A method for controlling fuel injection of a hybrid vehicle engine

Abstract

The application discloses a kind of hybrid vehicle engine oil injection control methods, and the control method includes the following steps: obtaining engine long-term fuel correction value, engine speed in self-learning storage phase is judged, when meeting update condition, the coordinate value of engine speed and load is updated, otherwise not updated;According to engine speed and load, determine the long-term fuel correction coefficient f (n, rho) in engine starting process LT ;According to atmospheric pressure and water temperature, determine the long-term fuel correction coefficient f (p Amb ,T Coolant ) LT In carbon tank, shield carbon tank opening time oil injection correction;f (n, rho) LT ×f (p Amb ,T Coolant ) LT As the multiplication correction factor of injection amount, oil injection compensation is carried out.The application can identify engine speed, load, atmospheric pressure, starting water temperature, carbon tank and other factors in starting process to optimize starting fuel correction, to improve engine speed smoothness in starting process, avoid engine speed fluctuation in starting process.

Description

Technical Field

[0001] This invention belongs to the field of engine control, and specifically relates to a fuel injection control method for a hybrid vehicle engine. Background Technology

[0002] Patent CN202010246641.0, "A Self-Learning Method for Long-Term Fuel Correction of a Gasoline Engine," proposes a self-learning control method for long-term fuel correction of an engine. Other existing patents also disclose similar self-learning methods for long-term fuel correction. After long-term fuel correction learning, a long-term fuel correction learning value is introduced and used as a correction for engine fuel injection. However, this learning value is stored based on engine speed and load as coordinate axes, and the reading of the long-term fuel correction learning value is also based on engine speed and load. However, during engine start-up, the oxygen sensor in the exhaust system may not yet be activated, preventing closed-loop fuel control. Furthermore, the engine speed and load are relatively low. A common approach is to use linear interpolation. However, in actual development, it was found that the long-term fuel correction value after linear interpolation is not necessarily reasonable, potentially causing engine speed fluctuations and poor start-up smoothness during the start-up process. Summary of the Invention

[0003] The purpose of this invention is to provide a fuel injection control method for a hybrid vehicle engine, which can identify factors such as engine speed, load, atmospheric pressure, starter coolant temperature, and carbon canister during the starting process and perform starting fuel correction and optimization to improve the smoothness of engine speed during the starting process and avoid engine speed fluctuations during the starting process.

[0004] To solve the above-mentioned technical problems, the technical solution of the present invention is as follows: a fuel injection control method for a hybrid electric vehicle engine, which obtains the long-term fuel correction value of the engine through a self-learning method for long-term fuel correction of a gasoline engine. The self-learning method for long-term fuel correction of a gasoline engine includes determining whether the self-learning operating condition judgment condition is met; if so, entering the self-learning operating condition stabilization stage; determining whether the self-learning stabilization stage has ended; if so, entering the self-learning storage activation judgment stage; after the self-learning storage activation judgment stage ends, automatically entering the self-learning storage stage; the self-learning storage activation judgment stage includes: collecting the total engine speed, total load, and total short-term fuel correction within the T2 time period; the self-learning storage stage includes: root... Based on the total engine speed, total load, total atmospheric pressure, total coolant temperature, and total short-term fuel correction collected during time period T2, the average engine speed nAvg, average load rhoAvg, average atmospheric pressure, average coolant temperature, and average short-term fuel correction STFTAvg for time period T2 are calculated. Based on the previously updated original long-term fuel correction values ​​r1 (engine speed load (A,a), r2 (engine speed load (A,b), r3 (engine speed load (B,a), and r4 (engine speed load (B,b)), the previous engine speed load (nAvg, rhoAvg) is calculated. The next update is the long-term fuel trim value rBef; based on the previously updated long-term fuel trim value rBef under engine speed load (nAvg, rhoAvg) and combined with the short-term fuel trim average value STFTAvg within time period T2, the long-term fuel trim values ​​r′1, r′2, r′3, and r′4 under engine speed load (B, b) are calculated; r′1, r′2, r′3, and r′4 are stored as new long-term fuel trim data in the corresponding engine speed load, and the long-term fuel trim self-learning count is incremented by 1; where A B and A are two adjacent values ​​in the engine speed coordinate axis array (A1, A2, A3, ..., AK), and the two values ​​with the smallest absolute difference from the engine speed average value nAvg, and A < B. a and b are two adjacent values ​​in the load coordinate axis array (B1, B2, B3, ..., BJ), and the two values ​​with the smallest absolute difference from the load average value rhoAvg, and a < b. In particular, if the engine speed average value nAvg is less than or equal to A1, then A1 = A. Using the same method, only the long-term fuel correction value r′1 under engine speed load (A, a) and the long-term fuel correction value r′2 under engine speed load (A, b) are updated, and r′3 and r′4 are not updated.If the average load value rhoAvg is less than or equal to B1, then B1 = a. Using the same method, only update the long-term fuel correction value r′1 under engine speed load (A,a) and the long-term fuel correction value r′3 under engine speed load (B,a), without updating r′2 or r′4. This control method includes the following steps:

[0005] After obtaining the long-term fuel correction value of the engine, the engine speed in the self-learning storage stage is judged. When the update conditions are met, the coordinate values ​​of engine speed and load are updated; otherwise, they are not updated.

[0006] The long-term fuel correction factor f(n,rho) during engine start-up is determined based on engine speed and load. LT ;

[0007] The long-term fuel correction factor f(p) during engine starting is determined based on atmospheric pressure and water temperature. Amb ,T Coolant ) LT ;

[0008] Close the carbon canister to disable fuel injection correction when the carbon canister is open;

[0009] f(n,rho) LT ×f(p Amb ,T Coolant ) LT Fuel injection compensation is performed as a multiplicative correction factor for the fuel injection quantity.

[0010] In judging the engine speed during the self-learning storage phase, the update condition is as follows: Establish a coordinate system with engine speed and load as the horizontal and vertical axes, respectively. Set the engine speed coordinate axis array as (A1, A2, A3, ..., AK) and the load coordinate axis array as (B1, B2, B3, ..., BJ). That is, use K engine speed coordinate values ​​and J load coordinate values ​​as the coordinate values ​​of the coordinate system on the corresponding engine speed and load coordinate axes, respectively. When the engine speed during the self-learning storage phase... If the engine speed A1' is less than A1, the coordinate value of the engine speed is updated, i.e., (A1, A2, A3, ..., AK) is updated to (A1', A1, A2, A3, ..., AK). Or if the load B1' in the self-learning storage stage is less than B1, the coordinate value of the load is updated, i.e., (B1, B2, B3, ..., BJ) is updated to (B1', B1, B2, B3, ..., BJ). Otherwise, no update is performed. Here, both the engine speed A1' and the load B1' are real-time values ​​in the self-learning storage stage.

