US20160039406A1 - Output bump management in a strong hybrid vehicle - Google Patents
Output bump management in a strong hybrid vehicle Download PDFInfo
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- US20160039406A1 US20160039406A1 US14/454,967 US201414454967A US2016039406A1 US 20160039406 A1 US20160039406 A1 US 20160039406A1 US 201414454967 A US201414454967 A US 201414454967A US 2016039406 A1 US2016039406 A1 US 2016039406A1
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- 238000000034 method Methods 0.000 claims abstract description 28
- 238000004891 communication Methods 0.000 claims description 3
- 238000012545 processing Methods 0.000 claims description 3
- 238000013461 design Methods 0.000 description 7
- 238000013459 approach Methods 0.000 description 3
- 238000006243 chemical reaction Methods 0.000 description 3
- 230000007704 transition Effects 0.000 description 3
- 239000000872 buffer Substances 0.000 description 2
- 238000002485 combustion reaction Methods 0.000 description 2
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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
- B60W20/00—Control systems specially adapted for hybrid vehicles
- B60W20/10—Controlling the power contribution of each of the prime movers to meet required power demand
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
- B60L15/00—Methods, circuits, or devices for controlling the traction-motor speed of electrically-propelled vehicles
- B60L15/20—Methods, circuits, or devices for controlling the traction-motor speed of electrically-propelled vehicles for control of the vehicle or its driving motor to achieve a desired performance, e.g. speed, torque, programmed variation of speed
-
- 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
- B60W20/00—Control systems specially adapted for hybrid vehicles
- B60W20/10—Controlling the power contribution of each of the prime movers to meet required power demand
- B60W20/11—Controlling the power contribution of each of the prime movers to meet required power demand using model predictive control [MPC] strategies, i.e. control methods based on models predicting performance
-
- B60W20/108—
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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
-
- 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
- B60W10/08—Conjoint control of vehicle sub-units of different type or different function including control of propulsion units including control of electric propulsion units, e.g. motors or generators
-
- 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
- B60W20/00—Control systems specially adapted for hybrid vehicles
- B60W20/10—Controlling the power contribution of each of the prime movers to meet required power demand
- B60W20/15—Control strategies specially adapted for achieving a particular effect
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- B—PERFORMING OPERATIONS; TRANSPORTING
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- 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
- B60W30/188—Controlling power parameters of the driveline, e.g. determining the required power
- B60W30/1886—Controlling power supply to auxiliary devices
- B60W30/1888—Control of power take off [PTO]
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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
- B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
- B60L2260/00—Operating Modes
- B60L2260/20—Drive modes; Transition between modes
- B60L2260/24—Coasting mode
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
- B60L2270/00—Problem solutions or means not otherwise provided for
- B60L2270/10—Emission reduction
- B60L2270/14—Emission reduction of noise
- B60L2270/145—Structure borne vibrations
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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
- B60W2710/08—Electric propulsion units
- B60W2710/083—Torque
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T10/00—Road transport of goods or passengers
- Y02T10/60—Other road transportation technologies with climate change mitigation effect
- Y02T10/64—Electric machine technologies in electromobility
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T10/00—Road transport of goods or passengers
- Y02T10/60—Other road transportation technologies with climate change mitigation effect
- Y02T10/72—Electric energy management in electromobility
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10S903/00—Hybrid electric vehicles, HEVS
- Y10S903/902—Prime movers comprising electrical and internal combustion motors
Definitions
- the present disclosure relates to the management of driveline output bump in a strong hybrid vehicle.
- Strong hybrid vehicles use an internal combustion engine and one or more electric traction motors to provide input torque to gear sets of a transmission.
- the available modes of a strong hybrid may therefore include an engine-only mode, one or more electric-only/electric vehicle modes, and multiple hybrid or electrically variable transmission modes.
- geared neutral As a result, a condition referred to as driveline output bump may result when operating the transmission in neutral due to transient torque disturbances from the engine.
- the terms “output bump” and “clunk” are conventionally used in the art to describe the perceived sound and/or feel of any undesirable engine output torque oscillations.
