Variable valve engine valve timing auxiliary heating control method, device and system

Abstract

The present application relates to the technical field of diesel engine valve train, and discloses a kind of auxiliary heating control method of variable valve engine valve train, comprising: obtaining engine speed, engine battery voltage, engine coolant temperature, first oil temperature and second oil temperature;According to engine coolant temperature, first oil temperature and second oil temperature, oil heating reference temperature is calculated, and oil heating time is determined;According to engine speed and oil heating reference temperature, the current heating control mode of valve train is determined;According to engine battery voltage and heating device fault state, heating device is controlled to heat the oil in auxiliary oil tank according to the current heating control mode within oil heating time.The present application also discloses a kind of auxiliary heating control device and system of variable valve engine valve train.The variable valve engine valve train auxiliary heating control method provided by the present application can improve engine power and fuel economy.

Description

Technical Field

[0001] This invention relates to the field of diesel engine valve train technology, and in particular to an auxiliary heating control method, a variable valve timing engine valve train auxiliary heating control device, and a variable valve timing engine valve train auxiliary heating control system. Background Technology

[0002] Traditional mechanical variable valve timing systems, due to their simple structure and limited adjustment range, cannot meet increasingly stringent emission requirements. Electro-hydraulic fully variable valve timing technology, by adjusting the flow of high and low pressure oil, can achieve continuous variation in valve opening and closing times across the entire valve lift range, thus achieving precise control of engine valve timing.

[0003] However, during cold starts at low temperatures, problems arise such as high oil viscosity, poor fluidity, slow system pressure build-up, and significant valve lag. Existing technologies primarily focus on the system layout of the heating device for the valve train of fully variable valve timing diesel engines, with little attention paid to its control methods. Summary of the Invention

[0004] This invention provides a method, device, and system for auxiliary heating control of the valve train of a variable valve engine, which solves the problems in related technologies, such as high oil viscosity, poor fluidity, slow system pressure build-up, and large valve lag during low-temperature cold starts.

[0005] As a first aspect of the present invention, an auxiliary heating control method for the valve train of a variable valve timing engine is provided. When the engine is operating normally, a fuel pump delivers engine oil from the main fuel tank to an auxiliary fuel tank. A first oil temperature sensor and a heating device are installed in the auxiliary fuel tank. The outlet of the auxiliary fuel tank is connected to a high-pressure fuel pump, and a second oil temperature sensor is installed on the high-pressure fuel pump. The auxiliary heating control method for the variable valve timing engine includes:

[0006] Step S1: Obtain engine speed, engine battery voltage, engine coolant temperature, heating device fault status, first oil temperature detected by the first oil temperature sensor, and second oil temperature detected by the second oil temperature sensor;

[0007] Step S2: Calculate the oil heating reference temperature based on the engine coolant temperature, the first oil temperature, and the second oil temperature, and determine the oil heating time based on the oil heating reference temperature;

[0008] Step S3: Determine the current heating control mode of the variable valve timing mechanism based on the engine speed and the oil heating reference temperature;

[0009] Step S4: Based on the engine battery voltage and the fault status of the heating device, control the heating device to heat the oil in the auxiliary oil tank during the oil heating time according to the current heating control mode of the variable valve timing mechanism, so as to achieve auxiliary heating of the variable valve timing mechanism.

[0010] Further, the step of calculating the oil heating reference temperature based on the engine coolant temperature, the first oil temperature, and the second oil temperature, and determining the oil heating time based on the oil heating reference temperature, includes:

[0011] Step S201: Determine whether the first oil temperature sensor is faulty; if yes, proceed to step S202; if no, proceed to step S205.

[0012] Step S202: Determine whether the communication enable for the engine coolant temperature is turned on; if yes, proceed to step S203; if no, proceed to step S204.

[0013] Step S203: The reference temperature for heating the engine oil is the smaller of the engine coolant temperature and the second engine oil temperature;

[0014] Step S204: The reference temperature for heating the engine oil is taken as the second engine oil temperature;

[0015] Step S205: The oil heating reference temperature is taken as the first oil temperature;

[0016] Step S206: Determine the first oil heating time by querying the first oil heating time curve in real time based on the oil heating reference temperature;

[0017] Step S207: Determine the second oil heating time by querying the second oil heating time curve in real time based on the oil heating reference temperature.

[0018] Further, determining the current heating control mode of the variable valve timing mechanism based on the engine speed and the oil heating reference temperature includes:

[0019] Step S301: Determine whether the oil heating reference temperature is less than the first preset oil temperature threshold; if yes, proceed to step S302; if no, proceed to step S305.

[0020] Step S302: The variable valve timing mechanism of the engine needs to be preheated. Control the variable valve timing mechanism of the engine to switch from the non-heating mode to the first heating mode, and start timing through the first heating timer.

