[0033] figure 1 It is a flowchart of the steps of a shifting method of an AMT automatic transmission according to an embodiment of the present invention. Such as figure 1 As shown, in this embodiment, the gear shifting method of the present invention includes the following steps:
[0034] Step S101: the vehicle is ignited and starts to travel.
[0035] Step S102: During the running of the vehicle, the AMT automatic transmission is in any forward gear, and it is judged whether it is necessary to shift to other forward gears according to the vehicle driving state parameters and the control signal. If the gear needs to be shifted, proceed to step 103 , Otherwise repeat step S102.
[0036] Step S103: Determine the target gear to be shifted.
[0037] Step S104: Calculate the desired engine target speed Engine_TargetSPD when the target gear clutch is fully engaged according to the current vehicle speed and the gear ratio of the target gear.
[0038] Step S105: Determine whether the engine target speed Engine_TargetSPD is greater than or equal to the idling speed of the engine. If it is judged that the engine target speed Engine_TargetSPD is less than the idling speed of the engine, use the clutch disengagement, shift motor action, and clutch reconnection in step 109 The gear shift procedure is performed. If the engine target speed Engine_TargetSPD is greater than or equal to the idle speed of the engine, proceed to step 106, step 107, and step 108.
[0039] Step 106: Control the current speed of the engine to remain unchanged, and the shift motor moves to retract the current gear synchronizer to neutral.
[0040] Step 107: Control the action of the gear selection motor, move the gear selection motor to the target gear position to be engaged, and control the engine speed to the engine target speed Engine_TargetSPD at the same time.
[0041] Step 108: Control the action of the shift motor, hook the target gear synchronizer into the target gear, and cancel the control of the engine speed. At the beginning of the step 106, the engine speed control flag is set to a valid state, and until the step 108 is completed, the engine speed control flag is cleared to notify the vehicle controller and/or the engine controller and/ Or the transmission controller will control the engine speed to the target engine speed during the entire process from step 106 to step 108. During this period, the vehicle controller and/or engine controller and/or transmission controller are prohibited from performing other controls on the engine speed according to the vehicle driving state parameters and control signals.
[0042] Step 109: End the gear shift.
[0043] In the above process, the present invention always keeps the AMT automatic transmission clutch fully engaged, so that the clutch can be shifted without separation. Moreover, since the engine speed has been controlled to the target speed before the target gear synchronizer is engaged in the target gear, the speed of the synchronizing ring of the target gear is synchronized with the speed of the ring gear to be combined with the target gear at this time, so it can be reduced Small shift shock, shorten shift time.
[0044] In an embodiment of the present invention, the gear shift time can be controlled within the range of 1 second to 2 seconds, during which time the vehicle speed will not change greatly. In another embodiment of the present invention, the low gear shift time can be set to be longer than the high gear shift time according to the change law of vehicle acceleration and the magnitude of the shift shock.
[0045] In an embodiment of the present invention, when the engine speed reaches the target speed, the target gear synchronizer will synchronize the speed of the engine speed according to the current vehicle speed while the target gear synchronizer is in gear to reduce the synchronization ring speed of the target gear. The speed difference of the ring gear speed to be combined with the target gear is also beneficial to reduce the shift shock.
[0046] The following takes the AMT automatic transmission with 2 gears up to 3 gears as an example for specific description. figure 2 It is a flow chart of the steps of the AMT automatic transmission shifting method according to an embodiment of the present invention in this situation, image 3 It is a control sequence diagram of the AMT automatic transmission shifting method according to an embodiment of the present invention in this situation.
[0047] See figure 2 ,in figure 2 In step S201 shown, the vehicle is ignited and started to travel. In step S202, it is detected that the vehicle is in the second gear driving state. In step S203, according to the current vehicle speed and accelerator opening signal of the second gear, it is judged whether to shift gears. If it is necessary to shift gears, proceed to step S204; otherwise, proceed to step 213 to end the gear shifting. Generally, the vehicle driving state parameters and control signals are basically the current vehicle speed and throttle opening signals, but other parameters can still be selected as a basis as needed. In step S204, it is determined that the gear to be shifted is gear 3, that is, the target gear Gear_Target=3.