- a method for managing output bump/clunk in a strong hybrid vehicle having an engine, a transmission, and a controller.
- the transmission includes an input member, an output member, and a planetary gear set.
- the method includes calculating a motor torque for an electric traction motor connected to a third node of the planetary gear set.
- the motor torque is calculated as a product of a predetermined inertia of the electric traction motor, a calculated acceleration of an output shaft of the engine, and a gear ratio of the planetary gear set, or an equivalent planetary gear set when multiple gear sets are used.
- the method also includes commanding the calculated motor torque from the electric traction motor via the controller in a direction opposite the calculated acceleration of the output shaft, including transmitting a motor torque command to the electric traction motor for the duration of the neutral state.
- a system is also disclosed that includes the transmission and the controller.
- a strong hybrid vehicle includes an engine having an output shaft.
- the vehicle also includes a damper assembly, a transmission, and a controller.
- the transmission includes an input member, an output member, at least one planetary gear set, and an electric traction motor.
- the controller which is in communication with the transmission, includes a processor and memory on which is recorded instructions for managing output bump or clunk during neutral. Execution of the instructions causes the controller to perform the steps of the method noted above.
- FIG. 1 is a schematic illustration of an example strong hybrid vehicle having a controller programmed to manage driveline output bump or clunk when operating in neutral.
- FIG. 2 is a flow chart describing an example method for managing driveline output bump or clunk in the vehicle shown in FIG. 1 .
- an example vehicle 10 is shown in FIG. 1 having an internal combustion engine (E) 12 , a transmission 14 , and a controller (C) 50 .
- the vehicle 10 is a strong hybrid electric vehicle. That is, the transmission 14 is connected to or includes multiple sources of possible input torque, including the engine 12 and an electric traction motor 16 (M A ). Additional electric traction motors may be used as part of the transmission 14 without departing from the untended inventive scope.
- the transmission 14 is shown in schematic lever diagram format to include a planetary gear set 30 .
- a planetary gear set 30 As is well known in the art, multiple interconnected gear sets of a transmission may be reduced schematically to a single equivalent gear set as shown in FIG. 1 . Therefore, the depiction of a single planetary gear set in FIG. 1 does not limit the present approach to transmissions having only one planetary gear set.
- the controller 50 is programmed to manage a condition referred to as output “bump” or “clunk” whenever the transmission 14 is operating in a neutral state. To this end, the controller 50 is operable for selectively executing instructions embodying a method 100 , an example of which is shown in FIG. 2 and described below. In executing the method 100 , the controller 50 activates the electric traction motor 16 by selectively delivering an engine speed-based motor torque command (arrow CC M ) to a motor control processor 16 P of the electric traction motor 16 .
- CC M engine speed-based motor torque command
- the electric traction motor 16 e.g., a relatively high-voltage, polyphase electric machine in the form of a motor/generator unit, responds to the motor torque command (arrow CC M ) by cancelling engine disturbances for the duration of the neutral state.
- the controller 50 may be embodied as a digital computer having a processor P and memory M.
- the memory M includes sufficient amounts of tangible, non-transitory memory, e.g., read only memory (ROM), flash memory, optical and/or magnetic memory, electrically-programmable read only memory (EPROM), and the like.
- Memory M also includes sufficient transient memory such as random access memory (RAM), electronic buffers.
- Hardware of the controller 50 includes a high-speed clock, analog-to-digital (A/D) and digital-to-analog (D/A) circuitry, and input/output (I/O) circuitry and devices, as well as appropriate signal conditioning and buffer circuitry.
- the planetary gear set 30 includes first, second, and third nodes 32 , 34 , and 36 , respectively. Such nodes may be configured in one possible embodiment as respective ring gear, carrier member, and sun gear, without being limited to such a design.
- the engine 12 includes an output shaft 13 that rotates at engine speed (arrow N E ) with an engine torque (arrow T E ).
- the output shaft 13 may be selectively connected to an input member 15 of the transmission 14 at the first node 32 via actuation of a damper assembly 20 .
