CN110077408B - Intelligent downshift control method for automatic-gear vehicle - Google Patents
Intelligent downshift control method for automatic-gear vehicle Download PDFInfo
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
- B60W10/00—Conjoint control of vehicle sub-units of different type or different function
- B60W10/02—Conjoint control of vehicle sub-units of different type or different function including control of driveline clutches
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
- B60W10/00—Conjoint control of vehicle sub-units of different type or different function
- B60W10/04—Conjoint control of vehicle sub-units of different type or different function including control of propulsion units
- B60W10/06—Conjoint control of vehicle sub-units of different type or different function including control of propulsion units including control of combustion engines
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
- B60W30/00—Purposes of road vehicle drive control systems not related to the control of a particular sub-unit, e.g. of systems using conjoint control of vehicle sub-units
- B60W30/18—Propelling the vehicle
- B60W30/19—Improvement of gear change, e.g. by synchronisation or smoothing gear shift
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
- B60W30/00—Purposes of road vehicle drive control systems not related to the control of a particular sub-unit, e.g. of systems using conjoint control of vehicle sub-units
- B60W30/18—Propelling the vehicle
- B60W30/20—Reducing vibrations in the driveline
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
- B60W30/00—Purposes of road vehicle drive control systems not related to the control of a particular sub-unit, e.g. of systems using conjoint control of vehicle sub-units
- B60W30/18—Propelling the vehicle
- B60W30/20—Reducing vibrations in the driveline
- B60W2030/203—Reducing vibrations in the driveline related or induced by the clutch
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
- B60W2710/00—Output or target parameters relating to a particular sub-units
- B60W2710/02—Clutches
- B60W2710/027—Clutch torque
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
- B60W2710/00—Output or target parameters relating to a particular sub-units
- B60W2710/06—Combustion engines, Gas turbines
- B60W2710/0666—Engine torque
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02D—CONTROLLING COMBUSTION ENGINES
- F02D2250/00—Engine control related to specific problems or objectives
- F02D2250/18—Control of the engine output torque
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- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
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- Control Of Transmission Device (AREA)
- Control Of Driving Devices And Active Controlling Of Vehicle (AREA)
- Control Of Vehicle Engines Or Engines For Specific Uses (AREA)
Abstract
The invention relates to the technical field of vehicles, in particular to an intelligent downshift control method for an automatic-gear vehicle, which comprises a TCU (train control unit), an EMS (energy management system) unit, an engine, a first clutch and a second clutch, wherein the TCU unit calculates torque required by the engine and torque required by the clutch according to the vehicle sliding condition, controls the clutch torque to be combined with a target position, simultaneously provides an engine torque request to the EMS unit, the EMS unit controls the engine to output corresponding engine torque according to the torque request, and the TCU unit calculates the clutch torque and the engine torque through three time periods of a first stage, a second stage and a third stage respectively, so that the engine torque and the clutch torque are matched with each other in real time in the downshift process, the whole vehicle slides and downshifts smoothly, and the comfort of a driver and passengers is improved.
Description
Technical Field
The invention relates to the technical field of vehicles, in particular to an intelligent downshift control method for an automatic-gear vehicle.
Background
Coast downshifts are a common operating condition for dual clutch transmissions, but if engine torque control is not appropriate, or clutch torque control is not appropriate, jerk may result, which may affect the driver's driving feel and the passengers' riding feel. Therefore, in order to reduce the bumpiness, the vehicle needs to be subjected to downshift treatment, which is a complicated process and involves matching the engine torque and the transmission clutch torque, and if the downshift method is not adopted, the torque is interrupted, and the riding feeling is affected. And each time quantum of the intelligent downshift of the automatic-gear vehicle in the prior art is not well jointed, so that the whole vehicle cannot run smoothly enough.
Disclosure of Invention
Aiming at the technical problems in the prior art, the invention provides an intelligent downshift control method for an automatic-gear vehicle, which can adjust the torque of an engine and the torque of a clutch in real time so that the vehicle can run smoothly when downshifting.
