A two-stage boost control system and method for a P1 hybrid commercial vehicle

Abstract

The present invention provides a two-stage supercharging control system and method for a P1 hybrid commercial vehicle, which belongs to the field of engine electronic control technology. The system includes a P1 body structure, a power module and a two-stage supercharging module; the two-stage supercharging module includes an exhaust gas turbocharger, an electric supercharger and a hybrid controller, and the hybrid controller is connected to the exhaust gas turbocharger and the electric supercharger; the P1 body structure includes an engine, a P1 motor, a clutch, a gearbox, a transmission shaft and axle tires arranged coaxially in sequence; the power module includes a power battery and a high-voltage distribution box connected to each other; a gas pipeline is provided on the first side of the P1 body structure, and the exhaust gas turbocharger and the electric supercharger are arranged in the gas pipeline, and the exhaust gas turbocharger is connected to the engine, and the electric supercharger is connected to the high-voltage distribution box. The present invention uses a two-stage supercharging system to replace the exhaust gas turbocharger, and uses the recovered energy to improve the power of the engine under various load conditions.

Description

Technical Field

[0001] The present invention belongs to the technical field of engine electronic control, and in particular relates to a two-stage boost control system and method for a P1 configuration hybrid commercial vehicle. Background Art

[0002] Vehicle energy conservation and emission reduction performance is an important indicator of current vehicle design and application. Hybrid commercial vehicles can effectively reduce carbon emissions in 48V hybrid mode under the P1 architecture, and can recover part of the energy through power battery charging, which has an important impact on improving the vehicle's energy conservation and emission reduction performance.

[0003] Traditional vehicles use exhaust gas turbochargers to increase engine output power, and the energy consumption is obviously low. The new generation of two-stage supercharging systems have been used in vehicles, but because it is impossible to ensure the impact of the supercharging system on the stability of hybrid commercial vehicles, and it is impossible to solve the coordinated distribution of pressure in the two-stage supercharging system, it has not yet been applied to high-horsepower commercial vehicle engines. Uneven pressure distribution can easily cause surge and affect engine efficiency. In summary, there is no control strategy for the two-stage supercharging system in current hybrid commercial vehicles.

[0004] This is a shortcoming of the prior art. Therefore, in view of the above-mentioned defects in the prior art, it is very necessary to provide a two-stage boost control system and method for a P1 configuration hybrid commercial vehicle. Summary of the invention

[0005] In view of the defect in the prior art that the current hybrid commercial vehicles do not have a control strategy for the two-stage supercharging system, the present invention provides a two-stage supercharging control system and method for a P1 configuration hybrid commercial vehicle to solve the above technical problems.

[0006] In a first aspect, the present invention provides a two-stage supercharging control system for a P1-configuration hybrid commercial vehicle, comprising a P1 vehicle body structure, a power module, and a two-stage supercharging module;

[0007] The two-stage supercharging module includes an exhaust gas turbocharger, an electric supercharger and a hybrid controller, and the hybrid controller is connected to the exhaust gas turbocharger and the electric supercharger;

[0008] The P1 body structure includes the engine, P1 motor, clutch, gearbox, drive shaft and axle tires which are coaxially arranged in sequence;

[0009] The power module includes a power battery and a high-voltage distribution box, and the power battery is connected to the high-voltage distribution box;

[0010] A gas pipeline is arranged on the first side of the P1 vehicle body structure, an exhaust gas turbocharger and an electric supercharger are arranged in the gas pipeline, the exhaust gas turbocharger is connected to the engine, and the electric supercharger is connected to the high-voltage distribution box;

[0011] The P1 motor is connected to a motor controller, which is also connected to the high-voltage distribution box;

[0012] The engine is connected to an engine controller, the hybrid controller is connected to the engine controller, and the hybrid controller is also connected to the vehicle controller.

[0013] Furthermore, the power battery output voltage is the same as the P1 motor operating voltage.

[0014] Further, the gas pipeline includes an air inlet and an air outlet, and the air inlet is connected to a first air path and a second air path connected in parallel;

[0015] The electric supercharger is arranged in the first gas circuit, and a throttle valve is arranged in the second gas circuit;

[0016] The first gas path end and the second gas path end are connected to the exhaust gas turbocharger input end, and the exhaust gas turbocharger output end is connected to the gas outlet.

[0017] Furthermore, the P1 motor is connected to the motor controller via a first cable, the motor controller is connected to the high-voltage distribution box via a second cable, the high-voltage distribution box is connected to the power battery via a third cable, and the high-voltage distribution box is connected to the electric supercharger via a fourth cable.

[0018] In a second aspect, the present invention provides a two-stage boost control method for a P1 hybrid commercial vehicle, comprising the following steps:

[0019] S1. Pre-set the engine boost pressure requirement value according to the engine operating parameters, environmental parameters and vehicle operation mode;

[0020] S2. Pre-set the current feedforward value according to the engine operating parameters and environmental parameters, and use a two-stage boost control mode with feedforward and feedback superposition;

[0021] S3. Pre-set the open and closed loop conditions of the two-stage supercharging system based on the engine injection amount and engine speed;

[0022] S4. Pre-set a delay when switching the open and closed loop control switch state of the two-stage boost system;

[0023] S5. Coordinate and control the actual opening degree and open-loop and closed-loop states of the two-stage boosting system according to the required boosting pressure to ensure that at most one boosting system is in a closed-loop state.