- the damper assembly 20 is represented schematically in FIG. 1 as a spring 21 and a damper 22 .
- a bypass lockup clutch 23 may be used to rigidly connect the engine 12 to the transmission 14 as needed, for instance during engine start/stop events.
- the approach described herein is independent of the damper assembly 20 .
- the electric traction motor 16 will control the first node 32 so that the first node 32 has the same speed and acceleration as the engine 12 .
- the design described herein will work for a vehicle 10 having the damper assembly 20 or a rigid connection (not shown) between the engine 12 and the first node 32 .
- the transmission 14 includes an output member 24 that is connected to the second node 34 .
- the output member 24 rotates with an output speed (arrow N O ).
- the output member 24 transmits an output torque (arrow T O ) to drive axle(s) 25 , and ultimately to a set of drive wheels 26 to propel the vehicle 10 .
- the electric traction motor 16 is connected to the third node 36 via an interconnecting member 17 rotating at a motor speed (arrow N A ).
- the electric traction motor 16 ultimately delivers a motor torque (T A ) to the planetary gear set 30 at the third node 36 .
- the controller 50 is programmed with predetermined inertia values I E and I M for the engine 12 and the electric traction motor 16 , respectively.
- the lengths a and b denoted on the schematic planetary gear set 30 represent the lengths from the output member 24 at the second node 34 to the respective first and third nodes 32 and 36 .
- Such lengths may be considered in terms of a number of gear teeth of each gear elements embodying the various nodes 32 , 34 , and 36 , and are therefore used by the controller 50 to determine gear ratios during control of the transmission 14 .
- the vehicle 10 includes a park, reverse, neutral, drive, low (PRNDL) input device 11 of the type known in the art.
- the PRNDL input device 11 may be conventional, such as a cable-actuated gear shift lever, or it may be by-wire/electrically-actuated push-button device.
- a PRNDL valve (not shown) connected to the transmission 14 moves in response to movement of the PRNDL device to shift the transmission 14 into the requested PRNDL mode.
- the controller 50 receives a PRNDL signal (arrow 11 S) describing the position of the PRNDL input device 11 , or of the controlled PRNDL valve (not shown), and is thus informed of the state or position of the PRNDL input device 11 .
- the controller 50 also receives the engine speed (arrow N E ), e.g., as measured at the output shaft 13 via a speed sensor S N in the embodiment of FIG. 1 , or alternatively as reported to the controller 50 by a separate engine control module (not shown), calculated, or modeled/estimated.
- the controller 50 of FIG. 1 is programmed to calculate the acceleration of the engine 12 , with the acceleration represented below as ⁇ dot over (N) ⁇ E , upon receipt, estimation, or other determination of the engine speed (arrow N E ).
- the force balance equation is as follows:
- the moment balance at the first node 32 of the planetary gear set 30 is defined as:
- the motor torque command (arrow CC M ) for control of the electric traction motor 16 determined per equation (5) above may be selectively implemented by the controller 50 to eliminate driveline clunk or bump whenever the transmission 14 is in a neutral state.
- an example embodiment of the method 100 begins with step 102 .
- the controller 50 of FIG. 1 receives the PRNDL signal (arrow 11 S) or otherwise measures or determines the present commanded position of the PRNDL input device 11 or of a PRNDL valve (not shown) controlled by the PRNDL input device 11 .
- the method 100 proceeds to step 104 once the requested state of the transmission 14 is known.
- Step 104 entails determining whether the present state of the transmission 14 determined at step 102 is a neutral state. If not, step 102 is repeated. The method 100 proceeds to step 106 when the controller 50 has verified that the transmission 14 is operating in the neutral state.
- the controller 50 next determines the present engine speed (N E ).
- the speed sensor S N is positioned with respect to the output shaft 13 to directly measure the engine speed (N E ).
- the controller 50 may receive the engine speed (N E ) as a reported value, such as from an engine control module (not shown), or engine speed (N E ) may be estimated or modeled using a state machine as is known in the art.
- the method 100 proceeds to step 108 when engine speed (N E ) is known.
