Self-adaptive fuel oil heating driving control method and system based on hybrid power vehicle

Abstract

The invention provides a self-adaptive fuel heating drive control method and system based on a hybrid vehicle. The method comprises the steps that whether an engine is in a starting operation state or a shutdown state is judged; if the engine is in the starting operation state, detecting the voltage of a small battery and the temperature of fuel oil, and calculating a heating duty ratio according to the voltage of the small battery and the temperature of the fuel oil so as to carry out fuel oil heating driving control; if the engine is in the shutdown state, the current driving mode and the large battery charge capacity are obtained, the driving mode comprises the pure electricity priority mode, the forced pure electricity mode, the oil-electricity hybrid driving mode and the fuel oil priority mode, and according to the current driving mode and the large battery charge capacity, the corresponding heating duty ratio is obtained through calculation and used for fuel oil heating driving control. The optimal fuel oil heating strategy can be determined according to the engine state, the driving mode and the SOC of the hybrid electric vehicle, the fuel oil atomization performance and the fuel oil economical efficiency are improved, and the PN particulate matter emission level of engine operation is improved.

Description

Technical Field

[0001] This invention relates to the field of hybrid vehicle technology, and in particular to an adaptive fuel heating drive control method and system based on hybrid vehicles. Background Technology

[0002] In hybrid vehicles, the power source switches between fuel and electricity due to different driving modes and battery states of charge. Therefore, it is necessary to continuously adjust the fuel heating to heat the fuel in a timely manner, while avoiding heating when the engine does not need to be started, so as to save energy.

[0003] However, in low-temperature environments, the fuel tank is exposed to the environment for a long time, and the temperature of the stored fuel is close to the ambient temperature. This causes the fuel injected from the injector to enter the cylinder at a lower temperature, resulting in poor fuel atomization performance. At the same time, the low-temperature fuel jet quenches with the rapidly heating cylinder.

[0004] In addition, poor atomization performance will significantly affect the amount of fuel injected during the cold start phase (in order to ensure start reliability, more fuel is usually injected). In addition to poor fuel economy, it will also lead to a significant increase in PN (Particulate Number) particles during the cold start process. After the start is completed, the quenching phenomenon that occurs when cold oil comes into contact with the cylinder will also exacerbate the cylinder wall wetting, which will further lead to a significant increase in PN particles.

[0005] Therefore, there is an urgent need for a fuel-heated drive control method that can improve the PN emission level of hybrid vehicle engine operation and the fuel economy of engine start-up. Summary of the Invention

[0006] Therefore, it is necessary to provide an adaptive fuel heating drive control method and system based on hybrid vehicles to address the problems of poor engine atomization performance and high particulate matter emissions during operation caused by low fuel temperature when the vehicle is in a low-temperature environment.

[0007] An adaptive fuel heating drive control method for hybrid vehicles includes the following steps: determining the engine state, which includes a start-up state and a stop state; if the engine is in the start-up state, detecting the small battery voltage and fuel temperature, calculating the heating duty cycle based on the small battery voltage and fuel temperature, and performing fuel heating drive control based on the heating duty cycle; if the engine is in the stop state, acquiring the current driving mode and the large battery charge, where the driving mode includes pure electric priority mode, forced pure electric mode, hybrid electric drive mode, and fuel priority mode, calculating the corresponding heating duty cycle based on the current driving mode and the large battery charge, and performing fuel heating drive control based on the heating duty cycle.

[0008] In one embodiment, if the engine is in a running state, detecting the small battery voltage and fuel temperature, and calculating the heating duty cycle based on the small battery voltage and fuel temperature, includes: if the engine is in a running state, detecting the small battery voltage and fuel temperature; when the small battery voltage is greater than a voltage threshold and the fuel temperature is less than a target fuel temperature, calculating the heating duty cycle based on the feedforward duty cycle, the target fuel temperature, and the engine speed and load, using the following formula:

[0009]

[0010] T delta =T target -T

[0011] In the formula, D drive For heating duty cycle, D f K is the feedforward duty cycle. p and K i The parameter T is obtained based on engine speed and load. target The target fuel temperature is T; otherwise, if the voltage of the small battery is less than or equal to the voltage threshold, the heating duty cycle is determined to be 0, and a charging request is sent to the DC / DC controller to charge the small battery through the large battery until the voltage of the small battery is greater than the sum of the voltage threshold and the floating voltage value; then return to the step of detecting the voltage of the small battery and the fuel temperature, and calculate the heating duty cycle in a loop.

