CN111997766A

CN111997766A - Control method applied to automobile controller

Info

Publication number: CN111997766A
Application number: CN202010911251.0A
Authority: CN
Inventors: 任冰禹; 何烈永; 李吉爽; 李耀辉; 韩晶; 全鹍翔; 胡博; 胡景彦; 郭如强
Original assignee: Ningbo City Yinzhou Delight Technology Co ltd
Current assignee: Ningbo City Yinzhou Delight Technology Co ltd
Priority date: 2020-09-02
Filing date: 2020-09-02
Publication date: 2020-11-27
Anticipated expiration: 2040-09-02
Also published as: CN111997766B

Abstract

A control method applied to an automobile controller is provided, which designs an embedded software and hardware, a control, calibration and diagnosis system of an electronic controller, a system working flow and CAN, a data interaction method of each subsystem, a mode switching and processing method, and a torque calculation method of a motor during power assistance, intelligent charging and energy recovery. The electronic turbine can increase the peak torque of the engine at a low rotating speed, the electronic turbine can improve the torque response speed of the engine, particularly the sudden high power demand of large oil and the 48V electronic turbine can quickly complete the pressure building process, and the torque of the engine rises more quickly than that of an exhaust turbine.

Description

Control method applied to automobile controller

Technical Field

The invention belongs to the field of automobile controllers, and particularly relates to a control method applied to an automobile controller.

Background

With the increasingly stringent regulations on automobile emission and oil consumption and the improvement of the requirements of consumers on drivability and comfort of the whole automobile, a great deal of research is being conducted on how to reduce oil consumption and improve power performance in a host factory.

In recent years, 48V hybrid schemes with a P0 configuration are introduced in various major main engine plants, the schemes can realize the functions of start and stop, energy recovery, assistance and the like, and the fuel consumption of the whole vehicle is reduced while the dynamic property is improved. The 48V scheme is lower in cost, small in change of the original fuel vehicle and outstanding in cost performance.

The core of the 48V hybrid control system, namely the control strategy, is always controlled by an electric control large abroad, and no mature control, calibration and diagnosis strategy is used for mass production of vehicle models in China.

The control system of the present invention has the following two problems: 1) the boosting effect is limited due to insufficient energy of exhaust gas at low speed of the engine; 2) the speed of the pressure build-up at the intake end caused by turbo lag is insufficient, resulting in a slow torque response speed of the engine.

Disclosure of Invention

Aiming at the defects in the prior art, the invention provides a control method applied to an automobile controller, and the 48V hybrid system provided with a 48V electronic turbocharging system can overcome the defect of turbo lag of an exhaust gas turbocharging system. When a driver needs high power, the pressure building of the air inlet system is completed quickly, the quick torque response capability of the 48V motor is combined, the power performance and the response speed of the whole vehicle are improved, and the 48V motor carried by the invention can realize the intelligent starting and stopping function of the engine. Compared with a 12V starting and stopping system, the power of the motor is higher, the engine can be more quickly dragged from zero rotating speed to idling rotating speed, and can also be quickly dragged from high rotating speed to zero rotating speed, the shaking of the engine when a traditional vehicle is started and stopped is avoided, and the comfort of the starting and stopping system is improved.

The invention is realized by the following technical scheme.