- Step 108 includes calculating, via the controller 50 , the acceleration ⁇ dot over (N) ⁇ E of the engine 12 , i.e., the rate of change in the rotational speed of the output shaft 13 shown in FIG. 1 .
- the value of the calculated engine acceleration ⁇ dot over (N) ⁇ E is temporarily recorded in memory M of the controller 50 before the method 100 continues to step 110 .
- Step 110 includes calculating the required motor torque from the electric traction motor 16 .
- Step 110 may entail solving equation (5) above via the controller 50 . That is, as
- T A - I A ⁇ N . E ⁇ b a ,
- step 108 i.e., the calculated engine acceleration ⁇ dot over (N) ⁇ E , is all that is required to determine the necessary torque value to be commanded.
- Step 110 may be tuned to provide the desired transition, and thus feel, of any application of the motor torque T A to third node 36 . That is, the motor torque T A may be simply commanded on upon entering neutral. Alternatively, the motor torque T A may be ramped on over a calibrated duration to smooth the transition, thereby making the onset of the motor torque T A less noticeable to the driver.
- the method 100 then proceeds to step 114 .
- step 114 the controller 50 determines whether the PRNDL input device 11 is still in neutral. As with step 104 , this may entail processing the PRNDL signal (arrow 11 S) or otherwise verifying the setting of the PRNDL input device 11 . Steps 112 and 114 are repeated until the driver of the vehicle 10 shifts the transmission 14 out of neutral, at which point the method 100 proceeds to step 116 .
- Step 116 entails aborting the motor torque command (arrow CC M ) applied at step 112 .
- Step 116 may include commanding the motor torque T A off instantaneously upon leaving the neutral state.
- the motor torque T A may be ramped off over a calibrated duration as in step 114 so as to smooth the transition, thereby making the discontinuation of the motor torque T A less noticeable to the driver. That is, discontinuing the motor torque T A may occur gradually according to a calibrated ramp profile, e.g., at the same rate or a different rate than that used in applying the motor torque T A in step 112 .
- the method 100 is then finished.
- the controller 50 selectively applies motor torque T A from the electric traction motor 16 to the planetary gear set 30 to actively respond to the inertia reaction of the electric traction motor 16 to any engine torque disturbances while operating in neutral.
- the method 100 is intended to help eliminate output bump/clunk in neutral. Such an advantageous result can be achieved even with relatively large oscillations in engine speed (arrow N E ) provided the motor torque command (arrow CC M ) remains within the capacity of the electric traction motor 16 .
- engine acceleration is used at step 110 instead of the acceleration of the electric traction motor 16 , phase delay and other issues are avoided.
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- Mechanical Engineering (AREA)
- Automation & Control Theory (AREA)
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Abstract
Description
- The present disclosure relates to the management of driveline output bump in a strong hybrid vehicle.
- Strong hybrid vehicles use an internal combustion engine and one or more electric traction motors to provide input torque to gear sets of a transmission. The available modes of a strong hybrid may therefore include an engine-only mode, one or more electric-only/electric vehicle modes, and multiple hybrid or electrically variable transmission modes. In some strong hybrid designs, there is no method for opening the mechanical path between the engine and an output shaft of the transmission. Neutral is achieved in such designs by counter rotating one of the electric traction motors at idle to nullify engine speed. This is known as “geared neutral”. As a result, a condition referred to as driveline output bump may result when operating the transmission in neutral due to transient torque disturbances from the engine. The terms “output bump” and “clunk” are conventionally used in the art to describe the perceived sound and/or feel of any undesirable engine output torque oscillations.
- A method is disclosed herein for managing output bump/clunk in a strong hybrid vehicle having an engine, a transmission, and a controller. The transmission includes an input member, an output member, and a planetary gear set. The method includes calculating a motor torque for an electric traction motor connected to a third node of the planetary gear set. The motor torque is calculated as a product of a predetermined inertia of the electric traction motor, a calculated acceleration of an output shaft of the engine, and a gear ratio of the planetary gear set, or an equivalent planetary gear set when multiple gear sets are used. The method also includes commanding the calculated motor torque from the electric traction motor via the controller in a direction opposite the calculated acceleration of the output shaft, including transmitting a motor torque command to the electric traction motor for the duration of the neutral state.
