 0.0000 0.0000 4.6914 3.4824 2.0878 1.8906 301.00 0.0000 0.0000 0.0000 0.0000 0.0000 10.648 7.9042 4.7421 4.2929 375.00 0.0000 0.0000 0.0000 0.0000 0.0000 15.011 11.140 6.6875 6.6875 455.00 0.0000 0.0000 0.0000 0.0000 0.0000 19.734 14.644 7.9550 7.9550

[0173] In some embodiments, after obtaining the corrected expected value of VVT for idle intake air, saturation processing is performed on the corrected expected value of VVT for idle intake air to limit the excessive change in the gradient of the corrected expected value of VVT for idle intake air. Specifically, add the expected value of VVT for idle intake air at the previous moment and the increase rate of the expected value of VVT for intake air to obtain the upper limit value of the VVT expectation; subtract the expected value of VVT for idle intake air at the previous moment and the decrease rate of the expected value of VVT for intake air to obtain the lower limit value of the VVT expectation; when the expected value of VVT for idle intake air at the current moment is greater than the upper limit value of the VVT expectation, update the expected value of VVT for idle intake air at the current moment according to the upper limit value of the VVT expectation; or, when the expected value of VVT for idle intake air at the current moment is less than the lower limit value of the VVT expectation, update the expected value of VVT for idle intake air at the current moment according to the lower limit value of the VVT expectation.

[0174] The specific calculation formula is as follows:

[0175] an_IncRate + an_Idle(n - 1) ≥ an_IdlePreSm(n) ≥ an_Idle(n - 1) - an_DecRate;

[0176] an_IdlePreSm(n) = an_Idle(n).

[0177] Where:

[0178] an_Idle(n - 1) - - The expected value of the idle intake VVT at the previous moment;

[0179] an_IncRate - - The MAP table, representing the increase rate of the expected value of the intake VVT, which is related to the time after starting;

[0180] an_DecRate - - The decrease rate of the expected value of the intake VVT;

[0181] an_Idle(n) - - The expected value of the idle intake VVT at the current moment after saturation processing;

[0182] an_IdlePreSm(n) - - The expected value of the idle intake VVT at the current moment without saturation processing.

[0183] In one embodiment, in order to prevent engine jitter caused by the rapid change of the expected value of the intake VVT after starting is completed, a corresponding delay process is performed on the expected value of the intake VVT an_Idle under the idle condition. Specifically, when the time count after the engine starting is completed is less than the delay time t_AftStrtDly, an_Idle = 0; otherwise an_Idle = an_IdlePreSm.

[0184] Step S206, calculate the VVT limit angle. Determine the VVT limit angle according to the engine speed and the engine oil temperature. When the engine speed is less than the engine speed threshold, trigger the calculation of the VVT limit angle to prevent the expected value of the intake VVT from being set too large in the engine condition or driving condition, and reduce the impact on the engine's charging efficiency. The VVT limit angle can be calculated according to the characteristic curve an_MaxGuard, which is a function of the engine speed and the engine oil temperature. The lower the oil temperature, the greater the viscosity and the worse the fluidity. At a lower oil temperature, a smaller VVT limit angle is set. The data for constructing the characteristic curve an_MaxGuard limit angle is shown in Table 5, where x represents the engine speed and y represents the engine oil temperature.

[0185] Table 5

[0186] y\x 500.00 800.00 1000.0 1250.0 1500.0 2000.0 4000.0 6000.0 -30.00 30.000 30.000 30.000 30.000 30.000 30.000 30.000 30.000 -10.00 30.000 30.000 30.000 30.000 30.000 30.000 30.000 30.000 0.000 30.000 30.000 30.000 30.000 30.000 30.000 30.000 30.000 35.000 35.000 35.000 35.000 35.000 35.000 35.000 35.000 35.000 40.000 50.000 50.000 50.000 50.000 50.000 50.000 50.000 50.000 60.000 50.000 50.000 50.000 50.000 50.000 50.000 50.000 50.000 130.00 50.000 50.000 50.000 50.000 50.000 50.000 50.000 50.000 140.00 50.000 50.000 50.000 50.000 50.000 50.000 50.000 50.000 150.00 50.000 50.000 50.000 50.000 50.000 50.000 50.000 50.000

[0187] Step S207, compare the corrected expected value of the idle intake VVT with the VVT limit angle, and take the smaller one as the final expected value of the idle intake VVT.

[0188] Step S208, calculate the intake VVT expected value of the engine. The intake VVT expected values respectively include the catalytic heating intake VVT expected value, the cold engine intake VVT expected value, and the scavenging intake VVT expected value. Among them, the calculation method of the scavenging intake VVT expected value is as follows:

[0189] Obtain the warm engine intake VVT expected value and the intake VVT expected value when the valve overlap is restricted; subtract the intake VVT expected value when the valve overlap is restricted from the warm engine intake VVT expected value, multiply the obtained difference by the scavenging compensation coefficient, and add the obtained product to the intake VVT expected value when the valve overlap is restricted to obtain the scavenging intake VVT expected value.

[0190] The scavenging intake VVT expected value an_BasAfrScav is related to the intake VVT expected value an_BasLim Overlap when the valve overlap is restricted, and the calculation formula is as follows:

[0191] an_BasAfrScav = ac_ScavWght × (an_Bas - an_BasLimOverlap) + an_BasLimOverlap.

[0192] In the formula:

[0193] an_Bas - The warm engine intake VVT expected value. The data for constructing this characteristic curve is shown in Table 6-1, where x represents the engine speed and y represents the engine load;

[0194] an_BasLimOverlap - The VVT expected value when the valve overlap is restricted;

[0195] fac_ScavWght - The scavenging intake VVT expected value compensation coefficient;

[0196] an_BasAfrScav - The scavenging intake VVT expected value.