A control method applied to an automobile controller is characterized by comprising the following steps of 1) checking an engine torque MAP table by an accelerator pedal K1 and an engine speed N1 to obtain a desired engine torque T1, wherein the engine torque MAP table responding to the accelerator pedal and the engine speed is shown by a table 10, wherein the horizontal axis is the engine speed N1, and the vertical axis is the accelerator pedal opening K1; 2) the target intake pressure P2 is obtained by looking up the boost pressure MAP table from the desired engine torque T1 and the actual engine speed N1, and the engine boost pressure table of the engine boost pressure with the engine speed and torque is shown in table 11, in which the horizontal axis is the engine speed N1 and the vertical axis is the engine torque T1; 3) the ratio R1, i.e. the supercharging pressure ratio, of the target intake pressure P2 to the pressure P3 at the inlet end of the electronic supercharger is calculated by the following formula for R1: r1 ═ P2/P3; 4) looking up a rotating speed output table of the rotating speed of the electronic supercharger along with the air flow and the supercharging ratio by using the supercharging ratio R1 and the air flow W1 calculated by the ECU to obtain a feedforward target value N2 of the rotating speed of the electronic supercharger, wherein the rotating speed output table of the rotating speed of the electronic supercharger along with the air flow and the supercharging ratio is shown by a table 12, wherein the horizontal axis is the axial pressure ratio R1, and the vertical axis is the air flow W1; 5) collecting pressure P4 at the end of the intake manifold by a pressure sensor, and calculating the pressure difference P5 between the pressure P4 of the intake manifold and target intake pressure P2, wherein the calculation formula of P5 is as follows: p5 ═ P2-P4; 6) the rotating speed value N3 which needs to be increased or decreased is calculated by taking the pressure difference P5 as an input of PID control, and the calculation formula is as follows:

wherein K_p1000, is increased in proportionBenefiting; k_i400 is the integration constant; 7) the final supercharger target speed N4 and N4 are calculated by adding the speed value N3 and the feedforward control speed target value N2 as follows: n4 ═ N2+ N3; 8) because the supercharger has a maximum rotation speed limit value, the target rotation speed N4 needs to be limited to obtain a final target rotation speed N5, and the limiting method is as follows: n5 is equal to the minimum of N4 and 90000; 9) the 48V controller sends a target rotating speed value N5 of the electronic supercharger to the supercharger through a CAN signal; 10) the supercharger executes the speed value N5 request sent by the 48V controller.

Compared with the prior art: the electronic turbine can increase the peak torque of the engine at low rotating speed, can improve the torque response speed of the engine, particularly the sudden high power demand of large oil and gas, can quickly complete the pressure building process by the 48V electronic turbine, and can climb the torque of the engine more quickly than an exhaust turbine.

Drawings

FIG. 1 is a block diagram of control software according to the present invention.

FIG. 2 is a block diagram of mode switching according to the present invention.

FIG. 3 is a flow chart of the engine start of the present invention.

FIG. 4 is a timing diagram illustrating the normal startup process of the 48V system of the present invention.

Fig. 5 is a torque switching diagram of a BSG motor of the present invention.

FIG. 6 is a torque limiting block diagram of the present invention.

Fig. 7 is a block diagram of the electronic turbocharging control of the present invention.

Fig. 8 is one of the graphs of the electric turbocharging effect of the present invention.

Fig. 9 shows the second effect of the electric turbocharging according to the present invention.

Fig. 10 is a diagram showing the effect of the 48V engine start according to the present invention.

Detailed Description

The invention is further described with reference to the following drawings and detailed description.

The 48V hybrid system comprises 48V controller software, controller hardware, a calibration upper computer (consisting of software and hardware), a diagnosis upper computer (consisting of software and hardware), a display module, a Battery Management System (BMS), a direct current power converter (DCDC), a belt drive integrated starter/generator (BSG), an Engine Management System (EMS) and the like.

The 48V controller software mainly comprises an input module, a mode judging and torque analyzing module, an accessory control module, an output module, a single chip microcomputer bottom layer drive, a calibration service program, a diagnosis service program and the like. The control software block diagram is shown in fig. 1.

The software input module mainly comprises a CAN input analysis module, a digital input analysis module and an A/D filtering analysis module, wherein the CAN input analysis module mainly has the CAN communication matrix analysis function, and the control system has three CAN channels which are respectively used for the whole vehicle and a 48V system for calibration diagnosis. The first path of CAN interface receives CAN signals of the whole vehicle, the second path of 48V system CAN interface performs data interaction with BMS, DCDC and BSG, the third path of CAN is used for calibration diagnosis, and digital input comprises 48V system starting signals, a forced charging switch, KL15 signals, 12V ignition high level and reverse gear signals. The software carries out filtering processing on digital signals collected at the bottom layer, the jumping can be confirmed by keeping N times (such as 5 times) after the signals jump, analog inputs comprise an accelerator pedal signal 1, an accelerator pedal 2, a clutch pedal signal and a brake pedal signal, signals given by the bottom layer are register values, the values are converted into voltage physical values, the analog input interference is large, and the signals are subjected to low-pass filtering and then are used by a follow-up module. The software output module mainly comprises a CAN packaging output module and a digital output module. CAN encapsulation output mainly is CAN communication matrix encapsulation and sends, and digital output module includes ECU relay on-off control volume, BSG relay on-off control volume, BMS relay on-off control volume, DCDC relay on-off control volume, pre-charge relay on-off control volume.