- A system is also disclosed that includes the transmission and the controller.
- A strong hybrid vehicle includes an engine having an output shaft. The vehicle also includes a damper assembly, a transmission, and a controller. The transmission includes an input member, an output member, at least one planetary gear set, and an electric traction motor. The controller, which is in communication with the transmission, includes a processor and memory on which is recorded instructions for managing output bump or clunk during neutral. Execution of the instructions causes the controller to perform the steps of the method noted above.
- The above features and advantages and other features and advantages of the present invention will be readily apparent from the following detailed description of the preferred embodiments and best modes for carrying out the present invention when taken in connection with the accompanying drawings and appended claims.
-
FIG. 1 is a schematic illustration of an example strong hybrid vehicle having a controller programmed to manage driveline output bump or clunk when operating in neutral. -
FIG. 2 is a flow chart describing an example method for managing driveline output bump or clunk in the vehicle shown inFIG. 1 . - Referring to the Figures, an
example vehicle 10 is shown inFIG. 1 having an internal combustion engine (E) 12, a transmission 14, and a controller (C) 50. Thevehicle 10 is a strong hybrid electric vehicle. That is, the transmission 14 is connected to or includes multiple sources of possible input torque, including theengine 12 and an electric traction motor 16 (MA). Additional electric traction motors may be used as part of the transmission 14 without departing from the untended inventive scope. - The transmission 14 is shown in schematic lever diagram format to include a
planetary gear set 30. As is well known in the art, multiple interconnected gear sets of a transmission may be reduced schematically to a single equivalent gear set as shown inFIG. 1 . Therefore, the depiction of a single planetary gear set inFIG. 1 does not limit the present approach to transmissions having only one planetary gear set. - The
controller 50 is programmed to manage a condition referred to as output “bump” or “clunk” whenever the transmission 14 is operating in a neutral state. To this end, thecontroller 50 is operable for selectively executing instructions embodying amethod 100, an example of which is shown inFIG. 2 and described below. In executing themethod 100, thecontroller 50 activates theelectric traction motor 16 by selectively delivering an engine speed-based motor torque command (arrow CCM) to amotor control processor 16P of theelectric traction motor 16. Theelectric traction motor 16, e.g., a relatively high-voltage, polyphase electric machine in the form of a motor/generator unit, responds to the motor torque command (arrow CCM) by cancelling engine disturbances for the duration of the neutral state. - The
controller 50 may be embodied as a digital computer having a processor P and memory M. The memory M includes sufficient amounts of tangible, non-transitory memory, e.g., read only memory (ROM), flash memory, optical and/or magnetic memory, electrically-programmable read only memory (EPROM), and the like. Memory M also includes sufficient transient memory such as random access memory (RAM), electronic buffers. Hardware of thecontroller 50 includes a high-speed clock, analog-to-digital (A/D) and digital-to-analog (D/A) circuitry, and input/output (I/O) circuitry and devices, as well as appropriate signal conditioning and buffer circuitry. - In the example transmission 14 of
FIG. 1 , theplanetary gear set 30 includes first, second, andthird nodes engine 12 includes anoutput shaft 13 that rotates at engine speed (arrow NE) with an engine torque (arrow TE). Theoutput shaft 13 may be selectively connected to aninput member 15 of the transmission 14 at thefirst node 32 via actuation of adamper assembly 20. Thedamper assembly 20 is represented schematically inFIG. 1 as aspring 21 and adamper 22. Abypass lockup clutch 23 may be used to rigidly connect theengine 12 to the transmission 14 as needed, for instance during engine start/stop events. - The approach described herein is independent of the
damper assembly 20. In order to ensure that a reaction disturbance torque is not imposed on thefirst node 32, there should be no difference in speed or acceleration between thefirst node 32 and theengine 12. Per equation (5) as set forth below, theelectric traction motor 16 will control thefirst node 32 so that thefirst node 32 has the same speed and acceleration as theengine 12. In other words, the design described herein will work for avehicle 10 having thedamper assembly 20 or a rigid connection (not shown) between theengine 12 and thefirst node 32. - Further with respect to the