[0011] The long-term fuel correction factor f(n,rho) during engine start-up is determined based on engine speed and load. LTThe specific determination method is as follows: The long-term fuel correction value rBef of the engine is obtained through a self-learning method for long-term fuel correction of a gasoline engine. The long-term fuel correction value rBef is then interpolated in the following form: If the engine speed and load during startup fall within the coordinate value boundaries, the long-term fuel correction coefficient is obtained through linear interpolation. The general equation for linear interpolation is: y = kx + c, that is, linear interpolation is performed using two adjacent coordinate values. If the engine speed or load during startup does not fall within the coordinate value boundaries, the engine speed or load during startup is less than the minimum value of the corresponding coordinate value. In this case, the five points with the smallest engine speed coordinate value and the five points with the smallest load coordinate value are read for interpolation. The general equation for interpolation is: y = jx 2 +lx+m; where k, c, j, l, and m are coefficients, x is the engine speed or load, and y is the long-term fuel correction coefficient; when the engine speed is fixed, it is calculated using y = jx 2 The relationship between load and long-term fuel correction factor is calculated using +lx+m; when the load is fixed, it is obtained through y=jx 2 +lx+m calculates the relationship between engine speed and long-term fuel correction factor. (First, according to the formula y=jx) 2 +lx+m determines the relationship between the current engine speed and the long-term fuel correction factor. This allows us to determine the long-term fuel correction factor at the current engine speed corresponding to the load point with the smallest of these five coordinate values. Then, using the same formula y=jx 2 +lx+m determines the long-term fuel correction factor under the current load, which is the final long-term fuel correction factor under the current engine speed and current load. The parameters j, l, m from engine speed to long-term fuel correction factor may differ from those from load to long-term fuel correction factor. The specific method for determining the parameters j, l, m from engine speed to long-term fuel correction factor is as follows: Select the load point p at the center of the 5 points with the smallest load coordinate value, and then combine p with the 5 points with the smallest engine speed coordinate value to form 5 points. Look up the long-term fuel correction factor table (based on the long-term fuel correction factor table learned and stored according to engine speed and load) to obtain 5 corresponding long-term fuel correction factors [u1, u2, u3, u4, u5]; Select the load point p at the center of the 5 points with the smallest load coordinate value, and use the formula y = jx+m. 2 Similarly, using +lx+m, we can determine the long-term fuel correction coefficients [u1',u2',u3',u4',u5'] corresponding to the five identical engine speeds and loads. Once... The j, l, and m that correspond to the minimum value are the suitable choices. If there are multiple combinations of j, l, and m determined by this method, then choose the one that best fits the given value. The smallest corresponding j, l, and m are obtained. Similarly, the parameters j, l, and m for the load-to-long-term fuel correction factor are obtained using the same method.

[0012] The long-term fuel correction factor f(p) during engine starting is determined based on atmospheric pressure and water temperature. Amb ,T Coolant ) LT The specific process is as follows: During each engine start-up, record: the number of times the engine speed change rate is lower than the preset rate of change (Cnt) from the starter disengagement to the engine speed rising to the preset engine speed; the time t1 from the start of fuel injection to the engine speed rising to the preset engine speed; and the starting atmospheric pressure p. Amb and starting water temperature T Coolant The initial long-term fuel correction factor f(p) is obtained under the condition. Amb ,T Coolant ) LTRaw Take the initial long-term fuel correction factor f(p) with the fewest Cnt counts and shortest time t1 from multiple records. Amb ,T Coolant ) LTRaw As f(p) Amb ,T Coolant ) LT If the initial long-term fuel correction factor corresponding to the minimum Cnt is not the initial long-term fuel correction factor with the shortest time t1, then the initial long-term fuel correction factor corresponding to the minimum Cnt is selected as f(p). Amb ,T Coolant ) LT .

[0013] If the engine speed or load does not fall within the coordinate boundary during startup, then the engine speed or load during startup is less than the minimum value of the corresponding coordinate value. If one of the five points has a long-term fuel correction value that matches the interpolation equation y = jx 2 If the deviation of the correction value determined by +lx+m, i.e., the absolute value of the difference between the two divided by the true value of the long-term fuel correction value, exceeds ±1%, then linear interpolation is used for interpolation. If the total number of coordinate axes is less than 5 points, then linear interpolation is also used for interpolation.

[0014] If the starting atmospheric pressure is p Amb and starting water temperature T Coolant If Cnt does not exceed 1 under the given condition, then the initial long-term fuel correction factor f(p) with the shortest time t1 is adopted. Amb ,T Coolant ) LTRaw As f(p) Amb ,T Coolant ) LT ;

[0015] Finally As a multiplicative correction factor for fuel injection quantity during engine starting, fuel injection compensation is performed. CNT is a preset value, and Cnt1 is incremented by 1 for each ignition after engine start-up until the engine starts or its value is not less than CNT and remains unchanged. After the engine stops, Cnt1 is reset to zero until the engine restarts and then begins counting again. After the engine starts, the multiplicative correction factor for fuel injection quantity gradually transitions to 1. The transition method is as follows: the multiplicative correction factor for fuel injection quantity in the current sampling period is equal to the multiplicative correction factor for fuel injection quantity in the previous sampling period minus the first difference. Among them, the multiplicative correction factor for fuel injection quantity in the first sampling period is equal to the value read when the engine just started. The first difference consists of two parts: the first part is determined by looking up the engine speed and load from a table, and the second part is determined by the water temperature. The product of the two parts is the cumulative amount. The evaluation method for the first difference is that if the engine speed fluctuation does not exceed ±20 rpm after the engine starts, the error of the first difference is considered to be small.

[0016] When the engine speed rises above the preset engine speed and is maintained for more than the first preset time, the engine is considered to have started successfully.

[0017] As the engine's lifespan progresses and engine components age, the first differential needs to self-learn. The conditions for self-learning are:

[0018] ①After the engine starts, it enters idle closed-loop control; the speed fluctuation range is used to check whether the first differential needs self-learning. If abnormal speed fluctuation occurs, it needs to be handled.

[0019] ②The oxygen sensor before the catalyst is not activated;

[0020] ③ The vehicle mileage corresponding to the first differential not being updated exceeds the preset mileage;

[0021] The first differential self-learning is allowed only if all the above conditions are met; if any one of the conditions is not met, the self-learning will be terminated.

[0022] The normal range for speed fluctuation is ±20 rpm. When the speed fluctuation is normal or abnormal, the handling method is as follows:

[0023] 1) If, after starting, the engine speed fluctuates by more than ±20 rpm for more than (0.2 * second preset time) within the second preset time of idling closed-loop control, the previously saved first difference is multiplied by (1 + second preset time) to obtain the updated first difference, which is saved after the vehicle is powered off. The updated first difference will only take effect after the engine starts in the next vehicle driving cycle.