[0021] Step S303: Determine whether the current engine speed is less than the preset lower speed limit; if yes, proceed to step S304; if no, proceed to step S305.

[0022] Step S304: Determine whether the timing duration of the first heating timer is greater than or equal to the first oil heating time, and simultaneously determine whether the oil heating reference temperature is greater than or equal to the first preset heating termination temperature; if the timing duration of the first heating timer is greater than or equal to the first oil heating time or the oil heating reference temperature is greater than or equal to the first preset heating termination temperature, then proceed to step S305; otherwise, return to step S302, and control the variable valve timing mechanism to continue maintaining the first heating mode;

[0023] Step S305: Control the variable valve timing mechanism of the engine to enter the non-heating mode;

[0024] Step S306: Determine whether the current engine speed is greater than or equal to the preset upper limit of speed; if yes, proceed to step S308; if no, proceed to step S307.

[0025] Step S307: Determine whether the number of times the engine failed to start is greater than or equal to 3; if yes, proceed to step S311; if no, return to step S301.

[0026] Step S308: Determine whether the oil heating reference temperature is less than the second preset oil temperature threshold; if yes, proceed to step S309; ​​if no, proceed to step S311.

[0027] Step S309: The variable valve timing mechanism of the engine requires post-heating. Control the variable valve timing mechanism of the engine to switch from the non-heating mode to the second heating mode, and start timing through the second heating timer.

[0028] Step S310: Determine whether the timing duration of the second heating timer is greater than or equal to the second oil heating time, and simultaneously determine whether the oil heating reference temperature is greater than or equal to the second preset heating termination temperature; if the timing duration of the second heating timer is greater than or equal to the second oil heating time or the oil heating reference temperature is greater than or equal to the second preset heating termination temperature, then execute step S311; otherwise, return to step S309, and control the variable valve timing mechanism to continue maintaining the second heating mode;

[0029] Step S311: Control the variable valve timing mechanism of the engine to switch from the second heating mode to the heating end mode.

[0030] Further, the step of controlling the heating device to heat the oil in the auxiliary oil tank according to the current heating control mode of the variable valve timing mechanism during the oil heating time, based on the engine battery voltage and the fault status of the heating device, to achieve auxiliary heating of the variable valve timing mechanism, includes:

[0031] Step S401: Determine whether the heating device is faulty; if yes, proceed to step S406; if no, proceed to step S402.

[0032] Step S402: Determine whether the current engine battery voltage is greater than the preset lower limit of battery voltage; if yes, proceed to step S403; if no, proceed to step S406.

[0033] Step S403: Determine whether the variable valve timing mechanism of the engine is in the first heating mode or the second heating mode; if yes, proceed to step S404; if no, proceed to step S406.

[0034] Step S404: Determine the corresponding target oil heating time based on the heating mode of the variable valve timing mechanism of the engine;

[0035] Step S405: Control the heating device to enter the heating state; wherein, control the heating device to heat the oil in the auxiliary oil tank according to the current heating mode of the variable valve timing mechanism of the engine within the corresponding target oil heating time;

[0036] Step S406: Control the heating device to enter a non-heating state.

[0037] Further, determining the corresponding target oil heating time based on the heating mode of the variable valve timing mechanism includes:

[0038] When the current heating control mode of the variable valve timing mechanism is the first heating mode, the corresponding target heating time is determined to be the first oil heating time at the last moment of the previous heating control mode.

[0039] When the current heating control mode of the variable valve timing engine is the second heating mode, the corresponding target heating time is determined to be the second oil heating time at the last moment of the previous heating control mode.

[0040] As another aspect of the present invention, an auxiliary heating control device for a variable valve timing mechanism is provided to implement the aforementioned auxiliary heating control method for a variable valve timing mechanism. When the engine is operating normally, the fuel pump delivers engine oil from the main fuel tank to the auxiliary fuel tank. A first oil temperature sensor and a heating device are installed in the auxiliary fuel tank. The outlet of the auxiliary fuel tank is connected to a high-pressure fuel pump, and a second oil temperature sensor is installed on the high-pressure fuel pump. The auxiliary heating control device for a variable valve timing mechanism includes:

[0041] The acquisition module is used to acquire engine speed, engine battery voltage, engine coolant temperature, heating device fault status, first oil temperature detected by the first oil temperature sensor, and second oil temperature detected by the second oil temperature sensor.

[0042] The calculation module is used to calculate the oil heating reference temperature based on the engine coolant temperature, the first oil temperature and the second oil temperature, and to determine the oil heating time based on the oil heating reference temperature.

[0043] The determination module is used to determine the current heating control mode of the variable valve timing mechanism based on the engine speed and the oil heating reference temperature.

[0044] The control module is used to control the heating device to heat the oil in the auxiliary oil tank according to the current heating control mode of the variable valve timing mechanism of the engine battery and the fault status of the heating device during the oil heating time, so as to achieve auxiliary heating of the variable valve timing mechanism of the engine.

