Engine combustion determination method and device

Abstract

The application discloses an engine combustion judging method and device, which comprises the following steps: obtaining the theoretical torque of an engine, the output torque of a generator, the rotating speed of a generator shaft, the rotating speed of an engine shaft, the moment of inertia of the generator and the moment of inertia of the engine in the power split mode of the engine; obtaining the estimated torque of the engine according to the output torque of the generator, the rotating speed of the generator shaft, the rotating speed of the engine shaft, the moment of inertia of the generator and the moment of inertia of the engine; comparing the estimated torque of the engine with the theoretical torque of the engine, and judging whether the engine cylinder is truly combusted according to the comparison result. Thus, the engine torque is indirectly estimated accurately, the trueness of the engine combustion is effectively judged, and the reliable and safe operation of a vehicle is ensured.

Description

Technical Field

[0001] This invention relates to the field of new energy vehicle technology, and in particular to an engine combustion determination method and device. Background Technology

[0002] For hybrid vehicles, when the hybrid mode is power-split mode, after the generator outputs positive torque to start the engine, the engine outputs positive torque and operates normally. The actual engine torque is related to parameters such as fuel energy density, ignition efficiency, and intake air volume. In existing technologies, this is generally obtained through actual bench calibration. However, this method assumes actual combustion within the engine cylinders.

[0003] In actual operation, it's possible for combustion to fail within the engine cylinders. However, the actual engine torque can still be determined by consulting tables or similar methods. Furthermore, because the alternator outputs positive torque to maintain the engine speed during engine speed control, it's impossible to determine whether combustion is actually occurring within the cylinders solely based on engine torque and speed. If combustion fails, it can lead to insufficient vehicle power and reduced comfort. In severe cases, it can even cause complete power loss and vehicle breakdown. Summary of the Invention

[0004] In view of the above problems, the present invention is proposed to provide an engine combustion judgment method and device, which can effectively judge the authenticity of engine combustion by accurately and indirectly estimating engine torque, thereby ensuring the reliable and safe operation of vehicles.

[0005] According to a first aspect of the present invention, an engine combustion determination method is provided, which is applied to hybrid vehicles;

[0006] The method includes:

[0007] In engine power split mode, the theoretical torque of the engine, the output torque of the generator, the generator shaft speed, the engine shaft speed, the moment of inertia of the generator, and the moment of inertia of the engine are obtained.

[0008] The estimated torque of the engine is obtained based on the generator output torque, the generator shaft speed, the engine shaft speed, the generator moment of inertia, and the engine moment of inertia.

[0009] The estimated torque of the engine is compared with the theoretical torque of the engine, and based on the comparison result, it is determined whether there is actual combustion in the engine cylinder.

[0010] Optionally, obtaining the estimated torque of the engine based on the generator output torque, the generator shaft speed, the engine shaft speed, the generator moment of inertia, and the engine moment of inertia includes:

[0011] Obtain the gear status of the hybrid vehicle;

[0012] If the gear position is the power split gear, then the estimated torque of the engine is obtained based on the generator output torque, the generator shaft speed, the engine shaft speed, the generator moment of inertia, and the engine moment of inertia.

[0013] If the gear position is a direct drive gear, then during the process of changing from the power split gear to the direct drive gear, the estimated torque of the engine is obtained based on the generator output torque and the generator shaft speed.

[0014] Optionally, obtaining the estimated torque of the engine based on the generator output torque, the generator shaft speed, the engine shaft speed, the generator moment of inertia, and the engine moment of inertia includes:

[0015] The inertial torque of the generator is determined based on the generator shaft speed and the generator's moment of inertia.

[0016] The inertial torque of the engine is determined based on the engine shaft rotation speed and the engine's moment of inertia.

[0017] The estimated torque of the engine is obtained based on the inertial torque of the generator, the inertial torque of the engine, the output torque of the generator, and a preset gear ratio.

[0018] Optionally, obtaining the estimated torque of the engine based on the inertial torque of the generator, the inertial torque of the engine, the output torque of the generator, and a preset gear ratio includes:

[0019] Obtain the engine target speed corresponding to the power split gear;

[0020] The inertial torque correction coefficient is determined based on the target engine speed, the engine shaft speed, and the generator shaft speed.

[0021] Based on the inertial torque correction coefficient, the inertial torque of the engine and the inertial torque of the generator are corrected respectively to obtain the corrected inertial torque of the engine and the corrected inertial torque of the generator.