In order to achieve the purpose, the invention provides the following technical scheme:
the control method for intelligent downshift of the automatic-gear vehicle comprises a TCU unit, an EMS unit, an engine, a first clutch and a second clutch, wherein the TCU unit calculates torque required by the engine and torque required by the clutch according to vehicle sliding conditions, the TCU unit controls the clutch torque to be combined to a target position, the TCU unit simultaneously provides an engine torque request to the EMS unit, the EMS unit controls the engine to output corresponding engine torque according to the torque request, and the calculation steps of the engine torque and the clutch torque are as follows:
A. when the even gear is reduced to the odd gear, the second clutch torque is firstly calculated because the engine speed and the second clutch speed are in a synchronous state, and the method comprises the following calculation steps:
1) the first stage is as follows: calculating a second clutch torque and an engine torque before and including time a
2) And a second stage: between time a and time b and including time b, time b is a critical point
In this stage, the engine speed is not synchronized with the first clutch speed, the engine speed is synchronized with the second clutch speed, and the stage is in the process of switching the second clutch torque to the first clutch torque, and the time point a is a starting point, the time point b is an ending point,
i) when the time point b is the critical time point, the second clutch is completely disengaged at the time point, the first clutch completely takes over the engine torque, and the rotating speed of the second clutch is consistent with the rotating speed of the engine, so that the first clutch torque and the engine torque are calculated;
ii) when the process of switching from the time point a to the time point b is carried out, the combination speed of the first clutch is controlled, the TCU unit actively controls the torque of the first clutch, the starting torque is required to be coordinated with the first clutch at any time, at the moment, the torque of the second clutch cannot be combined too little, a certain torque is required to be kept, otherwise, acceleration discontinuity is generated, the response speed factor of the engine is considered, the torque of the second clutch is required to be matched with the torque of the engine at the stage and is required to be combined according to a proper combination speed, the second clutch keeps a certain torque trend in a separation mode, the torque of the second clutch and the torque of the engine are calculated, and at the moment, the TCU unit requests the torque of the engine in real time according to the calculated value;
3) and a third stage: the engine torque is completely taken over by the first clutch between the time point b and the time point c, including the time point c, the first clutch torque needs to keep the first clutch transmission torque unchanged in order to keep the value acceleration dwv/dt, and the engine speed is gradually synchronized to the first clutch speed;
i) when the time point c is a critical time point, the first clutch rotating speed is still synchronous with the engine rotating speed, and the first clutch torque and the engine torque are calculated;
ii) in the process of switching from the time point b to the time point c, keeping the torque of the first clutch unchanged, but in order to synchronize the rotating speed of the engine and the rotating speed of the first clutch, the torque of the engine needs to be improved, at the moment, an engine target rotating speed curve can be calibrated, the aim is achieved by controlling the torque of the engine through a request, but the torque of the engine needs to be controlled to rotate from the time point b to the time point c, at the moment, three stages are finished, each stage is provided with a definite control method, the control is carried out according to the stages, and the whole vehicle can smoothly pass through the sliding downshift;
B. when the gear is reduced from the odd gear to the even gear, the second clutch torque is firstly calculated because the engine speed and the second clutch speed are in a synchronous state, and the method comprises the following calculation steps:
1) the first stage is as follows: calculating a first clutch torque and an engine torque before and including time point a
2) And a second stage: between time a and time b and including time b, time b is a critical point
In this stage, the engine speed is not synchronized with the second clutch speed, the engine speed is synchronized with the first clutch speed, and the stage is in the process of switching the second clutch torque to the first clutch torque, and the time point a is a starting point, the time point b is an ending point,
i) when the time point b is the critical time point, the first clutch is completely disengaged, the second clutch completely takes over the engine torque, and the rotating speed of the first clutch is consistent with the rotating speed of the engine, so that the second clutch torque and the engine torque are calculated;