[0045] As another aspect of the present invention, a variable valve timing engine auxiliary heating control system is provided, comprising: an electronic control unit, an oil pump, a main oil tank, an auxiliary oil tank, a first oil temperature sensor, a heating device, a low-pressure oil pump, a high-pressure oil pump, an oil rail, a second oil temperature sensor, and a speed sensor. The electronic control unit includes the aforementioned variable valve timing engine auxiliary heating control device. During normal engine operation, the oil pump delivers oil from the main oil tank to the auxiliary oil tank. The auxiliary oil tank houses the first oil temperature sensor and the heating device. A first outlet of the auxiliary oil tank is connected to the low-pressure oil pump, and a second outlet is connected to the high-pressure oil pump. Oil from the auxiliary oil tank is delivered by the low-pressure oil pump to the low-pressure chamber of the oil rail and by the high-pressure oil pump to the high-pressure chamber of the oil rail. The oil pump is equipped with a second oil temperature sensor. The electronic control unit is connected to the heating device, the first oil temperature sensor, the second oil temperature sensor, and the speed sensor via wiring harnesses. The heating device is used to heat the oil in the auxiliary oil tank. The first oil temperature sensor is used to detect the oil temperature in the auxiliary oil tank. The second oil temperature sensor is used to detect the oil temperature at the inlet of the high-pressure oil pump. The speed sensor is used to detect the engine speed. The variable valve timing auxiliary heating control device can control the heating device to heat the oil in the auxiliary oil tank according to the current heating control mode of the variable valve timing mechanism within the oil heating time, based on the engine battery voltage and the fault status of the heating device, so as to achieve auxiliary heating of the variable valve timing mechanism.

[0046] The auxiliary heating control method for the variable valve timing mechanism of an engine provided by this invention has the following beneficial effects:

[0047] (1) This control method preheats the valve train mechanism of the fully variable valve engine before driving it, ensuring that the valve train system can quickly build up pressure and drive quickly in a low temperature environment;

[0048] (2) After the valve train is driven, the secondary heating quickly increases the oil temperature, reduces system friction resistance, shortens valve drive lag time, and improves engine power and fuel economy.

[0049] (3) Preset the lower limit of the battery voltage and detect the fault status of the heating device to ensure the safety and reliability of the heating process. Attached Figure Description

[0050] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the following detailed description to explain the invention, but do not constitute a limitation thereof. In the drawings:

[0051] Figure 1 The flowchart shows the auxiliary heating control method for the variable valve timing mechanism of an engine provided by the present invention.

[0052] Figure 2 The flowchart for calculating the oil heating reference temperature and oil heating time provided by the present invention.

[0053] Figure 3 A flowchart for determining the heating mode provided by the present invention.

[0054] Figure 4 The control flowchart for the final working state of the heating device provided by the present invention.

[0055] Figure 5 This is a structural diagram of the auxiliary heating control system for the variable valve timing mechanism of an engine provided by the present invention. Detailed Implementation

[0056] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0057] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0058] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate for the embodiments of the invention described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0059] This embodiment provides an auxiliary heating control method for the valve train of a variable valve timing engine. When the engine is operating normally, the fuel pump delivers oil from the main fuel tank to the auxiliary fuel tank. The auxiliary fuel tank contains a first oil temperature sensor and a heating device. The outlet of the auxiliary fuel tank is connected to a high-pressure fuel pump, which is equipped with a second oil temperature sensor. Figure 1As shown, the auxiliary heating control method for the variable valve timing mechanism of the engine includes:

[0060] Step S1: Obtain engine speed, engine battery voltage, engine coolant temperature, heating device fault status, first oil temperature detected by the first oil temperature sensor, and second oil temperature detected by the second oil temperature sensor;

[0061] Step S2: Calculate the oil heating reference temperature based on the engine coolant temperature, the first oil temperature, and the second oil temperature, and determine the oil heating time based on the oil heating reference temperature;

[0062] Preferably, such as Figure 2 As shown, the step of calculating the oil heating reference temperature based on the engine coolant temperature, the first oil temperature, and the second oil temperature, and determining the oil heating time based on the oil heating reference temperature, includes:

[0063] Step S201: Determine whether the first oil temperature sensor is faulty; if yes, proceed to step S202; if no, proceed to step S205.

[0064] Step S202: Determine whether the communication enable for the engine coolant temperature is turned on; if yes, proceed to step S203; if no, proceed to step S204.

[0065] Step S203: The reference temperature for heating the engine oil is the smaller of the engine coolant temperature and the second engine oil temperature;

[0066] Step S204: The reference temperature for heating the engine oil is taken as the second engine oil temperature;

[0067] Step S205: The oil heating reference temperature is taken as the first oil temperature;

[0068] Step S206: Determine the first oil heating time by querying the first oil heating time curve in real time based on the oil heating reference temperature;

[0069] Step S207: Determine the second oil heating time by querying the second oil heating time curve in real time based on the oil heating reference temperature.