[0022] The estimated torque of the engine is obtained based on the corrected inertial torque of the engine, the corrected inertial torque of the generator, the output torque of the generator, and the gear ratio.

[0023] Optionally, determining the inertial torque correction coefficient based on the target engine speed, the engine shaft speed, and the generator shaft speed includes:

[0024] The speed difference is determined based on the target engine speed and the engine shaft speed;

[0025] The target angular acceleration is determined based on the generator shaft speed and the engine shaft speed.

[0026] Based on the speed difference and the target angular acceleration, the inertial torque correction coefficient is determined by searching in a preset correction coefficient table; the correction coefficient table includes the calibration speed difference and the calibration angular acceleration, and also includes the calibration correction coefficients corresponding to the calibration speed difference and the calibration angular acceleration.

[0027] Optionally, obtaining the estimated torque of the engine based on the generator output torque and the generator shaft speed includes:

[0028] Obtain the generator target speed corresponding to the direct drive gear;

[0029] The generator shifting torque is determined based on the generator target speed and the generator shaft speed.

[0030] The estimated torque of the engine is obtained based on the generator shift speed regulation torque, the generator output torque, and the preset gear ratio.

[0031] Optionally, in the engine power split mode, acquiring the engine's theoretical torque, generator output torque, generator shaft speed, engine shaft speed, generator moment of inertia, and engine moment of inertia includes:

[0032] If the engine shaft speed is greater than the speed threshold, then after a preset time, it is determined that the engine is in the power split mode.

[0033] In the engine power split mode, the theoretical torque of the engine, the output torque of the generator, the rotational speed of the generator shaft, the rotational speed of the engine shaft, the rotational inertia of the generator, and the rotational inertia of the engine are obtained.

[0034] Optionally, comparing the estimated torque of the engine with the theoretical torque of the engine includes:

[0035] Obtain the front and rear wheel speeds of the vehicle;

[0036] The wheel speed difference is determined based on the front wheel speed and the rear wheel speed;

[0037] The validity of the estimated torque is determined based on the wheel speed difference.

[0038] If the estimated torque is determined to be valid, the estimated torque of the engine is compared with the theoretical torque of the engine.

[0039] Optionally, the method further includes:

[0040] If the difference between the theoretical torque of the engine and the estimated torque of the engine is greater than the target threshold, then the in-cylinder combustion of the engine is determined to be a failure.

[0041] If the difference between the theoretical torque of the engine and the estimated torque of the engine is less than or equal to the target threshold, then it is determined that the engine is undergoing true combustion in the cylinder.

[0042] According to a second aspect of the present invention, an engine combustion determination device is provided, comprising:

[0043] The acquisition module is used to acquire the engine's theoretical torque, generator output torque, generator shaft speed, engine shaft speed, generator moment of inertia, and engine moment of inertia in engine power split mode.

[0044] The torque estimation module is used to obtain the estimated torque of the engine based on the output torque of the generator, the rotational speed of the generator shaft, the rotational speed of the engine shaft, the moment of inertia of the generator, and the moment of inertia of the engine.

[0045] The judgment module is used to compare the estimated torque of the engine with the theoretical torque of the engine, and based on the comparison result, to determine whether there is actual combustion in the engine cylinder.

[0046] The above-described one or more technical solutions in the embodiments of this specification have at least the following technical effects:

[0047] This specification provides an engine combustion determination method and apparatus. In engine power split mode, it acquires the engine's theoretical torque, generator output torque, generator shaft speed, engine shaft speed, generator moment of inertia, and engine moment of inertia. Based on these parameters, an estimated engine torque is obtained. The estimated torque is compared with the engine's theoretical torque, and the comparison result determines whether actual combustion occurs within the engine cylinders. Thus, by accurately and indirectly estimating engine torque, the authenticity of engine combustion is effectively determined, ensuring reliable and safe vehicle operation.

[0048] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention are described below. Attached Figure Description

[0049] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0050] Figure 1 A flowchart of an engine combustion determination method according to an embodiment of the present invention is shown.

[0051] Figure 2 A structural diagram of a power-split mode multi-speed hybrid transmission according to an embodiment of the present invention is shown.

[0052] Figure 3 A schematic diagram showing the input-output torque relationship of each component in a single planetary gear mechanism according to an embodiment of the present invention is shown.