[0024] Furthermore, the specific steps of step S1 are as follows:

[0025] S11. The hybrid controller obtains the current engine speed and fuel volume parameters through the engine controller, obtains the altitude, pressure, and temperature parameters of the vehicle through the vehicle controller, and obtains the vehicle operation mode through the vehicle controller;

[0026] S12. The hybrid controller obtains a basic boost pressure value by looking up a table based on the engine operating condition, and performs steady-state correction to obtain a steady-state set basic value of the boost pressure;

[0027] S13. The hybrid controller introduces an adjustment speed parameter, determines the value of the adjustment speed parameter according to the relationship between the steady-state set basic value and the preset upper and lower limit thresholds, and dynamically corrects the steady-state set basic value of the boost pressure based on the value of the adjustment speed parameter;

[0028] S14. The hybrid controller coordinates and limits the dynamically corrected set value based on the engine speed and atmospheric pressure table, and sets an upper limit value and a lower limit value;

[0029] S15. The hybrid controller introduces a hysteresis adjustment parameter and a filter parameter to filter the set value after dynamic correction to obtain a final boost pressure demand set value.

[0030] Furthermore, the specific steps of step S2 are as follows:

[0031] S21. The hybrid controller obtains the current engine speed and fuel quantity parameters through the engine controller, obtains the altitude, pressure, and temperature parameters of the vehicle through the vehicle controller, and obtains the vehicle operation mode through the vehicle controller;

[0032] S22. Pre-set the feedforward value of engine speed and bleed valve opening according to the current engine speed, fuel quantity parameters, vehicle altitude, pressure, and temperature parameters;

[0033] S23. Perform steady-state correction, dynamic correction, coordination restriction and filtering on the set feedforward value according to step S1 to obtain the final feedforward set value.

[0034] Furthermore, the specific steps of step S3 are as follows:

[0035] S31. Preset the upper limit table of engine speed and fuel injection amount and the lower limit table of engine speed and fuel injection amount under each vehicle operation mode;

[0036] S32. The hybrid controller determines the vehicle operation mode, and searches the table of engine speed and fuel injection amount corresponding to the vehicle operation mode to set the upper limit of the hysteresis oil amount, and searches the table of engine speed and fuel injection amount corresponding to the engine operation mode to set the lower limit of the hysteresis oil amount;

[0037] S33. The hybrid controller obtains the current actual fuel injection amount of the engine, and compares the current actual fuel injection amount of the engine with the upper limit of the hysteresis oil amount. If it exceeds the upper limit, the seasonal open-closed loop control switch is set to complete the open-loop to closed-loop control of the exhaust gas turbocharger. The hybrid controller also compares the current actual fuel injection amount of the engine with the lower limit of the hysteresis oil amount. If it is lower than the upper limit, the seasonal open-closed loop control switch is invalid to complete the closed-loop to open-loop control of the exhaust gas turbocharger.

[0038] Furthermore, the specific steps of step S4 are as follows:

[0039] S41. Preset engine speed and delay schedule;

[0040] S42. Determine the actual load in advance through the actual fuel injection amount of the engine, and when the actual load is lower than the threshold, look up the engine speed and delay time table for each level of supercharger to determine the delay time, and use the delay time to delay the switching of each level of supercharger from closed-loop to open-loop regulation.

[0041] Furthermore, the specific steps of step S5 are as follows:

[0042] S51. The hybrid controller determines whether the actual fuel injection amount of the engine is lower than the lower limit of the hysteresis fuel amount obtained by looking up the table;

[0043] If yes, go to step S52;

[0044] If not, proceed to step S53;

[0045] S52. The hybrid controller determines that the engine is in a low-load operation state, controls the engine speed to be lower than the speed threshold, controls the exhaust gas turbocharger to be in an open-loop state, controls the proportional valve of the exhaust gas turbocharger to be closed, sets the electric supercharger closed-loop control, and sets the opening of the electric supercharger, and returns to step S51;

[0046] S53. The hybrid controller determines that the engine is in a high-load operation state, and determines whether the exhaust gas turbocharger can meet the required boost pressure according to the altitude of the vehicle;

[0047] If so, proceed to step S54;

[0048] If not, proceed to step S55;

[0049] S54. The hybrid controller controls the electric supercharger to stop running, sets the exhaust gas turbocharger closed-loop control, and returns to step S51;

[0050] S55. The hybrid controller turns on the electric supercharger, controls the opening of the proportional valve of the electric supercharger through closed-loop control, and sets the exhaust gas turbocharger open-loop control, and returns to step S51.

