DE102013224274B4 - Method for detecting backlash in a transmission and for controlling an engine and/or a motor based on backlash detections - Google Patents

Abstract

A method of controlling a transmission (120) of a vehicle, comprising:determining a first angular rotation of a first shaft during a first predetermined period of time based on a first signal generated by a first sensor;determining a second angular rotation of a second shaft during the first predetermined period of time based on a second signal generated by a second sensor; andselectively detecting backlash between gears of the transmission (120) based on the first angular rotation and the second angular rotation; characterized in that the first shaft is a transmission input shaft (TIS), the first shaft sensor is a TIS sensor (274), the second shaft is a transmission output shaft (TOS), and the second shaft sensor is a TOS sensor (280); The method further comprises:increasing a desired torque (410) of the transmission input to a first torque level at a first rate before backlash between gears of the transmission (120) is detected during a backlash event, the first torque level being selected to prevent a final drive shock when backlash occurs;maintaining the target torque (410) of the transmission (120) at the first torque level when backlash between gears of the transmission (120) is detected; andincreasing the target torque (410) of the transmission input to a second torque level at a second rate that is greater than the first rate when backlash between gears of the transmission (120) is no longer detected.

Description

AREA

The present disclosure relates to a method according to the preamble of claim 1 for detecting backlash in a transmission and for controlling an engine, of the type essentially from DE 10 2009 051 474 A1 is known.
With regard to the further state of the art, reference should be made at this point DE 10 2006 027 834 A1 referred.

BACKGROUND

Internal combustion engines burn an air/fuel mixture to produce driving torque. One or more electric motors can additionally or alternatively generate drive torque. Driving torque is delivered to a transmission, and the transmission transmits torque to one or more wheels to propel the vehicle.

A dual clutch transmission (DCT) includes two clutches. Each clutch is associated with an independent input shaft. An odd gear set is coupled to one of the two input shafts, and an even gear set is coupled to the other of the two input shafts. Generally, one of the two clutches is engaged while the other of the two clutches is not. In this way, drive torque is transmitted to one of the two input shafts and gear sets.

Gear synchronizers move along an output shaft of the DCT to mechanically couple gear sets to the output shaft. While torque is being transmitted to one of the two input shafts and gear sets, the other gear set, coupled to the other of the two input shafts, may be mechanically coupled to the output shaft in anticipation of a shift to that gear set. Shifting to this gear set can then be accomplished quickly by disengaging one clutch and engaging the other clutch.

The invention is based on the object of specifying a method for controlling a transmission, with which not only play between gears of the transmission can be detected, but also play-related shocks in the transmission can be prevented.

SUMMARY

This task is achieved using a method with the features of claim 1.
Further areas of applicability of the present disclosure will become apparent from the detailed description, claims and drawings. The detailed description and specific examples are provided for illustrative purposes only.

BRIEF DESCRIPTION OF DRAWINGS

• 1 ein Funktionsblockdiagramm eines beispielhaften Antriebsstrangsystems eines Fahrzeugs gemäß der vorliegenden Offenbarung ist;
• 2 ein Diagramm eines beispielhaften Systems eines Doppelkupplungsgetriebes (DCT) gemäß der vorliegenden Offenbarung ist;
• 3 ein Funktionsblockdiagramm eines beispielhaften Steuerungssystems gemäß der vorliegenden Offenbarung ist;
• 4 eine beispielhafte graphische Darstellung einer Drosselklappenstellung, einer Änderung einer Drehdifferenz zwischen Eingangs- und Ausgangswellen des Getriebes, eines Ausgangsdrehmoments der Kraftmaschine und eines Soll-Drehmoments der Kraftmaschine während eines Niederdrückens des Gaspedals gemäß der vorliegenden Offenbarung ist;
• 5 eine beispielhafte graphische Darstellung einer Drosselklappenstellung, einer Änderung einer Drehdifferenz zwischen Eingangs- und Ausgangswellen des Getriebes, eines Ausgangsdrehmoments der Kraftmaschine und eines Soll-Drehmoments der Kraftmaschine während eines Loslassens des Gaspedals gemäß der vorliegenden Offenbarung ist; und
• 6 ein Flussdiagramm eines beispielhaften Verfahrens zum Detektieren von Spiel in einem Getriebe und zum Steuern einer Kraftmaschine und/oder eines Motors auf der Basis von Spieldetektionen gemäß der vorliegenden Offenbarung ist.