[0053] Figure 4 A block diagram of an engine combustion determination device according to an embodiment of the present invention is shown. Detailed Implementation

[0054] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0055] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0056] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0057] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0058] In hybrid vehicles, combined with Figure 2 As shown, the engine's flywheel is connected to the planet carrier of the single planetary gear set, the generator is connected to the sun gear, and the ring gear is connected to both sides of the S1 synchronizer (i.e., Figure 2 The S1L and S1R gears are connected to the wheels via differentials and half-shafts, respectively, with two sets of gears having different speed ratios. The drive motor is also connected to the wheels via differentials and half-shafts with another set of gears. When synchronizer S2 is in the middle position and either the left or right side of synchronizer S1 is engaged, two hybrid transmission gears with different speed ratios (ECVT1 and ECVT2) are formed. When synchronizers S1 and S2 are combined in pairs, four direct-drive gears (1st, 2nd, 3rd, and 4th) are achieved. When synchronizer S2 is connected on the left and synchronizer S1 is in the middle, it is a series gear; when both synchronizers S1 and S2 are in the middle, it is neutral, i.e., the pure electric EV gear (driven by the battery and drive motor). Rotating the shift drum to different positions (positions 1-10) controls the two synchronizers to different positions, corresponding to different gears. The shift drum position changes are performed sequentially, as shown in Table 1 below. In ECVT1 or ECVT2 mode, after the engine power is transmitted to the planetary carrier via the transmission input shaft, part of the power is transmitted to the generator via the sun gear, and the other part is transmitted to the wheel ends via the ring gear system, thus achieving engine power splitting. Furthermore, the electrical energy generated by the generator or directly supplied by the power battery is transmitted to the drive motor and output to the wheel ends in parallel via the gear system. This hybrid mode under this condition is defined as ECVT power splitting mode.

[0059]

[0060] Table 1

[0061] In actual operation, incomplete combustion may occur within the engine cylinders. Because the generator outputs positive torque to maintain the engine speed during engine speed control, it is impossible to determine whether actual combustion is occurring within the engine cylinders solely based on engine torque and speed.

[0062] Currently, the actual combustion situation in an engine cylinder can be determined by measuring the air-fuel ratio using an engine oxygen sensor. An excessively high or low air-fuel ratio can be considered a combustion failure. However, using an oxygen sensor requires that combustion has already occurred in the engine and the sensor temperature has reached a certain value; it is not applicable to the conditions during engine startup and has certain limitations.

[0063] Based on the above, in power split mode, the engine torque can be indirectly estimated by the torque of other power components such as generators. When the difference between the directly calculated engine torque and the indirectly estimated engine torque exceeds the target threshold, the engine combustion is considered to have failed.

[0064] Specifically, embodiments of the present invention provide an engine combustion determination method, combined with Figure 1 The flowchart shown illustrates that the engine combustion determination method includes steps 101 to 103:

[0065] Step 101: In engine power split mode, obtain the engine's theoretical torque, generator output torque, generator shaft speed, engine shaft speed, generator moment of inertia, and engine moment of inertia.

[0066] In this embodiment, the power split mode refers to a hybrid mode in which electrical energy generated by a generator or directly supplied to the drive motor by a power battery is then output to the wheel end in parallel via a gear system.

[0067] The theoretical torque of an engine refers to the engine torque obtained by looking up a table after the generator outputs positive torque to start the engine, assuming that the engine outputs positive torque and runs normally.

[0068] The generator output torque, generator shaft speed, and engine shaft speed can be acquired in real time. The generator's moment of inertia and the engine's moment of inertia are set constants and can also be directly obtained.

[0069] It should be noted that calculating the estimated torque of the engine requires the engine to be fully started and in stable operation first. After the engine starts, it will be checked whether it is in engine power split mode.

[0070] In this embodiment, the engine startup status can be determined by the engine speed. If the engine shaft speed is greater than a speed threshold, the engine is considered to have started. The speed threshold can be 800 rpm.

[0071] In practical logic, a preset time confirmation can also be added (for example, a preset time of 1 second) to ensure that the engine starts fully and enters a stable operating state.

[0072] Specifically, if the engine shaft speed is greater than the speed threshold, then after a preset time, it is determined that the engine is in the power split mode.

[0073] In the engine power split mode, the theoretical torque of the engine, the output torque of the generator, the rotational speed of the generator shaft, the rotational speed of the engine shaft, the rotational inertia of the generator, and the rotational inertia of the engine are obtained.