The power-on and power-off module refers to a power-on process of the BMS, the DCDC and the BSG after the key of the vehicle is unscrewed; after the whole vehicle is powered off by the key, the power-off process of the whole 48V system also comprises a system power-off process in an emergency.

The system power-on process comprises the following steps:

1) a driver inserts a key ring, a 48V controller is powered on, and the system is initialized to start running;

2) after initialization, enabling the ECU relay switch control quantity to be 1, and controlling the ECU to control the relay to be connected;

3) the system waits for the KL15 signal to be at a high level, and if the KL15 signal is at the high level (the ECU is started to work), the 48V controller controls each 48V system to be electrified;

4) the relays of the BMS, the DCDC and the BSG are closed at the same time, namely the switch control quantity of the BSG relay, the switch control quantity of the BMS relay and the switch control quantity of the DCDC relay are controlled to be 1;

5) the 48V controller receives the 48V battery SOC and the 48V battery fault grade in the CAN signal sent by the BMS, if the 48V battery SOC is greater than 0 and the 48V battery fault grade is 0, the BMS is started successfully, and a BMS start completion zone bit signal is output;

6) the 48V controller receives a working state signal and a fault signal sent by the DCDC, if the working state of the DCDC is 1 and the input voltage of the DCDC is low, the DCDC is successfully started, and a DCDC starting completion flag bit signal is output;

7) if the 48V controller receives that the BSG controller initialization state sent by the BSG is 1, the BSG initialization is completed, and a DCDC start completion flag bit signal is output;

8) if BMS, DCDC and BSG are all electrified at low voltage, the system enters a 48V electrifying state, the 48V controller controls the pre-charging relay to be closed, and when the 48V battery voltage at the BMS end is 0.9< the 48V battery voltage at the BSG end, the 48V controller sends a BMS main relay closing command to the BMS through the CAN; after the 48V controller receives that the state of the BMS main relay sent by the BMS is 1, the 48V controller controls the pre-charging relay to be switched off, and the electrification is completed; the system then remains in operation until a system power down request is initiated.

9) After the pre-charging relay is closed for 1s, if the BMS terminal 48V battery voltage is 0.9> the BSG terminal 48V battery voltage, the failure of the pre-charging relay is explained, at this time, the 48V controller CAN send a BMS main relay closing command to the BMS through the CAN, and after the 48V controller receives the BMS main relay state sent by the BMS, the 48V controller controls the pre-charging relay to be opened.

The current process under the system is as follows:

1) after the key is pulled out, namely after the KL15 is detected to be powered off, the 48V controller needs to be powered on for 3 seconds to be powered off;

2) when the key is pulled out, the 48V controller sends a BSG starting command to the BSG, wherein the BSG starting command is equal to 0, and the BSG is closed; after the 48V controller receives that the BSG enable state sent by the BSG is 1, the BSG relay is controlled to be powered off;

3) the key is pulled out, the 48V controller sends an operation command to the DCDC to be 0, the DCDC is closed, and after the 48V controller receives a working state sent by the DCDC to be 1, the DCDC relay is controlled to be powered off;

4) when the BSG relay is equal to 0 and the DCDC relay is equal to 0, the HCU sends a BMS main relay opening command to the BMS, the BMS main relay closing command is equal to 0, and the BMS relay is controlled to be powered off when the BMS main relay state sent by the BSG is equal to 0;

5) and if the key is dialed back to the ON gear in the power-off process or after the power-off process, restarting the power-ON procedure.