vehicle 10, the transmission 14 includes anoutput member 24 that is connected to thesecond node 34. Theoutput member 24 rotates with an output speed (arrow NO). Theoutput member 24 transmits an output torque (arrow TO) to drive axle(s) 25, and ultimately to a set ofdrive wheels 26 to propel thevehicle 10. Theelectric traction motor 16 is connected to thethird node 36 via an interconnectingmember 17 rotating at a motor speed (arrow NA). Theelectric traction motor 16 ultimately delivers a motor torque (TA) to the planetary gear set 30 at thethird node 36. - Still referring to
FIG. 1 , thecontroller 50 is programmed with predetermined inertia values IE and IM for theengine 12 and theelectric traction motor 16, respectively. The lengths a and b denoted on the schematic planetary gear set 30 represent the lengths from theoutput member 24 at thesecond node 34 to the respective first andthird nodes various nodes controller 50 to determine gear ratios during control of the transmission 14. - The
vehicle 10 includes a park, reverse, neutral, drive, low (PRNDL)input device 11 of the type known in the art. The PRNDLinput device 11 may be conventional, such as a cable-actuated gear shift lever, or it may be by-wire/electrically-actuated push-button device. In either case, a PRNDL valve (not shown) connected to the transmission 14 moves in response to movement of the PRNDL device to shift the transmission 14 into the requested PRNDL mode. As part of themethod 100, thecontroller 50 receives a PRNDL signal (arrow 11S) describing the position of thePRNDL input device 11, or of the controlled PRNDL valve (not shown), and is thus informed of the state or position of thePRNDL input device 11. Thecontroller 50 also receives the engine speed (arrow NE), e.g., as measured at theoutput shaft 13 via a speed sensor SN in the embodiment ofFIG. 1 , or alternatively as reported to thecontroller 50 by a separate engine control module (not shown), calculated, or modeled/estimated. - The
controller 50 ofFIG. 1 is programmed to calculate the acceleration of theengine 12, with the acceleration represented below as {dot over (N)}E, upon receipt, estimation, or other determination of the engine speed (arrow NE). At steady-state idle conditions of theengine 12 when the transmission 14 is in a neutral state, engine acceleration should be zero, i.e., {dot over (N)}E=0. According to the equivalent/simplified planetary gear arrangement shown inFIG. 1 , this condition implies that motor acceleration and acceleration of theoutput member 24 of the transmission 14 are also zero, i.e., {dot over (N)}A={dot over (N)}O=0. However, due to torque disturbances from theengine 12 when the transmission 14 is operating in neutral, acceleration of theengine 12 and of theelectric traction motor 16 will tend to vary from zero. Any non-zero motor accelerations will in turn induce an inertia reaction torque of theelectric traction motor 16 that is transmitted through the planetary gear set 30 to theoutput member 24. The result of this inertia torque transmission is output bump or clunk, which if severe enough may be perceived by an occupant of thevehicle 10 as driveline noise, vibration, and harshness. - Neglecting damper and friction forces for simplicity, the Coriolis forces and centrifugal acceleration present in the driveline will be constrained by the planetary gear set 30. Therefore, only tangential acceleration is considered in the following equations (1)-(6). The following equation is obtained from the lever diagram of the transmission 14 shown in
FIG. 1 : -
- The force balance equation is as follows:
-
T E +T O +T A −I A −I E {dot over (N)} E=0 (2) - The moment balance at the
first node 32 of the planetary gear set 30 is defined as: -
(T A −I A {dot over (N)} A)×(a+b)+T O ×a=0 (3) - Since the objective of the present design is to ensure zero torque and no acceleration of the
output member 24, the desired output acceleration and torque should both be zero. From equation (1) above, assuming that {dot over (N)}O=0, the desired acceleration ofmotor 16 is described as: -
- From equations (3) and (4), and assuming that TO=0, the desired motor to be output from
electric traction motor 16 is as follows: -
- From equations (2), (4), and (5) above, it can be seen that if the desired conditions of {dot over (N)}O=0 and {dot over (T)}O=0 are satisfied, engine torque (TE) should be as follows:
-
T E =I E {dot over (N)} E (6) - From equations (5) and (6), in order to have an output torque of zero the
engine 12 and theelectric traction motor 16 must produce sufficient torque to balance their own inertia-resistant torques. In other words, no torque transfer can occur between theengine 12 and theelectric traction motor 16. As a result, the motor torque command (arrow CCM) for control of theelectric traction motor 16 determined per equation (5) above may be selectively implemented by thecontroller 50 to eliminate driveline clunk or bump whenever the transmission 14 is in a neutral state. - Referring to