[0070] Step S3: Determine the current heating control mode of the variable valve timing mechanism based on the engine speed and the oil heating reference temperature;

[0071] It should be noted that the oil heating reference temperature, the first oil heating time, and the second oil heating time are all calculated in real time.

[0072] Preferably, such as Figure 3 As shown, determining the current heating control mode of the variable valve timing mechanism based on the engine speed and the oil heating reference temperature includes:

[0073] Step S301: Determine whether the oil heating reference temperature is less than the first preset oil temperature threshold; if yes, proceed to step S302; if no, proceed to step S305.

[0074] Step S302: The variable valve timing mechanism of the engine needs to be preheated. Control the variable valve timing mechanism of the engine to switch from the non-heating mode to the first heating mode, and start timing through the first heating timer; when the system heating mode changes, the heating timer is reset to zero.

[0075] Step S303: Determine whether the current engine speed is less than the preset lower speed limit; if yes, proceed to step S304; if no, proceed to step S305.

[0076] Step S304: Determine whether the timing duration of the first heating timer is greater than or equal to the first oil heating time, and simultaneously determine whether the oil heating reference temperature is greater than or equal to the first preset heating termination temperature; if the timing duration of the first heating timer is greater than or equal to the first oil heating time or the oil heating reference temperature is greater than or equal to the first preset heating termination temperature, then proceed to step S305; otherwise, return to step S302, and control the variable valve timing mechanism to continue maintaining the first heating mode;

[0077] Step S305: Control the variable valve timing mechanism of the engine to enter the non-heating mode;

[0078] Step S306: Determine whether the current engine speed is greater than or equal to the preset upper limit of speed; if yes, proceed to step S308; if no, proceed to step S307.

[0079] Step S307: Determine whether the number of times the engine failed to start is greater than or equal to 3; if yes, proceed to step S311; if no, return to step S301.

[0080] It should be noted that in non-heating mode, if the preset lower speed limit is detected to be less than or equal to the engine speed at the previous moment, and the engine speed at the next moment is always less than the preset upper speed limit, then the engine is considered to have failed to start, and the number of unsuccessful engine starts is counted as i. When i ≤ 3, the system needs to re-determine whether to perform preheating after each engine start failure to prepare for the next start attempt; when i > 3, once the engine starts, the system directly enters the heating end mode and stops heating.

[0081] Step S308: Determine whether the oil heating reference temperature is less than the second preset oil temperature threshold; if yes, proceed to step S309; ​​if no, proceed to step S311.

[0082] Step S309: The variable valve timing mechanism of the engine requires post-heating. Control the variable valve timing mechanism of the engine to switch from the non-heating mode to the second heating mode, and start timing through the second heating timer; when the system heating mode changes, the heating timer is reset to zero.

[0083] Step S310: Determine whether the timing duration of the second heating timer is greater than or equal to the second oil heating time, and simultaneously determine whether the oil heating reference temperature is greater than or equal to the second preset heating termination temperature; if the timing duration of the second heating timer is greater than or equal to the second oil heating time or the oil heating reference temperature is greater than or equal to the second preset heating termination temperature, then execute step S311; otherwise, return to step S309, and control the variable valve timing mechanism to continue maintaining the second heating mode;

[0084] Step S311: Control the variable valve timing mechanism of the engine to switch from the second heating mode to the heating end mode.

[0085] Step S4: Based on the engine battery voltage and the fault status of the heating device, control the heating device to heat the oil in the auxiliary oil tank during the oil heating time according to the current heating control mode of the variable valve timing mechanism, so as to achieve auxiliary heating of the variable valve timing mechanism.

[0086] Preferably, such as Figure 4 As shown, the step of controlling the heating device to heat the oil in the auxiliary oil tank according to the current heating control mode of the variable valve timing mechanism during the oil heating time, based on the engine battery voltage and the fault status of the heating device, to achieve auxiliary heating of the variable valve timing mechanism, includes:

[0087] Step S401: Determine whether the heating device is faulty; if yes, proceed to step S406; if no, proceed to step S402.

[0088] Step S402: Determine whether the current engine battery voltage is greater than the preset lower limit of battery voltage; if yes, proceed to step S403; if no, proceed to step S406.

[0089] Step S403: Determine whether the variable valve timing mechanism of the engine is in the first heating mode or the second heating mode; if yes, proceed to step S404; if no, proceed to step S406.

[0090] Step S404: Determine the corresponding target oil heating time based on the heating mode of the variable valve timing mechanism of the engine;

[0091] Specifically, determining the corresponding target oil heating time based on the heating mode of the variable valve timing mechanism includes:

[0092] When the current heating control mode of the variable valve timing mechanism is the first heating mode, the corresponding target heating time is determined to be the first oil heating time at the last moment of the previous heating control mode.