[0012] In one embodiment, if the engine is in a stopped state, acquiring the current driving mode and the large battery charge, and calculating the corresponding heating duty cycle based on the current driving mode and the large battery charge, includes: if the engine is in a stopped state, acquiring the current driving mode and the large battery charge; when the current driving mode is pure electric priority mode and the large battery charge is greater than a first charge threshold, or the current driving mode is forced pure electric mode and the large battery charge is greater than a second charge threshold, the heating duty cycle is 0; when the current driving mode is pure electric priority mode and the large battery charge is less than or equal to the first charge threshold, forced pure electric mode and the large battery charge is less than or equal to the second charge threshold, hybrid electric drive mode, and fuel priority mode, detecting the small battery voltage and fuel temperature; if the small battery voltage is greater than the voltage threshold and the fuel temperature is less than the target fuel temperature, calculating the heating duty cycle based on the feedforward duty cycle, the target fuel temperature, and the engine speed and load, using the following formula:

[0013]

[0014] T delta =T target -T

[0015] In the formula, D drive For heating duty cycle, D f For the feedforward duty cycle, based on the ambient temperature and T delta K was obtained. p and K i The parameter T is obtained based on engine speed and load. target The target fuel temperature is T; conversely, if the small battery voltage is less than or equal to the voltage threshold, the heating duty cycle is determined to be 0, and a charging request is sent to the DC / DC controller to charge the small battery through the large battery until the small battery voltage is greater than the sum of the voltage threshold and the floating voltage value; then return to the step of obtaining the current driving mode and the large battery charge, and calculate the heating duty cycle in a loop.

[0016] In one embodiment, the first charge threshold is the sum of the charge balance point and the first safety control amount, wherein the charge balance point is 20% and the first safety control amount is 5%.

[0017] In one embodiment, the second charge threshold is the sum of the forced pure electric threshold and the second safety control quantity, wherein the forced pure electric threshold is 6% and the second safety control quantity is 4%.

[0018] An adaptive fuel heating drive control system for hybrid vehicles is disclosed, used to implement the adaptive fuel heating drive control method for hybrid vehicles as described above. The system includes: a vehicle controller unit, an engine, an adaptive fuel heating drive control unit, a small battery, and a fuel supply system. The vehicle controller unit, engine, small battery, and fuel supply system are all connected to the adaptive fuel heating drive control unit. The vehicle controller unit acquires the driving mode of the hybrid vehicle and the charge level of the large battery, and transmits this information to the adaptive fuel heating drive control unit. The engine acquires the engine operating status, including engine speed and load, and transmits this information to the adaptive fuel heating drive control unit. The small battery transmits its voltage to the adaptive fuel heating drive control unit. The system includes a drive control unit; the fuel supply system is used to heat and supply fuel under the control of the adaptive fuel heating drive control unit; the adaptive fuel heating drive control unit is used to determine the engine status, including the engine running state and the engine stopped state; if the engine is running, it detects the small battery voltage and fuel temperature, calculates the heating duty cycle based on the small battery voltage and fuel temperature, and performs fuel heating drive control based on the heating duty cycle; if the engine is stopped, it obtains the current driving mode and the large battery charge, the driving mode including pure electric priority mode, forced pure electric mode, hybrid electric drive mode and fuel priority mode, calculates the corresponding heating duty cycle based on the current driving mode and the large battery charge, and performs fuel heating drive control based on the heating duty cycle.

[0019] In one embodiment, the fuel supply system includes: a fuel tank, a fuel pump, a fuel rail, a fuel heater, and a fuel injector; the fuel tank and the fuel rail are both connected to the fuel pump, which pumps fuel from the fuel tank to the fuel rail; the fuel heater is disposed between the fuel rail and the fuel injector nozzle, and communicates with both the fuel rail and the fuel injector, and includes a fuel temperature sensor, as well as an integrated heater and a heating chamber, for heating the fuel entering the heating chamber according to a heating duty cycle, and the fuel heater is used to detect the fuel temperature; the fuel injector includes a nozzle for injecting the heated fuel into the engine cylinder for vehicle starting.

[0020] In one embodiment, it further includes: a DC / DC controller unit connected to the adaptive fuel heating drive control unit, for receiving a small battery charging request sent by the adaptive fuel heating drive control unit, and controlling the large battery to charge the small battery until the voltage of the small battery is greater than the sum of the voltage threshold and the floating voltage value.