FIG. 2 , an example embodiment of themethod 100 begins withstep 102. Thecontroller 50 ofFIG. 1 receives the PRNDL signal (arrow 11S) or otherwise measures or determines the present commanded position of thePRNDL input device 11 or of a PRNDL valve (not shown) controlled by thePRNDL input device 11. Themethod 100 proceeds to step 104 once the requested state of the transmission 14 is known. - Step 104 entails determining whether the present state of the transmission 14 determined at
step 102 is a neutral state. If not, step 102 is repeated. Themethod 100 proceeds to step 106 when thecontroller 50 has verified that the transmission 14 is operating in the neutral state. - At
step 106, thecontroller 50 next determines the present engine speed (NE). In the example configuration shown inFIG. 1 , the speed sensor SN is positioned with respect to theoutput shaft 13 to directly measure the engine speed (NE). In other approaches, thecontroller 50 may receive the engine speed (NE) as a reported value, such as from an engine control module (not shown), or engine speed (NE) may be estimated or modeled using a state machine as is known in the art. Themethod 100 proceeds to step 108 when engine speed (NE) is known. - Step 108 includes calculating, via the
controller 50, the acceleration {dot over (N)}E of theengine 12, i.e., the rate of change in the rotational speed of theoutput shaft 13 shown inFIG. 1 . The value of the calculated engine acceleration {dot over (N)}E is temporarily recorded in memory M of thecontroller 50 before themethod 100 continues to step 110. - Step 110 includes calculating the required motor torque from the
electric traction motor 16. Step 110 may entail solving equation (5) above via thecontroller 50. That is, as -
- and as the values for motor inertia IA and lengths a and b are known to the
controller 50, the result ofstep 108, i.e., the calculated engine acceleration {dot over (N)}E, is all that is required to determine the necessary torque value to be commanded. - The motor torque TA calculated at
step 110 is then applied atstep 112 via transmission of the motor torque command (arrow CCM) to themotor control processor 16P. Step 110 may be tuned to provide the desired transition, and thus feel, of any application of the motor torque TA tothird node 36. That is, the motor torque TA may be simply commanded on upon entering neutral. Alternatively, the motor torque TA may be ramped on over a calibrated duration to smooth the transition, thereby making the onset of the motor torque TA less noticeable to the driver. Themethod 100 then proceeds to step 114. - At
step 114, thecontroller 50 determines whether thePRNDL input device 11 is still in neutral. As withstep 104, this may entail processing the PRNDL signal (arrow 11S) or otherwise verifying the setting of thePRNDL input device 11.Steps vehicle 10 shifts the transmission 14 out of neutral, at which point themethod 100 proceeds to step 116. - Step 116 entails aborting the motor torque command (arrow CCM) applied at
step 112. Step 116 may include commanding the motor torque TA off instantaneously upon leaving the neutral state. Alternatively, the motor torque TA may be ramped off over a calibrated duration as instep 114 so as to smooth the transition, thereby making the discontinuation of the motor torque TA less noticeable to the driver. That is, discontinuing the motor torque TA may occur gradually according to a calibrated ramp profile, e.g., at the same rate or a different rate than that used in applying the motor torque TA instep 112. Themethod 100 is then finished. - Using the
method 100, thecontroller 50 selectively applies motor torque TA from theelectric traction motor 16 to the planetary gear set 30 to actively respond to the inertia reaction of theelectric traction motor 16 to any engine torque disturbances while operating in neutral. Themethod 100 is intended to help eliminate output bump/clunk in neutral. Such an advantageous result can be achieved even with relatively large oscillations in engine speed (arrow NE) provided the motor torque command (arrow CCM) remains within the capacity of theelectric traction motor 16. Moreover, as engine acceleration is used atstep 110 instead of the acceleration of theelectric traction motor 16, phase delay and other issues are avoided. - While the best modes for carrying out the disclosure have been described in detail, those familiar with the art to which this disclosure relates will recognize various alternative designs and embodiments for practicing the disclosure within the scope of the appended claims.
