Hybrid cars electronic shift lever control signal reliability design

 

(1 Nanjing University of Aeronautics Energy and Power Engineering, Nanjing 210016; 2. Shanghai Maple Automobile Co., Ltd., Shanghai 201501)

 

    Abstract hybrid car based electronic shift lever structure and signal control logic, fault handling and strategies through the signal redundancy algorithm designed shift lever signal reliability electronic control method, through the establishment of Simulink control model, and uses fast control prototyping manner shift lever signal control simulation testing to verify the reliability of control. Test results show that the control method of the hybrid vehicle to meet the demand for a shift and the shift lever signal is controlled to ensure the reliability and safety of vehicles.

 

    Keywords: electronic shift lever hybrid vehicle reliability design

 

    CLC: U463. 212: U469. 79 Document code: A Article ID :1000-1298 ∞ 12) 06-0025 -05

 

    Introduction

 

    Hybrid hybrid vehicles combining means through the power from the engine and power of the motor to drive the vehicle to run the synthesis, the synthesis unit can be used as power hybrid vehicle transmissions, and more often used in the form of planetary gear coupling recess, by adjusting the planet discharge speed of each element, so as to work as CVT. Due to the different structure and working principle, applicable to traditional auto transmission shifting mechanism on the mechanical and satisfaction has been unable to match the hybrid vehicle transmission mechanical structure and operating characteristics, comes with electronic shift mechanism can solve this problem.

 

Electronic shifting mechanism is different from the mechanical shifting mechanism, its transmission is controlled by the signal recognition, transmission and delivery of instruction mode hybrid vehicle transmission with no direct mechanical connection. Hybrid electronic control unit ECU by collecting this electronic gear shift mechanism position sensor sends a voltage analog signal, the analysis and calculation, the judged gear state, the gear according to the vehicle driving state and changing transmission instruction control the transmission mode of operation.

 

 As electronic shift mechanism instead of using the signal transmission mode of a mechanical connection, in the course of its operation, in order to control and guarantee the gear state, the gear to prevent recognition error, signal transmission error, the state with the current gear cars discrepancies fault condition, the need for electronic shifting mechanism operating characteristics and signal control logic for research, to ensure the reliability and accuracy of their shift. Electronic shift mechanism has been in a variety of Toyota Motor Corporation hybrid vehicles have been mature application, but the application of other car manufacturers have not yet gained popularity at home and abroad, and reliability of its signal control logic control design method is also less Studies have. Based on electronic shifting mechanism structure and working principle, the signal control logic design and reliability of control method, and through modeling and simulation clever three days and rapid control prototyping technology and reliability of the control logic control method for authentication.

 

A shift signal control logic

 

1.1 gear structure

 

    Figure 1 shows a schematic diagram for the electronic shift lever position, there are five gear, namely: the original block 0 block, neutral N block, D block forward gears with the engine block DB motored forward gears and reverse gear R block. The initial shift lever position is 0 block, when the shift lever to toggle outside except O block any gear, the gear lever will automatically return to the O position. Electronic shift lever on the power system is no direct mechanical action, which has a four-channel sensor signal, the hybrid electronic control unit ECU through the collection and analysis of sensor signals from various quarters to determine their gear state, thereby controlling the external output corresponding powertrain torque mode. In addition, hybrid cars there by the parking control buttons to enter the parking gear Park block. Parking the vehicle to allow the state, by pressing the parking button electronic control unit sends the request to the parking system control mechanical parking lock mechanism output shaft of the transmission, the vehicle into the parking state.

 

1.2 shift lever control logic output signals

 

    There are two electronic shift lever of 4 channel voltage sensor analog signal, wherein the sensor signal X 2 prostrate Ge and Ge, are equal, the two sensor signals Yi Y and y: equal. Each signal in the case of failure are not, set the output signal of the sensor of X x = x,, the sensor output signal Y y = Yi, Ge and y according to the type of signal values, the handle position determination function P = f &, y ), determine the current position of the handle.

 

Analyzing the handle position shown in Table 1.

 

    Table 1, the signal state T represents the condition is met, F indicates the signal does not meet the set conditions; handle position corresponding to the value 0 if the function P is O block, block 1 is N, D 2 is a block, block DB 3, 4 R block.

 

    Shift signal control logic should be able to meet the needs of the driver normal shift, shift operations to simplify the process, reduce and eliminate misuse while parking mechanism and the driving system damage. Shift signal control logic shown in Figure 2, the figure "represents the vehicle speed, d represents the opening degree of the brake pedal.

 

    Vehicles entering the system default after power neutral position; when the vehicle is started, the brake pedal is stepped on more than 30% of the opening, by operating the shift lever so that the system can be powered from neutral into any gear; vehicles moving forward in the process, N block, D block and DB block between the three can be arbitrarily interchanged; D block and DB forward gears and reverse gear block prohibits direct interchange between R block, the speed must be "less than 5 km / h and the brake pedal opening degree d when more than 30% can be switched in order to prevent the vehicle powertrain of the impact by the vehicle inertia; The vehicle in any case, only by operating the shift lever in neutral, the system can be entered from the power gear neutral.