[0021] Compared to existing technologies, the advantages and beneficial effects of this invention are as follows: By judging the engine state, which includes a start-up state and a stop state, when the engine is in the start-up state, the small battery voltage and fuel temperature are detected. Based on the small battery voltage and fuel temperature, the heating duty cycle is calculated, and fuel heating drive control is performed according to the heating duty cycle to keep the fuel at a suitable temperature for engine operation. If the engine is in the stop state, the current driving mode and the large battery charge are obtained. The driving modes include pure electric priority mode, forced pure electric mode, hybrid electric drive mode, and fuel priority mode. Based on the current driving mode and the large battery charge, the corresponding heating duty cycle is calculated, and fuel heating drive control is performed according to the heating duty cycle. This invention is applicable to hybrid vehicles and can determine the fuel heating strategy according to the vehicle's driving mode, improve fuel atomization performance, reduce the amount of fuel injected during the start-up phase, thereby improving the PN emission level of the engine and the fuel economy during engine start-up. Attached Figure Description

[0022] Figure 1 This is a flowchart illustrating an adaptive fuel heating drive control method based on a hybrid vehicle in one embodiment.

[0023] Figure 2 This is a schematic diagram illustrating the calculation process of the heating duty cycle when the engine is in the start-up and running state in one embodiment;

[0024] Figure 3 This is a schematic diagram illustrating the calculation process of the heating duty cycle when the engine is in a stopped state in one embodiment;

[0025] Figure 4 This is a schematic diagram of an adaptive fuel heating drive control system based on a hybrid vehicle in one embodiment. Detailed Implementation

[0026] Before describing the specific embodiments of the present invention, the overall concept of the present invention will be explained as follows:

[0027] This invention is mainly based on the engine fuel heating drive control process. Currently, the fuel in the fuel tank enters the cylinder at a relatively low temperature, resulting in poor fuel atomization performance and economy.

[0028] Therefore, this invention proposes an adaptive fuel heating drive control method for hybrid vehicles. By determining the engine state, including start-up and shutdown states, when the engine is in start-up state, the small battery voltage and fuel temperature are detected. Based on the small battery voltage and fuel temperature, the heating duty cycle is calculated, and fuel heating drive control is performed according to the heating duty cycle to ensure the fuel is at a suitable temperature for engine operation. If the engine is in shutdown state, the current driving mode and large battery charge are obtained. Driving modes include pure electric priority mode, forced pure electric mode, hybrid electric drive mode, and fuel priority mode. Based on the current driving mode and large battery charge, the corresponding heating duty cycle is calculated, and fuel heating drive control is performed according to the heating duty cycle. This method is applicable to hybrid vehicles and can determine the fuel heating strategy based on the vehicle's driving mode, improving fuel atomization performance, improving PN emission levels during engine operation, and enhancing fuel economy during engine start-up.

[0029] Having introduced the overall concept of the present invention, to make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below through specific embodiments in conjunction with the accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and are not intended to limit the present invention.

[0030] In one embodiment, such as Figure 1 As shown, an adaptive fuel heating drive control method based on hybrid vehicles is provided, including the following steps:

[0031] Step S110: Determine the engine status, which includes the engine running status and the engine stopped status.

[0032] Specifically, in order to better control the fuel heating drive of hybrid vehicles, the engine status is first determined, including the start-up and shutdown status. The shutdown status needs to be prepared for the random start-up of the engine under the condition that it is possible to start. Therefore, fuel heating control needs to be performed according to the engine running and non-running status to achieve precise control of fuel heating of hybrid vehicles.

[0033] Step S120: If the engine is in the running state, detect the small battery voltage and fuel temperature, calculate the heating duty cycle based on the small battery voltage and fuel temperature, and perform fuel heating drive control based on the heating duty cycle.

[0034] Specifically, when the engine is running, the voltage of the small battery (a lead-acid battery) is detected. This battery is used to start the engine in hybrid vehicles and to power the entire vehicle's electrical system. At the same time, the current fuel temperature of the engine is detected. The heating duty cycle is obtained based on the small battery voltage and the fuel temperature. The heating duty cycle directly affects the heating power and efficiency. Finally, fuel heating drive control is performed based on this heating duty cycle to improve fuel atomization performance, fuel economy, and particulate matter emissions.