[0051] The beneficial effects of the present invention are:

[0052] The present invention provides a two-stage supercharging control system and method for a P1 configuration hybrid commercial vehicle. The whole vehicle platform adopts the P1 configuration scheme, and the motor, power battery, and two-stage supercharging system are all 48V platforms. The voltage conversion of DC-DC equipment is omitted, thereby reducing the energy loss caused by the DC-DC equipment. Under the hybrid platform, the recovered energy can be used for the two-stage supercharging system to do work. The two-stage supercharging system is used to replace the exhaust gas turbocharger, which can improve the power of the engine under high and low load conditions, especially in high altitude areas, and reduce the problem of reduced output torque due to insufficient engine intake pressure.

[0053] In addition, the invention has a reliable design principle, a simple structure and a very broad application prospect.

[0054] It can be seen that compared with the prior art, the present invention has outstanding substantive features and significant progress, and the beneficial effects of its implementation are also obvious. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0056] Figure 1 It is a schematic diagram of a two-stage boost control system for a P1 configuration hybrid commercial vehicle of the present invention.

[0057] Figure 2 It is a control schematic diagram of a two-stage boost control system for a P1 configuration hybrid commercial vehicle of the present invention.

[0058] Figure 3 It is a flow chart of an embodiment of a two-stage boost control method for a P1 configuration hybrid commercial vehicle of the present invention.

[0059] Figure 4 It is a flow chart of another embodiment of the two-stage boost control method for a P1 configuration hybrid commercial vehicle of the present invention.

[0060] Figure 5 Table 1 is a schematic diagram of the two-stage boost control method for a P1 configuration hybrid commercial vehicle of the present invention.

[0061] Figure 6 Table 2 is a schematic diagram of the two-stage boost control method for a P1 configuration hybrid commercial vehicle of the present invention.

[0062] Figure 7 Table 3 is a schematic diagram of the two-stage boost control method for a P1 configuration hybrid commercial vehicle of the present invention.

[0063] Figure 8Table 4 is a schematic diagram of the two-stage boost control method for a P1 configuration hybrid commercial vehicle of the present invention.

[0064] Fig. 9 Table 5 is a schematic diagram of the two-stage boost control method for a P1 configuration hybrid commercial vehicle of the present invention.

[0065] Fig.10 Table 6 is a schematic diagram of the two-stage boost control method for a P1 configuration hybrid commercial vehicle of the present invention.

[0066] Fig.11 Table 7 is a schematic diagram of the two-stage boost control method for a P1 configuration hybrid commercial vehicle of the present invention.

[0067] Description of main reference numerals

[0068] 1. Engine, 2. P1 motor, 3. Exhaust gas turbocharger, 4. Power battery, 5. Clutch, 6. Gearbox, 7. Axle tire, 8. High-voltage distribution box, 9. Motor controller, 10. Throttle valve, 11. Electric supercharger; 12- Hybrid controller; 13- Vehicle controller; 14- Engine controller. DETAILED DESCRIPTION

[0069] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0070] Embodiment 1:

[0071] like Figure 1 and Figure 2 As shown, the present invention provides a two-stage supercharging control system for a P1-configuration hybrid commercial vehicle, including a P1 vehicle body structure, a power module and a two-stage supercharging module;

[0072] The two-stage supercharging module includes an exhaust gas turbocharger 3, an electric supercharger 11 and a hybrid controller 12, and the hybrid controller 12 is connected to the exhaust gas turbocharger 3 and the electric supercharger 11;

[0073] The P1 vehicle body structure includes an engine 1, a P1 motor 2, a clutch 5, a gearbox 6, a transmission shaft, and axle tires 7 that are coaxially arranged in sequence;

[0074] The power module includes a power battery 4 and a high-voltage distribution box 8, and the power battery 4 is connected to the high-voltage distribution box 8;

[0075] A gas pipeline is arranged on the first side of the P1 vehicle body structure, an exhaust gas turbocharger 3 and an electric supercharger 11 are arranged in the gas pipeline, and the exhaust gas turbocharger 3 is connected to the engine 1, and the electric supercharger 11 is connected to the high-voltage distribution box 8;

[0076] The P1 motor 2 is connected to a motor controller 9, which is also connected to a high voltage distribution box 8;

[0077] The engine 1 is connected to an engine controller 14 , the hybrid controller 12 is connected to the engine controller 14 , and the hybrid controller 12 is also connected to a vehicle controller 13 .

[0078] Embodiment 2:

[0079] like Figure 1 and Figure 2 As shown, the present invention provides a two-stage supercharging control system for a P1-configuration hybrid commercial vehicle, including a P1 vehicle body structure, a power module and a two-stage supercharging module;

[0080] The two-stage supercharging module includes an exhaust gas turbocharger 3, an electric supercharger 11 and a hybrid controller 12, and the hybrid controller 12 is connected to the exhaust gas turbocharger 3 and the electric supercharger 11;

[0081] The P1 vehicle body structure includes an engine 1, a P1 motor 2, a clutch 5, a gearbox 6, a transmission shaft, and axle tires 7 that are coaxially arranged in sequence;

[0082] It should be noted that after the original flywheel housing is removed from the rear of the engine 1, a P1 motor 2 with a flywheel housing is used instead, the operating voltage is 48V, the P1 motor is fixed by long bolts, and the length of the new flywheel housing is increased by 110 compared with the original flywheel housing;

[0083] The center of the engine 1 and the P1 motor 2 are coaxial, ensuring a compact structure. The center of the clutch 5 is coaxial with the axis of the P1 motor 2. The clutch 5 is connected to the transmission 6 behind it. The output shaft of the transmission 6 is connected to the transmission shaft through a flange. The rear of the transmission shaft is connected to the differential and the power is transmitted to the axle tire 7.