ii) when the process of switching from the time point a to the time point b is carried out, the combination speed of the second clutch is controlled, the TCU unit actively controls the torque of the second clutch, the starting torque is required to be coordinated with the TCU unit at any time, at the moment, the torque of the first clutch cannot be combined too little, a certain torque is required to be kept, otherwise, acceleration discontinuity is generated, the response speed factor of the engine is considered, at the moment, the torque of the first clutch is required to be matched with the torque of the engine and is required to be combined according to a proper combination speed, the first clutch keeps a certain torque trend in a separation mode, the torque of the first clutch and the torque of the engine are calculated, and at the moment, the TCU unit requests the torque of the engine in real time according to the calculated value;
3) and a third stage: between and including time b and time c, where time c is a critical point, the engine torque is completely taken over by the second clutch, the second clutch torque is required to maintain the second clutch transmission torque for maintaining the value acceleration dwv/dt, and the engine speed is gradually synchronized to the second clutch speed,
i) when the time point c is a critical time point, the rotating speed of the second clutch is synchronous with the rotating speed of the engine, and the torque of the second clutch and the torque of the engine are calculated;
ii) in the process of switching from the time point b to the time point c, keeping the torque of the second clutch unchanged, but in order to synchronize the rotating speed of the engine and the rotating speed of the second clutch, the torque of the engine needs to be improved, at the moment, an engine target rotating speed curve can be calibrated, the aim is achieved by controlling the torque of the engine through a request, but the torque of the engine needs to be controlled to rotate from the time point b to the time point c, at the moment, three stages are finished, each stage is provided with a definite control method, the control is carried out according to the stages, and the whole vehicle can smoothly pass through the sliding downshift;
when the even gear is reduced to the odd gear, the method comprises the following calculation steps:
1) the first stage is as follows: calculating a second clutch torque and an engine torque before and including time a
The second clutch torque is calculated as: tc2 ═ Jv × dwv/dt + Tr)/i 2:
and (3) calculating:
the product is prepared from i2 Tc2-Tr Jv dwv/dt,
tc2 is (Jv × dwv/dt + Tr)/i2, and the engine torque is calculated as: te ═ Jv × dwv/dt + Tr)/i2+ Je × i2 × dwv/dt:
and (3) calculating:
from Te-Tc 2-Je dwe/dt and dwe/dt-i 2-dwv/dt
The result is that Te is Tc2+ Je i2 i dwv/dt (Jv dwv/dt + Tr)/i2+ Je i2 i dwv/dt,
2) and a second stage: between time a and time b and including time b, time b is a critical point
i) When it is time point b, the first clutch torque and the engine torque are calculated
The first clutch torque is calculated as: tc1 ═ Jv × dwv/dt + Tr)/i 1;
and (3) calculating: the product is prepared from i1 Tc1-Tr Jv dwv/dt,
tc1 ═ (Jv × dwv/dt + Tr)/i 1;
the engine torque is calculated as: te ═ Jv × dwv/dt + Tr)/i1+ i2 × Je × dwv/dt,
and (3) calculating:
from Te-Tc 1-Je dwe/dt and dwe/dt-i 2-dwv/dt
Obtaining Te (Tc 1+ Je dwe/dt) (Jv dwv/dt + Tr)/i1+ i2 Je dwv/dt;
ii) calculating a second clutch torque and an engine torque during a shift from time a to time b
The second clutch torque is calculated as: tc2 (Jv dwv/dt + Tr-i 1 Tc1)/i2,
the calculation process is carried out according to the calculation result,
from i2 Tc2+ i1 Tc1-Tr Jv dwv/dt
Getting Tc2 ═ (Jv dwv/dt + Tr-i 1 ═ Tc1)/i 2;
calculation of engine torque: te ═ Je × i2 × dwv/dt + Tc1+ (Jv × dwv/dt + Tr-i 1 × Tc1)/i2,
Te-Tc 2-Tc 1 ═ Je ═ dwe/dt and dwe/dt ═ i2 ═ dwv/dt
The result is Te ═ Je × dwe/dt + Tc1+ Tc2
＝Je*i2*dwv/dt+Tc1+(Jv*dwv/dt+Tr–i1*Tc1)/i2
Wherein Tc1 and Tc2 at this stage are obtained from the above calculations, in known amounts,
3) and a third stage: a time point c between the time point b and the time point c, the time point c being a critical point
i) At time point c, the first clutch torque and the engine torque are calculated
The first clutch torque is calculated as: tc1 ═ Jv × dwv/dt + Tr)/i 1;
and (3) calculating: the product is prepared from i1 Tc1-Tr Jv dwv/dt,
tc1 ═ (Jv × dwv/dt + Tr)/i 1;
the engine torque is calculated as: te ═ Jv × dwv/dt + Tr)/i1+ Je × i1 × dwv/dt,
and (3) calculating:
from Te-Tc 1-Je dwe/dt and dwe/dt-i 1-dwv/dt
Obtaining Te (Tc 1+ Je i 1) dwv/dt (Jv dwv/dt + Tr)/i1+ Je i 1) dwv/dt;
ii) keeping the first clutch torque constant during the switching from time point b to time point c, and controlling the engine torque from Te at time point b to (Jv × dwv/dt + Tr)/i1+ i2 × Je dwv/dt to Te at time point c to (Jv × dwv/dt + Tr)/i1+ Je i1 dwv/dt.
In all the calculation processes, Te is engine torque; tc1 is the first clutch torque; tc2 is the second clutch torque; je is engine inertia; jv is the inertia of the whole vehicle; dwe/dt is engine acceleration; dwv/dt is the acceleration of the whole vehicle, i2 is the even gear transmission ratio; i1 is an odd-gear transmission ratio; tr is the vehicle resistance, and Jv, i2, i2, Tr, dwv/dt, Je are known quantities.