[0035] Step S120 includes: if the engine is running, detecting the small battery voltage and fuel temperature; when the small battery voltage is greater than the voltage threshold and the fuel temperature is less than the target fuel temperature, calculating the heating duty cycle based on the feedforward duty cycle, the target fuel temperature, and the engine speed and load, using the following formula:

[0036]

[0037] T delta =T target -T

[0038] In the formula, D drive For heating duty cycle, D f K is the feedforward duty cycle. p and K i The parameter T is obtained based on engine speed and load. target The target fuel temperature is T; otherwise, if the voltage of the small battery is less than or equal to the voltage threshold, the heating duty cycle is determined to be 0, and a charging request is sent to the DC / DC controller to charge the small battery through the large battery until the voltage of the small battery is greater than the sum of the voltage threshold and the floating voltage value; then return to the step of detecting the voltage of the small battery and the fuel temperature, and calculate the heating duty cycle in a loop.

[0039] Specifically, such as Figure 2 As shown, when the engine is running, the voltage of the small battery and the fuel temperature are detected. When the voltage of the small battery is greater than the set voltage threshold, such as 10V, and the fuel temperature is close to the target fuel temperature, it indicates that the fuel needs to be heated. The heating duty cycle is calculated based on the feedforward duty cycle, the target fuel temperature, and the engine speed and load. The fuel heating drive control is performed according to the heating duty cycle to ensure that the fuel supplied to the engine cylinder is at an appropriate temperature, thereby improving the fuel economy during engine start-up and the level of emissions during operation.

[0040] The feedforward duty cycle can be obtained based on the difference between ambient temperature and fuel temperature and the target fuel temperature. It adjusts the duty cycle in advance based on the predicted input signal transformation, which can improve the response speed and stability of the control system. The target fuel temperature can be obtained based on engine speed and load, or determined based on the PN emission levels produced by different fuels entering the cylinder during engine operation. The optimal fuel temperature for emissions is scanned and used as the target temperature.

[0041] Conversely, if the small battery voltage is less than or equal to the set voltage threshold, it indicates that there are no conditions for engine starting, and fuel heating control is not required. The heating duty cycle is determined to be 0 to save energy. However, the small battery needs to be charged at this time. A charging request is sent to the DC / DC controller (i.e., the voltage conversion controller), and the large battery of the hybrid vehicle charges the small battery until the small battery voltage is greater than the sum of the voltage threshold and the floating voltage value. The floating voltage value can be set to 2V, meaning that when the small battery voltage is greater than 12V, the charging request to the DC / DC controller is stopped.

[0042] In addition, if the fuel temperature is greater than or equal to the target fuel temperature, it means that the fuel temperature has reached the target temperature and no heating control is required; the heating duty cycle is 0.

[0043] After obtaining the heating duty cycle, the process returns to the step of detecting the small battery voltage and fuel temperature, and the heating duty cycle is calculated again to achieve continuous control of fuel heating during vehicle start-up and improve fuel PN emission levels.

[0044] Step S130: If the engine is in a stopped state, obtain the current driving mode and the battery charge. The driving modes include pure electric priority mode, forced pure electric mode, hybrid electric drive mode and fuel priority mode. Calculate the corresponding heating duty cycle based on the current driving mode and the battery charge, and perform fuel heating drive control based on the heating duty cycle.

[0045] Specifically, when the engine is off, since hybrid vehicles have multiple driving modes, such as pure electric priority mode, forced pure electric mode, hybrid electric drive mode and fuel priority mode, it is necessary to obtain the current driving mode and the maximum battery charge. Based on different driving modes and the maximum battery charge, the corresponding heating duty cycle is calculated and used for fuel heating drive control to improve fuel atomization performance, improve fuel economy and PN particulate emissions.