[0084] The power module includes a power battery 4 and a high-voltage distribution box 8, and the power battery 4 is connected to the high-voltage distribution box 8;

[0085] A gas pipeline is arranged on the first side of the P1 vehicle body structure, an exhaust gas turbocharger 3 and an electric supercharger 11 are arranged in the gas pipeline, and the exhaust gas turbocharger 3 is connected to the engine 1, and the electric supercharger 11 is connected to the high-voltage distribution box 8; the exhaust gas turbocharger 3 and the electric supercharger 11 are arranged on the same side of the engine 1;

[0086] The P1 motor 2 is connected to a motor controller 9, which is also connected to a high voltage distribution box 8;

[0087] The engine 1 is connected to an engine controller 14, the hybrid controller 12 is connected to the engine controller 14, and the hybrid controller 12 is also connected to a vehicle controller 13;

[0088] The output voltage of the power battery 4 is the same as the working voltage of the P1 motor 2, both of which are 48V;

[0089] The gas pipeline includes an air inlet and an air outlet, and the air inlet is connected to a first air path and a second air path in parallel;

[0090] The electric supercharger 11 is arranged in the first gas circuit, and the throttle valve 10 is arranged in the second gas circuit;

[0091] The first gas path end and the second gas path end are connected to the exhaust gas turbocharger 3 input end, and the exhaust gas turbocharger 3 output end is connected to the gas outlet;

[0092] Among them, the exhaust gas turbocharger 3 is an original component, and the electric supercharger 11 is a new component. The electric supercharger 11 is connected in series to the intake front section of the exhaust gas turbocharger 3;

[0093] It should be noted that when the electric supercharger 11 is required to work, it can be directly bypassed, and the throttle valve 10 is in the bypass pipeline serving as the second gas path, and the original control of the bypass is used to close;

[0094] P1 motor 2 is connected to motor controller 9 via a first cable, motor controller 9 is connected to high-voltage distribution box 8 via a second cable, high-voltage distribution box 8 is connected to power battery 4 via a third cable, and high-voltage distribution box 8 is connected to electric supercharger 11 via a fourth cable;

[0095] The first cable uses a 75 square three-phase cable, and both ends of the cable are fixed with M6 copper bolts;

[0096] The current of the second cable is within 1000A, and two 100 square wire harnesses are used, and the copper noses at both ends of the wire harness are also connected by copper bolts;

[0097] The third cable uses two 100 square wire harnesses, positive and negative;

[0098] The fourth cable uses two 25-square positive and negative wire harnesses.

[0099] It should be noted that the charging and discharging process of the power battery 4 is as follows:

[0100] When the power battery 4 is discharged, the current flows from the power battery simulator to the high-voltage distribution box 8, and the hybrid controller 12 determines whether the high-voltage distribution box 8 supplies power to the electric supercharger 11 and the 48V P1 motor 2;

[0101] When power supply is needed, the high-voltage distribution box 8 will turn on the switch, and the current will flow to the motor controller 9 and the electric supercharger 11 respectively. The motor controller 9 will convert the received DC into three-phase current to control the operation of the P1 motor 2;

[0102] When the power battery 4 needs to be charged, the current flows in the opposite direction.

[0103] It should be noted that the P1 motor 2, power battery 4 and two-stage boost system are all powered by 48V, thus avoiding the use of DC-DC device conversion.

[0104] Embodiment 3:

[0105] like Figure 3 As shown, the present invention provides a two-stage boost control method for a P1 configuration hybrid commercial vehicle, comprising the following steps:

[0106] S1. Pre-set the engine boost pressure requirement value according to the engine operating parameters, environmental parameters and vehicle operation mode;

[0107] S2. Pre-set the current feedforward value according to the engine operating parameters and environmental parameters, and use a two-stage boost control mode with feedforward and feedback superposition;

[0108] S3. Pre-set the open and closed loop conditions of the two-stage supercharging system based on the engine injection amount and engine speed;

[0109] S4. Pre-set a delay when switching the open and closed loop control switch state of the two-stage boost system;

[0110] S5. Coordinate and control the actual opening degree and open-loop and closed-loop states of the two-stage boosting system according to the required boosting pressure to ensure that at most one boosting system is in a closed-loop state.

[0111] The present invention improves the power and economy of the entire vehicle through the P1 hybrid architecture and the two-stage supercharging system platform, allowing the engine to burn completely even in low load and high altitude areas, thereby improving the engine's power generation.

[0112] Embodiment 4:

[0113] It should be noted that the hybrid controller switches the logic control of the two-stage supercharging system according to the engine operating state, which includes the normal vehicle operating mode and the unconventional vehicle operating mode; the unconventional vehicle operating mode includes the driving regeneration mode, the parking regeneration mode and the exhaust brake mode;

[0114] During engine operation, the engine controller detects and displays the current operating mode and sends the current operating mode to the hybrid controller via CAN messages. The HCU performs open-loop and closed-loop control of the two-stage supercharging system and calculates the required boost pressure for each operating mode.