[0093] When the current heating control mode of the variable valve timing engine is the second heating mode, the corresponding target heating time is determined to be the second oil heating time at the last moment of the previous heating control mode.

[0094] Step S405: Control the heating device to enter the heating state; wherein, control the heating device to heat the oil in the auxiliary oil tank according to the current heating mode of the variable valve timing mechanism of the engine within the corresponding target oil heating time;

[0095] Step S406: Control the heating device to enter a non-heating state.

[0096] The following is a detailed description of the auxiliary heating control method for the variable valve timing mechanism of an engine provided by the present invention, using a specific implementation example.

[0097] Some parameter settings are as follows:

[0098] (1) The first preset temperature threshold is 0℃;

[0099] (2) The second preset temperature threshold is 50℃;

[0100] (3) The first preset heating termination temperature is 20℃;

[0101] (4) The second preset heating termination temperature is 70℃;

[0102] (5) The preset lower limit of the rotational speed is 150 r / min;

[0103] (6) The preset upper limit of rotational speed is 500 r / min;

[0104] (7) The current ambient temperature is -10℃;

[0105] (8) The battery voltage is 24V;

[0106] (9) The preset lower limit of the battery voltage is 18V;

[0107] (10) The first oil temperature sensor is fault-free;

[0108] (11) The heating device is a resistance wire;

[0109] (12) The resistance wire relay is fault-free;

[0110] The electronic control unit is powered on, the system completes initialization, and the heating mode is set to non-heating mode by default. The electronic control unit detects that the first oil temperature sensor is fault-free, and the oil heating reference temperature is directly taken as the first oil temperature (-10℃). The first heating time is found to be 20s from the oil heating time curve 1, and the second heating time is found to be 80s from the oil heating time curve 2.

[0111] Simultaneously, if the oil heating reference temperature (-10℃) is less than the first preset temperature threshold (0℃), the system switches from the non-heating mode to the first heating mode, and the heating timer starts counting. The target heating time at this point is set to the first heating time of 20 seconds. Meanwhile, since the battery voltage (24V) is greater than the preset lower battery voltage limit (18V) and the resistance wire relay is functioning correctly, the electronic control unit controls the relay to engage, and the resistance wire remains in the heating state, continuously heating the oil in the auxiliary oil tank. After 16 seconds of heating, the oil in the auxiliary oil tank is heated to 21℃, which is greater than the first preset heating termination temperature (20℃), and the system switches from the first heating mode to the non-heating mode, with the resistance wire switching from the heating state to the non-heating state. After preheating is complete, the engine is started, and the electronic control unit, based on the speed sensor signal, detects that the engine speed is 180 r / min, which is greater than the preset lower speed limit, and the system maintains the non-heating mode. Eight seconds after startup, the engine speed rises to 503 r / min, exceeding the preset speed limit. During this process, as low-temperature oil from the main oil tank is continuously pumped into the auxiliary oil tank, the oil heating reference temperature drops to 8℃, below the second preset temperature threshold (50℃). The system switches from the non-heating mode to the second heating mode. At this point, based on the oil heating reference temperature of 8℃ at the last moment of the non-heating mode, the oil heating time curve 2 is consulted to obtain the updated second heating time of 50 seconds. The target heating time for the second heating mode is taken as the updated second heating time (50 seconds). The electronic control unit controls the relay to engage, and the resistance wire is in the heating state, continuously heating the oil in the auxiliary oil tank. After 50 seconds, the oil heating reference temperature rises to 63℃, the entire heating process is completed, and the system switches to the heating end mode.

[0112] The auxiliary heating control method for the variable valve timing mechanism of an engine provided in this invention uses an auxiliary oil tank and a heating device installed in the auxiliary oil tank to provide auxiliary heating for the fully variable valve timing system. Preheating is performed before the fully variable valve timing mechanism is driven, ensuring that the timing system can quickly build pressure and drive rapidly in low-temperature environments. After the timing mechanism is driven, secondary heating quickly increases the engine oil temperature, reduces system friction resistance, shortens valve drive lag time, and improves engine power and fuel economy. A preset battery voltage lower limit and detection of the heating device's fault status ensure the safety and reliability of the heating process.

[0113] As another embodiment of the present invention, an auxiliary heating control device for a variable valve timing engine is provided to implement the aforementioned auxiliary heating control method for a variable valve timing engine. When the engine is operating normally, the fuel pump delivers oil from the main fuel tank to the auxiliary fuel tank. A first oil temperature sensor and a heating device are installed in the auxiliary fuel tank. The outlet of the auxiliary fuel tank is connected to a high-pressure fuel pump, and a second oil temperature sensor is installed on the high-pressure fuel pump. The auxiliary heating control device for the variable valve timing engine includes:

[0114] The acquisition module is used to acquire engine speed, engine battery voltage, engine coolant temperature, heating device fault status, first oil temperature detected by the first oil temperature sensor, and second oil temperature detected by the second oil temperature sensor.