[0197] Table 6-1

[0198] y\x 400.00 900.00 1200.00 1500.00 1800.00 2100.00 2500.00 3250.00 3400.00 4000.00 60.00 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 85.00 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 116.00 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 2.0000 7.0000 165.00 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 10.0000 7.0000 12.0000 200.00 0.0000 0.0000 5.0000 10.0000 5.0000 5.0000 5.0000 18.0000 20.0000 25.0000 301.00 0.0000 0.0000 10.0000 12.0000 15.0000 17.0000 25.0000 32.0000 34.0000 35.0000 375.00 0.0000 10.0000 20.0000 20.0000 25.0000 30.0000 35.0000 40.0000 40.0000 40.0000

[0199] Among them, the value of an_BasLimOverlap depends on the driving mode, and the driving mode includes 3 types: normal mode, economy mode, and sport mode. The sport mode is calculated by the characteristic curve an_SptModNoScav; in the economy mode, the value of an_BasLimOverlap is calculated by the characteristic curve an_EcoModNoScav; otherwise, the driving mode enters the normal mode and the characteristic curve an_BasNoScav is selected for calculation. The characteristic curve is related to the engine speed and load and is mainly for the engine non-scavenging working mode.

[0200] The data for constructing the characteristic curve an_EcoModNoScav is shown in Table 6-2, where x represents the engine speed and y represents the engine load.

[0201] Table 6-2

[0202] y\x 400.00 900.00 1200.00 1500.00 1800.00 2100.00 2500.00 3250.00 3400.00 60.00 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 85.00 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 116.00 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 2.0000 165.00 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 10.0000 7.0000 200.00 0.0000 0.0000 5.0000 10.0000 5.0000 5.0000 5.0000 18.0000 20.0000 301.00 0.0000 10.0000 10.0000 12.0000 15.0000 17.0000 25.0000 32.0000 34.0000 375.00 0.0000 10.0000 20.0000 20.0000 25.0000 30.0000 35.0000 40.0000 40.0000

[0203] The data for constructing the characteristic curve an_SptModNoScav is shown in Table 6-3, where x represents the engine speed and y represents the engine load.

[0204] Table 6-3

[0205] y\x 400.00 900.00 1200.00 1500.00 1800.00 2100.00 2500.00 3250.00 3400.00 60.00 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 85.00 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 116.00 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 2.0000 165.00 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 10.0000 7.0000 200.00 0.0000 0.0000 5.0000 10.0000 5.0000 5.0000 5.0000 18.0000 20.0000 301.00 0.0000 10.0000 10.0000 12.0000 15.0000 17.0000 25.0000 32.0000 34.0000 375.00 0.0000 10.0000 20.0000 20.0000 25.0000 30.0000 35.0000 40.0000 40.0000

[0206] Step S209: Obtain the compensation coefficients for each intake VVT expected value and correct the intake VVT expected value. The compensation coefficients for the intake VVT expected value include a catalytic heating compensation coefficient and a cold engine compensation coefficient respectively. This step includes:

[0207] Subtract the catalytic heating intake VVT expected value from the scavenging intake VVT expected value, multiply the obtained difference by the catalytic heating compensation coefficient, and add the obtained product to the scavenging VVT base expected value to obtain the non-idle catalytic heating intake VVT expected value; subtract the cold engine intake VVT expected value from the scavenging intake VVT expected value, multiply the obtained difference by the cold engine compensation coefficient to obtain a fourth product, and add the obtained product to the scavenging intake VVT expected value to obtain the non-idle cold engine intake VVT expected value; compare the non-idle catalytic heating intake VVT expected value with the non-idle cold engine intake VVT expected value, and take the smaller of them as the corrected non-idle intake VVT expected value.

[0208] The calculation formula for the non-idle intake VVT expected value an_OffIdle is as follows:

[0209] an_OffIdle = min(A, B);

[0210] A = fac_CatWght × (an_CaT - an_BasAfrScav) + an_BasAfrScav;

[0211] B = fac_ColdWght × (an_Cold - an_BasAfrScav) + an_BasAfrScav.

[0212] In the formula:

[0213] fac_CatWght - Catalytic heating compensation coefficient;

[0214] fac_ColdWght - Cold engine compensation factor;

[0215] an_CAT - Desired value of catalytic heating intake VVT. The data for constructing this characteristic curve is shown in Table 7-1, where x represents the engine speed and y represents the target load;

[0216] an_Cold - Desired value of intake VVT in cold engine mode. The data for constructing this characteristic curve is shown in Table 7-2, where x represents the engine speed and y represents the target load;

[0217] an_BasAfrScav - Basic desired value of intake VVT during scavenging. The data for constructing this characteristic curve is shown in Table 7-3, where x represents the engine speed and y represents the target load.

[0218] Table 7-1

[0219] y\x 400.00 900.00 1200.00 1500.00 1800.00 2100.00 2500.00 3250.00 3400.00 4000.00 60.00 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 85.00 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 116.00 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 2.0000 7.0000 165.00 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 10.0000 7.0000 12.0000 200.00 0.0000 0.0000 50.0000 10.0000 10.0000 10.0000 12.0000 18.0000 20.0000 25.0000 301.00 0.0000 10.0000 10.0000 12.0000 15.0000 15.0000 20.0000 25.0000 34.0000 35.0000 375.00 0.0000 10.0000 20.0000 20.0000 20.0000 25.0000 30.0000 35.0000 40.0000 40.0000

[0220] Table 7-2

[0221] y\x 400.00 900.00 1200.00 1500.00 1800.00 2100.00 2500.00 3250.00 60.00 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 85.00 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 116.00 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 165.00 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 5.0000 200.00 0.0000 0.0000 0.0000 5.0000 0.0000 0.0000 0.0000 13.0000 301.00 0.0000 5.0000 5.0000 7.0000 10.0000 12.0000 20.0000 27.0000 375.00 0.0000 5.0000 15.0000 15.0000 20.0000 25.0000 30.0000 35.0000