Emergency power-off process:

1) when the fault diagnosis system notifies an emergency power-off, the HCU controls the BMS to turn off the main relay.

2) After the 48V power-down flag bit is received, the high voltage is powered down, but the low voltage end is kept powered up.

The 12V battery provides power for all electric systems and control systems of the whole vehicle, and if the voltage of the 12V battery is insufficient, the electric control system of the whole vehicle is closed. The 12V battery electric quantity keeping module is that the 48V controller needs to detect the voltage of the 12V battery, when the voltage of the 12V battery is insufficient, the DCDC is controlled, the voltage of the 48V is reduced to the voltage of the 12V battery, the 12V battery is charged, and the voltage stability of the battery is ensured. The specific working process is as follows:

1) when the 48V battery voltage is greater than 40V and the DCDC has no fault, if the 12V battery voltage is less than the 12V battery voltage upper limit value, the 48V controller sends a starting control quantity of 1 and an output voltage of 14 to the DCDC, and the DCDC starts; if the 12V battery voltage is greater than the 12V battery voltage upper limit value, the 48V controller sends the opening control amount to the DCDC to be 0, and the DCDC stops working;

2) if the DCDC has a fault, the HCU needs to suspend the DCDC;

3) if the fault handling module requests the DCDC to suspend operation, the HCU sends a stop command to the DCDC. The pedal analysis module is divided into an accelerator pedal, a brake pedal and a clutch pedal module. Taking an accelerator pedal module as an example, a 48V controller respectively collects two paths of accelerator pedal sensor signals 1 and 2, wherein the collection frequency is 1000Hz, a first sensing voltage corresponding to 0% of pedal depth is Acc _1_ Low, and a second sensing voltage corresponding to Acc _2_ Low in the conversion process; the first sensor voltage corresponding to 100% of the pedal depth is Acc _1_ High, and the second sensor voltage is Acc _2_ High. The 0-100% pedal depth is linearly proportional to the voltage value. The two groups of signals obtained through calculation are respectively an accelerator pedal position 1 and an accelerator pedal position 2, if the deviation between the accelerator pedal position 1 and the accelerator pedal position 2 is within 3%, the pedal depth acquisition is correct, and the minimum value of the two groups of signals is used as a pedal depth signal to be output; if the difference between the two signals is larger than 3%, an error is reported, and the accelerator opening signal transmitted by the ECU is used as a correct accelerator pedal depth signal.

The mode selection is the most key function of the 48V system, the module takes signals of a pedal, the vehicle speed and the like as input, selects a driving mode of the whole vehicle in the state, calculates the torque output of a motor in the driving mode, and realizes the functions of starting and stopping, boosting, energy recovery and the like so as to improve the dynamic property and the economic performance of the whole vehicle.

Mode selection, namely determining the following state of the whole vehicle according to the pedal requirement of a driver and the real-time state of the vehicle:

1) start and stop functions: the engine is stopped at idle speed, and the engine is quickly started when the vehicle travels;

2) assisting in power: when the torque demand is high, the BSG assists;

3) energy recovery: the accelerator and the brake are not stepped on, the BSG negative torque generates electricity, and a part of kinetic energy is recycled;

4) recovering braking energy: the brake pedal is stepped, and the BSG generates power along with the depth negative torque of the brake pedal;

5) running charging: in the running process, if the battery power of 48V is low, the BSG negative torque generates power to supplement the SOC power;

6) and (3) idle charging: when the engine is in idle speed, the water temperature of the engine is low or the SOC is low, and the BSG negative torque is charged; 7) and (3) idle forced charging: charging the 48V battery in response to the idle forced charging switch;

8) normal driving mode: the BSG is not operated, only in engine operating mode.

The overall execution logic for mode selection is shown in fig. 2, and the mode selection is divided into three large blocks: a running state, a braking state, and a parking state. The mode selection switching conditions are as follows: .

Table 1:

table 1 is a table of each driving state switching condition.

The parking state is a default entering state of the system, and the operations to be executed are as follows: a1 (first enter park state), first

1 is started; a2 (first enter drive state), and the first start flag is 0.