[0074] It should be noted that the power split mode can be determined by the gear position. If the current gear position is a power split gear (e.g., ECVT1 or ECVT2), then it is considered to be in power split mode.

[0075] In addition, during the process of shifting from ECVT to direct drive, this embodiment assumes that the actual hybrid mode is still the power split mode. The direct drive gears include: gears 1, 2, 3, and 4 in Table 1.

[0076] For example, if the current gear of the hybrid vehicle is ECVT1 or ECVT2, it is in power split mode; if the gear is detected to change from ECVT1 to 2, it is considered to still be in power split mode during the process of changing from ECVT1 to 2.

[0077] Step 102: Based on the generator output torque, the generator shaft speed, the engine shaft speed, the generator moment of inertia, and the engine moment of inertia, obtain the estimated torque of the engine;

[0078] In this embodiment, the method for calculating the estimated torque differs slightly due to the different power splitting modes.

[0079] In one embodiment, if the engine is in a stable power-split mode, i.e., the gear is in a power-split gear (e.g., ECVT1 or ECVT2), the estimated torque of the engine can be obtained based on the generator output torque, the generator shaft speed, the engine shaft speed, the generator moment of inertia, and the engine moment of inertia.

[0080] In one embodiment, if the gear position is direct drive, then during the transition from the power split gear to the direct drive gear, the estimated torque of the engine can be obtained based on the generator output torque and the generator shaft speed.

[0081] Step 103: Compare the estimated torque of the engine with the theoretical torque of the engine, and determine whether there is actual combustion in the engine cylinder based on the comparison result.

[0082] In this embodiment, after obtaining the estimated torque, comparing the estimated torque with the theoretical torque allows for a determination of whether actual combustion occurs within the engine cylinders. If actual combustion does not occur within the engine cylinders, it indicates insufficient work being done, and the estimated torque will be significantly lower than the theoretical torque. If actual combustion occurs within the engine cylinders, the indirectly obtained estimated torque will be closer to the theoretical torque.

[0083] Therefore, this embodiment is based on engine calibration experiments and a target threshold is preset.

[0084] If the difference between the theoretical torque of the engine and the estimated torque of the engine is greater than the target threshold, then the combustion in the engine cylinder is judged to have failed, that is, there is no actual combustion.

[0085] If the difference between the theoretical torque of the engine and the estimated torque of the engine is less than or equal to the target threshold, then it is determined that the engine is undergoing true combustion in the cylinder.

[0086] In summary, this embodiment accurately and indirectly estimates engine torque, effectively determining the authenticity of combustion within the engine cylinders. This allows for timely engine shutdown in the event of combustion failure, preventing the generator from continuously outputting positive torque and dragging the engine due to lack of ignition. Simultaneously, it ensures reliable and safe vehicle operation.

[0087] The calculation method for estimated torque differs slightly depending on the power shunt mode mentioned in the foregoing embodiments. Specifically, for the power shunt mode under stable operation, the estimated torque can be determined by referring to the following steps:

[0088] The inertial torque of the generator is determined based on the generator shaft speed and the generator's moment of inertia.

[0089] The inertial torque of the engine is determined based on the engine shaft rotation speed and the engine's moment of inertia.

[0090] The estimated torque of the engine is obtained based on the inertial torque of the generator, the inertial torque of the engine, the output torque of the generator, and a preset gear ratio.

[0091] Specifically, combining Figure 3As shown, the dynamics of a single planetary gear set and the torque relationship under power split mode are analyzed as follows:

[0092] Based on the motion and dynamics analysis of a single planetary gear set, the rotational speeds of the sun gear, ring gear, and planet carrier are as follows:

[0093] n S +Kn R =(1+K)n PC

[0094] The relationship between the torques acting on these three components is as follows:

[0095] T S :T R :T PC =1:K:-(1+K)

[0096] Where, n s n is the rotational speed of the sun gear. R n is the rotational speed of the gear ring. pc T is the rotational speed of the planetary carrier. s T represents the torque of the sun gear. R T is the gear ring torque. PC The planetary carrier torque is K = Z. R :Z S K is the number of teeth Z of the gear ring. R With the number of teeth Z of the sun gear S The ratio of the number of teeth.