[0046] Step S130 includes: if the engine is in a stopped state, obtaining the current driving mode and the large battery charge; when the current driving mode is pure electric priority mode and the large battery charge is greater than the first charge threshold, or when the current driving mode is forced pure electric mode and the large battery charge is greater than the second charge threshold, the heating duty cycle is 0; when the current driving mode is pure electric priority mode and the large battery charge is less than or equal to the first charge threshold, forced pure electric mode and the large battery charge is less than or equal to the second charge threshold, hybrid electric drive mode, and fuel priority mode, detecting the small battery voltage and fuel temperature; if the small battery voltage is greater than the voltage threshold and the fuel temperature is less than the target fuel temperature, calculating the heating duty cycle based on the feedforward duty cycle, the target fuel temperature, and the engine speed and load, using the following formula:

[0047]

[0048] T delta =T target -T

[0049] In the formula, D drive For heating duty cycle, D f K is the feedforward duty cycle. p and K i The parameter T is obtained based on engine speed and load. target The target fuel temperature is T; conversely, if the small battery voltage is less than or equal to the voltage threshold, the heating duty cycle is determined to be 0, and a charging request is sent to the DC / DC controller to charge the small battery through the large battery until the small battery voltage is greater than the sum of the voltage threshold and the floating voltage value; then return to the step of obtaining the current driving mode and the large battery charge, and calculate the heating duty cycle in a loop.

[0050] The first charge threshold is the sum of the charge balance point and the first safety control quantity. The charge balance point varies for different vehicle models, for example, it can be set to 20%. The first safety control quantity can be adaptively set according to different vehicle models, for example, it can be set to 5%.

[0051] The second charge threshold is the sum of the forced pure electric threshold and the second safety control quantity. The forced pure electric threshold varies for different vehicle models, for example, it is set to 6%. The second safety control quantity can be adaptively set according to different vehicle models, for example, it is set to 4%.

[0052] Specifically, such as Figure 3 As shown, when the engine is off, the current driving mode and the maximum battery charge are obtained.

[0053] When the current driving mode is pure electric priority mode and the battery charge is greater than the first charge threshold (SOC > 20% + 5%), or when the current driving mode is forced pure electric mode and the battery charge is greater than the second charge threshold (SOC > 6% + 4%), the heating duty cycle is 0. In this case, since electricity is used as the power source, the probability of the engine starting and running is extremely low, and no fuel is consumed; therefore, there is no need to heat the fuel.

[0054] When the current driving mode is pure electric priority mode and the large battery charge is less than or equal to the first charge threshold, forced pure electric mode and the large battery charge is less than or equal to the second charge threshold, hybrid electric drive mode and fuel priority mode, fuel is used as the power source, which means that the probability of the engine starting and running is relatively high, and fuel consumption is required. Therefore, fuel heating control is required, and the small battery voltage and fuel temperature are detected.

[0055] When the small battery voltage is greater than a preset voltage threshold, such as 10V, and the fuel temperature is less than the target temperature, the heating duty cycle is calculated based on the feedforward duty cycle, the target fuel temperature, the engine speed, and the load. This allows for fuel heating drive control based on the feedforward duty cycle, which improves fuel atomization performance, reduces the amount of fuel injected during the start-up phase, improves PN emissions and fuel economy, and helps to break the critical temperature boundary for low-temperature start-up.

[0056] Conversely, if the small battery voltage is less than or equal to the set voltage threshold, it indicates that there are no conditions for engine starting, and fuel heating control is not required. The heating duty cycle is determined to be 0 to save energy. However, the small battery needs to be charged at this time. A charging request is sent to the DC / DC controller (i.e., the voltage conversion controller), and the large battery of the hybrid vehicle charges the small battery until the small battery voltage is greater than the sum of the voltage threshold and the floating voltage value. The floating voltage value can be set to 2V. When the small battery voltage is greater than 12V, the charging request to the DC / DC controller is stopped.

[0057] In addition, if the fuel temperature is greater than or equal to the target fuel temperature, it means that the fuel temperature has reached the target temperature and no heating control is required; the heating duty cycle is 0.

[0058] After obtaining the heating duty cycle, return to the step of obtaining the current driving mode and recalculate the heating duty cycle to achieve continuous control of fuel heating when the vehicle is stopped, ensuring timely fuel heating.

[0059] Because the engine has no possibility of starting under certain modes and power levels, the fuel is not heated in this case to save energy. In other modes and power levels where the engine can be started, the fuel is continuously heated to prepare for engine startup and improve starting performance and emissions levels after startup.