[0115] The calculation module is used to calculate the oil heating reference temperature based on the engine coolant temperature, the first oil temperature and the second oil temperature, and to determine the oil heating time based on the oil heating reference temperature.

[0116] The determination module is used to determine the current heating control mode of the variable valve timing mechanism based on the engine speed and the oil heating reference temperature.

[0117] The control module is used to control the heating device to heat the oil in the auxiliary oil tank according to the current heating control mode of the variable valve timing mechanism of the engine battery and the fault status of the heating device during the oil heating time, so as to achieve auxiliary heating of the variable valve timing mechanism of the engine.

[0118] The working principle of the auxiliary heating control device for the variable valve timing mechanism of the engine provided by this invention can be referred to the description of the auxiliary heating control method for the variable valve timing mechanism of the engine above, and will not be repeated here.

[0119] As another embodiment of the present invention, an auxiliary heating control system for a variable valve timing engine is provided, such as... Figure 5As shown, the system includes: an electronic control unit (ECU), an oil pump 1, a main oil tank 2, an auxiliary oil tank 3, a first oil temperature sensor 4, a heating device 5, a low-pressure oil pump 6, a high-pressure oil pump 7, an oil rail 8, a second oil temperature sensor 9, and a speed sensor 10. The ECU includes the auxiliary heating control device for the variable valve timing mechanism of the engine described above. When the engine is operating normally, the oil pump 1 delivers oil from the main oil tank 2 to the auxiliary oil tank 3. The auxiliary oil tank 3 is equipped with the first oil temperature sensor 4 and the heating device 5. The first outlet of the auxiliary oil tank 3 is connected to the low-pressure oil pump 6, and the second outlet is connected to the high-pressure oil pump 7. The oil in the auxiliary oil tank 3 is delivered to the low-pressure chamber of the oil rail 8 via the low-pressure oil pump 6, and to the high-pressure chamber of the oil rail 8 via the high-pressure oil pump 7. The second oil temperature sensor 9 is installed on the high-pressure oil pump 7. The oil temperature sensor 9 is connected to the heating device 5, the first oil temperature sensor 4, the second oil temperature sensor 9, and the speed sensor 10 via wiring harnesses. The heating device 5 is used to heat the oil in the auxiliary oil tank 3. The first oil temperature sensor 4 is used to detect the oil temperature in the auxiliary oil tank 3. The second oil temperature sensor 9 is used to detect the oil temperature at the inlet of the high-pressure oil pump 7. The speed sensor 10 is used to detect the engine speed. The variable valve timing auxiliary heating control device can control the heating device to heat the oil in the auxiliary oil tank according to the current heating control mode of the variable valve timing mechanism within the oil heating time, based on the engine battery voltage and the fault status of the heating device, so as to achieve auxiliary heating of the variable valve timing mechanism.

[0120] In this embodiment of the invention, the heating device 5 includes a resistance wire or a semiconductor heating ceramic.

[0121] It should be noted that during a cold start in low temperatures, the ECU (Electronic Control Unit) is powered on and completes its initialization settings. The entire auxiliary heating control calculation for the variable valve timing engine includes three parts: heating parameter calculation, heating control mode calculation, and calculation of the final operating state of the heating device.

[0122] Heating parameter calculation: The electronic control unit detects the fault status of the first oil temperature sensor and calculates the oil heating reference temperature. Based on the real-time calculated oil heating reference temperature, the system looks up the two-dimensional curve to obtain the first heating time and the second heating time.

[0123] Heating control mode calculation: There are four heating control modes: no heating mode, first heating mode, second heating mode, and heating end mode. After system initialization, the default is no heating mode. The electronic control unit (ECU) determines whether the system needs preheating based on the oil heating reference temperature. If preheating is needed, the system enters the first heating mode; otherwise, it remains in no heating mode. In the first heating mode, if the engine speed is detected to be greater than the preset lower speed limit, the system switches to no heating mode. In the no heating mode, if the engine speed is detected to be greater than or equal to the preset upper speed limit, the system determines whether post-heating is needed. If so, the system switches to the second heating mode; otherwise, it switches to the heating end mode. Furthermore, when the system is in no heating mode, if the preset lower speed limit is less than or equal to the previous engine speed, and the engine speed remains less than the preset upper speed limit in the next moment, the system considers the start-up to have failed and determines whether preheating is needed again.

[0124] The final operating state calculation for the heating device: The heating device is only allowed to heat when it is fault-free and the engine battery voltage is greater than the preset battery voltage. Based on this, when the heating mode is the first heating mode or the second heating mode, the target heating time is calculated, and heating is performed according to the calculated result.