When the gear is shifted from the odd gear to the even gear, the method comprises the following calculation steps:
1) the first stage is as follows: calculating a first clutch torque and an engine torque before and including time point a
The first clutch torque is calculated as: tc1 ═ Jv × dwv/dt + Tr)/i 1:
and (3) calculating:
the product is prepared from i1 Tc1-Tr Jv dwv/dt,
tc1 is (Jv × dwv/dt + Tr)/i1, and the engine torque is calculated as: te ═ Jv × dwv/dt + Tr)/i1+ Je × i1 × dwv/dt:
and (3) calculating:
from Te-Tc 1-Je dwe/dt and dwe/dt-i 1-dwv/dt
The result is that Te is Tc1+ Je i1 i dwv/dt (Jv dwv/dt + Tr)/i1+ Je i1 i dwv/dt,
2) and a second stage: between time a and time b and including time b, time b is a critical point
i) When it is time point b, the second clutch torque and the engine torque are calculated
The second clutch torque is calculated as: tc2 ═ Jv × dwv/dt + Tr)/i 2;
and (3) calculating: the product is prepared from i2 Tc2-Tr Jv dwv/dt,
tc2 ═ (Jv × dwv/dt + Tr)/i 2;
the engine torque is calculated as: te ═ Jv × dwv/dt + Tr)/i2+ i1 × Je × dwv/dt,
and (3) calculating:
from Te-Tc 2-Je dwe/dt and dwe/dt-i 1-dwv/dt
Obtaining Te (Tc 2+ Je dwe/dt) (Jv dwv/dt + Tr)/i2+ i1 Je dwv/dt;
ii) calculating a first clutch torque and an engine torque during a transition from time a to time b
The first clutch torque is calculated as: tc1 (Jv dwv/dt + Tr-i 2 Tc1)/i1,
the calculation process is carried out according to the calculation result,
from i1 Tc1+ i2 Tc2-Tr Jv dwv/dt
Getting Tc1 ═ (Jv dwv/dt + Tr-i 2 ═ Tc1)/i 1;
calculation of engine torque: te ═ Je × i1 × dwv/dt + Tc2+ (Jv × dwv/dt + Tr-i 2 × Tc2)/i1,
Te-Tc 1-Tc 2 ═ Je ═ dwe/dt and dwe/dt ═ i1 ═ dwv/dt
The result is Te ═ Je × dwe/dt + Tc2+ Tc1
＝Je*i1*dwv/dt+Tc2+(Jv*dwv/dt+Tr–i2*Tc2)/i1
Wherein Tc1 and Tc2 at this stage are obtained from the above calculations, in known amounts,
3) and a third stage: a time point c between the time point b and the time point c, the time point c being a critical point
i) When the time point c is, the second clutch torque and the engine torque are calculated
The second clutch torque is calculated as: tc2 ═ Jv × dwv/dt + Tr)/i 2;
and (3) calculating: the product is prepared from i2 Tc2-Tr Jv dwv/dt,
tc2 ═ (Jv × dwv/dt + Tr)/i 2;
the engine torque is calculated as: te ═ Jv × dwv/dt + Tr)/i2+ Je × i2 × dwv/dt,
and (3) calculating:
from Te-Tc 2-Je dwe/dt and dwe/dt-i 2-dwv/dt
Obtaining Te (Tc 2+ Je i 2) dwv/dt (Jv dwv/dt + Tr)/i2+ Je i 2) dwv/dt;
ii) keeping the first clutch torque constant during the switching from time point b to time point c, and controlling the engine torque from Te at time point b to (Jv × dwv/dt + Tr)/i2+ i1 × Je dwv/dt to Te at time point c to (Jv × dwv/dt + Tr)/i2+ Je i2 dwv/dt.
In all the calculation processes, Te is engine torque; tc1 is the first clutch torque; tc2 is the second clutch torque; je is engine inertia; jv is the inertia of the whole vehicle; dwe/dt is engine acceleration; dwv/dt is the acceleration of the whole vehicle, i2 is the even gear transmission ratio; i1 is an odd-gear transmission ratio; tr is the vehicle resistance, and Jv, i2, i2, Tr, dwv/dt, Je are known quantities.