[0060] In this embodiment, the engine status is determined, including both start-up and shutdown states. When the engine is in start-up state, the small battery voltage and fuel temperature are detected. Based on the small battery voltage and fuel temperature, the heating duty cycle is calculated, and fuel heating drive control is performed according to the heating duty cycle to ensure the fuel is at a suitable temperature for engine operation. If the engine is in shutdown state, the current driving mode and large battery charge are obtained. Driving modes include pure electric priority mode, forced pure electric mode, hybrid electric drive mode, and fuel priority mode. Based on the current driving mode and large battery charge, the corresponding heating duty cycle is calculated, and fuel heating drive control is performed according to the heating duty cycle. This method is applicable to hybrid vehicles and can determine the fuel heating strategy according to the vehicle's driving mode, improving fuel atomization performance, improving PN emission levels during engine operation, and enhancing fuel economy during engine start-up.

[0061] like Figure 4 As shown, an adaptive fuel heating drive control system based on a hybrid vehicle is provided to implement the adaptive fuel heating drive control method for a hybrid vehicle as described above. The system includes: a vehicle control unit 10, an engine 20, an adaptive fuel heating drive control unit 30, a small battery 40, and a fuel supply system 50. The vehicle control unit 10, engine 20, small battery 40, and fuel supply system 50 are all connected to the adaptive fuel heating drive control unit 30. The vehicle control unit 10 acquires the driving mode of the hybrid vehicle and the battery charge of the large battery, and transmits this information to the adaptive fuel heating drive control unit 30. The engine 20 acquires the engine operating status, including engine speed and load, and transmits this information to the adaptive fuel heating drive control unit 30. The small battery 40 transmits its voltage to the adaptive fuel heating drive control unit 30; the fuel supply system 50 heats and supplies fuel; the adaptive fuel heating drive control unit 30 determines the engine status, including start-up and shutdown states; if the engine is start-up, it detects the small battery voltage and fuel temperature, calculates the heating duty cycle based on the small battery voltage and fuel temperature, and performs fuel heating drive control based on the heating duty cycle; if the engine is shutdown, it obtains the current driving mode and the main battery charge, including pure electric priority mode, forced pure electric mode, hybrid electric drive mode, and fuel priority mode, calculates the corresponding heating duty cycle based on the current driving mode and the main battery charge, and performs fuel heating drive control based on the heating duty cycle.

[0062] In this embodiment, the vehicle controller unit 10 acquires the driving mode of the hybrid vehicle and the state of charge of the large battery, the engine 20 acquires the engine operating status, including engine speed and load, and the small battery acquires the small battery voltage. All the acquired information is transmitted to the adaptive fuel heating drive control unit 30. The adaptive fuel heating drive control unit 30 determines whether the engine is in a starting or stopped state. When in a starting state, it detects the small battery voltage and fuel temperature, calculates the heating duty cycle based on the small battery voltage and fuel temperature, and controls the fuel supply system to heat and supply fuel according to the heating duty cycle. When in a stopped state, it acquires the current driving mode, including pure electric priority mode, forced pure electric mode, hybrid electric drive mode, and fuel priority mode, calculates the corresponding heating duty cycle based on the current driving mode, and controls the fuel supply system to heat and supply fuel according to the heating duty cycle. This adaptive drive control of the heating duty cycle in both the engine starting and stopped states ensures that the fuel supplied to the engine cylinders is always at a suitable temperature, improving engine starting fuel economy and operating emissions.

[0063] The fuel supply system 50 includes a fuel tank 51, a fuel pump 52, a fuel rail 53, a fuel heater 54, and a fuel injector 55. The fuel tank 51 and the fuel rail 53 are both connected to the fuel pump 52, which pumps fuel from the fuel tank 51 to the fuel rail 53. The fuel heater 54 is located between the fuel rail 52 and the fuel injector nozzle and is connected to both the fuel rail 52 and the fuel injector 55. It includes a fuel temperature sensor, an integrated heater, and a heating chamber, and is used to heat the fuel entering the heating chamber according to the heating duty cycle. The fuel heater is used to detect the fuel temperature. The fuel injector 55 includes a nozzle and is used to inject the heated fuel into the engine cylinder for vehicle starting.

[0064] Specifically, in the fuel supply system 50, fuel in the fuel tank 51 is pumped out to the fuel rail 53 by the fuel pump 52. The fuel rail 53 transports fuel. The fuel heater 54 is located between the fuel rail 53 and the nozzle of the injector 55 and is connected to the fuel rail 53 and the injector 55. When fuel enters the heating chamber of the fuel heater, the fuel in the heating chamber can be heated by the heater, and the heated fuel is injected into the cylinder of the engine through the injector 55 for vehicle starting. This ensures that the temperature of the fuel entering the cylinder is at a suitable level, so as to obtain higher fuel performance and reduce PN emissions.