The present disclosure will be more fully understood from the detailed description and the accompanying drawings, in which:

• 1 is a functional block diagram of an example powertrain system of a vehicle in accordance with the present disclosure;
• 2 is a diagram of an exemplary dual clutch transmission (DCT) system in accordance with the present disclosure;
• 3 is a functional block diagram of an example control system in accordance with the present disclosure;
• 4 is an exemplary graphical representation of a throttle position, a change in a rotation difference between input and output shafts of the transmission, an engine output torque, and a target engine torque during accelerator pedal depression in accordance with the present disclosure;
• 5 is an exemplary graphical representation of a throttle position, a change in a rotational difference between input and output shafts of the transmission, an engine output torque, and a target engine torque during an accelerator pedal release in accordance with the present disclosure; and
• 6 is a flowchart of an example method for detecting backlash in a transmission and controlling an engine and/or a motor based on backlash detections in accordance with the present disclosure.

Reference numerals may be reused in the drawings to identify similar and/or identical components.

DETAILED DESCRIPTION

A transmission input shaft (TIS) receives drive torque when a clutch engages has moved. Torque is transmitted from the TIS to a transmission output shaft (TOS) via a selected gear set. The TOS transfers torque to a differential, and the differential transfers torque to wheels. A TIS sensor generates a first output signal based on rotation of the TIS. A TOS sensor generates a second output signal based on rotation of the TOS.

A gear backlash module determines a first amount of rotation of the TIS that occurs within a certain period of time based on the first output signal during the predetermined period of time. The gear backlash module determines a second amount of rotation of the TOS occurring during the predetermined period of time based on the second output signal during the predetermined period of time. The gear backlash module detects backlash in a transmission based on a difference between the first amount of rotation of the TIS and the second amount of rotation of the TOS (set for the gear ratio of the selected gear set).

Backlash can refer to a gap between meshing gears of the transmission. Alternatively, backlash may refer to the amount of backlash due to clearance or looseness between gears during a period of play between a first time when relative motion of the gears is reversed and a second time when contact between the gears is restored. Additionally, play can refer to the movement of the gears during the game period. Backlash may occur during a gear shift when a driver presses on or releases an accelerator pedal, or when a hybrid vehicle shifts modes, for example by switching from using an engine to generate drive torque to using one or more motors to generate drive torque.

When no gear shifting occurs, a difference between the first amount of rotation of the TIS and the second amount of rotation of the TOS (set for the gear ratio of the selected gear set) should remain relatively constant. The gear backlash module according to the present disclosure detects backlash in a gear based on a change in the difference. For example, the gear backlash module may determine that backlash occurs when the change in difference is outside a predetermined range and may determine that no backlash occurs when the change in difference is within the predetermined range.

Now referring to 1 1 shows a functional block diagram of an exemplary powertrain system of a vehicle. The vehicle includes an engine 102 that generates drive torque. One or more electric motors (or motor generators) 103 may additionally or alternatively generate drive torque. Although the engine 102 is described as a gasoline-type internal combustion engine (BK), the engine 102 could include another suitable type of engine, such as a diesel-type engine, an electric-type engine, or a hybrid-type engine.