[0097] Based on the motion and dynamics analysis of the planetary gearbox components, and the component connection relationships of the hybrid transmission structure described above, the torque relationship between the input and output torques of the engine, generator, and vehicle load end of the single planetary gearbox mechanism, after considering the component inertia, is shown below under the power split mode. Furthermore, the relationship between the estimated engine torque and the generator output torque can be derived:

[0098]

[0099] Wherein: T e For the estimated torque of the engine, T P1 T is the output torque of the generator. Sin T is the input torque for the sun gear. Sout Js is the output torque of the sun gear, ω is the moment of inertia of the sun gear. S T is the angular velocity of the sun wheel. PCin To input torque to the planetary carrier, J PC Let ω be the moment of inertia of the planetary carrier. PC n is the angular velocity of the planetary carrier. S n is the rotational speed of the sun gear. P1 n is the generator shaft speed. PC n is the rotational speed of the planetary carrier. eT is the engine shaft speed. PCout The output torque of the planetary carrier is K, where K is the gear ratio and ω is ω. P1 The angular velocity of the generator shaft, ω e T is the angular velocity of the engine shaft. Rin T is the input torque for the gear ring. Rout J is the output torque of the gear ring. R Let be the moment of inertia of the gear ring.

[0100] First, determine the engine's angular velocity based on the engine shaft speed, and then calculate the engine's inertial torque based on the engine's angular velocity and moment of inertia.

[0101] Next, based on the generator shaft speed, determine the generator's angular velocity, and then calculate the generator's inertial torque based on the generator's angular velocity and moment of inertia.

[0102] Finally, based on the generator's inertial torque, the engine's inertial torque, the generator's output torque, and the preset gear ratio, the estimated torque of the engine can be calculated.

[0103] It is important to note that when calculating the inertial torque of the generator and engine, the angular acceleration is calculated using the quotient of the speed difference and then filtered through a low-pass filter. The accuracy decreases when the angular velocity is large. Furthermore, the accuracy of the inertial torque also decreases when the engine is under speed control, especially during large speed differences (such as when the engine has just started and is not yet stable). Therefore, the inertial torque is corrected using a calibrable correction factor based on the target angular acceleration and the speed difference. Specific steps may include:

[0104] Obtain the engine target speed corresponding to the power split gear;

[0105] The inertial torque correction coefficient is determined based on the target engine speed, the engine shaft speed, and the generator shaft speed.

[0106] Based on the inertial torque correction coefficient, the inertial torque of the engine and the inertial torque of the generator are corrected respectively to obtain the corrected inertial torque of the engine and the corrected inertial torque of the generator.

[0107] The estimated torque of the engine is obtained based on the corrected inertial torque of the engine, the corrected inertial torque of the generator, the output torque of the generator, and the gear ratio.

[0108] In this embodiment, the power split settings include ECVT1 and ECVT2. Each power split setting has a corresponding target engine speed. Based on the target engine speed and the engine shaft speed, the speed difference can be determined. Then, based on the generator shaft speed and the engine shaft speed, the target angular acceleration is calculated; specifically, the angular acceleration of the generator and the engine needs to be calculated first, and then the larger value between the generator's angular acceleration and the engine's angular acceleration is taken as the target angular acceleration.

[0109] Then, based on the speed difference and the target angular acceleration, the inertial torque correction coefficient is determined by looking up the value in a preset correction coefficient table. The correction coefficient table includes the calibration speed difference and the calibration angular acceleration, and also includes calibration correction coefficients corresponding to the calibration speed difference and the calibration angular acceleration. The data in the correction coefficient table and the correspondence between the data can be obtained through calibration experiments.

[0110] Finally, the inertial torque of the engine and the inertial torque of the generator are multiplied by the inertial torque correction factor to obtain the corrected inertial torque of the engine and the corrected inertial torque of the generator, respectively. When calculating the estimated torque, the corrected inertial torque of the engine and the corrected inertial torque of the generator are substituted into the aforementioned formula for calculation.

[0111] For the other power split mode, namely when shifting from power split mode to direct drive mode, the following steps can be used to calculate and estimate torque:

[0112] Obtain the generator target speed corresponding to the direct drive gear;

[0113] The generator shifting torque is determined based on the generator target speed and the generator shaft speed.

[0114] The estimated torque of the engine is obtained based on the generator shift speed regulation torque, the generator output torque, and the preset gear ratio.