[0222] Table 7-3

[0223] y\x 400.00 900.00 1200.00 1500.00 1800.00 2100.00 2500.00 3250.00 3400.00 60.00 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 85.00 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 116.00 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 2.0000 165.00 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 10.0000 7.0000 200.00 0.0000 0.0000 5.0000 10.0000 5.0000 5.0000 5.0000 18.0000 20.0000 301.00 0.0000 10.0000 10.0000 12.0000 15.0000 17.0000 25.0000 32.0000 34.0000 375.00 0.0000 10.0000 20.0000 20.0000 25.0000 30.0000 35.0000 40.0000 40.0000

[0224] Step S210, calculate the VVT limit angle. Specifically, determine the VVT limit angle according to the engine speed and the engine oil temperature.

[0225] Step S211, compare the corrected non-idle intake VVT desired value with the VVT limit angle, and take the smaller one as the final non-idle intake VVT desired value.

[0226] Step S212, determine whether the engine speed is less than the speed threshold; if so, execute Step S213; if not, end the process.

[0227] Step S213, determine the VVT limit angle according to the engine speed and the engine oil temperature.

[0228] Step S214, determine whether the engine triggers the idle condition; if so, execute Step S215; if not, execute Step S217.

[0229] Step S215, calculate the corrected idle intake VVT desired value. This step is similar to Step S205 for calculating the corrected idle intake VVT desired value above, and will not be elaborated here.

[0230] Step S216: Compare the corrected idle intake VVT expected value with the VVT limit angle, and take the smaller one as the final fuel cut-off idle intake VVT expected value.

[0231] Step S217: Calculate the corrected non-idle intake VVT expected value. This step is similar to Step S209 for calculating the corrected non-idle intake VVT expected value above, and will not be elaborated here.

[0232] Step S218: Compare the corrected non-idle intake VVT expected value with the VVT limit angle, and take the smaller one as the final fuel cut-off non-idle intake VVT expected value.

[0233] In Steps S212 to S218, in the fuel cut-off mode, when the engine speed is less than the engine speed threshold, trigger the calculation of the intake VVT expected value.

[0234] The calculation formula for the fuel cut-off idle intake VVT expected value an_TarLimd is as follows:

[0235] an_TarLimd = min(an_Lim, an_BasTar)

[0236] In the formula, the value of an_BasTar depends on whether the idle control flag bit is activated. When the idle control flag bit is activated, an_BasTar = an_Idle, that is, the corrected idle intake VVT expected value; otherwise, an_BasTar = an_OffIdle, that is, the corrected non-idle intake VVT expected value, and an_Lim is the VVT limit angle.

[0237] In the fuel cut-off mode, the calculation of the intake VVT expected value targets three fuel cut-off modes: Mode 1 is no fuel cut-off; Mode 2 is partial cylinder fuel cut-off; Mode 3 is full cylinder fuel cut-off, which is mainly related to the value of D_OverlapMod when there is valve overlap. In addition, when entering the second and third fuel cut-off modes, the intake VVT expected values are calculated by looking up the MAP tables an_PtlFuCut and an_FullFuCut respectively, and an_PtlFuCut and an_FullFuCut are related to the engine speed. The calculation of D_OverlapMod is determined by the flag bit B_Ena. When B_Ena = 1, D_OverlapMod = D_FCMod, and the fuel cut-off mode selection is entered. In this fuel cut-off mode, the VVT is triggered to form a valve overlap angle, which can help reduce emissions and fuel consumption during fuel cut-off recovery. The main reason is that during the valve overlap duration, the pressures in the intake and exhaust manifolds are quite similar. While fresh air enters the cylinder, part of the exhaust gas flows back into the cylinder from the intake port, forming internal EGR, and the air entering the catalyst decreases, and the oxygen storage capacity of the catalyst reduces. When the fuel cut-off is restored, only less fuel is needed to neutralize the oxygen in the catalyst, effectively reducing the release of NOx. Of course, this fuel cut-off method is only applicable to short-term fuel cut-off; when B_Ena = 0, D_OverlapMod = 1, that is, the fuel cut-off mode is not selected, and an_TarLimd is directly output as the intake VVT expected value.

[0238] The calculation of the fuel cut-off mode mainly depends on the fuel cut-off rate. The calculation of the fuel cut-off mode D_FCMod is shown in the following table:

[0239] Fuel Cut-off Mode Calculation Table

[0240]

[0241] In one embodiment, Figure 9 a schematic diagram of the calculation process of the exhaust VVT expected value is provided, as Figure 9 shown. This process includes the following steps:

[0242] Step S301, determine whether the engine is in the fuel cut-off state; if not, then execute Step S302; if so, then execute Step S312.

[0243] Step S302, determine whether the engine speed is less than the speed threshold; if so, then execute Step S303; if not, then end the process.

[0244] Step S303, determine whether the engine triggers the idle condition; if so, then execute Step S304; if not, then execute Step S308.

[0245] Step S304: Calculate the expected value of the exhaust VVT of the engine. The expected value of the exhaust VVT includes the expected value of the catalytic heating exhaust VVT, the expected value of the cold engine exhaust VVT, and the expected value of the warm engine idle exhaust VVT respectively.