Air is drawn into the engine 102 through an intake manifold 104. The volume of air drawn into the engine 102 can be changed using a throttle 106. The position of the throttle 106 may be measured using one or more throttle position sensors 107. One or more fuel injectors 108 mix fuel with the air to form a combustible air/fuel mixture. The air/fuel mixture is combusted within one or more cylinders of the engine 102, such as cylinder 110. Although the engine 102 is shown as including one cylinder, the engine 102 may include a larger number of cylinders.

The cylinder 110 includes a piston (not shown) that is mechanically connected to a crankshaft 112. A combustion event within the cylinder 110 can be described in four phases: an intake phase, a compression phase, a combustion phase (or work phase), and an exhaust phase. During the intake phase, the piston moves towards a lowermost position in the cylinder 110. During the compression phase, the piston moves to an uppermost position and compresses the contents of the cylinder 110.

The combustion phase begins when, for example, a spark from a spark plug 114 ignites the air/fuel mixture. Combustion of the air/fuel mixture drives the piston, and the piston drives rotation of the crankshaft 112. Exhaust gas resulting from combustion is expelled from cylinder 110 during the exhaust phase. An engine control module (ECM) 116 controls the torque output of the engine 102 and/or the electric motors 103 based on one or more driver inputs and/or one or more other parameters.

The engine 102 transmits torque to a transmission 120 via the crankshaft 112. The transmission 120 receives torque output from the engine 102 via one or more clutches, such as a torque converter lockup clutch (TCC) or multiple clutches of various types Driven, on. Torque input to the transmission 120 is selectively transmitted to a transmission output shaft 122 based on a gear ratio engaged in the transmission 120. The transmission output shaft 122 transmits torque to a differential 124, which transmits torque to one or more wheels (not shown) of the vehicle. In various implementations, one or more other components may be employed to transmit torque to other wheels of the vehicle. The electric motors 103 may be located in the transmission 120 as shown, or the electric motors 103 may be located elsewhere, such as on the wheels of the vehicle.

A transmission control module (TCM) 130 controls the gear ratio of the transmission 120. The TCM 130 may control the gear ratio based on various shift maps, measured parameters (e.g., throttle opening and vehicle speed), and/or inputs from a driver (e.g., upshifts and downshifts). The ECM 116 and the TCM 130 may communicate with each other, for example, over a vehicle area network (CAN) to coordinate shifts in the transmission 120 and to share parameters. A gear ratio (or drive ratio) can be defined as the gear ratio of a gear set used to transmit torque between a transmission input shaft and a transmission output shaft.

Now referring to 2 an exemplary diagram of a system of a dual clutch transmission (DCT) is shown. Although the present disclosure is discussed in the context of the transmission 120 being a DCT, the transmission 120 may be another type of transmission that includes one or more clutches that are automatically controlled (eg, by the TCM 130), such as Automatic transmissions that include a TCC, automated manual transmissions (AMT from Auto-Manual Transmissions) and clutch-to-clutch transmissions, continuously variable transmissions (CVTs) (belt, chain, traction, etc.), hybrid transmissions and other types of transmissions.

The transmission 120 may include a clutch pack 201 that includes two clutches: a first clutch 202 and a second clutch 204. The first clutch 202 is connected to a first input shaft 206 and the second clutch 204 is connected to a second input shaft 208. The first and second input shafts 206 and 208 may be implemented in an embedded orientation. More specifically, one of the first and second input shafts 206 and 208 may be disposed within the other of the first and second input shafts 206 and 208. By way of example only, the first input shaft 206 can be arranged within the second input shaft 208, as shown in 2 is shown.

Generally, one of the first and second clutches 202 and 204 is engaged to transmit torque between the engine 102 and the transmission 120 at a given time. A first and second return spring (not shown) biases the first and second clutches 202 and 204 toward disengagement, respectively. When the first clutch 202 is engaged, torque is transmitted to an odd gear set 210 via the first input shaft 206. When the second clutch 204 is engaged, torque is transmitted to a straight gear set 212 via the second input shaft 208.