[0115] In this embodiment, similar to the previous one, the direct drive gears include gears 1, 2, 3, and 4. Each direct drive gear has a corresponding target generator speed. There is a process from the power split gear to the direct drive gear, which lasts approximately 1.5-2 seconds. During this process, it is still considered to be in power split mode. During this process, the generator speed is adjusted to the target speed of the S2 synchronizer. Once the S2 synchronizer speed is synchronized to the target speed, gear engagement is performed, either by engaging the left side (i.e., the planetary gear ring speed) or the right side (0) of the S2 synchronizer to complete the gear engagement. The final generator output torque T... P1This is the sum of the engine power split balancing negative torque (estimated engine torque) and the shifting speed regulation torque based on the generator target speed difference using PID control. In power split mode, during stable operation, the engine and generator satisfy the torque relationship of the planetary gearbox power components described above. Additionally, the generator shifting speed regulation torque disrupts the original stable balance, causing a change in the generator shaft speed to achieve speed regulation. The torque relationship between the engine and generator can be expressed by the following formula:

[0116] T e =-(1+K)(T) P1 -T P1Spd )

[0117] Among them, T e The estimated torque of the engine is given by K, where K is the gear ratio and T is the torque of the engine. P1 T is the output torque of the generator. P1Spd This refers to the torque used for shifting and adjusting the speed of the generator.

[0118] In summary, the above methods address engine torque estimation under two conditions: stable operation in power-split mode and power-split mode with direct drive. To ensure a smooth torque transition, the estimated torque under the two conditions can be controlled by a preset slope during switching. For example, a target upward slope and a target downward slope can be preset. If the currently calculated estimated torque differs significantly from the previously calculated estimated torque (e.g., the upward slope is greater than the target upward slope, or the downward slope is less than the target downward slope), then the current estimated torque is calculated using the preset target upward slope or target downward slope, combined with the previously calculated estimated torque, and used to replace the currently calculated estimated torque.

[0119] Additionally, it should be noted that this embodiment also performs a validity assessment of the estimated engine torque in power split mode.

[0120] Considering the potential for vehicle slippage on low-friction surfaces, the engine, generator, and gear ring speeds change rapidly in short bursts during power-split mode. This results in a significant discrepancy between the calculated engine and generator inertial torque and the actual torque. Therefore, to avoid misjudging the true nature of engine combustion under such conditions, the estimated engine torque can be considered invalid. Specific steps may include:

[0121] Obtain the front and rear wheel speeds of the vehicle;

[0122] The wheel speed difference is determined based on the front wheel speed and the rear wheel speed;

[0123] The validity of the estimated torque is determined based on the wheel speed difference.

[0124] If the estimated torque is determined to be valid, the estimated torque of the engine is compared with the theoretical torque of the engine.

[0125] In this embodiment, the difference in wheel speed between the driving wheels (front wheels) and non-driving wheels (rear wheels) during driving is compared with a wheel speed threshold. By adding a hysteresis loop for the vehicle speed difference, frequent oscillations in the judgment result are effectively avoided. When the wheel speed difference is greater than the wheel speed threshold, the vehicle is considered to be slipping, and the estimated torque is determined to be invalid. When the wheel speed difference is less than or equal to the wheel speed threshold, the vehicle is considered not to be slipping, and the estimated torque is determined to be valid. At this time, the estimated torque of the engine can continue to be compared with the theoretical torque of the engine.

[0126] In summary, the engine combustion determination method provided in this specification obtains the engine's theoretical torque, generator output torque, generator shaft speed, engine shaft speed, generator moment of inertia, and engine moment of inertia in engine power split mode. Based on the generator output torque, generator shaft speed, engine shaft speed, generator moment of inertia, and engine moment of inertia, an estimated engine torque is obtained. The estimated engine torque is compared with the engine's theoretical torque, and based on the comparison result, it is determined whether actual combustion occurs in the engine cylinders. Thus, by accurately and indirectly estimating engine torque, the authenticity of engine combustion is effectively determined, ensuring reliable and safe vehicle operation.

[0127] Based on the same inventive concept, combined with Figure 4 As shown, this embodiment of the invention also provides an engine combustion determination device, comprising:

[0128] The acquisition module is used to acquire the engine's theoretical torque, generator output torque, generator shaft speed, engine shaft speed, generator moment of inertia, and engine moment of inertia in engine power split mode.

[0129] The torque estimation module is used to obtain the estimated torque of the engine based on the output torque of the generator, the rotational speed of the generator shaft, the rotational speed of the engine shaft, the moment of inertia of the generator, and the moment of inertia of the engine.

[0130] The judgment module is used to compare the estimated torque of the engine with the theoretical torque of the engine, and based on the comparison result, to determine whether there is actual combustion in the engine cylinder.