[0125] The working principle of the auxiliary heating control system for the variable valve timing mechanism of the engine provided in this embodiment of the invention can be referred to the description of the auxiliary heating control method for the variable valve timing mechanism of the engine above, and will not be repeated here.

[0126] It is understood that the above embodiments are merely exemplary implementations used to illustrate the principles of the present invention, and the present invention is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. A method for auxiliary heating control of the valve train of a variable valve timing engine, characterized in that, When the engine is operating normally, the fuel pump delivers engine oil from the main fuel tank to the auxiliary fuel tank. The auxiliary fuel tank is equipped with a first oil temperature sensor and a heating device. The outlet of the auxiliary fuel tank is connected to a high-pressure fuel pump, which is equipped with a second oil temperature sensor. The auxiliary heating control method for the variable valve timing mechanism of the engine includes: Step S1: Obtain engine speed, engine battery voltage, engine coolant temperature, heating device fault status, first oil temperature detected by the first oil temperature sensor, and second oil temperature detected by the second oil temperature sensor; Step S2: Calculate the oil heating reference temperature based on the engine coolant temperature, the first oil temperature, and the second oil temperature, and determine the oil heating time based on the oil heating reference temperature; Step S3: Determine the current heating control mode of the variable valve timing mechanism based on the engine speed and the oil heating reference temperature; Step S4: Based on the engine battery voltage and the fault status of the heating device, control the heating device to heat the oil in the auxiliary oil tank during the oil heating time according to the current heating control mode of the variable valve timing mechanism, so as to achieve auxiliary heating of the variable valve timing mechanism. The step of determining the current heating control mode of the variable valve timing mechanism based on the engine speed and the oil heating reference temperature includes: Step S301: Determine whether the oil heating reference temperature is less than the first preset oil temperature threshold; if yes, proceed to step S302; if no, proceed to step S305. Step S302: The variable valve timing mechanism of the engine needs to be preheated. Control the variable valve timing mechanism of the engine to switch from the non-heating mode to the first heating mode, and start timing through the first heating timer. Step S303: Determine whether the current engine speed is less than the preset lower speed limit; if yes, proceed to step S304; if no, proceed to step S305. Step S304: Determine whether the timing duration of the first heating timer is greater than or equal to the first oil heating time, and simultaneously determine whether the oil heating reference temperature is greater than or equal to the first preset heating termination temperature; if the timing duration of the first heating timer is greater than or equal to the first oil heating time or the oil heating reference temperature is greater than or equal to the first preset heating termination temperature, then proceed to step S305; otherwise, return to step S302, and control the variable valve timing mechanism to continue maintaining the first heating mode; Step S305: Control the variable valve timing mechanism of the engine to enter the non-heating mode; Step S306: Determine whether the current engine speed is greater than or equal to the preset upper limit of speed; if yes, proceed to step S308; if no, proceed to step S307. Step S307: Determine whether the number of times the engine failed to start is greater than or equal to 3; if yes, proceed to step S311; if no, return to step S301. Step S308: Determine whether the oil heating reference temperature is less than the second preset oil temperature threshold; if yes, proceed to step S309; ​​if no, proceed to step S311. Step S309: The variable valve timing mechanism of the engine requires post-heating. Control the variable valve timing mechanism of the engine to switch from the non-heating mode to the second heating mode, and start timing through the second heating timer. Step S310: Determine whether the timing duration of the second heating timer is greater than or equal to the second oil heating time, and simultaneously determine whether the oil heating reference temperature is greater than or equal to the second preset heating termination temperature; if the timing duration of the second heating timer is greater than or equal to the second oil heating time or the oil heating reference temperature is greater than or equal to the second preset heating termination temperature, then execute step S311; otherwise, return to step S309, and control the variable valve timing mechanism to continue maintaining the second heating mode; Step S311: Control the variable valve timing mechanism of the engine to switch from the second heating mode to the heating end mode; The step of controlling the heating device to heat the oil in the auxiliary oil tank according to the current heating control mode of the variable valve timing mechanism within the oil heating time, based on the engine battery voltage and the fault status of the heating device, to achieve auxiliary heating of the variable valve timing mechanism, includes: Step S401: Determine whether the heating device is faulty; if yes, proceed to step S406; if no, proceed to step S402. Step S402: Determine whether the current engine battery voltage is greater than the preset lower limit of battery voltage; if yes, proceed to step S403; if no, proceed to step S406. Step S403: Determine whether the variable valve timing mechanism of the engine is in the first heating mode or the second heating mode; if yes, proceed to step S404; if no, proceed to step S406. Step S404: Determine the corresponding target oil heating time based on the current heating control mode of the variable valve timing mechanism of the engine; Step S405: Control the heating device to enter the heating state; wherein, control the heating device to heat the oil in the auxiliary oil tank according to the current heating control mode of the variable valve timing mechanism of the engine within the corresponding target oil heating time; Step S406: Control the heating device to enter a non-heating state.