[0024] 2) If the engine speed fluctuation exceeds ±20 rpm for more than (0.3 * second preset time) within the second preset time, the first difference saved last time will be multiplied by (1 + second preset time) to obtain the first difference after this update, and it will be saved after the vehicle is powered off. The updated first difference will only take effect after the engine is started in the next vehicle driving cycle.

[0025] 3) If no engine speed fluctuation exceeds ±20 rpm within the second preset time, the first difference saved last time is multiplied by (1 - second preset time) to obtain the updated first difference, and it is saved after the vehicle is powered off. The updated first difference will only take effect after the engine is started in the next vehicle driving cycle.

[0026] The preset engine speed is 500-2000 rpm, and the preset variation rate is 10-40 rpm / s.

[0027] A computer device is also provided, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the steps of the control method as described in any of the preceding claims.

[0028] A computer-readable storage medium is also provided, on which a computer program is stored, which, when executed by a processor, implements the steps of the control method as described in any of the preceding claims.

[0029] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0030] This invention can identify factors such as engine speed, load, atmospheric pressure, starter coolant temperature, and carbon canister during the starting process and perform starting fuel correction and optimization to improve the smoothness of engine speed during the starting process and avoid engine speed fluctuations during the starting process. Attached Figure Description

[0031] Figure 1 This is a flowchart illustrating an embodiment of the present invention. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of this invention clearer, the invention 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 merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0033] The purpose of this patent is to propose a fuel injection control method for hybrid vehicle engines.

[0034] Example 1:

[0035] The technical solution of this invention is: a fuel injection control method for a hybrid electric vehicle engine, which obtains the long-term fuel correction value of the engine through a self-learning method for long-term fuel correction of a gasoline engine. The self-learning method for long-term fuel correction of a gasoline engine includes determining whether a self-learning operating condition judgment condition is met; if so, entering a self-learning operating condition stabilization stage; determining whether the self-learning stabilization stage has ended; if so, entering a self-learning storage activation judgment stage; after the self-learning storage activation judgment stage ends, automatically entering a self-learning storage stage; the self-learning storage activation judgment stage includes: collecting the total engine speed, total load, and total short-term fuel correction within a time period T2; the self-learning storage stage includes: based on the collected T2 time... The average engine speed (nAvg), average load (rhoAvg), average atmospheric pressure, average water temperature, and average short-term fuel correction (STFTAvg) for time period T2 are calculated from the sum of engine speeds, total loads, total atmospheric pressures, total coolant temperatures, and total short-term fuel corrections within the time period. Based on the previously updated original long-term fuel correction values ​​r1 (engine speed load (A,a), r2 (engine speed load (A,b), r3 (engine speed load (B,a), and r4 (engine speed load (B,b))), the previously updated long-term fuel correction values ​​(nAvg, rhoAvg) for engine speed load (nAvg, rhoAvg) are then calculated. The long-term fuel trim value rBef is calculated. Based on the previously updated long-term fuel trim value rBef under engine speed load (nAvg, rhoAvg) and the average short-term fuel trim value STFTAvg within time period T2, the long-term fuel trim values ​​r′1, r′2, r′3, and r′4 under engine speed load (B, b) are calculated. r′1, r′2, r′3, and r′4 are stored as new long-term fuel trim data in the corresponding engine speed load, and the long-term fuel trim self-learning count is incremented by 1. Among them, A and B... Both values ​​are two adjacent values ​​in the engine speed coordinate axis array (A1, A2, A3, ..., AK), and the two values ​​with the smallest absolute difference from the engine speed average value nAvg, where A < B. Both a and b are two adjacent values ​​in the load coordinate axis array (B1, B2, B3, ..., BJ), and the two values ​​with the smallest absolute difference from the load average value rhoAvg, where a < b. In particular, if the engine speed average value nAvg is less than or equal to A1, then A1 = A. Using the same method, only the long-term fuel correction value r′1 under engine speed load (A, a) and the long-term fuel correction value r′2 under engine speed load (A, b) are updated, while r′3 and r′4 are not updated.If the average load value rhoAvg is less than or equal to B1, then B1 = a. Using the same method, only update the long-term fuel correction value r′1 under engine speed load (A,a) and the long-term fuel correction value r′3 under engine speed load (B,a), without updating r′2 or r′4. This control method includes the following steps:

[0036] After obtaining the long-term fuel correction value of the engine, the engine speed in the self-learning storage stage is judged. When the update conditions are met, the coordinate values ​​of engine speed and load are updated; otherwise, they are not updated.

[0037] The long-term fuel correction factor f(n,rho) during engine start-up is determined based on engine speed and load. LT ;

[0038] The long-term fuel correction factor f(p) during engine starting is determined based on atmospheric pressure and water temperature. Amb ,T Coolant ) LT ;

[0039] Close the carbon canister to disable fuel injection correction when the carbon canister is open;

[0040] Will Fuel injection compensation is performed as a multiplicative correction factor for the fuel injection quantity.

[0041] In judging the engine speed during the self-learning storage phase, the update condition is as follows: Establish a coordinate system with engine speed and load as the horizontal and vertical axes, respectively. Set the engine speed coordinate axis array as (A1, A2, A3, ..., AK) and the load coordinate axis array as (B1, B2, B3, ..., BJ). That is, use K engine speed coordinate values ​​and J load coordinate values ​​as the coordinate values ​​of the coordinate system on the corresponding engine speed and load coordinate axes, respectively. When the engine speed during the self-learning storage phase... If the engine speed A1' is less than A1, the coordinate values ​​of the engine speed are updated, i.e., (A1, A2, A3, ..., AK) are updated to (A1', A1, A2, A3, ..., AK). Alternatively, if the load B1' in the self-learning storage stage is less than B1, the coordinate values ​​of the load are updated, i.e., (B1, B2, B3, ..., BJ) are updated to (B1', B1, B2, B3, ..., BJ). Otherwise, no updates are performed. Here, both engine speed A1' and load B1' are real-time values ​​from the self-learning storage stage. This part is an optimization of patent CN202010246641.0, "A Self-Learning Method for Long-Term Fuel Correction of a Gasoline Engine." This patent does not update the engine speed and load in the learned long-term fuel correction coordinate axis even if the engine speed A1' or load B1' in the self-learning storage stage is less than A1 or B1. This patent updates the engine speed and load, which is more conducive to fuel injection optimization during engine start-up (when the engine speed and load are relatively low), thus improving start-up.