The switching conditions of the parking state are as follows:

table 2:

table 2 shows switching conditions of the parking state.

And in the idle stop state, the 48V controller controls the ECU relay to be disconnected, and meanwhile, the HCU controls the BSG output torque to be-20 Nm through the CAN. And after the BSG rotating speed is 0, enabling the BSG output torque to be 0, keeping the rotating speed to be 0 for 1s, and then closing the ECU relay again. The engine start completion flag is set to 0.

The engine start-up process is shown in fig. 3 and the normal start-up process is shown in fig. 4.

Firstly, the HCU controls the ECU relay to be disconnected, the BSG reversely drags the motor with the BSG starting torque of 30Nm, the reverse dragging time is ECU starting delay time, then the ECU relay is closed, and the motor stops torque output when the motor rotating speed reaches an engine starting rotating speed threshold value which is 1100 rpm. If the motor reaches the threshold value of the starting rotating speed of the engine within the starting delay time of the ECU, the ECU relay is controlled to be closed, the motor stops torque output, and the engine can automatically ignite and spray oil after being electrified. Wherein, ECU starts the delay time 500 ms.

1) And after the ECU relay is closed, timing is started, if the ECU relay is not started successfully within 1s, the starting failure is indicated, and then a second normal starting process is started. Setting the number of times of engine starting failure, wherein the first time of starting failure is set to be 1, the second time of starting failure is set to be 2, and the third time of starting failure is set to be 3; resetting to 0 when exiting the engine start mode;

2) if the clutch is released in the starting process, the starting process is stopped, and the motor stops running;

3) when the number of times of failed starting of the engine is 3, the motor fails to start, a driver needs to manually start the engine at the moment, and the manual starting process is that the driver adopts a key to strike sparks;

4) when entering an engine starting state, enabling an idle starting state mark to be 1; the flag is 0 when exiting this state;

5) the successful engine start is marked by: the HCU receives that the running state of the engine on the CAN is 1 or 1s after the ECU relay is closed, and the rotating speed of the engine is more than 750 rpm;

6) the sign of the engine starting failure is 1s after the ECU relay is closed, the running state of the engine is 0 or the rotating speed of the engine is less than 500 rpm;

7) the maximum continuous operation time of the motor is 1s, and after the time exceeds, the torque output of the motor is forbidden;

8) and after the engine is successfully started, outputting an engine starting completion flag to be 1.

When the engine is in an idle state, the BSG selects whether to output negative torque to generate power according to the SOC value, a forced charging switch signal and the like so as to supplement the 48V battery power.

1) When the forced charging switch is closed and the clutch pedal is not stepped on, if the SOC is less than 85%, the forced charging can be started, the SOC electric quantity exceeds 90%, and the forced charging is finished;

2) in order to avoid the situation that the SOC is turned over up and down at 90% during forced charging, the motor is repeatedly switched on and off, and forced charging can be started again after the SOC is reduced to 85%;

3) and when the SOC is smaller than the starting SOC threshold value of the idling stop forward engine, the idling charge is started. Stopping the idle charging after the SOC reaches the threshold value of the idle charging to idle stop SOC;

4) the method comprises the following steps that idle charging and forced idle charging are carried out, a motor generates power with a torque of-10 Nm, in order to avoid overheating of the motor caused by long-time power generation, the temperature of the motor needs to be monitored, the power generation torque of BSG is reduced when the temperature of a motor controller is high, and the temperature limit MAP is as shown in the following table:

table 3:

motor controller temperature	-40	0	70	80	85	90
							Percentage of restriction	1	1	1	1	0.5	0

Table 3 is a motor controller temperature limit table.

5) When the idle charging is started, the loading speed of the negative torque needs to be controlled, and the change rate of torque loading is limited to 2 Nm/s;

6) and (5) stepping on a clutch pedal to finish the charging state, and enabling the engine to enter a normal idling state.

The braking state is divided into three sub-states, which are respectively:

mechanical braking, i.e. using only the original vehicle braking system, is entered when the clutch pedal is depressed at high SOC, the vehicle speed is less than 10km/h, or the 48V system fails.

