At present, the research on energy-saving controller of hybrid electric vehicle engine is not perfect in many countries, and the product stability and energy-saving effect are poor.Therefore, an energy-saving controller for hybrid electric vehicle engine is designed, which takes into account both high stability and high energy-saving effect.The X186 single chip microcontroller of the energy-saving controller uses PID control to supervise real-time signals such as engine speed and driving instructions of hybrid electric vehicle, and reprocesses the speed signals through signal secondary processing circuit, so as to reduce the energy consumption of hybrid electric vehicle caused by engine speed.The energy-saving control signals obtained by X186 single chip microcontroller and signal secondary processing circuit are transmitted to the output control circuit for summary and analysis, and ultimately the optimal energy-saving scheme is output.In the realization part of the controller, the function diagram is given, and the process of energy-saving control of the engine by using PID control algorithm is given.The experimental results show that the energy-saving control effect of the engine energy-saving controller of hybrid electric vehicle is obvious and has high stability.At present, automobile has become an indispensable means of transportation in people’s life, and the shortage of resources caused by the development of automobile industry can not be underestimated.Based on the above reasons, a hybrid electric vehicle which can comprehensively utilize electric energy, gas and coal-diesel oil has been produced.The research and development of engine energy-saving controller for hybrid electric vehicles is an important technological innovation in the field of transportation [1?3].Because the research on energy-saving controller of hybrid electric vehicle engine is not perfect in many countries, the products studied often have poor stability and energy-saving effect.Therefore, the development of hybrid electric vehicle engine energy-saving controller with high stability and high energy-saving effect is the current key research project in the field of transportation [4?6].There are some problems in the energy-saving controller of HEV engine developed by various scientific research organizations. For example, THS? II HEV engine energy-saving controller is developed in document [7]. The energy-saving controller can implement all-round energy-saving control for HEV engine driving system, and its energy-saving effect is good.But its price is too expensive to be widely used.Document [8] Develops the engine energy-saving controller of Honda hybrid electric vehicle. The designer of the energy-saving controller realizes that the energy consumption of hybrid electric vehicle is the greatest when the engine is in a sudden stop. Therefore, when the engine is running at a high speed, the designer adds a slow deceleration function to the engine of hybrid electric vehicle, thereby reducing the start of hybrid electric vehicle. The energy consumption of the machine.
However, the energy consumption reduction effect of the energy-saving controller is not obvious, and the control ability needs to be improved.Reference [9] Develops an energy-saving controller for hybrid electric vehicle engine based on on line control. The energy-saving controller divides the hybrid electric vehicle engine into three levels of energy consumption intervals by using the engine energy consumption line control chart, and carries out energy-saving control for three energy consumption intervals respectively.Because the energy-saving controller requires the relevant personnel to have a high level of control, its energy-saving effect is not ideal.Reference [10] develops an energy-saving controller for hybrid electric vehicle engine based on real-time energy-saving optimization algorithm. The energy-saving controller predicts the energy consumption trend of hybrid electric vehicle engine by constructing an energy consumption objective function, and then minimizes the energy consumption of engine.However, the stability of the energy-saving controller is poor, and the control of global energy consumption needs to be strengthened.In order to solve the above problems, an energy-saving controller for hybrid electric vehicle engine with strong stability and obvious energy-saving effect was developed.The experimental results show that the energy-saving control effect of the engine energy-saving controller of hybrid electric vehicle is obvious and has high stability.The energy-saving controller of hybrid electric vehicle engine is mainly composed of control chip and functional circuits.The control chip of HEV engine energy-saving controller is a single chip microcontroller. Because there are many internal components of HEV engine, the selected MCU must have strong hardware compatibility and be able to correct the high energy-consuming signal of HEV engine in real time and output it accurately.Based on the above constraints, the latest embedded X186 single chip microcontroller of a company is selected as the engine energy-saving controller of hybrid electric vehicle.In view of the energy consumption characteristics of hybrid electric vehicle engine, the company’s designers matched the real-time energy-saving control function for X186 single chip microcontroller, enabling it to mine and process the engine signal of hybrid electric vehicle pertinently, and strongly guaranteed the sound transmission of engine signal.When the hybrid electric vehicle starts to use the engine to drive slowly, how to ensure the safety and stability of the vehicle is the primary issue to be considered by the engine energy-saving controller of the hybrid electric vehicle.In the X186 single chip microcontroller, the PID control method is used to control the engine torque of hybrid electric vehicle in real time. The purpose of this method is to convert the surplus mechanical energy in the engine of hybrid electric vehicle into the electric energy with high utilization rate in the driving of the vehicle.The torque of hybrid electric vehicle engine mainly includes speed, driving instructions, power and so on.Fig.