[0042] The long-term fuel correction factor f(n,rho) during engine start-up is determined based on engine speed and load. LT The specific determination method is as follows: The basic method remains the same as patent CN202010246641.0, "A Self-Learning Method for Long-Term Fuel Correction of Gasoline Engines." After updating the coordinate values ​​of engine speed and load, the long-term fuel correction coefficient is obtained (the long-term fuel correction coefficient is the long-term fuel correction value obtained by this patent). The following interpolation optimization is then performed: If the engine speed and load fall within the coordinate value boundaries during startup, the long-term fuel correction coefficient is obtained through linear interpolation. The general equation form of linear interpolation is: y = kx + c, that is, linear interpolation is performed using two adjacent coordinate values. If the engine speed or load does not fall within the coordinate value boundaries during startup, the engine speed or load is less than the minimum value of the corresponding coordinate value. In this case, the 5 points with the smallest engine speed coordinate value and the 5 points with the smallest load coordinate value are read for interpolation. The general equation form of interpolation is: y = jx 2 +lx+m; where k, c, j, l, and m are coefficients, x is the engine speed or load, and y is the long-term fuel correction coefficient; when the engine speed is fixed, it is calculated using y = jx 2The relationship between load and long-term fuel correction factor is calculated using +lx+m; when the load is fixed, it is obtained through y=jx 2 +lx+m calculates the relationship between engine speed and long-term fuel correction factor. (First, according to the formula y=jx) 2 +lx+m determines the relationship between the current engine speed and the long-term fuel correction factor. This allows us to determine the long-term fuel correction factor at the current engine speed corresponding to the load point with the smallest of these five coordinate values. Then, using the same formula y=jx 2 +lx+m determines the long-term fuel correction factor under the current load, which is the final long-term fuel correction factor under the current engine speed and current load. The parameters j, l, m from engine speed to long-term fuel correction factor may be different from the parameters j, l, m from load to long-term fuel correction factor.

[0043] The following example illustrates the specific interpolation optimization. Assume the long-term fuel correction coefficients obtained from patent CN202010246641.0, "A Self-Learning Method for Long-Term Fuel Correction of Gasoline Engines," are as shown in the table below:

[0044]

[0045]

[0046] 1. Assuming that the engine speed and load fall within the coordinate boundaries during the starting process, and assuming that one of the engine speeds is 850 rpm and the load is 450 mgpl, then the values ​​can be obtained by linear interpolation using y = kx + c based on the four engine speed and load points (800 rpm, 400 mgpl), (900 rpm, 400 mgpl), (800 rpm, 500 mgpl), and (900 rpm, 500 mgpl) in the table above.

[0047] First, obtain the long-term fuel correction coefficients for an engine speed of 850 rpm and loads of 400 mgpl and 500 mgpl, respectively, using linear interpolation of y = kx + c. At a load of 400 mgpl, based on the long-term fuel correction coefficients determined at engine speeds of 800 rpm and 900 rpm (0.95 and 0.95 respectively in this example), we can obtain k and c corresponding to a load of 400 mgpl. Then, using y = kx + c, we can obtain the long-term fuel correction coefficient for (850 rpm, 400 mgpl). The same method is used to obtain the long-term fuel correction coefficient for (850 rpm, 500 mgpl).

[0048] Then, after determining the long-term fuel correction coefficients for (850rpm, 400mgpl) and (850rpm, 500mgpl), the corresponding long-term fuel correction coefficient for (850rpm, 450mgpl) is obtained by linear interpolation using y = kx + c.

[0049] 2. Assuming that the engine speed and load fall within the coordinate boundaries during startup, and assuming that one of the engine speeds is 500 rpm and the load is 200 mgpl, then according to y = jx 2 The result is obtained using interpolation with +lx+m.

[0050] First, obtain the long-term fuel correction factor corresponding to (500rpm, 300mgpl). Based on (700rpm, 300mgpl), (800rpm, 300mgpl), (900rpm, 300mgpl), (1000rpm, 300mgpl), and (110rpm, 300mgpl) and their corresponding long-term fuel correction factors, use y = jx 2 The interpolation of +lx+m calculates j, l and m, and then the long-term fuel correction factor corresponding to (500rpm, 300mgpl) can be obtained.

[0051] Secondly, using the same method, the long-term fuel correction coefficients corresponding to (500rpm, 400mgpl), (500rpm, 500mgpl), (500rpm, 600mgpl), and (500rpm, 700mgpl) were obtained respectively.

[0052] Finally, based on (500rpm, 300mgpl), (500rpm, 400mgpl), (500rpm, 500mgpl), (500rpm, 600mgpl), (500rpm, 700mgpl) and the corresponding long-term fuel correction coefficients, we use y = jx 2 The interpolation +lx+m is used to calculate j, l, and m at this point. Then, the long-term fuel correction factor corresponding to (500 rpm, 200 mgpl) can be obtained.

[0053] The specific methods for determining the parameters j, l, and m of the engine speed to the long-term fuel correction factor are as follows: Select the center load point p from the five points with the smallest load coordinate values. Then combine p with the five points with the smallest engine speed coordinate values ​​to form five points. Look up the five corresponding long-term fuel correction factors [u1, u2, u3, u4, u5] from the long-term fuel correction factor table (a table of long-term fuel correction factors learned and stored based on engine speed and load). Select the center load point p from the five points with the smallest load coordinate values, and then use the formula y = jx 2Similarly, using +lx+m, we can determine the long-term fuel correction coefficients [u1',u2',u3',u4',u5'] corresponding to the five identical engine speeds and loads. Once... The j, l, and m that correspond to the minimum value are the suitable choices. If there are multiple combinations of j, l, and m determined by this method, then choose the one that best fits the given value. The smallest corresponding j, l, and m are obtained. Similarly, the parameters j, l, and m for the load-to-long-term fuel correction factor are obtained using the same method.

[0054] The long-term fuel correction factor f(p) during engine starting is determined based on atmospheric pressure and water temperature. Amb ,T Coolant ) LT The specific process is as follows: During each engine start-up, record: the number of times the engine speed change rate is lower than the preset rate of change (Cnt) from the starter disengagement to the engine speed rising to the preset engine speed; the time t1 from the start of fuel injection to the engine speed rising to the preset engine speed; and the starting atmospheric pressure p. Amb and starting water temperature T Coolant The initial long-term fuel correction factor f(p) is obtained under the condition. Amb ,T Coolant ) LTRaw Take the initial long-term fuel correction factor f(p) with the fewest Cnt counts and shortest time t1 from multiple records. Amb ,T Coolant ) LTRaw As f(p) Amb ,T Coolant ) LT If the initial long-term fuel correction factor corresponding to the minimum Cnt is not the initial long-term fuel correction factor with the shortest time t1, then the initial long-term fuel correction factor corresponding to the minimum Cnt is selected as f(p). Amb ,T Coolant ) LT .