[0048] In step S205, after determining the target gear to be shifted Gear_Target=3, first calculate the engine target speed Engine_TargetSPD when the target gear clutch is required to be fully engaged at the current vehicle speed according to the gear ratio. If the calculated engine target speed Engine_TargetSPD is less than the engine idling speed (for example, 800rpm/min), in order to prevent the engine from stalling due to the engine speed being too low, the clutch disengagement and gear shifting motor action shown in step S212 is required , The AMT shift control program of the clutch recombination to shift gears. When the calculated engine target speed Engine_TargetSPD is greater than or equal to the engine idle speed, the clutch non-disengagement shift mode is adopted, which specifically may include: step S207, step S208, step S209, step S210, and step S211.
[0049] in image 3 Among them, L1 represents the target gear, L2 represents the current gear, L3 represents the shift motor action flag, L4 represents the gear selection motor action flag, L5 represents the engine speed control flag, L6 represents the engine speed; for the shift motor action In terms of flag bit L3, gear selection motor action flag bit L4, and engine speed control flag bit L5, the number 1 in the figure indicates that the corresponding flag bit is in a valid state, and the number 0 indicates that the corresponding flag bit is in a failed state.
[0050] See figure 2 with image 3 When the calculated engine target speed Engine_TargetSPD is greater than or equal to the engine idling speed, the engine speed control flag is set at 1 as in step 207, which is the effective state, so as to control the current engine speed to remain unchanged. Then proceed to step 208: the shift motor action flag is at 1, that is, the shift motor is activated, and the synchronizer of the current gear 2 is returned to the neutral gear. Then proceed to step 209: the gear selection motor action flag is at 1, that is, the gear selection motor will act, move the gear selection motor to the 3rd gear position of the target gear to be engaged, and control the engine speed to drop to the target engine when the 3rd gear is combined Rotating speed. Then proceed to step 210: when the shift motor action flag is at 1, the shift motor is activated, and the target gear synchronizer, that is, the third gear synchronizer, is hooked into the target gear 3 gear. Then proceed to step 211: set the engine speed control flag to 0, that is, the invalid state, and cancel the control of the engine speed. Step 213 represents the end of the gear shift.
[0051] In this embodiment, the transmission controller of the vehicle is an automatic transmission control unit TCU. The TCU is often used in automatic transmissions such as AMT, AT, DCT, and CVT to realize automatic transmission control and make driving easier. The gear shift method of the present invention is programmed in the transmission controller of the vehicle. When the vehicle is driving in the second gear, the control program in the TCU will determine whether there is an upshift request based on the current throttle opening signal and the vehicle speed signal. If it is determined that the TCU has a third gear request, the target gear signal Gear_Target signal Change to 3 gears.
[0052] In the above description, the engine target speed Engine_TargetSPD is calculated as follows:
[0053] Engine _ T arg etSPD = v 3.6 * 2 πr * 60 * r Gear _ T arg et
[0054] among them,
[0055] Engine_TargetSPD: engine target speed, unit rpm;
[0056] V: current vehicle speed, in km/h;
[0057] r: wheel radius, unit m;
[0058] r Gear_Target : The gear ratio of the target gear.
[0059] The invention solves the problems of clutch slippage or burnout, severe vehicle impact and engine suffocation caused by clutch control problems during the gear shifting process, and at the same time improves the shift quality and the shift response. Moreover, the present invention shortens the time of vehicle power interruption, shortens the shift time, and improves the shift quality.
[0060] So far, those skilled in the art should realize that although several exemplary embodiments of the present invention have been illustrated and described in detail herein, they can still be disclosed according to the present invention without departing from the spirit and scope of the present invention. The content directly determines or derives many other variations or modifications that conform to the principles of the present invention. Therefore, the scope of the present invention should be understood and deemed to cover all these other variations or modifications.