The invention has the beneficial effects that:
the TCU unit calculates the torque required by an engine and the torque required by a clutch according to the vehicle sliding scene, controls the clutch torque to be combined to a target position, simultaneously provides an engine torque request to the EMS unit, controls the engine to output corresponding engine torque according to the torque request, and respectively calculates the clutch torque and the engine torque through the first stage, the second stage and the third stage, so that the engine torque and the clutch torque are matched in real time in the downshift process, the whole vehicle slides and downshifts smoothly, and the comfort of a driver and passengers is improved.
Drawings
Fig. 1 is a schematic diagram of the operating state of the 4 th-gear 3 rd-gear lower clutch of embodiment 1.
Fig. 2 is a schematic view of the operating state of the 3 rd gear and 2 nd gear reduction clutch of embodiment 1.
Detailed Description
The present invention will be described in detail below with reference to specific embodiments and the accompanying drawings.
Example 1
The control method for intelligent downshift of the automatic-gear vehicle comprises a TCU unit, an EMS unit, an engine, a first clutch and a second clutch, wherein the TCU unit calculates torque required by the engine and torque required by the clutch according to vehicle sliding conditions, the TCU unit controls the clutch torque to be combined to a target position, the TCU unit simultaneously provides an engine torque request to the EMS unit, the EMS unit controls the engine to output corresponding engine torque according to the torque request, and the calculation steps of the engine torque and the clutch torque are as follows:
when the gear 4 is reduced to the gear 3, the TCU unit comprises the following calculation steps:
1) the first stage is as follows: calculating a second clutch torque and an engine torque before and including time a
The second clutch torque is calculated as: tc2 ═ Jv × dwv/dt + Tr)/i 2;
the engine torque is calculated as: te ═ Jv × dwv/dt + Tr)/i2+ Je × i2 × dwv/dt;
2) and a second stage: between time a and time b and including time b, time b is a critical point
i) When it is time point b, the first clutch torque and the engine torque are calculated
The first clutch torque is calculated as: tc1 ═ Jv × dwv/dt + Tr)/i 1;
the engine torque is calculated as: te ═ Jv × dwv/dt + Tr)/i1+ i2 × Je × dwv/dt;
ii) calculating a second clutch torque and an engine torque during a shift from time a to time b
The second clutch torque is calculated as: tc2 ═ Jv × dwv/dt + Tr-i 1 × Tc1)/i 2;
calculation of engine torque: te ═ Je × i2 × dwv/dt + Tc1+ (Jv × dwv/dt + Tr-i 1 × Tc1)/i 2;
3) and a third stage: a time point c between the time point b and the time point c, the time point c being a critical point
i) At time point c, the first clutch torque and the engine torque are calculated
The first clutch torque is calculated as: tc1 ═ Jv × dwv/dt + Tr)/i 1;
the engine torque is calculated as: te ═ Jv × dwv/dt + Tr)/i1+ Je × i1 × dwv/dt;
ii) keeping the first clutch torque constant during the switching from time b to time c, and controlling the engine torque Te at time b to (Jv × dwv/dt + Tr)/i1+ i2 × Je dwv/dt to (Jv × dwv/dt + Tr)/i1+ Je i1 i dwv/dt,
wherein Te is engine torque; tc1 is the first clutch torque; tc2 is the second clutch torque; je is engine inertia; jv is the inertia of the whole vehicle; dwe/dt is engine acceleration; dwv/dt is the acceleration of the whole vehicle, i2 is the even gear transmission ratio; i1 is an odd-gear transmission ratio; tr is the vehicle resistance, and Jv, i2, i2, Tr, dwv/dt, Je are known quantities.
Explanation of fig. 1:
FIG. 1 is a diagram of the operating states of the clutches when the 4-speed is down to the 3-speed, and is shown in FIG. 1, (1) before time a, when the current speed is the 4-speed, it is not yet down, so that the first clutch torque and the second clutch torque are both in the current speed, and at this time, the second clutch is in the 4-speed connection, so that the second clutch torque is above the first clutch torque, and the first clutch speed and the second clutch speed are both synchronously reduced to keep the speed reduction trend;
(2) the time point a to the time point b are a process in which the second clutch torque is switched to the first clutch torque and a process in which the second clutch torque is switched to the first clutch torque, and thus, both of them generate a downward trend and an upward trend, respectively, to reach the required torque;
(3) the time point b to the time point c is that the first clutch completely takes over the engine torque, so that the first clutch torque is located above the second clutch torque, and the first clutch torque is kept unchanged in order to keep the acceleration of the whole vehicle unchanged.