[0055] When the engine speed rises above the preset engine speed and is maintained for more than the first preset time, the engine is considered to have started successfully.

[0056] As the engine's lifespan progresses and engine components age, the first differential needs to self-learn. The conditions for self-learning are:

[0057] ①After the engine starts, it enters idle closed-loop control; the speed fluctuation range is used to check whether the first differential needs self-learning. If abnormal speed fluctuation occurs, it needs to be handled.

[0058] ②The oxygen sensor before the catalyst is not activated;

[0059] ③ The vehicle mileage corresponding to the first differential not being updated exceeds the preset mileage;

[0060] The first differential self-learning is allowed only if all the above conditions are met; if any one of the conditions is not met, the self-learning will be terminated.

[0061] The normal range for speed fluctuation is ±20 rpm. When the speed fluctuation is normal or abnormal, the handling method is as follows:

[0062] 1) If, after starting, the engine speed fluctuates by more than ±20 rpm for more than (0.2 * second preset time) within the second preset time of idling closed-loop control, the previously saved first difference is multiplied by (1 + second preset time) to obtain the updated first difference, which is saved after the vehicle is powered off. The updated first difference will only take effect after the engine starts in the next vehicle driving cycle.

[0063] 2) If the engine speed fluctuation exceeds ±20 rpm for more than (0.3 * second preset time) within the second preset time, the first difference saved last time will be multiplied by (1 + second preset time) to obtain the first difference after this update, and it will be saved after the vehicle is powered off. The updated first difference will only take effect after the engine is started in the next vehicle driving cycle.

[0064] 3) If no engine speed fluctuation exceeds ±20 rpm within the second preset time, the first difference saved last time is multiplied by (1 - second preset time) to obtain the updated first difference, and it is saved after the vehicle is powered off. The updated first difference will only take effect after the engine is started in the next vehicle driving cycle.

[0065] The preset engine speed is 500-2000 rpm, and 750 rpm is used in this embodiment; the preset rate of change is 10-40 rpm / s, and 15 rpm / s is used in this embodiment.

[0066] A computer device is also provided, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the steps of the control method as described in any of the preceding claims.

[0067] A computer-readable storage medium is also provided, on which a computer program is stored, which, when executed by a processor, implements the steps of the control method as described in any of the preceding claims.

[0068] Example 2:

[0069] In another possible embodiment, all other implementation steps are the same as in Embodiment 1, except that:

[0070] The long-term fuel correction factor f(n,rho) during engine start-up is determined based on engine speed and load. LT The specific determination method is as follows: The basic method is still to obtain the long-term fuel correction coefficient in the patent CN202010246641.0 "A self-learning method for long-term fuel correction of gasoline engine" (the long-term fuel correction coefficient is the long-term fuel correction value obtained by the patent).

[0071] If the engine speed and load fall within the coordinate boundaries during startup, the long-term fuel correction coefficient is obtained through linear interpolation. The general equation for linear interpolation is: y = kx + c, which means linear interpolation is performed using two adjacent coordinate values. If the engine speed or load does not fall within the coordinate boundaries during startup, the engine speed or load is less than the minimum value of the corresponding coordinate value. In this case, the five points with the smallest engine speed coordinate value and the five points with the smallest load coordinate value are read for interpolation. The general equation for interpolation is: y = jx 2 +lx+m. Specifically, if the engine speed or load does not fall within the coordinate boundaries during startup, then the engine speed or load during startup is less than the minimum value of the corresponding coordinate value. If one of the five points has a long-term fuel correction value that matches the interpolation equation y=jx, then... 2 The correction value deviation determined by +lx+m is the absolute value of the difference between the two, |u i -u i Divide by the true value of the long-term fuel trim. If the difference exceeds ±1%, linear interpolation is used. If there are fewer than 5 points on the coordinate axes, linear interpolation is also used.

[0072] The long-term fuel correction factor f(p) during engine starting is determined based on atmospheric pressure and water temperature. Amb ,T Coolant ) LT The specific process is as follows: During each engine start-up, record: the number of times the engine speed change rate is lower than the preset rate of change (Cnt) from the starter disengagement to the engine speed rising to the preset engine speed; the time t1 from the start of fuel injection to the engine speed rising to the preset engine speed; and the starting atmospheric pressure p. Amb and starting water temperature T Coolant The initial long-term fuel correction factor f(p) is obtained under the condition. Amb ,T Coolant ) LTRaw Take the initial long-term fuel correction factor f(p) with the fewest Cnt counts and shortest time t1 from multiple records.Amb ,T Coolant ) LTRaw As f(p) Amb ,T Coolant ) LT If the initial long-term fuel correction factor corresponding to the minimum Cnt is not the initial long-term fuel correction factor with the shortest time t1, then the initial long-term fuel correction factor corresponding to the minimum Cnt is selected as f(p). Amb ,T Coolant ) LT Specifically, if the starting atmospheric pressure p Amb and starting water temperature T Coolant If Cnt does not exceed 1 under the given condition, then the initial long-term fuel correction factor f(p) with the shortest time t1 is adopted. Amb ,T Coolant ) LTRaw As f(p) Amb ,T Coolant ) LT .

[0073] If the engine speed or load does not fall within the coordinate boundary during startup, then the engine speed or load during startup is less than the minimum value of the corresponding coordinate value. If one of the five points has a long-term fuel correction value that matches the interpolation equation y = jx 2 If the deviation of the correction value determined by +lx+m, i.e., the absolute value of the difference between the two divided by the true value of the long-term fuel correction value, exceeds ±1%, then linear interpolation is used for interpolation. If the total number of coordinate axes is less than 5 points, then linear interpolation is also used for interpolation.

[0074] If the starting atmospheric pressure is p Amb and starting water temperature T Coolant If Cnt does not exceed 1 under the given condition, then the initial long-term fuel correction factor f(p) with the shortest time t1 is adopted. Amb ,T Coolant ) LTRaw As f(p) Amb ,T Coolant ) LT ;

[0075] Finally As a multiplicative correction factor for fuel injection quantity during engine starting, fuel injection compensation is performed. CNT is a preset value, and Cnt1 is incremented by 1 for each ignition after engine start-up until the engine starts or its value is not less than CNT and remains unchanged. After the engine stops, Cnt1 is reset to zero until the engine restarts and then begins counting again. After the engine starts, the multiplicative correction factor for fuel injection quantity gradually transitions to 1. The transition method is as follows: the multiplicative correction factor for fuel injection quantity in the current sampling period is equal to the multiplicative correction factor for fuel injection quantity in the previous sampling period minus the first difference. Among them, the multiplicative correction factor for fuel injection quantity in the first sampling period is equal to the value read when the engine just started. The first difference consists of two parts: the first part is determined by looking up the engine speed and load from a table, and the second part is determined by the water temperature. The product of the two parts is the cumulative amount. The evaluation method for the first difference is that if the engine speed fluctuation does not exceed ±20 rpm after the engine starts, the error of the first difference is considered to be small.