[0131] Optionally, the torque estimation module is also used for:

[0132] The inertial torque of the generator is determined based on the generator shaft speed and the generator's moment of inertia.

[0133] The inertial torque of the engine is determined based on the engine shaft rotation speed and the engine's moment of inertia.

[0134] The estimated torque of the engine is obtained based on the inertial torque of the generator, the inertial torque of the engine, the output torque of the generator, and a preset gear ratio.

[0135] Optionally, the torque estimation module is also used for:

[0136] Obtain the engine target speed corresponding to the power split gear;

[0137] The inertial torque correction coefficient is determined based on the target engine speed, the engine shaft speed, and the generator shaft speed.

[0138] Based on the inertial torque correction coefficient, the inertial torque of the engine and the inertial torque of the generator are corrected respectively to obtain the corrected inertial torque of the engine and the corrected inertial torque of the generator.

[0139] The estimated torque of the engine is obtained based on the corrected inertial torque of the engine, the corrected inertial torque of the generator, the output torque of the generator, and the gear ratio.

[0140] Optionally, the torque estimation module is also used for:

[0141] The speed difference is determined based on the target engine speed and the engine shaft speed;

[0142] The target angular acceleration is determined based on the generator shaft speed and the engine shaft speed.

[0143] Based on the speed difference and the target angular acceleration, the inertial torque correction coefficient is determined by searching in a preset correction coefficient table; the correction coefficient table includes the calibration speed difference and the calibration angular acceleration, and also includes the calibration correction coefficients corresponding to the calibration speed difference and the calibration angular acceleration.

[0144] Optionally, the torque estimation module is also used for:

[0145] Obtain the generator target speed corresponding to the direct drive gear;

[0146] The generator shifting torque is determined based on the generator target speed and the generator shaft speed.

[0147] The estimated torque of the engine is obtained based on the generator shift speed regulation torque, the generator output torque, and the preset gear ratio.

[0148] Optionally, the acquisition module is also used for:

[0149] If the engine shaft speed is greater than the speed threshold, then after a preset time, it is determined that the engine is in the power split mode.

[0150] In the engine power split mode, the theoretical torque of the engine, the output torque of the generator, the rotational speed of the generator shaft, the rotational speed of the engine shaft, the rotational inertia of the generator, and the rotational inertia of the engine are obtained.

[0151] Optionally, the judgment module is also used for:

[0152] Obtain the front and rear wheel speeds of the vehicle;

[0153] The wheel speed difference is determined based on the front wheel speed and the rear wheel speed;

[0154] The validity of the estimated torque is determined based on the wheel speed difference.

[0155] If the estimated torque is determined to be valid, the estimated torque of the engine is compared with the theoretical torque of the engine.

[0156] Optionally, the judgment module is also used for:

[0157] If the difference between the theoretical torque of the engine and the estimated torque of the engine is greater than the target threshold, then the in-cylinder combustion of the engine is determined to be a failure.

[0158] If the difference between the theoretical torque of the engine and the estimated torque of the engine is less than or equal to the target threshold, then it is determined that the engine is undergoing true combustion in the cylinder.

[0159] In summary, the engine combustion determination device provided in this specification acquires the engine's theoretical torque, generator output torque, generator shaft speed, engine shaft speed, generator moment of inertia, and engine moment of inertia in engine power split mode. Based on the generator output torque, generator shaft speed, engine shaft speed, generator moment of inertia, and engine moment of inertia, an estimated engine torque is obtained. The estimated engine torque is compared with the engine's theoretical torque, and based on the comparison result, it is determined whether actual combustion occurs in the engine cylinders. Thus, by accurately and indirectly estimating engine torque, the authenticity of engine combustion is effectively determined, ensuring reliable and safe vehicle operation.

[0160] Those skilled in the art will understand that, for the sake of convenience and brevity, the specific working process of the engine combustion judgment device described above can be referred to the corresponding process in the aforementioned method, and will not be elaborated further here.

[0161] The above are merely various embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for determining engine combustion, characterized in that, Applied to hybrid vehicles; The method includes: In engine power split mode, the theoretical torque of the engine, the output torque of the generator, the generator shaft speed, the engine shaft speed, the moment of inertia of the generator, and the moment of inertia of the engine are obtained. Obtain the gear status of the hybrid vehicle; If the gear position is a power split gear, then the inertial torque of the generator is determined based on the generator shaft speed and the generator's moment of inertia; the inertial torque of the engine is determined based on the engine shaft speed and the engine's moment of inertia; the inertial torques of the generator and the engine are corrected, and based on the corrected inertial torques of the generator and the engine, the generator output torque, and a preset gear ratio, the estimated torque of the engine is obtained. The estimated torque of the engine is compared with the theoretical torque of the engine, and based on the comparison result, it is determined whether there is actual combustion in the engine cylinder.