[0065] The system also includes a DC / DC controller unit 60, which is connected to the adaptive fuel heating drive control unit 30. It is used to receive the small battery charging request sent by the adaptive fuel heating drive control unit 30 and control the large battery to charge the small battery until the voltage of the small battery is greater than the sum of the voltage threshold and the floating voltage value.

[0066] Specifically, the large battery, or power battery, is used to drive the vehicle. The small battery 40 is the on-board battery, mainly used for vehicle starting, ignition, and auxiliary functions, and also to power the fuel heater in the fuel supply system 50. The system continuously monitors the voltage of the small battery. When the voltage of the small battery is lower than a threshold, the adaptive fuel heating drive control unit 30 can send a charging request to the DC / DC controller unit 60 to control the large battery to charge the small battery until the voltage of the small battery is greater than the sum of the voltage threshold and the floating voltage value. At this point, the adaptive fuel heating drive control unit 30 stops sending charging requests, completing the small battery charging process.

[0067] Those skilled in the art will understand that all or part of the processes in the above embodiments can be implemented by a computer program instructing related hardware. The program can be stored in a computer-readable storage medium, and when executed, it can include the processes of the embodiments of the above methods. The storage medium can be a magnetic disk, optical disk, read-only memory (ROM), or random access memory (RAM), etc.

[0068] It is obvious to those skilled in the art that the modules or steps of the present invention described above can be implemented using general-purpose computing devices. They can be centralized on a single computing device or distributed across a network of multiple computing devices. Optionally, they can be implemented using computer-executable program code, thereby storing them in a computer storage medium (ROM / RAM, magnetic disk, optical disk) for execution by the computing device. In some cases, the steps shown or described can be performed in a different order than those described herein, or they can be fabricated as separate integrated circuit modules, or multiple modules or steps can be fabricated as a single integrated circuit module. Therefore, the present invention is not limited to any particular hardware and software combination.

[0069] The above description, in conjunction with specific embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the concept of the present invention, and all such deductions or substitutions should be considered within the scope of protection of the present invention.

Claims

1. An adaptive fuel heating drive control method based on hybrid vehicles, characterized in that, Includes the following steps: Determine the engine status, which includes the engine running status and the engine stopped status; If the engine is running, the small battery voltage and fuel temperature are detected. Based on the small battery voltage and fuel temperature, the heating duty cycle is calculated, and fuel heating drive control is performed based on the heating duty cycle. If the engine is stopped, the current driving mode and the battery charge are obtained. The driving modes include pure electric priority mode, forced pure electric mode, hybrid electric drive mode and fuel priority mode. The corresponding heating duty cycle is calculated based on the current driving mode and the battery charge, and fuel heating drive control is performed based on the heating duty cycle.

2. The adaptive fuel heating drive control method based on hybrid vehicles according to claim 1, characterized in that, If the engine is running, the small battery voltage and fuel temperature are detected, and the heating duty cycle is calculated based on the small battery voltage and fuel temperature, including: If the engine is running, check the small battery voltage and fuel temperature; When the small battery voltage is greater than the voltage threshold and the fuel temperature is less than the target fuel temperature, the heating duty cycle is calculated based on the feedforward duty cycle, the target fuel temperature, and the engine speed and load. The formula is as follows: D drive =D f +K p ×T delta (t)+K i ×∫0 t T delta dt T delta =T target -T In the formula, D drive For heating duty cycle, D f K is the feedforward duty cycle. p and K i The parameter T is obtained based on engine speed and load. target The target fuel temperature is T, where T is the fuel temperature. Conversely, if the voltage of the small battery is less than or equal to the voltage threshold, the heating duty cycle is determined to be 0, and a charging request is sent to the DC / DC controller to charge the small battery through the large battery until the voltage of the small battery is greater than the sum of the voltage threshold and the floating voltage value. Return to the steps of detecting the small battery voltage and fuel temperature, and calculate the heating duty cycle in a loop.