Example 2
The control method for intelligent downshift of the automatic-gear vehicle comprises a TCU unit, an EMS unit, an engine, a first clutch and a second clutch, wherein the TCU unit calculates torque required by the engine and torque required by the clutch according to vehicle sliding conditions, the TCU unit controls the clutch torque to be combined to a target position, the TCU unit simultaneously provides an engine torque request to the EMS unit, the EMS unit controls the engine to output corresponding engine torque according to the torque request, and the calculation steps of the engine torque and the clutch torque are as follows:
when the gear 3 is reduced to the gear 2, the TCU unit comprises the following calculation steps:
when the gear is reduced from the odd gear to the even gear, the method comprises the following calculation steps:
1) the first stage is as follows: calculating a first clutch torque and an engine torque before and including time point a
The first clutch torque is calculated as: tc1 ═ Jv × dwv/dt + Tr)/i 1;
the engine torque is calculated as: te ═ Jv × dwv/dt + Tr)/i1+ Je × i1 × dwv/dt;
2) and a second stage: between time a and time b and including time b, time b is a critical point
i) When it is time point b, the second clutch torque and the engine torque are calculated
The second clutch torque is calculated as: tc2 ═ Jv × dwv/dt + Tr)/i 2;
the engine torque is calculated as: te ═ Te (Jv × dwv/dt + Tr/i2+ i1 × Je × dwv/dt;
ii) calculating a first clutch torque and an engine torque during a transition from time a to time b
The first clutch torque is calculated as: tc1 ═ Jv × dwv/dt + Tr-i 2 × Tc2)/i 1;
calculation of engine torque: te ═ Je × i1 × dwv/dt + Tc2+ (Jv × dwv/dt + Tr-i 2 × Tc2)/i 1;
3) and a third stage: a time point c between the time point b and the time point c, the time point c being a critical point
i) When the time point c is, the second clutch torque and the engine torque are calculated
The second clutch torque is calculated as: tc2 ═ Jv × dwv/dt + Tr)/i 2;
the engine torque is calculated as: te ═ Jv × dwv/dt + Tr)/i2+ Je × i2 × dwv/dt;
ii) during the shift from time b to time c, the second clutch torque is kept constant and the engine torque at time b is controlled to be shifted to the engine torque at time c,
wherein Te is engine torque; tc1 is the first clutch torque; tc2 is the second clutch torque; je is engine inertia; jv is the inertia of the whole vehicle; dwe/dt is engine acceleration; dwv/dt is the acceleration of the whole vehicle, i2 is the even gear transmission ratio; i1 is an odd-gear transmission ratio; tr is the vehicle resistance, and Jv, i2, i2, Tr, dwv/dt, Je are known quantities.
Explanation of fig. 2:
FIG. 2 is a diagram of the operating states of the clutches when the gear 3 is shifted down to the gear 2, and FIG. 2 shows that (1) before the time point a, the current gear is the gear 3, which is not shifted down, so that the first clutch torque and the second clutch torque are both in the current gear, and at this time, the first clutch is in the gear 4, so that the first clutch torque is above the second clutch torque, and the second clutch speed and the first clutch speed are both synchronously decreased to maintain the tendency of speed reduction;
(2) the time point a to the time point b are a process of switching the first clutch torque to the second clutch torque and a process of switching the first clutch torque to the second clutch torque, and thus, both of them generate a downward trend and an upward trend, respectively, to reach the required torque;
(3) the time point b to the time point c is that the second clutch completely takes over the engine torque, so that the second clutch torque is located above the first clutch torque, and the second clutch torque is kept unchanged in order to keep the acceleration of the whole vehicle unchanged.