A clutch actuator module 213 may control the first and second clutches 202 and 204 based on signals from the TCM 130. By way of example only, the clutch actuator module 213 may control pressures of fluid applied to the first and second clutches 202 and 204 to control the engagement, disengagement, and slip of the first and second clutches 202 and 204.

The odd gear set 210 is connected to and rotates with the first input shaft 206. The straight gear set 212 is connected to the second input shaft 208 and rotates with it. The odd gear set 210 includes pairs of input gears and output gears (each pair referred to as a gear set) that provide odd gear ratios.

By way of example only, if the transmission 120 is capable of providing six gear ratios (ie, is a six-speed transmission), the odd gear set 210 may include gear sets 214, 216, and 218. The gear sets 214, 216 and 218 correspond to a first gear ratio, a third gear ratio and a fifth gear ratio, respectively. The numerical designation added to a given gear ratio (e.g., first - sixth) may increase as the gear ratio it provides increases. Although the example of six gears is provided, The transmission 120 may include a larger or smaller number of gear ratios.

The even gear set 212 includes pairs of input gears and output gears (each pair referred to as a gear set) that provide even gear ratios. By way of example only, the straight gear set 212 may include gear sets 220, 222 and 224 if the transmission 120 is capable of providing six gear ratios. The gear sets 220, 222 and 224 correspond to a second gear ratio, a fourth gear ratio and a sixth gear ratio, respectively. A reverse gear set 226 may also be provided with the straight gear set 212.

As noted above, gear sets 214-226 each include an input gear and an output gear. The input gears of the gear sets 214-218 are coupled to and rotate with the first input shaft 206. The input gears of the gear sets 220-226 are coupled to and rotate with the second input shaft 208. The input and output gears of gear sets 214-226 mesh, and rotation of the input gear of one gear set causes rotation of the output gear of the gear set.

The first and second clutches 202 and 204 control whether torque is transmitted to the odd gear set 210 and the even gear set 212, respectively. Synchronizers 240, 242, 244 and 246 slide along the transmission output shaft 122 and mechanically couple the output gears of the gear sets 214-224 to the transmission output shaft 122. A gear actuator module 248 may control positions and movement of the synchronizers 240-246 based on signals from the TCM 130 . The TCM 130 controls the first and second clutches 202 and 204 and the synchronizers 240 - 246 to control the gear ratio of the transmission 120.

A first toothed wheel 260 is coupled to and rotates with the crankshaft 112. The first toothed wheel 260 includes a predetermined number of approximately equally spaced teeth. It can be said that the teeth are approximately equally spaced to allow for manufacturing tolerances. A crankshaft position sensor 262 monitors rotation of the first toothed wheel 260 and generates a crankshaft position signal 264 based on the rotation of the crankshaft 112. More specifically, the crankshaft position sensor 262 may generate a predetermined pulse in the crankshaft position signal 264 each time a tooth of the first toothed wheel 260 passes the crankshaft position sensor 262. By way of example only, the crankshaft position sensor 262 may include a variable reluctance (VR) sensor, a Hall effect sensor, or any other suitable type of position sensor.

The ECM 116 determines a position of the crankshaft 112 (crankshaft position) based on the crankshaft position signal 264. The ECM 116 may also determine a speed of the engine based on the position of the crankshaft 112 and may determine an acceleration of the engine based on the speed of the engine determine.

A second toothed wheel 266 is coupled to and rotates with the first input shaft 206. The second toothed wheel 266 includes a predetermined number of approximately equally spaced teeth. A first transmission input shaft sensor (TIS sensor) 268 monitors rotation of the second toothed wheel 266 and generates a first TIS position signal 270 based on the rotation of the first input shaft 206. More specifically, the first TIS sensor 268 may then generate a predetermined pulse each time generate the first TIS position signal 270 when a tooth of the second toothed wheel 266 passes the first TIS sensor 268. By way of example only, the first TIS sensor 268 may include a VR sensor, a Hall effect sensor, or any other suitable type of position sensor. In various implementations, the second toothed gear 266 may be omitted and the first TIS sensor 268 may generate the first TIS position signal 270 based on rotation of one of the input gears of the odd gear set 210.