[0076] Patent CN202010246641.0, "A Self-Learning Method for Long-Term Fuel Correction of a Gasoline Engine," obtains the engine's long-term fuel correction value. This long-term fuel correction value is a self-learning value, based on engine speed and load (intake air density) as coordinate axes. The learned long-term fuel correction value is filled into the default engine speed and load coordinate axes. Assuming the engine coordinate axis array is (A1, A2, A3, ..., AK) and the load coordinate axis array is (B1, B2, B3, ..., BJ), it is a horizontal and vertical axis composed of K engine speed coordinate values ​​and J load coordinate values. To improve the correct reading of the long-term fuel correction learning value under low engine speed and low load conditions:

[0077] The first step, after successful long-term fuel trim learning, is to replace the original engine coordinate axis array (A1, A2, A3, ..., AK) and load coordinate axis array (B1, B2, B3, ..., BJ) with (A1', A1, A2, A3, ..., AK) and (B1', B1, B2, B3, ..., BJ) respectively, as follows: This step has the highest priority and will continue to be executed as long as the condition is met. If the condition is not met, the coordinate values ​​of engine speed and load will not be updated.

[0078] The second step is to determine the long-term fuel correction coefficient f(n,rho) during the starting process based on engine speed and load. LTThe data can be stored after the vehicle is powered off. If the engine speed and load fall within the coordinate boundaries during startup (i.e., the engine speed is not less than the minimum engine speed of the coordinate value and not greater than the maximum engine speed of the coordinate value; the same applies to the same load), the long-term fuel correction coefficient is obtained through linear interpolation (the general equation for interpolation is: y = kx + c, i.e., linear interpolation is performed using two adjacent coordinate values). If the engine speed or load does not fall within the coordinate boundaries during startup, it means that the engine speed or load is less than the minimum value of the corresponding coordinate value at startup. In this case, the 5 points with the smallest engine speed coordinate value and the 5 points with the smallest load coordinate value are read for interpolation. The general equation for interpolation is preferably chosen as y = jx. 2 +lx+m (where j, l, and m are determined by experimental fitting). Specifically, if the true long-term fuel correction value at one of the five points deviates from the interpolation equation y = jx... 2 The correction deviation determined by +lx+m is the absolute value of the difference between the two divided by the true value of the long-term fuel correction. When the error exceeds ±1%, the 5-point interpolation method is not used; instead, a 2-point linear interpolation method is used (the general equation for interpolation is: y = kx + c, which means linear interpolation is performed using two adjacent coordinate values). This allows for more realistic fuel injection correction under low engine speed and low load conditions, optimizing starting performance.

[0079] The third step is to determine the long-term fuel correction factor f(p) during the starting process based on atmospheric pressure and water temperature. Amb ,T Coolant ) LT The system can be stored after the vehicle is powered off. The basic method remains the same as in patent CN202010246641.0, "A Self-Learning Method for Long-Term Fuel Correction of a Gasoline Engine," which obtains the long-term fuel correction coefficient (the long-term fuel correction coefficient is the long-term fuel correction value obtained by this patent). During the acquisition of the long-term fuel correction coefficient, the average engine coolant temperature and average atmospheric pressure during the self-learning activation phase of each long-term fuel correction learning process are read, and the long-term fuel correction value under each average engine coolant temperature and average atmospheric pressure is stored (i.e., based on coolant temperature and atmospheric pressure, the corresponding long-term fuel correction value under coolant temperature and atmospheric pressure is also stored, and this value can also be saved after power-off). If the long-term fuel correction value under the same coolant temperature or atmospheric pressure is updated, its corresponding long-term fuel correction value will be directly replaced. Therefore, during engine start-up, the initial long-term fuel correction coefficient f(p) is... Amb ,T Coolant ) LTRaw The method for determining it is as follows: linear interpolation is performed on the long-term fuel correction based on atmospheric pressure and water temperature learned and stored at the time of start-up.

[0080] During each engine start-up process, record: Cnt, the number of times the engine speed change rate is lower than the preset change rate (15 rpm / s) from the starter disengagement to the engine speed reaching the preset engine speed (750 rpm in this example); t1, the time t1 from the start of fuel injection to the engine speed reaching the preset engine speed (750 rpm in this example); and the starting atmospheric pressure p at the start-up time. Amb and starting water temperature T Coolant Linear interpolation yields the initial long-term fuel correction factor f(p) based on atmospheric pressure and starter coolant temperature. Amb ,T Coolant ) LTRaw Initial long-term fuel correction factor f(p) Amb ,T Coolant ) LTRaw (It will be recorded and saved after the vehicle is powered off). Generally, the final starting process f(p) Amb ,T Coolant ) LT Take the initial long-term fuel correction factor f(p) with the fewest Cnt occurrences and shortest time t1 from the records. Amb ,T Coolant ) LTRaw If the initial long-term fuel trim factor corresponding to the minimum Cnt is not the initial long-term fuel trim factor with the shortest time t1, then the initial long-term fuel trim factor corresponding to the minimum Cnt is selected as the final starting process f(p). Amb ,T Coolant ) LT Specifically, if Cnt at the starting atmospheric pressure and starting coolant temperature does not exceed 1, then the initial long-term fuel correction factor f(p) with the shortest time t1 is adopted. Amb ,T Coolant ) LTRaw As the final starting process f(p) Amb ,T Coolant ) LT Startup process f(p) Amb ,T Coolant ) LT Save after vehicle power is off

[0081] Fourth, when the carbon canister is open, the long-term fuel trim during startup is not updated, i.e., f(n,rho) is not updated. LT And do not update f(p) Amb ,T Coolant ) LT This is because the carbon canister is not opened during startup. Opening the carbon canister during startup would further compromise startup performance and make it difficult to guarantee a smooth start.

[0082] Finally As a multiplicative correction factor for the fuel injection quantity during engine starting, it is used for fuel injection compensation. CNT is a preset value, and Cnt1 is incremented by 1 for each ignition after engine start-up until the engine starts completely or its value is not less than CNT, at which point it remains unchanged. After the engine stops, Cnt1 is reset to zero and will continue counting until the engine restarts. In this example, CNT is set to 30.

[0083] The engine start is complete when the engine speed rises to a preset engine speed (750 rpm in this example) and is maintained for more than 0.2 seconds.