 

    Park parking gear as the auxiliary gear block through the parking lock mechanism to ensure the transmission output shaft stationary state of the vehicle. After power on the vehicle, in order to prevent parking mechanism for power systems and with damage to the system, you must first press the Park stop button to cancel the parking mechanism on the output shaft of the locking action, in order to effectively operate the shift lever from neutral into force gear, otherwise the system will remain neutral, no power output; vehicles in high speed process, the signal does not respond Park stop button, the system will maintain the current operating state, only when the speed of the "less than 5 km / h, press Park stop button, the system will be powered from the current into the neutral gear, power interruption, the vehicle is coasting until the speed of "less than 1 km / h, the system control parking lock mechanism output shaft, the vehicle enters the parking state; vehicle 5 km / h the following Park sliding block during the shift lever into the current operating state of the vehicle to allow the dynamic gear, will be canceled Park stop signal, the vehicle regain momentum.

 

2 Reliability Control Design

 

2.1 Signal Troubleshooting

 

    In order to ensure that the electronic shift lever sensor signal transmission and recognition reliability and prevent failure due to signal shift system does not work, the need for the state 4-way signal detection, signal status through the 4-way combination of function C = f New York. , Ge:, Y. , Y2), to classify the fault condition and be treated accordingly. State judgment sensor signal as shown in Table 2, the gear according to the table corresponding to each signal set signal value to determine the conditions, if the condition is satisfied then determined that the signal is correct, the error does not satisfy the identification signal. For gear state judgment in the process may still abnormal, leading to errors of judgment gear system and therefore require further through the system control strategies fail to do the redundant processing. Handle position determination redundant processing shown in Table 3, the sensor signal and y as long as a Ge error, the position of the handle to determine the function P = f &, y) to calculate the output P = l, the system enters the neutral position, the vehicle power interruption .

 

    In addition, the process of moving the vehicle, in order to prevent damage to transmission gear jump lead, affecting traffic safety, setting the operating handle gear shift must stay in the target 0.5 s or more, before they can enter the target gear. If the residence time is less than 0.1 s, then finds that the conditions for the jump stop, and keep current gear unchanged; if the residence time in between 0.1-0.5 s, then finds that the situation is shifting too fast, in line with the driver shift intention and to ensure traffic safety, setting this case the system into neutral, vehicle power interruption, until re-shifting and efficient stay longer than 0.5 s.

 

3 emulation test

 

3.1 Control System

 

    Figure 4 shows a method for establishing an electronic shift lever Simulink signal control model network. Figure Signal_lnput for the signal input module, including the brake pedal opening signal a. Speed ​​signal "and the parking block signal Park, as well as a 4-channel sensor signal Ge, Ge 2, Y1 and Y2; Signal_Processing for the signal processing module failure, enter 4 channel sensor signal, the output signal after Ge troubleshooting and y; Handle_Position force handle position determining module, the input processed by the failure of the sensor signal Ge and y, and by the handle position and strategy of redundancy algorithm to determine the function outputs the current handle position P; Control_Logic the shift signal control logic module, the module final output gear through state S. in Matlab environment, using rapid control prototyping tools MotoTron Philip cyberspace, will control model shown in Figure 4 compiled into code and brush written ECU in prototype testing constituting rapid control system, through the system reliability of the shift control lever signal simulation testing "u.

 

3.2 Testing and Analysis

 

    Figure 5-7 shows the simulation test input signal, wherein X 5 is a sensor signal, the Y signal of the sensor Figure 6, Figure 7 is a brake pedal opening degree a. Vehicle speed "and the parking gear signal; Figure 8 is a simulation test of the output signals, including gear lever position P and the state S.

 

    Set the simulation time is 40 s, the system execution cycle is 50 ms. Initially, the vehicle is in the parking state, the system defaults to neutral, press the Park stop button, the system opens the parking lock mechanism, allowing the vehicle to start; 5 seconds to start, step on the brake pedal to 50% open, simultaneous operation of the shift The neutral position of the handle into the D block location, stay neutral position after 0.6 s and then return to the original gear, neutral into forward gear system consists of D block, release the brake pedal, the vehicle starts, the speed increases slowly; in the first 10 to 15 seconds detected between Ge = 0, signal errors, while the other three signals correctly, the system triggers an event C2, so that x = x,, it is calculated to keep the D block state; in the first 15 to 20 seconds between the detection The two-way signal sensor X is 0, the trigger event Cl, and Cl continuous output over 10 execution cycle, in order to ensure traffic safety, so x = y = 0, the system enters the neutral of the D block, the vehicle is coasting deceleration; 20 seconds to start, re-operation shift lever to D range position detection sensor signal 4 normal operating state vehicles entering the D block; 25 seconds to start, operate to DB gear shift lever position, the system enters the D block with the engine motored The DB block, vehicle deceleration; 30 seconds to start, press the Park stop button, the system enters the neutral, power interruption while pedaling brake pedal, the vehicle decelerates to standstill, the system control parking lock mechanism output shaft of the vehicle into the parking state.

 

4 Conclusion

 

    d) the control methods to meet the shifting needs of the driver properly, to prevent misuse resulting shift change of state vehicles and power systems and running the impact and damage, to ensure smooth shifting.

 

    Q) signal processing using classification methods fail, you can simplify the process and means of preventing malfunction due to signal shift system does not work, to ensure the reliability of the shift signal control.

 

    (3) The fault signal processing algorithms through policy prevents redundant signal transmission and identify anomalies cause the system error of judgment on the gear and the gear jump out of view, to ensure the reliability and shift traffic safety.