[0246] Step S305: Obtain the compensation coefficients for each exhaust VVT expected value and correct the exhaust VVT expected value. The compensation coefficients for the exhaust VVT expected value include the catalytic heating compensation coefficient and the cold engine compensation coefficient respectively. This step includes:

[0247] Subtract the expected value of the catalytic heating exhaust VVT from the expected value of the warm engine idle exhaust VVT, multiply the obtained difference by the catalytic heating compensation coefficient, and add the obtained product to the expected value of the warm engine idle exhaust VVT to obtain the expected value of the catalytic heating idle exhaust VVT; subtract the expected value of the cold engine exhaust VVT from the expected value of the warm engine idle exhaust VVT, multiply the obtained difference by the cold engine compensation coefficient, and add the obtained product to the expected value of the warm engine idle exhaust VVT to obtain the expected value of the cold engine idle exhaust VVT; compare the expected value of the catalytic heating idle exhaust VVT with the expected value of the cold engine idle exhaust VVT, and take the smaller one as the corrected expected value of the idle exhaust VVT.

[0248] Specifically, the calculation formula for the expected value an_IdlePreSm of the idle exhaust VVT is as follows:

[0249] an_IdlePreSm = min(an_IdleCatLim, an_IdleColdLim);

[0250] an_IdleCatLim = (an_CaTIdle - an_IdleWarm) × fac_CatWght + an_IdleWarm;

[0251] an_IdleColdLim = (an_ColdIdle - an_IdleWarm) × fac_ColdWght + an_IdleWarm.

[0252] In the formula:

[0253] an_CaTIdle - The characteristic curve for calculating the expected value in the catalytic heating mode (i.e., the expected value of the catalytic heating exhaust VVT), which depends on the engine speed and load;

[0254] an_ColdIdle - The characteristic curve for calculating the expected value in the cold engine mode (i.e., the expected value of the cold engine exhaust VVT), which depends on the engine speed and load;

[0255] fac_CatWght - The catalytic heating compensation coefficient;

[0256] fac_ColdWght - Cold engine compensation factor;

[0257] an_IdleWarm - Expected value of exhaust VVT for warm-up idle speed;

[0258] an_IdleCatLim - Expected value of catalytic heating exhaust VVT for idle speed;

[0259] an_IdleColdLim - Expected value of exhaust VVT for cold engine idle speed.

[0260] Among them, the expected value of exhaust VVT for warm-up idle speed, an_IdleWarm, can be calculated by looking up a MAP table. When the vehicle selects to enter the sport mode, the calculation of the expected value of exhaust VVT at this time depends on the characteristic curve an_IdleSptMod; otherwise, the calculation of the expected value of exhaust VVT depends on the characteristic curve an_BaseIdle. Among them, the characteristic curve an_BasIdle and the characteristic curve an_IdleSptMod respectively represent the expected values of exhaust VVT for engine warm-up idle speed and vehicle sport mode idle speed, and the two characteristic curves are related to the engine speed and engine load.

[0261] The data for constructing the characteristic curve an_BasIdle is shown in Table 8-1, where x represents the engine speed and y represents the engine load.

[0262] Table 8-1

[0263] y\x 400.00 900.00 1200.00 1500.00 1800.00 2100.00 2500.00 3250.00 3400.00 4000.00 5000.00 40.00 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 4.0000 9.0000 10.875 14.000 60.00 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 4.0000 9.0000 10.875 14.000 85.00 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 4.0000 4.4863 6.4316 9.6757 116.00 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 1.6660 1.8691 2.6796 4.0312 165.00 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 200.00 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 301.00 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 375.00 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 455.00 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 531.00 8.4882 8.4882 8.4882 8.4882 7.1738 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 540.00 8.6601 8.6601 8.6601 8.6601 6.2988 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 560.00 9.0410 9.0410 9.0410 9.0410 6.5761 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 600.00 9.8007 9.8007 9.8007 9.8007 7.1289 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 800.00 11.000 11.000 11.000 11.000 8.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 1100.00 11.000 11.000 11.000 11.000 8.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000

[0264] The data for constructing the characteristic curve an_IdleSptMod is shown in Table 8-2, where x represents the engine speed and y represents the engine load.

[0265] Table 8-2

[0266] y\x 400.00 900.00 1200.00 1500.00 1800.00 2100.00 2500.00 3250.00 3400.00 40.00 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 4.0000 9.0000 85.00 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 4.0000 9.0000 116.00 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 4.0000 4.4863 165.00 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 1.6660 1.8691 200.00 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 301.00 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 375.00 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 455.00 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 531.00 8.4882 8.4882 8.4882 8.4882 6.1738 0.0000 0.0000 0.0000 0.0000 540.00 8.6601 8.6601 8.6601 8.6601 6.2988 0.0000 0.0000 0.0000 0.0000 560.00 9.0410 9.0410 9.0410 9.0410 6.5761 0.0000 0.0000 0.0000 0.0000 600.00 9.8007 9.8007 9.8007 9.8007 7.1289 0.0000 0.0000 0.0000 0.0000

[0267] In some embodiments, after obtaining the corrected expected value of exhaust VVT for idle speed, saturation processing is performed on the corrected expected value of exhaust VVT for idle speed to limit the excessive change in the gradient of the corrected expected value of exhaust VVT for idle speed. Specifically, add the expected value of exhaust VVT for the previous moment and the increase rate of the expected value of exhaust VVT to obtain the upper limit value of the VVT expectation; subtract the expected value of exhaust VVT for the previous moment and the decrease rate of the expected value of exhaust VVT to obtain the lower limit value of the VVT expectation; when the expected value of exhaust VVT for the current moment is greater than the upper limit value of the VVT expectation, update the expected value of exhaust VVT for the current moment according to the upper limit value of the VVT expectation; or, when the expected value of exhaust VVT for the current moment is less than the lower limit value of the VVT expectation, update the expected value of exhaust VVT for the current moment according to the lower limit value of the VVT expectation.

[0268] The specific calculation formula is as follows:

[0269] an_IncRate + an_Idle(n - 1) ≥ an_IdlePreSm(n) ≥ an_Idle(n - 1) - an_DecRate;

[0270] an_IdlePreSm(n) = an_Idle(n).