[0084] After the engine starts, the multiplicative correction factor for the fuel injection quantity gradually transitions to 1. The transition method is as follows: the multiplicative correction factor for the fuel injection quantity in the current sampling cycle is equal to the multiplicative correction factor for the fuel quantity in the previous sampling cycle (the multiplicative correction factor for the fuel quantity in the first sampling cycle is equal to the value read immediately after starting). Subtract the first differential (the initial value of the first differential consists of two parts: the first part is determined by looking up the engine speed and load from a table, and the second part is determined by the coolant temperature; the product of the two parts is the accumulated value) until it approaches 1 (approaching 1 means that the difference between the multiplication correction factor of the fuel injection quantity in the current sampling period and 1 does not exceed ±0.02), and then keep it unchanged. The evaluation method for the first differential is that the engine speed fluctuation does not exceed ±20 rpm after the engine is started. The first differential can be saved after the vehicle is powered off.

[0085] As the engine's lifespan progresses and engine components age, the first differential needs to self-learn. The conditions for self-learning are:

[0086] 1. After the engine has started, it enters the idle speed closed-loop control. The range of speed fluctuation can be used to check whether the first differential needs to be self-learned. If abnormal speed fluctuation occurs, it needs to be handled.

[0087] 2. The oxygen sensor before the catalytic converter is not activated; when the oxygen sensor before the catalytic converter is not activated, fuel injection closed-loop cannot be performed, thus failing to optimize the fuel injection control when the fuel is in open-loop after startup, and avoiding learning errors caused by fuel injection closed-loop.

[0088] 3. If the vehicle mileage exceeds the preset mileage (20,000 km in this example) before the first differential update, the mileage will be reset to zero and start accumulating again after the first differential update. Controlling the frequency of the first differential update is crucial, as slower-aging components cannot learn too quickly, thus avoiding incorrect learning.

[0089] The first differential self-learning is allowed only if all of the above conditions are met simultaneously; if any one of the conditions is not met, the learning will be terminated.

[0090] 1) If, after starting, the engine speed fluctuates by more than ±20 rpm for more than 0.2 * t2 within the second preset time t2 (0.5 s in this example) of the idle closed-loop control, the first difference saved last time is multiplied by 1.02 (1 + first preset time) to obtain the first difference after this update. This is saved after the vehicle is powered off. The updated first difference will only take effect after the engine starts in the next vehicle driving cycle.

[0091] 2) If the engine speed fluctuation exceeds ±20 rpm for more than 0.3*t2 within the second preset time (0.5s in this example), the first difference saved last time is multiplied by 1.05(1+second preset time) to obtain the first difference after this update, and it is saved after the vehicle is powered off. The updated first difference will only take effect after the engine is started in the next vehicle driving cycle.

[0092] 3) If no engine speed fluctuation exceeds ±20 rpm within the second preset time (0.5 s in this example), the first difference saved last time is multiplied by 0.95 (1 - second preset time) to obtain the first difference after this update, and it is saved after the vehicle is powered off. The updated first difference will only take effect after the engine is started in the next vehicle driving cycle.

[0093] The above completes the description of the fuel injection control method for hybrid vehicle engines.

[0094] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A fuel injection control method for a hybrid electric vehicle engine, characterized in that, Based on the engine's long-term fuel correction value, the engine speed during the self-learning storage phase is judged. When the preset update conditions are met, the coordinate values ​​of engine speed and load are updated; otherwise, they are not updated. The long-term fuel correction factor during engine start-up is determined based on engine speed and load. ; The long-term fuel correction factor during engine starting is determined based on atmospheric pressure and water temperature. ; Close the carbon canister to disable fuel injection correction when the carbon canister is open; Will Fuel injection compensation is performed as a multiplicative correction factor for the fuel injection quantity.

2. The fuel injection control method for a hybrid electric vehicle engine according to claim 1, characterized in that, The long-term fuel trim value of the engine is obtained through a self-learning method for long-term fuel trim of gasoline engines; The self-learning method for long-term fuel trim of gasoline engines includes: Determine whether the self-learning operating condition judgment condition is met. If it is met, proceed to the self-learning operating condition stabilization stage. Determine whether the self-learning stabilization phase has ended; if so, proceed to the self-learning storage activation determination phase. After the self-learning storage activation judgment phase ends, the system automatically enters the self-learning storage phase. The self-learning storage activation judgment phase includes: collecting the total engine speed, total load, and total short-term fuel correction within the T2 time period. The self-learning storage phase includes: calculating the average engine speed nAvg, average load rhoAvg, average atmospheric pressure, average water temperature, and average short-term fuel correction STFTAvg within the T2 time period based on the collected total engine speed, total load, total atmospheric pressure, total water temperature, and total short-term fuel correction. The system then calculates the average engine speed nAvg, average load rhoAvg, average atmospheric pressure, average water temperature, and average short-term fuel correction STFTAvg based on the previously updated engine speed and load data. The original long-term fuel trim value r1 under (A,a), the original long-term fuel trim value r2 under engine speed load (A,b), the original long-term fuel trim value r3 under engine speed load (B,a), and the original long-term fuel trim value r4 under engine speed load (B,b) are used to calculate the last updated long-term fuel trim value rBef under engine speed load (nAvg,rhoAvg). Based on the last updated long-term fuel trim value rBef under engine speed load (nAvg,rhoAvg) and the average short-term fuel trim value STFTAvg over time period T2, the engine speed load (A,b) is calculated. The following long-term fuel trim values ​​are defined: r′1 under engine speed load (A, b), r′2 under engine speed load (B, a), r′3 under engine speed load (B, b), and r′4 under engine speed load (B, b). r′1, r′2, r′3, and r′4 are stored as new long-term fuel trim data within their respective engine speed loads, and the long-term fuel trim self-learning count is incremented by 1. Here, A and B are two adjacent values ​​in the engine speed coordinate axis array (A1, A2, A3, ..., AK), and the absolute value of the difference between these values ​​and the engine speed average value nAvg is the smallest. Two values, where A < B, and a and b are two adjacent values ​​in the load coordinate axis array (B1, B2, B3, ..., BJ), and the two values ​​with the smallest absolute difference from the load average value rhoAvg, and a < b; In particular, if the engine speed average value nAvg is less than or equal to A1, then A1 = A, and the same method is used to update only the long-term fuel correction value r′1 under engine speed load (A, a) and the long-term fuel correction value r′2 under engine speed load (A, b), without updating r′3 and r′4; If the load average value rhoAvg is less than or equal to B1, then B1 = a, and the same method is used to update only the long-term fuel correction value r′1 under engine speed load (A, a) and the long-term fuel correction value r′3 under engine speed load (B, a), without updating r′2 and r′4.