1 is the principle diagram of X186 single chip microcontroller PID control.As shown in Fig. 1, the PID control flow of X186 single chip microcontroller is: X186 single chip microcontroller first carries out the torque identification of the engine signal collected by X186 single chip microcontroller.
Its main identification content is the speed of the engine of hybrid electric vehicle and the driving instructions given by the driver.
The X186 single chip microcontroller is processed step by step according to the type of torque it identifies.Torque that does not need to be adjusted enters the standard torque conversion operation and outputs directly; the torque that needs to be adjusted enters the PID control.In the PID control, the X186 single chip microcontroller enlarges the torque in equal proportion (among them, the driving instructions given by the driver are uncontrollable variables, although there are signals to be processed, but it can not be controlled by PID, and can be output directly). Then the torque adjustment is carried out, that is, the surplus mechanical energy in the engine signal is converted into electric energy. 。In the work of torque regulation, X186 single chip microcontroller should reduce the loss of PID control energy as much as possible to improve the energy efficiency of the engine energy-saving controller of hybrid electric vehicle.The engine signal of hybrid electric vehicle controlled by X186 MCU PID will be transmitted to the signal secondary processing circuit for further energy-saving control.
Because the engine speed has a great influence on the energy consumption of hybrid electric vehicle, a signal secondary processing circuit is constructed for the second processing of the speed signal of hybrid electric vehicle engine energy-saving controller.The signal processing requires that the signal secondary processing circuit has a very high signal transmission speed.Speed signal is mainly collected from crankshaft of hybrid electric vehicle engine.The signal secondary processing circuit is equipped with a specific sensor at the crankshaft. The second acquisition of engine speed is carried out through the sensor, and the output signal of X186 MCU PID control is combined to optimize the energy consumption of hybrid electric vehicle engine, as shown in Figure 2.When the car starts, the sensor installed on the engine crankshaft will filter and rectify the engine speed signal.Diodes and signal isolators are indispensable in the design of the signal secondary processing circuit shown in Figure 2 to avoid the interference of environmental factors on the energy-saving controller of hybrid electric vehicles.After the signal secondary processing circuit is finished, according to the formula [ek=] [TPS2k-TPS1k], the optimization deviation [ek] of hybrid electric vehicle engine is calculated.Among them, [TPS1k] is the signal output value of signal secondary processing circuit, [TPS2k] is the signal output value of X186 MCU PID control.The optimization deviation directly affects the stability of the energy-saving controller of hybrid electric vehicle. If the value is large, the optimization work should be done again. Otherwise, the energy-saving control signals obtained by X186 single chip microcontroller and signal secondary processing circuit will be fed back to the output control circuit.The design goal of the output control circuit is to aggregate and analyze the output signals of the X186 MCU and the signal secondary processing circuit, and finally to output the optimal energy-saving scheme, as shown in Figure 3.The output control circuit shown in Figure 3 can connect all processed signals in the engine energy-saving controller of hybrid electric vehicle, and transmit the engine energy-saving scheme quickly through format conversion and construction of transmission folder.Documents will be separated into specific locations in the transmission process in order to achieve specific energy-saving control for different locations of HEV engines.The output control circuit can also adjust the current transmission law of the electronic throttle of hybrid electric vehicle, and then control the engine torque.The output control circuit uses the parallel serial transmission interface 2,3,14,15 to carry out the serial transmission between the circuit and the engine. It can also detect and troubleshoot the engine at the same time.The energy-saving controller of hybrid electric vehicle engine has the functions of signal management, fault detection, signal analysis and background monitoring, as shown in Figure 4.
The signal management function in Figure 4 mainly manages the signal acquisition and signal processing of X186 single chip microcontroller and signal secondary processing circuit. Its management mode is mainly coding control. The fault detection function realizes the early warning and disposal of the fault of the engine energy-saving controller of hybrid electric vehicle by detecting the transmission signal of the hardware part. Reasonably, it is different from the output control circuit in troubleshooting of hybrid electric vehicle engine, so it should be distinguished; the signal analysis function manages the analysis of output control circuit; the background monitoring function can real-time monitor the energy-saving controller of hybrid electric vehicle engine and forecast the abnormal items of hybrid electric vehicle engine.