[0115] like Figure 4 As shown, the present invention provides a two-stage boost control method for a P1 configuration hybrid commercial vehicle, comprising the following steps:

[0116] S1. Pre-set the engine boost pressure requirement value according to the engine operating parameters, environmental parameters and vehicle operation mode; the specific steps of step S1 are as follows:

[0117] S11. The hybrid controller obtains the current engine speed and fuel volume parameters through the engine controller, obtains the altitude, pressure, and temperature parameters of the vehicle through the vehicle controller, and obtains the vehicle operation mode through the vehicle controller;

[0118] S12. The hybrid controller obtains a basic boost pressure value by looking up a table based on the engine operating condition, and performs steady-state correction to obtain a steady-state set basic value of the boost pressure;

[0119] The steady-state set basic value BST_pDesBase_N adds atmospheric pressure correction value, intake air temperature correction value and other pressure correction values ​​to the basic boost pressure calculation value BST_pDesBase_map. The basic boost pressure calculation value BST_pDesBase_map can be based on engine operating conditions such as speed, fuel volume / torque, etc. Figure 5 Table 1 is shown, where X is the engine speed, in r / min, and Y is the engine fuel injection amount, in mg / hub; the atmospheric pressure or altitude correction method is to look up the table to give the boost pressure value BST_pDesHiAltd_map according to the engine speed and the fuel injection amount under the current atmospheric pressure or altitude conditions, and multiply the difference between BST_pDesHiAltd_map and the basic boost pressure value BST_pDesBase_map by the atmospheric pressure correction coefficient to obtain the atmospheric pressure corrected boost pressure value; similarly, the intake temperature and other pressures, such as the correction value of adding a PDF particle trap, can be obtained;

[0120] S13. The hybrid controller introduces an adjustment speed parameter, determines the value of the adjustment speed parameter according to the relationship between the steady-state set basic value and the preset upper and lower limit thresholds, and dynamically corrects the steady-state set basic value of the boost pressure based on the value of the adjustment speed parameter;

[0121] The steady-state setting basic value BST_pDesBase_N is passed through the DT1 control link to obtain the dynamic boost pressure setting value BST_pDesDyn; the adjustment speed parameter K in the DT1 control link is mainly compared with the steady-state setting basic value and the setting upper limit BST_Pos_C and lower limit BST_Neg_C, and the corresponding value is set in different intervals;

[0122] For example, BST_pDesDyn>BST_Pos_C, then K=BST_Pos_K;

[0123] When BST_Neg_C<BST_pDesDyn≤BST_Pos_C, then K=BST_K; BST_pDesDyn<BST_Neg_C, then K=K=BST_Neg_K;

[0124] S14. The hybrid controller coordinates and limits the dynamically corrected set value based on the engine speed and atmospheric pressure table, and sets an upper limit value and a lower limit value;

[0125] Set the lower limit value to PCR_pMinDesVal_C = 0, and the upper limit value to PCR_pMaxDesValLim, in hPa, according to the engine speed and atmospheric pressure. Figure 6 Table 2 shown can be obtained, where X is the engine speed in r / min, Y is the current atmospheric pressure in hPa;

[0126] S15. The hybrid controller introduces a hysteresis adjustment parameter and a filter parameter to filter the dynamically corrected set value to obtain a final boost pressure demand set value;

[0127] The unfiltered boost pressure demand setting value is filtered by the hysteresis module and PT1 to give the final boost pressure demand setting value BST_pDes; after the hysteresis and PT1 filtering, the fluctuation of the vehicle accelerator pedal when tip-out occurs will be well suppressed, providing better intake system performance; the hysteresis module adjustment parameters based on the operating point are PCR_tiDes_Dely=100ms and PT1 filter parameters PCR_tiDes_PT1=90ms;

[0128] S2. Pre-set the current feedforward value according to the engine operating parameters and environmental parameters, and use the two-stage boost control mode with feedforward and feedback superposition; the specific steps of step S2 are as follows:

[0129] S21. The hybrid controller obtains the current engine speed and fuel quantity parameters through the engine controller, obtains the altitude, pressure, and temperature parameters of the vehicle through the vehicle controller, and obtains the vehicle operation mode through the vehicle controller;

[0130] S22. Pre-set the feedforward value of engine speed and bleed valve opening according to the current engine speed, fuel quantity parameters, vehicle altitude, pressure, and temperature parameters;

[0131] S23. Perform steady-state correction, dynamic correction, coordination restriction and filtering on the set feedforward value in accordance with step S1 to obtain the final feedforward set value;

[0132] It should be noted that, ideally, the speed and the bleed valve opening of the two-stage supercharging system are both stable near the feedforward set value. If there is a deviation, it can be adjusted through the closed loop of the two-stage supercharger.