The sliding energy recovery is that when the whole vehicle slides without stepping on an accelerator, a brake and a clutch pedal, the BSG provides certain negative torque to generate electricity so as to recover a part of kinetic energy, and the execution logic is as follows:

and (4) recovering braking energy, and simultaneously operating the BSG and the mechanical brake to decelerate the vehicle.

When the vehicle speed is more than 10km/h, the BSG outputs negative torque to generate power according to the motor rotating speed and the depth of a brake pedal, and outputs torque as follows:

table 4:

table 4 is a torque response table for BSG with speed and brake pedal depth.

The desired output torque needs to be limited as follows:

1) at high SOC, in order to avoid overcharging of the battery, the BSG power generation torque needs to be limited, and the energy recovery SOC limit MAP is as follows:

table 5:

SOC	0	80	86	89	92	100
							percentage of restriction	1	1	1	0.5	0	0

Table 5 is a table of the limit ratio of the BSG energy recovery torque with the battery SOC.

2) Energy recovery is not carried out during reverse gear;

3) when the clutch pedal is stepped on, energy recovery is not carried out;

4) when the power-on switch of the 48V system is equal to 0, no energy recovery is carried out;

5) when the fault level of the 48V controller is equal to 1, no energy recovery is carried out;

6) when the temperature of the motor is high, the torque output of the BSG needs to be limited, the overheating of a motor controller is avoided, and the percentage MAP of the BSG is limited due to the temperature as shown in the following table:

table 6:

Table 6 is a table of the limit ratios of BSG torque with temperature.

7) The motor rotating speed is less than 2500, and energy recovery is not carried out.

The driving state is as follows: and (3) normal driving state: that is, only the engine works, the BSG motor does not output power, and the BSG motor works in the state most of the time. A power-assisted state: when the engine works, the BSG outputs certain torque to drive the vehicle together with the engine, and the mode generally works under the working conditions that an accelerator pedal is deep and the torque demand is high and the vehicle runs in a charging state: when the engine drives the vehicle to run, part of the torque drags the BSG to generate electricity, and the mode is only entered when the 48V battery is seriously insufficient.

According to the depth of an accelerator pedal, the rotating speed of an engine and the difference of SOC, the BSG motor can be switched under three working states of positive torque output, idling and negative torque power generation so as to realize the functions of power assistance, driving power generation and the like, and the specific logic is shown in figure 5.

The torque response of the BSG is as follows:

table 7:

table 7 is a torque response table of BSG torque with engine speed and accelerator pedal depth while driving.

After the torque response of the BSG is obtained through table lookup, the torque of the BSG needs to be limited according to the state of the SOC.

When the SOC is high, the power generation torque of the BSG needs to be limited, and when the SOC is low, the power assisting torque of the BSG needs to be limited, so that the positive torque and the negative torque of the BSG are respectively limited by adopting two MAP with SOC torque limitation.

1) When the BSG positive torque is output, the torque of the motor is limited when the SOC is low, and the percentage MAP of the power-assisted SOC limit is shown as follows:

table 8:

SOC	0	10	20	30	40	45	50	60	70	80	90	100
													percentage of restriction	0	0	0	0	0	0	0	0.5	1	1	1	1

Table 8 is a table of SOC versus torque limit ratios for BSG positive torque output.

2) When BSG negative torque is output, the torque of the electric machine is limited when SOC is high, and the percentage MAP of the travel charge limit is given by the following table:

table 9:

SOC	0	10	20	30	35	40	50	60	70	80	90	100
													percentage of restriction	1	1	1	1	1	1	1	1	1	1	0	0

Table 9 is a table of the SOC to torque limit ratio at BSG negative torque output.