Example 3
The control method for the intelligent downshift of the automatic-gear vehicle comprises a TCU unit, an EMS unit, an engine, a first clutch and a second clutch, wherein the TCU unit calculates torque required by the engine and torque required by the clutch according to vehicle sliding conditions, the TCU unit controls the clutch torque to be combined to a target position, the TCU unit simultaneously provides an engine torque request to the EMS unit, the EMS unit controls the engine to output corresponding engine torque according to the torque request, and the calculation steps of the engine torque and the clutch torque are as follows:
when the gear 2 is reduced to the gear 1, the TCU unit comprises the following calculation steps:
1) the first stage is as follows: calculating a second clutch torque and an engine torque before and including time a
The second clutch torque is calculated as: tc2 ═ Jv × dwv/dt + Tr)/i 2;
the engine torque is calculated as: te ═ Jv × dwv/dt + Tr)/i2+ Je × i2 × dwv/dt;
2) and a second stage: between time a and time b and including time b, time b is a critical point
i) When it is time point b, the first clutch torque and the engine torque are calculated
The first clutch torque is calculated as: tc1 ═ Jv × dwv/dt + Tr)/i 1;
the engine torque is calculated as: te ═ Jv × dwv/dt + Tr)/i1+ i2 × Je × dwv/dt;
ii) calculating a second clutch torque and an engine torque during a shift from time a to time b
The second clutch torque is calculated as: tc2 ═ Jv × dwv/dt + Tr-i 1 × Tc1)/i 2;
calculation of engine torque: te ═ Je × i2 × dwv/dt + Tc1+ (Jv × dwv/dt + Tr-i 1 × Tc1)/i 2;
3) and a third stage: a time point c between the time point b and the time point c, the time point c being a critical point
i) At time point c, the first clutch torque and the engine torque are calculated
The first clutch torque is calculated as: tc1 ═ Jv × dwv/dt + Tr)/i 1;
the engine torque is calculated as: te ═ Jv × dwv/dt + Tr)/i1+ Je × i1 × dwv/dt;
ii) keeping the first clutch torque constant during the switching from time b to time c, and controlling the engine torque Te at time b to (Jv × dwv/dt + Tr)/i1+ i2 × Je dwv/dt to (Jv × dwv/dt + Tr)/i1+ Je i1 i dwv/dt,
wherein Te is engine torque; tc1 is the first clutch torque; tc2 is the second clutch torque; je is engine inertia; jv is the inertia of the whole vehicle; dwe/dt is engine acceleration; dwv/dt is the acceleration of the whole vehicle, i2 is the even gear transmission ratio; i1 is an odd-gear transmission ratio; tr is the vehicle resistance, and Jv, i2, i2, Tr, dwv/dt, Je are known quantities.
Example 4
The control method for intelligent downshift of the automatic-gear vehicle comprises a TCU unit, an EMS unit, an engine, a first clutch and a second clutch, wherein the TCU unit calculates torque required by the engine and torque required by the clutch according to vehicle sliding conditions, the TCU unit controls the clutch torque to be combined to a target position, the TCU unit simultaneously provides an engine torque request to the EMS unit, the EMS unit controls the engine to output corresponding engine torque according to the torque request, and the calculation steps of the engine torque and the clutch torque are as follows:
when the gear 5 is reduced to the gear 4, the TCU unit comprises the following calculation steps:
1) the first stage is as follows: calculating a first clutch torque and an engine torque before and including time point a
The first clutch torque is calculated as: tc1 ═ Jv × dwv/dt + Tr)/i 1;
the engine torque is calculated as: te ═ Jv × dwv/dt + Tr)/i1+ Je × i1 × dwv/dt;
2) and a second stage: between time a and time b and including time b, time b is a critical point
i) When it is time point b, the second clutch torque and the engine torque are calculated
The second clutch torque is calculated as: tc2 ═ Jv × dwv/dt + Tr)/i 2;
the engine torque is calculated as: te ═ Te (Jv × dwv/dt + Tr/i2+ i1 × Je × dwv/dt;
ii) calculating a first clutch torque and an engine torque during a transition from time a to time b
The first clutch torque is calculated as: tc1 ═ Jv × dwv/dt + Tr-i 2 × Tc2)/i 1;
calculation of engine torque: te ═ Je × i1 × dwv/dt + Tc2+ (Jv × dwv/dt + Tr-i 2 × Tc2)/i 1;
3) and a third stage: a time point c between the time point b and the time point c, the time point c being a critical point
i) When the time point c is, the second clutch torque and the engine torque are calculated
The second clutch torque is calculated as: tc2 ═ Jv × dwv/dt + Tr)/i 2;
the engine torque is calculated as: te ═ Jv × dwv/dt + Tr)/i2+ Je × i2 × dwv/dt;
ii) during the shift from time b to time c, the second clutch torque is kept constant and the engine torque at time b is controlled to be shifted to the engine torque at time c,
wherein Te is engine torque; tc1 is the first clutch torque; tc2 is the second clutch torque; je is engine inertia; jv is the inertia of the whole vehicle; dwe/dt is engine acceleration; dwv/dt is the acceleration of the whole vehicle, i2 is the even gear transmission ratio; i1 is an odd-gear transmission ratio; tr is the vehicle resistance, and Jv, i2, i2, Tr, dwv/dt, Je are known quantities.
Finally, it should be noted that the above embodiments are only used for illustrating the technical solutions of the present invention, and not for limiting the protection scope of the present invention, although the present invention is described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications or equivalent substitutions can be made on the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.