3. The adaptive fuel heating drive control method based on hybrid vehicles according to claim 1, characterized in that, If the engine is in a stopped state, the current driving mode and the main battery charge are obtained, and the corresponding heating duty cycle is calculated based on the current driving mode and the main battery charge, including: If the engine is off, obtain the current driving mode and the maximum battery charge. When the current driving mode is pure electric priority mode and the large battery charge is greater than the first charge threshold, or when the current driving mode is forced pure electric mode and the large battery charge is greater than the second charge threshold, the heating duty cycle is 0. When the current driving mode is pure electric priority mode and the large battery charge is less than or equal to the first charge threshold, forced pure electric mode and the large battery charge is less than or equal to the second charge threshold, hybrid electric drive mode and fuel priority mode, the small battery voltage and fuel temperature are detected. If the small battery voltage is greater than the voltage threshold and the fuel temperature is less than the target fuel temperature, the heating duty cycle is calculated based on the feedforward duty cycle, the target fuel temperature, and the engine speed and load. The formula is as follows: D drive =D f +K p ×T delta (t)+K i ×∫0 t T delat dt T delta =T target -T In the formula, D drive For heating duty cycle, D f For the feedforward duty cycle, based on the ambient temperature and T delta K was obtained. p and K i The parameter T is obtained based on engine speed and load. target The target fuel temperature is T, where T is the fuel temperature. Conversely, if the voltage of the small battery is less than or equal to the voltage threshold, the heating duty cycle is determined to be 0, and a charging request is sent to the DC / DC controller to charge the small battery through the large battery until the voltage of the small battery is greater than the sum of the voltage threshold and the floating voltage value. Return to the step of obtaining the current driving mode and the large battery charge, and calculate the heating duty cycle in a loop.

4. The adaptive fuel heating drive control method based on hybrid vehicles according to claim 3, characterized in that, The first charge threshold is the sum of the charge balance point and the first safety control quantity, wherein the charge balance point is 20% and the first safety control quantity is 5%.

5. The adaptive fuel heating drive control method based on hybrid vehicles according to claim 3, characterized in that, The second charge threshold is the sum of the forced pure electric critical point and the second safety control quantity, wherein the forced pure electric critical point is 6% and the second safety control quantity is 4%.

6. An adaptive fuel heating drive control system based on hybrid vehicles, characterized in that, The adaptive fuel heating drive control method for hybrid vehicles according to any one of claims 1-5 includes: The vehicle controller unit, engine, adaptive fuel heating drive control unit, small battery, and fuel supply system are all connected to the adaptive fuel heating drive control unit. The vehicle controller unit is used to acquire the driving mode and battery charge of the hybrid vehicle and transmit them to the adaptive fuel heating drive control unit. The engine is used to acquire the engine operating status, including the engine speed and load, and transmit it to the adaptive fuel heating drive control unit; The small battery is used to transmit the small battery voltage to the adaptive fuel heating drive control unit; The fuel supply system is used to heat and supply fuel under the control of the adaptive fuel heating drive control unit; The adaptive fuel heating drive control unit is used to determine the engine status, including the engine start-up state and the engine stop state. If the engine is in the start-up state, it detects the small battery voltage and fuel temperature, calculates the heating duty cycle based on the small battery voltage and fuel temperature, and performs fuel heating drive control based on the heating duty cycle. If the engine is in the stop state, it obtains the current driving mode and the main battery charge, including the pure electric priority mode, forced pure electric mode, hybrid electric drive mode, and fuel priority mode. Based on the current driving mode and the main battery charge, it calculates the corresponding heating duty cycle and performs fuel heating drive control based on the heating duty cycle.

7. The adaptive fuel heating drive control system based on hybrid vehicles according to claim 6, characterized in that, The fuel supply system includes: a fuel tank, a fuel pump, a fuel rail, a fuel heater, and fuel injectors; Both the fuel tank and the fuel rail are connected to the fuel pump, which pumps fuel from the fuel tank to the fuel rail. The fuel heater is disposed between the fuel rail and the injector nozzle and is in communication with the fuel rail and the injector. It includes a fuel temperature sensor, an integrated heater and a heating chamber, and is used to heat the fuel entering the heating chamber according to the heating duty cycle. The fuel heater is used to detect the fuel temperature. The injector includes a nozzle for injecting heated fuel into the engine cylinder for vehicle starting.

8. The adaptive fuel heating drive control system based on hybrid vehicles according to claim 6, characterized in that, Also includes: The DC / DC controller unit is connected to the adaptive fuel heating drive control unit and is used to receive the small battery charging request sent by the adaptive fuel heating drive control unit, and control the large battery to charge the small battery until the voltage of the small battery is greater than the sum of the voltage threshold and the floating voltage value.

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