[0271] In the formula:

[0272] an_Idle(n - 1) —— The expected value of the idle exhaust VVT at the previous moment;

[0273] an_IncRate —— The MAP table, representing the increase rate of the expected value of the exhaust VVT, which is related to the time after starting. The data for constructing the increase rate an_IncRate of the expected value of the exhaust VVT is shown in Table 9, where x represents the time after starting and z represents the increase rate of the expected value of the exhaust VVT;

[0274] an_DecRate —— The decrease rate of the expected value of the exhaust VVT (90CA);

[0275] an_Idle(n) —— The expected value of the idle exhaust VVT at the current moment after saturation processing;

[0276] an_IdlePreSm(n) —— The expected value of the idle exhaust VVT at the current moment without saturation processing.

[0277] Table 9

[0278] x 0.0000 2.0000 3.0000 4.0000 8.0000 10.0000 z 88.945 88.945 88.945 88.945 88.945 88.945

[0279] In one embodiment, in order to prevent engine jitter caused by the rapid change of the expected value of the exhaust VVT after starting is completed, a corresponding delay process is performed on the expected value an_Idle of the idle condition exhaust VVT. Specifically, when the time count t_AftStaTx after the engine starting is completed is less than the delay time t_AftStrtDly, an_Idle = 0; otherwise an_Idle = an_IdlePreSm.

[0280] Step S306, calculate the VVT limit angle. Determine the VVT limit angle according to the engine speed and the engine oil temperature. When the engine speed is less than the engine speed threshold, trigger the calculation of the VVT limit angle to prevent the exhaust VVT expected value from being set too large in the engine operating conditions or driving conditions, and reduce the impact on the engine's charging efficiency. The VVT limit angle can be calculated according to the characteristic curve an_MaxGuard, which is a function of the engine speed and the engine oil temperature. The lower the oil temperature, the greater the viscosity and the worse the fluidity. At a lower oil temperature, a smaller VVT limit angle is set. The data for constructing the characteristic curve an_MaxGuard limit angle is shown in Table 10, where x represents the engine speed and y represents the engine oil temperature.

[0281] Table 10

[0282] y\x 500.00 800.00 1000.00 1250.00 1500.00 -30.00 0.0000 0.0000 0.0000 0.0000 0.0000 -10.00 15.0000 15.0000 15.0000 15.0000 15.0000 0.0000 30.0000 30.0000 30.0000 30.0000 30.0000 40.0000 30.0000 30.0000 30.0000 30.0000 30.0000 60.0000 30.0000 30.0000 30.0000 30.0000 30.0000 80.0000 30.0000 30.0000 30.0000 30.0000 30.0000 100.0000 30.0000 30.0000 30.0000 30.0000 30.0000 120.0000 30.0000 30.0000 30.0000 30.0000 30.0000 140.0000 30.0000 30.0000 30.0000 30.0000 30.0000 150.0000 30.0000 30.0000 30.0000 30.0000 30.0000

[0283] Step S307, compare the corrected idle exhaust VVT expected value with the VVT limit angle, and take the smaller one as the final idle exhaust VVT expected value.

[0284] Step S308, calculate the engine's exhaust VVT expected value. The exhaust VVT expected value includes the catalytic heating exhaust VVT expected value, the cold engine exhaust VVT expected value, and the scavenging exhaust VVT expected value respectively. Among them, the calculation method of the scavenging exhaust VVT expected value is as follows:

[0285] Obtain the warm-up exhaust VVT expected value and the exhaust VVT expected value when the valve overlap is restricted; subtract the exhaust VVT expected value when the valve overlap is restricted from the warm-up exhaust VVT expected value, multiply the obtained difference by the scavenging compensation coefficient, and add the obtained product to the exhaust VVT expected value when the valve overlap is restricted to obtain the scavenging exhaust VVT expected value.

[0286] The scavenging exhaust VVT expected value an_BasAfrScav is related to the exhaust VVT expected value an_BasLim Overlap when the valve overlap is restricted, and the calculation formula is as follows:

[0287] an_BasAfrScav = ac_ScavWght × (an_Bas - an_BasLimOverlap) + an_BasLimOverlap.

[0288] In the formula:

[0289] an_Bas - The warm-up exhaust VVT expected value;

[0290] an_BasLimOverlap - The VVT expected value when the valve overlap is restricted;

[0291] fac_ScavWght - Scavenging and Exhaust VVT Expected Value Compensation Coefficient;

[0292] an_BasAfrScav - Scavenging and Exhaust VVT Expected Value.

[0293] Among them, the value of an_BasLimOverlap depends on the driving mode, and there are 3 driving modes: normal mode, economy mode, and sport mode. The sport mode is calculated by the characteristic curve an_SptModNoScav; in the economy mode, the value of an_BasLimOverlap is calculated by the characteristic curve an_EcoModNoScav; otherwise, the driving mode enters the normal mode and selects the characteristic curve an_BasNoScav for calculation. Among them, the characteristic curve is related to the engine speed and load, mainly for the engine non-scavenging working mode.

[0294] Step S309, obtain each exhaust VVT expected value compensation coefficient and correct the exhaust VVT expected value. Among them, the exhaust VVT expected value compensation coefficients respectively include the catalytic heating compensation coefficient and the cold engine compensation coefficient, and this step includes:

[0295] Subtract the catalytic heating exhaust VVT expected value from the scavenging and exhaust VVT expected value, multiply the obtained difference by the catalytic heating compensation coefficient, and add the obtained product to the scavenging VVT base expected value to obtain the catalytic heating non-idle exhaust VVT expected value; subtract the cold engine exhaust VVT expected value from the scavenging and exhaust VVT expected value, multiply the obtained difference by the cold engine compensation coefficient to obtain a fourth product, and add the obtained product to the scavenging and exhaust VVT expected value to obtain the cold engine non-idle exhaust VVT expected value; compare the catalytic heating non-idle exhaust VVT expected value with the cold engine non-idle exhaust VVT expected value, and take the smaller one as the corrected non-idle exhaust VVT expected value.