Claims (20)
Priority Applications (3)
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US14/454,967 US9238461B1 (en) | 2014-08-08 | 2014-08-08 | Output bump management in a strong hybrid vehicle |
CN201510446707.XA CN105365812B (en) | 2014-08-08 | 2015-07-27 | Manage the method for exporting chatter or clunk in strong hybrid electric vehicle |
DE102015112472.6A DE102015112472A1 (en) | 2014-08-08 | 2015-07-30 | MANAGEMENT OF A TRANSMISSION IN A STRONG HYBRID VEHICLE |
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US14/454,967 US9238461B1 (en) | 2014-08-08 | 2014-08-08 | Output bump management in a strong hybrid vehicle |
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US9873421B2 (en) | 2016-05-05 | 2018-01-23 | GM Global Technology Operations LLC | Control of engine pulse torque cancellation commands |
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US9885250B2 (en) * | 2015-10-23 | 2018-02-06 | United Technologies Corporation | Autonomous engine health management system |
CN113753016B (en) * | 2021-09-10 | 2023-07-25 | 上海汽车变速器有限公司 | Method, equipment, storage medium and device for controlling running of hybrid electric vehicle on bumpy road surface |
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US5738605A (en) * | 1996-06-28 | 1998-04-14 | Chrysler Corporation | Anti-hunt strategy for an automatic transmission |
US6945893B2 (en) * | 2002-05-28 | 2005-09-20 | Eaton Corporation | Hybrid powertrain system |
JP2004278713A (en) * | 2003-03-17 | 2004-10-07 | Toyota Motor Corp | Controller for hybrid vehicle |
US7079932B2 (en) * | 2003-10-29 | 2006-07-18 | Ford Global Technologies, Llc | Method for tie-up detection in an automatic transmission |
JP4046103B2 (en) * | 2004-06-07 | 2008-02-13 | トヨタ自動車株式会社 | Control device for vehicle drive device |
US20060116236A1 (en) * | 2004-12-01 | 2006-06-01 | Trush Christopher J | Torque converter clutch release to prevent engine stall |
US7881846B2 (en) * | 2006-01-31 | 2011-02-01 | Gm Global Technology Operations, Inc. | Driveline clunk detection and control |
JP4438812B2 (en) * | 2007-03-27 | 2010-03-24 | アイシン・エィ・ダブリュ株式会社 | Hybrid travel assist method and hybrid travel assist device |
US7918763B2 (en) * | 2007-04-12 | 2011-04-05 | Ford Global Technologies, Llc | Control strategy for multi-mode vehicle propulsion system |
US7971667B2 (en) * | 2007-04-19 | 2011-07-05 | Ford Global Technologies, Llc | System and method of inhibiting the effects of driveline backlash in a hybrid propulsion system |
US8565949B2 (en) * | 2010-09-14 | 2013-10-22 | GM Global Technology Operations LLC | Method of controlling a hybrid powertrain to ensure battery power and torque reserve for an engine start and hybrid powertrain with control system |
US8328682B2 (en) * | 2010-09-14 | 2012-12-11 | GM Global Technology Operations LLC | System and method for controlling amount of time needed to commence transmitting engine torque in a vehicle |
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US9873421B2 (en) | 2016-05-05 | 2018-01-23 | GM Global Technology Operations LLC | Control of engine pulse torque cancellation commands |
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