[0133] S3. Pre-set the open and closed loop conditions of the two-stage supercharging system based on the engine injection amount and engine speed;

[0134] It should be noted that the present invention defines the supercharger open-closed loop based on the oil volume, speed and other conditions; if the load exceeds the hysteresis oil volume value, the closed-loop control mode of the controller is released through the open-closed loop control switch BST_SwtGov;

[0135] The specific steps of step S3 are as follows:

[0136] S31. Preset the upper limit table of engine speed and fuel injection amount and the lower limit table of engine speed and fuel injection amount under each vehicle operation mode;

[0137] S32. The hybrid controller determines the vehicle operation mode, and searches the table of engine speed and fuel injection amount corresponding to the vehicle operation mode to set the upper limit of the hysteresis oil amount, and searches the table of engine speed and fuel injection amount corresponding to the engine operation mode to set the lower limit of the hysteresis oil amount;

[0138] S33. The hybrid controller obtains the current actual fuel injection amount of the engine, and compares the current actual fuel injection amount of the engine with the upper limit of the hysteresis oil amount. When it exceeds the upper limit, the seasonal open-closed loop control switch is set to complete the open-loop to closed control of the exhaust gas turbocharger, and compares the current actual fuel injection amount of the engine with the lower limit of the hysteresis oil amount. When it is lower than the lower limit, the seasonal open-closed loop control switch is invalid, and the closed-loop to open-loop control of the exhaust gas turbocharger is completed;

[0139] First, the open-loop and closed-loop definition judgment is mainly carried out for the high-pressure stage. The open-loop and closed-loop control switch BST_SwtGov is obtained by comparing the current actual engine injection amount BST_q_Gov with the hysteresis upper and lower limits BST_qGov_On and BST_qGov_Off; if the upper limit is exceeded, the switch BST_SwtGov will be set from 0 to 1, and the system will switch from open-loop to closed-loop control;

[0140] like Figure 7Table 3 shows the upper limit value of the hysteresis oil volume BST_qGov_On. According to the table, the engine is currently in the normal operation mode Normal; where X is the engine speed r / min, and Y is the BST_qGov_On oil volume unit mg / hub;

[0141] Same as above, Figure 8 Table 4 shows the lower limit value of the hysteresis oil volume BST_qGov_Off. According to the table, the engine is currently in the normal operation mode Normal, where X is the engine speed r / min, and Y is the BST_qGov_On oil volume unit mg / hub;

[0142] In addition to the Normal mode, you can add non-conventional operating modes such as driving regeneration mode Rgn1, parking regeneration mode Rgn2) and exhaust brake mode Ebrk. Taking the driving regeneration mode Rgn1 as an example, the upper limit of the hysteresis oil volume can be found as follows: Fig. 9 The lower limit of the hysteresis oil volume can be found in Table 5. Fig.10 Table 6 shown;

[0143] S4. Pre-set the delay when the open-closed loop control switch state of the two-stage boost system is switched; the specific steps of step S4 are as follows:

[0144] S41. Preset engine speed and delay schedule;

[0145] S42. Determine the actual load in advance by the actual fuel injection amount of the engine, and when the actual load is lower than the threshold, look up the engine speed and delay time table for each level of the booster to determine the delay time, and use the delay time to delay the switching of each level of the booster from closed-loop to open-loop regulation;

[0146] When the two-stage boost system is switched between open and closed loop control states, a delay needs to be added to prevent the booster from fluctuating at low load thresholds when the closed loop control is closed. The delay time BST_tiGovOff can be found by checking Fig.11 The table 7 shown shows that, where X is the engine speed in r / min, Y is the delay time in s;

[0147] It should be noted that this delay is mainly used when the high-pressure stage supercharger, i.e., the exhaust gas turbocharger, switches from closed-loop regulation to open-loop regulation in the normal operating mode of the vehicle. However, when the vehicle is in the driving regeneration state rgn1, the high-pressure stage supercharger, i.e., the exhaust gas turbocharger, switches from closed-loop regulation to open-loop regulation without delay;

[0148] S5. Coordinate the actual opening and open-loop and closed-loop states of the two-stage boosting system according to the required boosting pressure to ensure that at most one boosting system is in a closed-loop state;

[0149] The specific steps of step S5 are as follows:

[0150] S51. The hybrid controller determines whether the actual fuel injection amount of the engine is lower than the lower limit of the hysteresis fuel amount obtained by looking up the table;

[0151] If yes, go to step S52;

[0152] If not, proceed to step S53;

[0153] S52. The hybrid controller determines that the engine is in a low-load operation state, controls the engine speed to be lower than the speed threshold, controls the exhaust gas turbocharger to be in an open-loop state, controls the proportional valve of the exhaust gas turbocharger to be closed, sets the electric supercharger closed-loop control, and sets the opening of the electric supercharger, and returns to step S51;

[0154] S53. The hybrid controller determines that the engine is in a high-load operation state, and determines whether the exhaust gas turbocharger can meet the required boost pressure according to the altitude of the vehicle;

[0155] If so, proceed to step S54;

[0156] If not, proceed to step S55;

[0157] S54. The hybrid controller controls the electric supercharger to stop running, sets the exhaust gas turbocharger closed-loop control, and returns to step S51;