[0296] The formula for the non-idle exhaust VVT expected value an_OffIdle is as follows:

[0297] an_OffIdle = min(A, B);

[0298] A = fac_CatWght × (an_CaT - an_BasAfrScav) + an_BasAfrScav;

[0299] B = fac_ColdWght × (an_Cold - an_BasAfrScav) + an_BasAfrScav.

[0300] In the formula:

[0301] fac_CatWght - Catalytic heating compensation coefficient;

[0302] fac_ColdWght - Cold engine compensation coefficient;

[0303] an_CAT - Expected value of catalytic heating exhaust VVT;

[0304] an_Cold - Expected value of cold engine mode exhaust VVT;

[0305] an_BasAfrScav - Basic expected value of exhaust VVT during scavenging.

[0306] Step S310, calculate the VVT limit angle. Specifically, determine the VVT limit angle according to the engine speed and engine oil temperature.

[0307] Step S311, compare the corrected non-idle exhaust VVT expected value with the VVT limit angle, and take the smaller one as the final non-idle exhaust VVT expected value.

[0308] Step S312, determine whether the engine speed is less than the speed threshold; if so, execute Step S313; if not, end the process.

[0309] Step S313, determine the VVT limit angle according to the engine speed and engine oil temperature.

[0310] Step S314, determine whether the engine triggers the idle condition; if so, execute Step S315; if not, execute Step S317.

[0311] Step S315, calculate the corrected idle exhaust VVT expected value. This step is similar to Step S305 for calculating the corrected idle exhaust VVT expected value, and will not be elaborated here.

[0312] Step S316, compare the corrected idle exhaust VVT expected value with the VVT limit angle, and take the smaller one as the final fuel cut-off idle exhaust VVT expected value.

[0313] Step S317, calculate the corrected non-idle exhaust VVT expected value. This step is similar to Step S209 for calculating the corrected non-idle exhaust VVT expected value, and will not be elaborated here.

[0314] Step S318, compare the corrected non-idle exhaust VVT expected value with the VVT limit angle, and take the smaller one as the final fuel cut-off non-idle exhaust VVT expected value.

[0315] In steps S312 to S318, in the fuel cut-off mode, when the engine speed is less than the engine speed threshold, the calculation of the expected value of the exhaust VVT is triggered.

[0316] The calculation formula for the expected value of the exhaust VVT at fuel cut-off idle speed an_TarLimd is as follows:

[0317] an_TarLimd = min(an_Lim, an_BasTar)

[0318] In the formula, the value of an_BasTar depends on whether the idle control flag bit is activated. When the idle control flag bit is activated, an_BasTar = an_Idle, that is, the corrected expected value of the exhaust VVT at idle speed; otherwise, an_BasTar = an_OffIdle, that is, the corrected expected value of the exhaust VVT at non-idle speed, and an_Lim is the VVT limit angle.

[0319] In the fuel cut-off mode, the calculation of the expected value of the exhaust VVT is for three fuel cut-off modes: Mode 1 is no fuel cut-off; Mode 2 is partial cylinder fuel cut-off; Mode 3 is full cylinder fuel cut-off for all cylinders. This is mainly related to the value of D_OverlapMod when there is valve overlap. In addition, when entering Fuel Cut-off Modes 2 and 3, the expected values of the exhaust VVT are calculated by looking up the MAP tables an_PtlFuCut and an_FullFuCut respectively. an_PtlFuCut and an_FullFuCut are related to the engine speed. The calculation of D_OverlapMod is determined by the flag bit B_Ena. When B_Ena = 1, D_OverlapMod = D_FCMod, and the fuel cut-off mode selection is entered. In this fuel cut-off mode, the VVT will be triggered to form a valve overlap angle, which can help reduce emissions and fuel consumption during fuel cut-off recovery. The main reason is that during the valve overlap duration, the pressures in the intake and exhaust manifolds are equivalent. While fresh air enters the cylinder, part of the exhaust gas flows back into the cylinder from the exhaust port, forming internal EGR, and the air entering the catalyst decreases, and the oxygen storage capacity of the catalyst decreases. When the fuel cut-off is restored, only less fuel is needed to neutralize the oxygen in the catalyst, effectively reducing the release of NOx. Of course, this fuel cut-off method is only applicable to short-term fuel cut-off; when B_Ena = 0, D_OverlapMod = 1, that is, the fuel cut-off mode is not selected, and an_TarLimd is directly output as the expected value of the exhaust VVT.

[0320] In one embodiment, Figure 10 A structural schematic diagram of a vehicle engine system is provided, as Figure 10As shown in the figure, the vehicle engine system includes: a control system, a sensing system, and an oil control valve. The control system is respectively connected to the sensing system and the oil control valve. Among them, the control system is used to calculate the actual VVT position of the engine and the expected VVT value required by the engine, compare the actual VVT position with the expected VVT value, and generate a control signal according to the comparison result. The control system is also used to send the control signal to the oil control valve to control the position of the oil control valve.

[0321] Among them, the control system includes an Engine Electronic Control Unit (Engine ECU) and an Engine Management System (Engine EMS). In this embodiment, Figure 11 A flowchart of a vehicle control method is provided. The process includes the following steps:

[0322] Step S401, the engine management system receives the first sensing data collected by the first sensing module in the vehicle, and calculates the actual VVT position of the engine according to the first sensing data.

[0323] The first sensing module includes, but is not limited to, a crankshaft position sensor and a cam position sensor.

[0324] Step S401, the engine electronic control unit receives the second sensing data collected by the second sensing module in the vehicle, and executes any of the above method embodiments based on the second sensing data to obtain the expected VVT value of the engine.