2. The method according to claim 1, characterized in that, After obtaining the gear position of the hybrid vehicle, the method further includes: If the gear position is a direct drive gear, then during the process of changing from the power split gear to the direct drive gear, the estimated torque of the engine is obtained based on the generator output torque and the generator shaft speed.

3. The method according to claim 1, characterized in that, The step of correcting the inertial torque of the generator and the inertial torque of the engine, and obtaining the estimated torque of the engine based on the corrected inertial torque of the generator, the corrected inertial torque of the engine, the output torque of the generator, and a preset gear ratio, includes: Obtain the engine target speed corresponding to the power split gear; The inertial torque correction coefficient is determined based on the target engine speed, the engine shaft speed, and the generator shaft speed. Based on the inertial torque correction coefficient, the inertial torque of the engine and the inertial torque of the generator are corrected respectively to obtain the corrected inertial torque of the engine and the corrected inertial torque of the generator. The estimated torque of the engine is obtained based on the corrected inertial torque of the engine, the corrected inertial torque of the generator, the output torque of the generator, and the gear ratio.

4. The method according to claim 3, characterized in that, The step of determining the inertial torque correction coefficient based on the engine target speed, the engine shaft speed, and the generator shaft speed includes: The speed difference is determined based on the target engine speed and the engine shaft speed; The target angular acceleration is determined based on the generator shaft speed and the engine shaft speed. Based on the speed difference and the target angular acceleration, the inertial torque correction coefficient is determined by searching in a preset correction coefficient table; the correction coefficient table includes the calibration speed difference and the calibration angular acceleration, and also includes the calibration correction coefficients corresponding to the calibration speed difference and the calibration angular acceleration.

5. The method according to claim 2, characterized in that, The step of obtaining the estimated torque of the engine based on the generator output torque and the generator shaft speed includes: Obtain the generator target speed corresponding to the direct drive gear; The generator shifting torque is determined based on the generator target speed and the generator shaft speed. The estimated torque of the engine is obtained based on the generator shift speed regulation torque, the generator output torque, and the preset gear ratio.

6. The method according to claim 1, characterized in that, In the engine power split mode, the acquisition of the engine's theoretical torque, generator output torque, generator shaft speed, engine shaft speed, generator moment of inertia, and engine moment of inertia includes: If the engine shaft speed is greater than the speed threshold, then after a preset time, it is determined that the engine is in the power split mode. In the engine power split mode, the theoretical torque of the engine, the output torque of the generator, the rotational speed of the generator shaft, the rotational speed of the engine shaft, the rotational inertia of the generator, and the rotational inertia of the engine are obtained.

7. The method according to claim 1, characterized in that, The comparison of the estimated torque of the engine with the theoretical torque of the engine includes: Obtain the front and rear wheel speeds of the vehicle; The wheel speed difference is determined based on the front wheel speed and the rear wheel speed; The validity of the estimated torque is determined based on the wheel speed difference. If the estimated torque is determined to be valid, the estimated torque of the engine is compared with the theoretical torque of the engine.

8. The method according to claim 1, characterized in that, The method further includes: If the difference between the theoretical torque of the engine and the estimated torque of the engine is greater than the target threshold, then the in-cylinder combustion of the engine is determined to be a failure. If the difference between the theoretical torque of the engine and the estimated torque of the engine is less than or equal to the target threshold, then it is determined that the engine is undergoing true combustion in the cylinder.

9. An engine combustion detection device, characterized in that, The engine combustion determination method according to any one of claims 1-8; the apparatus includes: The acquisition module is used to acquire the engine's theoretical torque, generator output torque, generator shaft speed, engine shaft speed, generator moment of inertia, and engine moment of inertia in engine power split mode. The torque estimation target torque is used to obtain the estimated torque of the engine based on the generator output torque, the generator shaft speed, the engine shaft speed, the generator moment of inertia, and the engine moment of inertia. The judgment module is used to compare the estimated torque of the engine with the theoretical torque of the engine, and based on the comparison result, to determine whether there is actual combustion in the engine cylinder.

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