2. The auxiliary heating control method for the variable valve timing mechanism of an engine according to claim 1, characterized in that, The step of calculating an oil heating reference temperature based on the engine coolant temperature, the first oil temperature, and the second oil temperature, and determining the oil heating time based on the oil heating reference temperature, includes: Step S201: Determine whether the first oil temperature sensor is faulty; if yes, proceed to step S202; if no, proceed to step S205. Step S202: Determine whether the communication enable for the engine coolant temperature is turned on; if yes, proceed to step S203; if no, proceed to step S204. Step S203: The reference temperature for heating the engine oil is the smaller of the engine coolant temperature and the second engine oil temperature; Step S204: The reference temperature for heating the engine oil is taken as the second engine oil temperature; Step S205: The oil heating reference temperature is taken as the first oil temperature; Step S206: Determine the first oil heating time by querying the first oil heating time curve in real time based on the oil heating reference temperature; Step S207: Determine the second oil heating time by querying the second oil heating time curve in real time based on the oil heating reference temperature.

3. The auxiliary heating control method for the variable valve timing mechanism of an engine according to claim 1, characterized in that, The step of determining the corresponding target oil heating time based on the current heating control mode of the variable valve timing engine includes: When the current heating control mode of the variable valve timing mechanism is the first heating mode, the corresponding target heating time is determined to be the first oil heating time at the last moment of the previous heating control mode. When the current heating control mode of the variable valve timing engine is the second heating mode, the corresponding target heating time is determined to be the second oil heating time at the last moment of the previous heating control mode.

4. An auxiliary heating control device for a variable valve timing engine, used to implement the auxiliary heating control method for a variable valve timing engine as described in any one of claims 1 to 3, characterized in that, When the engine is operating normally, the fuel pump delivers engine oil from the main fuel tank to the auxiliary fuel tank. The auxiliary fuel tank contains a first oil temperature sensor and a heating device. The outlet of the auxiliary fuel tank is connected to a high-pressure fuel pump, which contains a second oil temperature sensor. The auxiliary heating control device for the variable valve timing mechanism includes: The acquisition module is used to acquire engine speed, engine battery voltage, engine coolant temperature, heating device fault status, first oil temperature detected by the first oil temperature sensor, and second oil temperature detected by the second oil temperature sensor. The calculation module is used to calculate the oil heating reference temperature based on the engine coolant temperature, the first oil temperature and the second oil temperature, and to determine the oil heating time based on the oil heating reference temperature. The determination module is used to determine the current heating control mode of the variable valve timing mechanism based on the engine speed and the oil heating reference temperature. The control module is used to control the heating device to heat the oil in the auxiliary oil tank according to the current heating control mode of the variable valve timing mechanism of the engine battery and the fault status of the heating device during the oil heating time, so as to achieve auxiliary heating of the variable valve timing mechanism of the engine.

5. An auxiliary heating control system for a variable valve timing engine, characterized in that, include: The system includes an electronic control unit, an oil pump (1), a main oil tank (2), an auxiliary oil tank (3), a first oil temperature sensor (4), a heating device (5), a low-pressure oil pump (6), a high-pressure oil pump (7), an oil rail (8), a second oil temperature sensor (9), and a speed sensor (10). The electronic control unit includes the auxiliary heating control device for the variable valve timing mechanism of the engine as described in claim 4. When the engine is working normally, the oil pump (1) delivers the oil in the main oil tank (2) to the auxiliary oil tank (3). The auxiliary oil tank (3) is equipped with the first oil temperature sensor (4) and the heating device (5). The first oil outlet of the auxiliary oil tank (3) is connected to the low-pressure oil pump (6), and the second oil outlet is connected to the high-pressure oil pump (7). The oil in the auxiliary oil tank (3) is delivered to the low-pressure cavity of the oil rail (8) by the low-pressure oil pump (6) and to the high-pressure cavity of the oil rail (8) by the high-pressure oil pump (7). (7) is equipped with the second oil temperature sensor (9). The electronic control unit is connected to the heating device (5), the first oil temperature sensor (4), the second oil temperature sensor (9) and the speed sensor (10) respectively through the wire harness. The heating device (5) is used to heat the oil in the auxiliary oil tank (3). The first oil temperature sensor (4) is used to detect the oil temperature in the auxiliary oil tank (3). The second oil temperature sensor (9) is used to detect the oil temperature at the inlet of the high-pressure oil pump (7). The speed sensor (10) is used to detect the engine speed. The variable valve timing auxiliary heating control device can control the heating device to heat the oil in the auxiliary oil tank according to the current heating control mode of the variable valve timing mechanism within the oil heating time, so as to realize the auxiliary heating of the variable valve timing mechanism.

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