[0325] The second sensing module includes, but is not limited to, a throttle opening sensor, an engine water temperature sensor, a speed sensor, and an air flow meter.

[0326] Step S403, the engine management system compares the actual VVT position with the expected VVT value, and controls the position of the oil control valve in the vehicle according to the comparison result.

[0327] Among them, the oil control valve (OCV valve) is a component that constitutes the VVT system. The VVT system also includes a cam phaser (Cam Phaser). In this step, by changing the position of the valve core in the oil control valve, the oil flow direction and flow rate in the oil circuit can be changed, and signals such as advance, lag, and remain unchanged are fed back to the cavity of the VVT phaser in the form of oil pressure to achieve the relative rotation between the stator and the rotor inside the phaser, and to adjust the timing angle of the camshaft, so as to adjust the intake / exhaust volume and the valve opening and closing time.

[0328] In this embodiment, Figure 12 A structural schematic diagram of a VVT system is provided, as Figure 12As shown below, the term explanations are as follows: Advanced Side: Advance side; Retard Side: Retard side; Engine ECU: Engine Electronic Control Unit; Spool Valve: Spool valve; Plunger: Plunger; Drain: Drain port; Oil Pressure: Oil pressure; Coll: Coil.

[0329] In this embodiment, the VVT system mainly consists of a phaser (Cam Phaser) and an oil control valve (OCV valve). The engine electronic control unit can collect data from the throttle position sensor, engine coolant temperature sensor, engine speed sensor, air flow meter, etc., look up the MAP diagram, and calculate the required valve timing angle of the engine under various operating conditions, that is, the VVT expected value. At the same time, the engine management system calculates the actual VVT position based on the data collected by the crankshaft position sensor and the camshaft position sensor. The engine management system compares the VVT expected value with the actual VVT position and, based on the control strategy, sends an actuation signal to the oil control valve to change the position of the spool valve in the oil control valve, thereby changing the oil flow direction and flow rate in the oil circuit, and feeding signals such as advance, retard, and remain unchanged to the cavity of the VVT phaser in the form of oil pressure, to achieve the relative rotation between the internal stator and the external rotor of the phaser, and adjust the timing angle of the camshaft, so as to adjust the intake / exhaust volume and the valve opening and closing time.

[0330] In one embodiment, an electronic device is provided, including a memory and a processor. A computer program is stored in the memory, and the processor is configured to run the computer program to execute the steps in any one of the above method embodiments. It should be noted that the specific examples in this embodiment can refer to the examples described in the above embodiments and optional implementation manners, and will not be repeated in this embodiment.

[0331] In addition, in combination with the method provided in the above embodiments, a storage medium can also be provided in this embodiment to implement. A computer program is stored on the storage medium; when the computer program is executed by the processor, the steps in any one of the above method embodiments are implemented.

[0332] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data for analysis, stored data, displayed data, etc.) involved in this application are all information and data that have been authorized by the user or fully authorized by all parties.

[0333] Those of ordinary skill in the art can understand that all or part of the processes in the methods of the above embodiments can be completed by instructing relevant hardware through a computer program. The computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above methods. Among them, any reference to a memory, database, or other medium used in the embodiments provided in the present application can include at least one of non-volatile and volatile memories. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetoresistive random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM), etc. The databases involved in the embodiments provided in the present application can include at least one of relational databases and non-relational databases. Non-relational databases can include distributed databases based on blockchain, etc., without limitation. The processors involved in the embodiments provided in the present application can be general-purpose processors, central processors, graphics processors, digital signal processors, programmable logic devices, data processing logics based on quantum computing, etc., without limitation.

[0334] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope recorded in this specification.

[0335] The above-described embodiments merely represent several implementation manners of the present application. The description thereof is relatively specific and detailed, but it should not be construed as a limitation on the patent scope of the present application. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several modifications and improvements can still be made, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the appended claims.

Claims

1. A method for calculating a vehicle VVT ​​expected value, characterized in that: include: Determine whether the vehicle's engine is in a fuel cut-off state; In the case where it is determined that the engine is not in a fuel cut-off state, determining whether the speed of the engine is less than a speed threshold; When it is determined that the engine speed is less than the speed threshold, the VVT ​​expected values ​​of the engine in idle conditions and non-idle conditions are calculated respectively, and the VVT ​​expected value is corrected according to the VVT ​​expected value compensation coefficient of the engine in cold engine mode, catalytic heating mode and scavenging mode respectively.

2. The method for calculating the expected value of vehicle VVT ​​according to claim 1, characterized in that: When it is determined that the speed of the engine is less than the speed threshold, the method further includes: Determining whether the engine triggers an idle condition; In the case where it is determined that the engine triggers the idle condition, the VVT ​​expected values ​​of the engine are calculated, the VVT ​​expected values ​​respectively including the catalytic heating VVT expected value, the cold engine VVT ​​expected value and the warm engine idle VVT ​​expected value; and the VVT ​​expected values ​​are corrected according to the VVT ​​expected value compensation coefficients, including: Subtracting the catalytic heating VVT expected value from the warm engine idle VVT ​​expected value, multiplying the obtained difference by the catalytic heating compensation coefficient, and adding the obtained product to the warm engine idle VVT ​​expected value to obtain the catalytic heating idle VVT ​​expected value; Subtracting the cold engine VVT ​​expected value from the warm engine idle VVT ​​expected value, multiplying the obtained difference by a cold engine compensation coefficient, and adding the obtained product to the warm engine idle VVT ​​expected value to obtain a cold engine idle VVT ​​expected value; The catalytic heating idle VVT ​​expected value is compared with the cold engine idle VVT ​​expected value, and the smaller one is used as the corrected idle VVT ​​expected value.