3. The fuel injection control method for a hybrid electric vehicle engine according to claim 1, characterized in that, In judging the engine speed during the self-learning storage phase, the update condition is as follows: Establish a coordinate system with engine speed and load as the horizontal and vertical axes, respectively. Set the engine speed coordinate axis array as (A1, A2, A3, ..., AK) and the load coordinate axis array as (B1, B2, B3, ..., BJ). That is, use K engine speed coordinate values ​​and J load coordinate values ​​as the coordinate system's coordinate values ​​on the corresponding engine speed and load axes, respectively. When the engine speed A1' during the self-learning storage phase is less than A1, update the engine speed coordinate values, i.e., (A1, A2, A3, ..., AK) is updated to (A1', ..., AK). When the load B1' in the self-learning storage phase is less than B1, the coordinate values ​​of the load are updated, i.e. (B1, B2, B3, ..., BJ) are updated to (B1', B1, B2, B3, ..., BJ), otherwise no update is performed; where engine speed A1' and load B1' are real-time values ​​in the self-learning storage phase.

4. The fuel injection control method for a hybrid electric vehicle engine according to claim 3, characterized in that, The long-term fuel correction factor during engine start-up is determined based on engine speed and load. The specific determination method is as follows: The long-term fuel correction value rBef of the engine is obtained through a self-learning method for long-term fuel correction of a gasoline engine. The long-term fuel correction value rBef is then interpolated in the following form: If the engine speed and load during startup fall within the coordinate value boundaries, the long-term fuel correction coefficient is obtained through linear interpolation. The general equation for linear interpolation is: y = kx + c, that is, linear interpolation is performed using two adjacent coordinate values. If the engine speed or load during startup does not fall within the coordinate value boundaries, then the engine speed or load during startup is less than the minimum value of the corresponding coordinate value. In this case, the five points with the smallest engine speed coordinate value and the five points with the smallest load coordinate value are read for interpolation. The general equation for interpolation is: y = jx 2 +lx+m; where k, c, j, l, and m are coefficients, x is the engine speed or load, and y is the long-term fuel correction coefficient; when the engine speed is fixed, it is obtained through y=jx 2 The relationship between load and long-term fuel correction factor is calculated using +lx+m; when the load is fixed, it is obtained through y=jx 2 +lx+m calculates the relationship between engine speed and long-term fuel correction factor.

5. The fuel injection control method for a hybrid electric vehicle engine according to claim 3, characterized in that, The long-term fuel correction factor during engine starting is determined based on atmospheric pressure and water temperature. The specific process is as follows: During each engine start-up, record: the number of times the engine speed change rate is lower than the preset rate of change (Cnt) from the starter disengagement to the engine speed rising to the preset engine speed; the time t1 from the start of fuel injection to the engine speed rising to the preset engine speed; and the starting atmospheric pressure. and starting water temperature The initial long-term fuel correction coefficient is obtained under the following conditions. Take the initial long-term fuel correction factor with the fewest Cnt occurrences and shortest time t1 from multiple records. As If the initial long-term fuel correction factor corresponding to the minimum Cnt is not the initial long-term fuel correction factor with the shortest time t1, then the initial long-term fuel correction factor corresponding to the minimum Cnt shall be selected as the initial long-term fuel correction factor. .

6. The fuel injection control method for a hybrid electric vehicle engine according to claim 4, characterized in that, If the engine speed or load does not fall within the coordinate boundary during startup, then if the engine speed or load during startup is less than the minimum value of the corresponding coordinate value, and if the true value of the long-term fuel correction value at one of the five points is consistent with the interpolation equation y=jx 2 If the deviation of the correction value determined by +lx+m, that is, the absolute value of the difference between the two divided by the true value of the long-term fuel correction value, exceeds ±1%, then linear interpolation is used for interpolation; if the total number of coordinate axes is less than 5 points, then linear interpolation is also used for interpolation.

7. The fuel injection control method for a hybrid electric vehicle engine according to claim 5, characterized in that, If starting atmospheric pressure and starting water temperature If Cnt does not exceed 1 under the given conditions, then the initial long-term fuel correction factor with the shortest time t1 is adopted. As ; Finally As a multiplicative correction factor for the amount of fuel injected during engine starting, fuel injection compensation is performed; As a preset value, The amount is increased by 1 for each ignition from the start of engine startup until the engine has started or the value is not less than CNT, after which it remains constant; after the engine stops... The count will be reset to zero until the engine restarts; after the engine restarts, the multiplication correction factor for the fuel injection quantity gradually transitions to 1. The transition method is as follows: the multiplication correction factor for the fuel injection quantity in the current sampling cycle is equal to the multiplication correction factor for the fuel quantity in the previous sampling cycle minus the first difference; where the multiplication correction factor for the fuel quantity in the first sampling cycle is equal to the value read immediately after starting. The first difference consists of two parts: the first part is determined by looking up the engine speed and load from a table, and the second part is determined by the water temperature. The product of the two parts is the cumulative amount. The evaluation method for the first difference is that the engine speed fluctuation does not exceed ±20 rpm after the engine starts.

8. The fuel injection control method for a hybrid electric vehicle engine according to claim 7, characterized in that, As the engine's lifespan progresses and engine components age, the first differential needs to self-learn. The conditions for self-learning are: ①After the engine starts, it enters idle closed-loop control; the speed fluctuation range is used to check whether the first differential needs self-learning. If abnormal speed fluctuation occurs, it needs to be handled. ②The oxygen sensor before the catalyst is not activated; ③ The vehicle mileage corresponding to the first differential not being updated exceeds the preset mileage; The first differential self-learning is allowed only if all the above conditions are met; if any one of the conditions is not met, the self-learning will be terminated.

9. The fuel injection control method for a hybrid electric vehicle engine according to claim 8, characterized in that, The normal range for speed fluctuation is ±20 rpm. When the speed fluctuation is normal or abnormal, the handling method is as follows: 1) If, after starting, the engine speed fluctuates by more than ±20 rpm for more than (0.2 * second preset time) within the second preset time of idling closed-loop control, the previously saved first difference is multiplied by (1 + second preset time) to obtain the updated first difference, which is saved after the vehicle is powered off. The updated first difference will only take effect after the engine starts in the next vehicle driving cycle. 2) If the engine speed fluctuation exceeds ±20 rpm for more than (0.3 * second preset time) within the second preset time, the first difference saved last time will be multiplied by (1 + second preset time) to obtain the first difference after this update, and it will be saved after the vehicle is powered off. The updated first difference will only take effect after the engine is started in the next vehicle driving cycle. 3) If no engine speed fluctuation exceeds ±20 rpm within the second preset time, the first difference saved last time is multiplied by (1 - second preset time) to obtain the updated first difference, and it is saved after the vehicle is powered off. The updated first difference will only take effect after the engine is started in the next vehicle driving cycle.

10. A fuel injection control method for a hybrid electric vehicle engine according to claim 5 or 7, characterized in that, The preset engine speed is 500-2000 rpm, and the preset variation rate is 10-40 rpm / s.

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