Including signal acquisition timeout, abnormal load trend of circuit, energy consumption exceeding limit, etc.The PID control algorithm of X186 single chip microcontroller is relatively simple. It has three control modes: proportional, integral and differential. In the practical application of the engine energy-saving controller of hybrid electric vehicle, the more suitable PID control should be selected according to the characteristics of these three modes.Proportional PID control can control the excess mechanical energy generated in the engine of hybrid electric vehicle in real time. It has high control efficiency and good effect.Proportional PID control requires that the excess mechanical energy controlled by it should be infinitely increased. Once the mechanical energy is maintained at a stable value, thermostatic element its control error will increase rapidly, which will reduce the stability of the energy-saving controller of hybrid electric vehicle engine. Integral PID control, contrary to proportional PID control, requires hybrid electric vehicle to start. The increase or decrease of surplus mechanical energy in the machine should be more stable.However, the control ability of this control method is effective, and can not give the engine a higher energy-saving effect. The control ability and control requirements of differential PID control are between proportional PID control and integral PID control.In the formula, [KP], [KI], [KD] represent the proportional coefficients of proportional, integral and differential PID control modes respectively, which work together and restrict each other; [e(t)] represents the difference between the signal input value of the hybrid electric vehicle engine and the output value of the energy-saving controller of the hybrid electric vehicle engine; [u0] represents the PID control constant.Experiments verify the stability and energy-saving effect of the engine energy-saving controller of hybrid electric vehicle designed in this paper.The total torque of the engine directly reflects the total energy consumption of the hybrid electric vehicle engine. The greater the speed of the engine, the greater the opening of the electronic throttle and the greater the real-time energy consumption.Therefore, reducing the total torque and speed of the engine can achieve good energy-saving control effect.At the same time, the smaller the fluctuation of the two curves after energy-saving control, the stronger the stability of the energy-saving controller of hybrid electric vehicle engine.In the experiment, the hybrid electric vehicle without the energy-saving controller in this paper drives 2,000 m in two and four gears respectively under the same road condition and weather. The driver’s operating factors such as sudden stop, start and acceleration are the same during the driving process. The total torque curve and speed curve of the engine during the driving process are shown in Fig. 5. Fig. 6 is shown.From Fig. 5 and Fig. 6, it can be seen that under the same conditions, the maximum total torque of the four-gear hybrid electric vehicle engine without the energy-saving controller in this paper is 70 N. m, and the maximum speed of the engine is 2 000 r/min.Excluding the starting state of the vehicle (at this time, the driving power of the vehicle mainly depends on the motor, so excluded), in the distance of 200-2 000 m, the average value of the total torque of the four gears is about 48 N.m, the average value of the engine speed is 1 355 r/min; the maximum value of the total torque of the two gears is 68 N.m, and the maximum value of the engine speed is 1 980 r/min.Within the distance of 200-2000 m, the average total torque of the two gears is about 40 N. m, and the average speed of the engine is 1 402 r/min.The total torque curve and engine speed curve of the engine after energy-saving control using the energy-saving controller in this paper are given, as shown in figs. 7 and 8.Compared with Fig. 5-8, we can see that the energy-saving controller of hybrid electric vehicle engine designed in this paper can control the energy-saving of engine, and the effect of energy-saving control is obvious.The curve fluctuations in figs. 7 and 8 are obviously lower than those in figs. 5 and 6, which proves that the hybrid electric vehicle engine energy-saving controller designed in this paper has high stability.This paper designs an energy-saving controller for hybrid electric vehicle engine with high stability and high energy-saving effect.
The X186 single chip microcontroller of the energy-saving controller uses PID control to supervise real-time signals such as engine speed and driving instructions of hybrid electric vehicle, and reprocesses the speed signals through signal secondary processing circuit, so as to reduce the energy consumption of hybrid electric vehicle caused by engine speed.The energy-saving control signals obtained by X186 single chip microcontroller and signal secondary processing circuit are transmitted to the output control circuit for summary and analysis, and ultimately the optimal energy-saving scheme is output.In the realization part of the controller, the function diagram is given, and the process of energy-saving control of the engine by using PID control algorithm is given.The experimental results show that the energy-saving control effect of the engine energy-saving controller of hybrid electric vehicle is obvious and has high stability.