Claims (1)
1. An intelligent downshift control method for an automatic-gear vehicle is characterized by comprising the following steps: the engine torque and clutch torque calculating method comprises a TCU unit, an EMS unit, an engine, a first clutch and a second clutch, wherein the TCU unit calculates the torque required by the engine and the torque required by the clutch according to the vehicle sliding condition, the TCU unit controls the clutch torque to be combined to a target position, the TCU unit simultaneously provides an engine torque request to the EMS unit, the EMS unit controls the engine to output corresponding engine torque according to the torque request, and the engine torque and the clutch torque are calculated by the following steps:
A. when the gear is reduced from the even gear to the odd gear, the method comprises the following calculation steps:
1) the first stage is as follows: before and including time a, second clutch torque and engine torque are calculated,
the second clutch torque is calculated as: tc2 ═ Jv × dwv/dt + Tr)/i2,
the engine torque is calculated as: te ═ Jv × dwv/dt + Tr)/i2+ Je × i2 × dwv/dt;
2) and a second stage: between and including time a and time b, time b is a critical point,
i) at time point b, the first clutch torque and the engine torque are calculated,
the first clutch torque is calculated as: tc1 ═ Jv × dwv/dt + Tr)/i1,
the engine torque is calculated as: te ═ Jv × dwv/dt + Tr)/i1+ i2 × Je × dwv/dt;
ii) calculating a second clutch torque and an engine torque during a shift from time a to time b,
the second clutch torque is calculated as: tc2 (Jv dwv/dt + Tr-i 1 Tc1)/i2,
calculation of engine torque: te ═ Je × i2 × dwv/dt + Tc1+ (Jv × dwv/dt + Tr-i 1 × Tc1)/i 2;
3) and a third stage: between and including time point b and time point c, time point c is a critical point,
i) when it is time point c, the first clutch torque and the engine torque are calculated,
the first clutch torque is calculated as: tc1 ═ Jv × dwv/dt + Tr)/i1,
the engine torque is calculated as: te ═ Jv × dwv/dt + Tr)/i1+ Je × i1 × dwv/dt;
ii) keeping the first clutch torque constant during the switching from time point b to time point c, and controlling the engine torque Te at time point b to (Jv × dwv/dt + Tr)/i1+ i2 × Je dwv/dt to (Jv × dwv/dt + Tr)/i1+ Je i1 i dwv/dt;
B. when the gear is reduced from the odd gear to the even gear, the method comprises the following calculation steps:
1) the first stage is as follows: before and including time a, first clutch torque and engine torque are calculated,
the first clutch torque is calculated as: tc1 ═ Jv × dwv/dt + Tr)/i1,
the engine torque is calculated as: te ═ Jv × dwv/dt + Tr)/i1+ Je × i1 × dwv/dt;
2) and a second stage: between and including time a and time b, time b is a critical point,
i) at time point b, the second clutch torque and the engine torque are calculated,
the second clutch torque is calculated as: tc2 ═ Jv × dwv/dt + Tr)/i2,
the engine torque is calculated as: te ═ Jv × dwv/dt + Tr)/i2+ i1 × Je × dwv/dt;
ii) calculating a first clutch torque and an engine torque during a shift from time a to time b,
the first clutch torque is calculated as: tc1 (Jv dwv/dt + Tr-i 2 Tc2)/i1,
calculation of engine torque: te ═ Je × i1 × dwv/dt + Tc2+ (Jv × dwv/dt + Tr-i 2 × Tc2)/i 1;
3) and a third stage: between and including time point b and time point c, time point c is a critical point,
i) at time point c, the second clutch torque and the engine torque are calculated,
the second clutch torque is calculated as: tc2 ═ Jv × dwv/dt + Tr)/i2,
the engine torque is calculated as: te ═ Jv × dwv/dt + Tr)/i2+ Je × i2 × dwv/dt;
ii) during the shift from time b to time c, the second clutch torque is kept constant and the engine torque at time b is controlled to be shifted to the engine torque at time c,
wherein Te is engine torque; tc1 is the first clutch torque; tc2 is the second clutch torque; je is engine inertia; jv is the inertia of the whole vehicle; dwe/dt is engine acceleration; dwv/dt is the acceleration of the whole vehicle, i2 is the even gear transmission ratio; i1 is an odd-gear transmission ratio; tr is the vehicle resistance, and Jv, i1, i2, Tr, dwv/dt, Je are known quantities.
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