[0158] S55. The hybrid controller turns on the electric supercharger, controls the opening of the proportional valve of the electric supercharger through closed-loop control, and sets the exhaust gas turbocharger open-loop control, and returns to step S51;

[0159] It should be noted that the required boost pressure of the high and low pressure stages of the two-stage boosting system is adjusted, and the actual opening of the high and low pressure stage boosters and the open and closed loop status of the current two-stage control are finally output. When there is a closed loop request for the high pressure stage, the high pressure level can only be closed when the low pressure stage closed loop is completed. If the low pressure stage closed loop is not completed, the high pressure stage cannot be switched from open loop to closed loop at this time; this ensures that the two boosters will not be closed at the same time based on the post-boosting pressure, avoiding the risk of loss of control of the two-stage boosting system during the closed loop process;

[0160] The boost pressure distribution problem of the two-stage boost system is divided into three different load stages:

[0161] When the engine is running at low load, the engine speed is lower than 1100 rpm. At this time, according to the open-closed loop judgment and adjustment, it can be known that the current injection amount is lower than the lower limit of the hysteresis loop, the waste turbocharger is in an open-loop state, and the turbocharger proportional valve is closed. However, even in the fully closed state, the exhaust gas turbine hardly runs because the engine speed is not high. The required boost pressure control can be compensated by the electric supercharger and closed-loop control can be performed; the two-stage supercharging system adopts the working mode of open-loop control of the high-pressure stage supercharger and closed-loop regulation of the low-pressure stage supercharger;

[0162] When the engine is running at high load and the engine speed is higher than 1100 rpm, the exhaust gas turbine performs closed-loop regulation. At the same time, in low-altitude areas, the exhaust gas turbine boost pressure can cover the required boost pressure. At this time, the electric supercharger can stop running to save electricity and energy. The two-stage boost system adopts a closed-loop regulation of the high-pressure stage supercharger, and the low-pressure stage supercharger does not work.

[0163] When the engine is running at high load and the engine speed is higher than 1100 rpm, and at high altitudes, the working capacity of the abandoned turbocharger still cannot meet the required boost pressure, so the electric supercharger can intervene to further increase the boost pressure; the two-stage supercharging system adopts open-loop regulation of the high and low-pressure superchargers and closed-loop regulation of the low-pressure supercharger.

[0164] Although the present invention has been described in detail by referring to the accompanying drawings and in combination with the preferred embodiments, the present invention is not limited thereto. Without departing from the spirit and essence of the present invention, a person of ordinary skill in the art may make various equivalent modifications or substitutions to the embodiments of the present invention, and these modifications or substitutions shall be within the scope of the present invention. Any person of ordinary skill in the art may easily think of changes or substitutions within the technical scope disclosed by the present invention, and these shall be within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be subject to the scope of protection of the claims.