3) When the clutch pedal is stepped, the torque output of the BSG needs to be limited within +/-4 Nm, so that the influence of the torque output of the BSG on gear shifting is avoided;

4) in order to avoid repeated triggering of the negative torque output of the BSG by the low pedal opening degree when the pedal is just stepped on, a low pedal depth filtering module is designed, the module needs to monitor the expected torque value of the BSG torque responding to the MAP output, and when the expected torque is a negative value and lasts for more than 2s, the motor can be controlled to output the negative torque to generate electricity;

5) when the temperature of the motor is high, the torque output of the BSG needs to be limited, and the limiting method is the same as that in the table 9;

6) when in reverse gear, the BSG torque output is limited to 0;

7) when the negative torque is output, if the rapid reduction of the rotating speed of the engine is detected, or the rotating speed is less than 700 revolutions, the negative torque output is stopped;

8) when SOC is less than 40, BSG motor-3 Nm torque generation is continuously maintained.

The torque limitation is shown in fig. 6. If the input and output power of the battery and the motor is too large, the battery and the motor may be damaged.

It is necessary to control the torque input and output of the motor according to the maximum input/output performance of the battery motor.

1) Limiting the maximum forward torque of the motor by using the maximum driving torque allowed by the motor;

2) limiting the maximum negative torque of the motor by using the maximum allowable generating torque of the motor;

3) converting the maximum allowable discharge power limit of the battery (the maximum allowable discharge power of the battery-DCDC real-time current 14) into torque, and then limiting the forward torque of the motor;

4) limiting the negative torque of the motor by the maximum allowable charging power of the battery;

5) after the BMS power limiting command is received, limiting the charge and discharge power within 2 kW;

6) and receiving a power generation only permission command, and forbidding the positive torque output of the motor.

A torque arbitration module:

1) when the ESP and the ABS work, namely the ABS is activated, the motor is in a standby state and does not respond to the torque demand; 2) when the BSG sent by the fault classification module is in fault, the motor is in standby and does not respond to the torque demand.

The 48V electronic supercharging system is carried to mainly solve two problems: the boosting effect is limited due to insufficient energy of exhaust gas at low speed of the engine; the speed of the pressure build-up at the intake end caused by turbo lag is insufficient, resulting in a slow torque response speed of the engine. The control block diagram of the 48V control electronic turbocharger is shown in FIG. 7, and the specific control strategy is as follows:

1) the desired engine torque T1 is obtained by looking up an engine torque MAP table, shown in table 9, with engine speed N1 on the vertical axis and accelerator pedal opening K1 on the horizontal axis, from accelerator pedal opening K1 and engine speed N1.

Table 10:

table 10 is a MAP table of engine torque response with accelerator pedal and speed.

2) The target intake pressure P2 is found by looking up the boost pressure MAP table from the desired engine torque T1 and the engine actual speed N1. The boost pressure MAP is shown by Table 11, where the horizontal axis represents engine speed N1 and the vertical axis represents engine torque T1.

Table 11:

table 11 is an engine boost pressure gauge of engine boost pressure versus engine speed and torque.

2) Calculating a ratio R1 of the target intake pressure P2 to the pressure P3 at the inlet end of the electronic supercharger, namely a supercharging ratio; the formula for R1 is as follows: r1 ═ P2/P3.

3) And checking a rotating speed output table of the rotating speed of the electronic supercharger along with the air flow and the supercharging ratio by the air flow W1 calculated by the supercharging ratio R1 and the ECU to obtain a feedforward target value N2 of the rotating speed of the electronic supercharger. The electronic supercharger MAP table is shown in table 11, in which the horizontal axis represents the air flow rate R1 and the vertical axis represents the supercharging ratio W1.

Table 12:

table 12 is a table of the rotational speed output of the electronic supercharger with the airflow and boost ratio.

4) The pressure P4 at the intake manifold end is collected by a pressure sensor, and the pressure difference P5 between the intake manifold pressure P4 and the target intake pressure P2 is calculated. Wherein the calculation formula of P5 is as follows: p5 ═ P2-P4.

5) The value of the rotational speed N3 that needs to be increased or decreased is calculated from the pressure difference P5 as an input to the PID control. The calculation formula is as follows:

wherein K_p1000, is the proportional gain; k_i400 is the integration constant.

6) The rotating speed value N3 is added with the feedforward control rotating speed target value N2, namely the final target rotating speed N4 of the supercharger. The calculation formula of N4 is as follows: n4 ═ N2+ N3.