3. The method for calculating the expected value of vehicle VVT ​​according to claim 2, characterized in that: After comparing the catalytic heating idle VVT ​​expected value and the cold engine idle VVT ​​expected value and taking the smaller one as the corrected idle VVT ​​expected value, the method further includes: Add the idle VVT ​​expected value and the VVT ​​expected value increase rate at the previous moment to obtain the VVT ​​expected upper limit value; Subtracting the idle VVT ​​expected value at the previous moment from the VVT ​​expected value reduction rate to obtain the VVT ​​expected lower limit value; When the current idle VVT ​​expected value is greater than the VVT ​​expected upper limit value, the current idle VVT ​​expected value is updated according to the VVT ​​expected upper limit value; or, when the current idle VVT ​​expected value is less than the VVT ​​expected lower limit value, the current idle VVT ​​expected value is updated according to the VVT ​​expected lower limit value.

4. The method for calculating the expected value of vehicle VVT ​​according to claim 2, characterized in that: The method further comprises: When it is determined that the engine has not triggered the idle condition, the VVT ​​expected values ​​of the engine are calculated, the VVT ​​expected values ​​respectively including the catalytic heating VVT expected value, the cooling VVT expected value and the scavenging VVT expected value; and the VVT ​​expected values ​​are corrected according to the VVT ​​expected value compensation coefficients, including: Subtracting the catalytic heating VVT expected value from the scavenging VVT expected value, multiplying the obtained difference by the catalytic heating compensation coefficient, and adding the obtained product to the scavenging VVT basic expected value to obtain the catalytic heating non-idle VVT ​​expected value; Subtracting the cooling machine VVT ​​expected value from the scavenging VVT expected value, multiplying the obtained difference by the cooling machine compensation coefficient, and adding the obtained product to the scavenging VVT expected value to obtain the cooling machine non-idling VVT expected value; The catalytic heating non-idle VVT ​​expected value and the cold engine non-idle VVT ​​expected value are compared, and the smaller one is used as the corrected non-idle VVT ​​expected value.

5. The method for calculating the expected value of vehicle VVT ​​according to claim 4, characterized in that: When it is determined that the engine has not triggered the idle condition, calculating the scavenging VVT expected value includes: Obtaining the warm-up VVT expected value and obtaining the VVT ​​expected value when limiting valve overlap; The warm-up VVT expected value is subtracted from the VVT ​​expected value when the valve overlap is limited, the obtained difference is multiplied by the scavenging compensation coefficient, and the obtained product is added to the VVT ​​expected value when the valve overlap is limited to obtain the scavenging VVT expected value.

6. The method for calculating the expected value of vehicle VVT ​​according to claim 1, characterized in that: The method further comprises: When it is determined that the engine is in a fuel cut-off state, determining whether the engine speed is less than the speed threshold; In the case where it is determined that the speed of the engine is less than the speed threshold, determining whether the engine triggers an idle condition; When it is determined that the engine triggers the idle condition, calculating a corrected idle VVT ​​expected value; Determining a VVT limit angle according to a rotation speed of the engine and an oil temperature of the engine; The corrected idle VVT ​​expected value is compared with the VVT ​​limited angle, and the smaller one is used as the final fuel cut idle VVT ​​expected value.

7. The method for calculating the expected value of vehicle VVT ​​according to claim 6, characterized in that: When it is determined that the speed of the engine is less than the speed threshold, the method further includes: When it is determined that the engine has not triggered the idle condition, calculating a corrected non-idle VVT ​​expected value; Determining a VVT limit angle according to a rotation speed of the engine and an oil temperature of the engine; The corrected non-idle VVT ​​expected value is compared with the VVT ​​limited angle, and the smaller one is used as the final fuel cut-off non-idle VVT ​​expected value.

8. The method for calculating the expected value of vehicle VVT ​​according to any one of claims 1 to 7, characterized in that: Before correcting the VVT ​​expected value according to the VVT ​​expected value compensation coefficients of the engine in the cold engine mode, the catalytic heating mode and the scavenging mode, the method further includes: generating a cold engine compensation coefficient table according to the engine start completion time and the compensation of the heater to the coolant temperature; Determine a temperature compensation characteristic curve according to the engine oil temperature and the compensation of the heater to the coolant temperature, and determine a catalytic heating coefficient compensation characteristic curve according to the catalytic heating coefficient, and generate a catalytic heating compensation coefficient table according to the temperature compensation characteristic curve and the catalytic heating coefficient compensation characteristic curve; A scavenging temperature compensation characteristic curve is determined based on the compensation for the VVT ​​expected value when the exhaust temperature is too high and the emission protection overheat coefficient, and a pressure ratio coefficient compensation characteristic curve is determined based on the pressure ratio coefficient and the engine speed. A scavenging compensation coefficient table is generated based on the scavenging temperature compensation characteristic curve and the pressure ratio coefficient compensation characteristic curve.

9. A vehicle control method, characterized in that: include: Receiving first sensor data collected by a first sensor module in the vehicle, and calculating the actual VVT position of the engine according to the first sensor data; Receiving second sensor data collected by a second sensor module in the vehicle, and executing the method according to any one of claims 1 to 8 above based on the second sensor data to obtain a VVT expected value of the engine; The VVT ​​actual position is compared with the VVT ​​desired value, and the position of the oil control valve in the vehicle is controlled according to the comparison result.

10. A vehicle engine system, characterized in that: include: A control system, a sensor system and an oil control valve, wherein the control system is connected to the sensor system and the oil control valve respectively; wherein, The control system is used to execute the method described in any one of claims 1 to 9 above, obtain the actual VVT position of the engine and the desired VVT value required by the engine, and compare the actual VVT position with the desired VVT value, and generate a control signal according to the comparison result; The control system is further configured to send the control signal to the oil control valve to control the position of the oil control valve.

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