Claims

1. A two-stage boost control method for a P1 hybrid commercial vehicle, characterized in that: A two-stage supercharging control system based on a P1 hybrid commercial vehicle is implemented, the system comprising a P1 vehicle body structure, a power module and a two-stage supercharging module; The two-stage supercharging module includes an exhaust gas turbocharger, an electric supercharger and a hybrid controller, and the hybrid controller is connected to the exhaust gas turbocharger and the electric supercharger; The P1 body structure includes the engine, P1 motor, clutch, gearbox, drive shaft and axle tires which are coaxially arranged in sequence; The power module includes a power battery and a high-voltage distribution box, and the power battery is connected to the high-voltage distribution box; A gas pipeline is arranged on the first side of the P1 vehicle body structure, an exhaust gas turbocharger and an electric supercharger are arranged in the gas pipeline, the exhaust gas turbocharger is connected to the engine, and the electric supercharger is connected to the high-voltage distribution box; The P1 motor is connected to a motor controller, which is also connected to the high-voltage distribution box; The engine is connected to an engine controller, the hybrid controller is connected to the engine controller, and the hybrid controller is also connected to the vehicle controller; The charging and discharging process of the power battery is as follows: When the power battery is discharged, the current flows from the power battery simulator to the high-voltage distribution box, and the hybrid controller determines whether the high-voltage distribution box supplies power to the electric supercharger and the 48V P1 motor; When power is needed, the high-voltage distribution box will turn on the switch, and the current will flow to the motor controller and the electric supercharger respectively. The motor controller will convert the received DC into three-phase current to control the operation of the P1 motor; When the power battery needs to be charged, the current flows in the opposite direction; The method comprises the following steps: S1. Pre-set the engine boost pressure requirement value according to the engine operating parameters, environmental parameters and vehicle operation mode; the specific steps of step S1 are as follows: S11. The hybrid controller obtains the current engine speed and fuel volume parameters through the engine controller, obtains the altitude, pressure, and temperature parameters of the vehicle through the vehicle controller, and obtains the vehicle operation mode through the vehicle controller; S12. The hybrid controller obtains a basic boost pressure value by looking up a table based on the engine operating condition, and performs steady-state correction to obtain a steady-state set basic value of the boost pressure; S13. The hybrid controller introduces an adjustment speed parameter, determines the value of the adjustment speed parameter according to the relationship between the steady-state set basic value and the preset upper and lower limit thresholds, and dynamically corrects the steady-state set basic value of the boost pressure based on the value of the adjustment speed parameter; S14. The hybrid controller coordinates and limits the dynamically corrected set value based on the engine speed and atmospheric pressure table, and sets an upper limit value and a lower limit value; S15. The hybrid controller introduces a hysteresis adjustment parameter and a filter parameter to filter the dynamically corrected set value to obtain a final boost pressure demand set value; S2. Pre-set the current feedforward value according to the engine operating parameters and environmental parameters, and use the two-stage boost control mode with feedforward and feedback superposition; the specific steps of step S2 are as follows: S21. The hybrid controller obtains the current engine speed and fuel quantity parameters through the engine controller, obtains the altitude, pressure, and temperature parameters of the vehicle through the vehicle controller, and obtains the vehicle operation mode through the vehicle controller; S22. Pre-set the feedforward value of engine speed and bleed valve opening according to the current engine speed, fuel quantity parameters, vehicle altitude, pressure, and temperature parameters; S23. Perform steady-state correction, dynamic correction, coordination restriction and filtering on the set feedforward value in accordance with step S1 to obtain the final feedforward set value; S3. The open-closed loop conditions of the two-stage supercharging system are set in advance based on the engine injection amount and the engine speed; the specific steps of step S3 are as follows: S31. Preset the upper limit table of engine speed and fuel injection amount and the lower limit table of engine speed and fuel injection amount under each vehicle operation mode; S32. The hybrid controller determines the vehicle operation mode, and searches the table of engine speed and fuel injection amount corresponding to the vehicle operation mode to set the upper limit of the hysteresis oil amount, and searches the table of engine speed and fuel injection amount corresponding to the engine operation mode to set the lower limit of the hysteresis oil amount; S33. The hybrid controller obtains the current actual fuel injection amount of the engine, and compares the current actual fuel injection amount of the engine with the upper limit of the hysteresis oil amount. When it exceeds the upper limit, the seasonal open-closed loop control switch is set to complete the open-loop to closed control of the exhaust gas turbocharger, and compares the current actual fuel injection amount of the engine with the lower limit of the hysteresis oil amount. When it is lower than the lower limit, the seasonal open-closed loop control switch is invalid, and the closed-loop to open-loop control of the exhaust gas turbocharger is completed; S4. Pre-set the delay when the open-closed loop control switch state of the two-stage boost system is switched; the specific steps of step S4 are as follows: S41. Preset engine speed and delay schedule; S42. Determine the actual load in advance by the actual fuel injection amount of the engine, and when the actual load is lower than the threshold, look up the engine speed and delay time table for each level of the booster to determine the delay time, and use the delay time to delay the switching of each level of the booster from closed-loop to open-loop regulation; S5. According to the required boost pressure, the actual opening and open-closed loop state of the two-stage boost system are coordinated and controlled to ensure that at most one boost system is in a closed loop state; the specific steps of step S5 are as follows: S51. The hybrid controller determines whether the actual fuel injection amount of the engine is lower than the lower limit of the hysteresis fuel amount obtained by looking up the table; If yes, go to step S52; If not, proceed to step S53; S52. The hybrid controller determines that the engine is in a low-load operation state, controls the engine speed to be lower than the speed threshold, controls the exhaust gas turbocharger to be in an open-loop state, controls the proportional valve of the exhaust gas turbocharger to be closed, sets the electric supercharger closed-loop control, and sets the opening of the electric supercharger, and returns to step S51; S53. The hybrid controller determines that the engine is in a high-load operation state, and determines whether the exhaust gas turbocharger can meet the required boost pressure according to the altitude of the vehicle; If yes, go to step S54; If not, proceed to step S55; S54. The hybrid controller controls the electric supercharger to stop running, sets the exhaust gas turbocharger closed-loop control, and returns to step S51; S55. The hybrid controller turns on the electric supercharger, controls the opening of the proportional valve of the electric supercharger through closed-loop control, and sets the exhaust gas turbocharger open-loop control, and returns to step S51.

2. The two-stage boost control method for a P1-configuration hybrid commercial vehicle according to claim 1, characterized in that: The power battery output voltage is the same as the P1 motor operating voltage.

3. The two-stage boost control method for a P1-configuration hybrid commercial vehicle according to claim 1, characterized in that: The gas pipeline includes an air inlet and an air outlet, and the air inlet is connected to a first air path and a second air path in parallel; The electric supercharger is arranged in the first gas circuit, and a throttle valve is arranged in the second gas circuit; The first gas path end and the second gas path end are connected to the exhaust gas turbocharger input end, and the exhaust gas turbocharger output end is connected to the gas outlet.

4. The two-stage boost control method for a P1-configuration hybrid commercial vehicle according to claim 1, characterized in that: The P1 motor is connected to the motor controller through a first cable, the motor controller is connected to the high-voltage distribution box through a second cable, the high-voltage distribution box is connected to the power battery through a third cable, and the high-voltage distribution box is connected to the electric supercharger through a fourth cable.

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