7) Because the supercharger has a maximum rotation speed limit, the target rotation speed N4 needs to be limited, and the final target rotation speed N5 is obtained. The limiting method is as follows, N5 is equal to the minimum of N4 and 90000.

8) The 48V controller sends the final target speed N5 to the supercharger via a CAN signal.

9) The supercharger executes the speed value N5 request sent by the 48V controller.

The advantages of the electronic supercharger are shown in figures 8 and 9.

Fig. 8 shows that the electronic turbine can increase the peak engine torque at low rotational speed, and fig. 9 shows a comparison of the external engine characteristics of exhaust gas turbocharging and electronic turbocharging.

The electronic turbine in FIG. 10 can improve the torque response speed of the engine, particularly the sudden high power demand of large oil, and the 48V electronic turbine can quickly complete the pressure build-up process, so that the torque of the engine rises more quickly than that of an exhaust turbine. CCP calibration and tool development are adopted, and the method comprises Flash partitioning, Flash configuration, interaction between Flash and RAM, Flash reading and writing and upper computer scripts. And fault diagnosis and BootLoader downloading are carried out by adopting a UDS protocol, and faults of BMS, BSG, DCDC and 48V controllers are classified and processed.

The 48V controller is connected with the display module through the CAN, the 48V controller sends a driving mode, the engine rotating speed/torque, the motor rotating speed/torque, 48V battery SOC information and the vehicle speed, and the refreshing frequency is less than 0.2 s. And the display module receives the data sent by the 48V controller, analyzes the data and displays the data visually through a graphical interface.

The scope of the present invention includes, but is not limited to, the above embodiments, and the present invention is defined by the appended claims, and any alterations, modifications, and improvements that may occur to those skilled in the art are all within the scope of the present invention.

Claims

1. A control method applied to an automobile controller is characterized by comprising the following steps of 1) checking an engine torque MAP table by an accelerator pedal opening K1 and an engine speed N1 to obtain a desired engine torque T1, wherein the horizontal axis is engine speed N1, and the vertical axis is accelerator pedal opening K1; 2) checking a boost pressure MAP table by the expected engine torque T1 and the actual engine speed N1 to obtain a target intake pressure P2, and an engine boost pressure gauge of the engine boost pressure along with the engine speed and the engine torque, wherein the horizontal axis is the engine speed N1, and the vertical axis is the engine torque T1; 3) the ratio R1, i.e. the supercharging pressure ratio, of the target pressure P2 to the pressure P3 at the inlet end of the electronic supercharger is calculated by the following formula of R1: r1 ═ P2/P3; 4) checking a rotating speed output table of the rotating speed of the electronic supercharger along with the air flow and the supercharging ratio by the air flow W1 calculated by the supercharging ratio R1 and the ECU to obtain a feedforward control rotating speed target value N2 of the rotating speed of the electronic supercharger and a rotating speed output table of the rotating speed of the electronic supercharger along with the air flow and the supercharging ratio, wherein the horizontal axis is the axial compression ratio R1, and the vertical axis is the air flow W1; 5)collecting an intake manifold pressure P4 at an intake manifold end by a pressure sensor, and calculating a pressure difference P5 between the intake manifold pressure P4 and a target pressure P2, wherein the calculation formula of P5 is as follows: p5 ═ P2-P4; 6) the rotating speed value N3 which needs to be increased or decreased is calculated by taking the pressure difference P5 as an input of PID control, and the calculation formula is as follows:

wherein K_p1000, is the proportional gain; k_i400, is the integration constant; 7) the final supercharger target speed N4 and N4 are calculated by adding the speed value N3 and the feedforward control speed target value N2 as follows: n4 ═ N2+ N3; 8) because the supercharger has the maximum rotation speed limit value, the target rotation speed N4 needs to be limited to obtain the final target rotation speed N5, and the limiting method is as follows: n5 is equal to the minimum of N4 and 90000; 9) the 48V controller sends the final target rotating speed N5 to the supercharger through a CAN signal; 10) the supercharger executes the final target speed value N5 request sent by the 48V controller.