A third toothed wheel 272 is coupled to and rotates with the second input shaft 208. The third toothed wheel 272 includes a predetermined number of approximately equally spaced teeth. A second TIS sensor 274 monitors rotation of the third toothed wheel 272 and generates a second TIS position signal 276 based on the rotation of the second input shaft 208. More specifically, the second TIS sensor 274 may then generate a predetermined pulse in the second TIS each time -Generate position signal 276 when a tooth of the third toothed wheel 272 passes the second TIS sensor 274. By way of example only, the second TIS sensor 274 may include a VR sensor, a Hall effect sensor, or another suitable type of position sensor. In various implementations, the third toothed wheel 272 may be omitted and the second TIS sensor 274 may provide the second TIS position signal 276 based on rotation from one of the input gears of the straight gear set 212.

A fourth toothed wheel 278 is coupled to and rotates with the transmission output shaft 122. The fourth toothed wheel 278 includes a predetermined number of approximately equally spaced teeth. A transmission output shaft (TOS) sensor 280 monitors rotation of the fourth toothed wheel 278 and generates a TOS position signal 282 based on the rotation of the transmission output shaft 122. More specifically, the TOS sensor 280 may then generate a predetermined pulse in the TOS position signal each time 282 generate when a tooth of the fourth toothed wheel 278 passes the TOS sensor 280. By way of example only, the TOS sensor 280 may include a VR sensor, a Hall effect sensor, or another suitable type of position sensor.

The vehicle may include one or more wheel sensors, such as wheel sensor 284. The wheel sensor 284 generates a wheel signal based on rotation of a wheel. A position of the wheel and a speed of the wheel can be determined based on the wheel signal.

A gear play module 290 (see also 3 ) may determine a first amount of rotation of an input shaft of the transmission 120 experienced during a predetermined period of time based on the associated TIS position signal during the predetermined period of time. The gear backlash module 290 may also determine a second amount of rotation of the second input shaft 208 experienced during the predetermined period based on the second TIS position signal 276 during the predetermined period.

When no gear shifting occurs and the input and output gears of the selected one of gear sets 214-226 are in contact, a difference between the first and second amounts (set for the ratio between the two shafts) should remain relatively constant. Therefore, the gear backlash module 290 detects backlash between the input and output gears of the selected one of the gear sets 214-226 based on the difference when no gear shifting occurs.

Now referring to 3 A functional block diagram of an exemplary control system is shown. An update module 304 generates an update signal 308 each time a predetermined period of time elapses. By way of example only, the predetermined period of time may be approximately 25 milliseconds (ms) or another suitable period of time.

A first timestamp module 312 receives the first TIS position signal 270 and generates a timestamp each time a pulse in the first TIS position signal 270 is detected. When the update signal 308 is generated, a first angular rotation module 316 determines an angular rotation of the first input shaft 206. The angular rotation of the first input shaft 206 is referred to as a first TIS rotation 320 and may be an amount of angular rotation (e.g., in degrees) of the first input shaft 206 during the predetermined period before the generation of the update signal 308. The first angular rotation module 316 determines the first TIS rotation 320 based on the timestamps generated by the first timestamp module 312 during the predetermined period before the generation of the update signal 308.

A second timestamp module 324 receives the second TIS position signal 276 and generates a timestamp each time a pulse in the second TIS position signal 276 is detected. When the update signal 308 is generated, a second angular rotation module 328 determines an angular rotation of the second input shaft 208. The angular rotation of the second input shaft 208 is referred to as a second TIS rotation 332 and may correspond to an amount of angular rotation (e.g., in degrees) of the second input shaft 208 during of the predetermined period of time before the generation of the update signal 308. The second angular rotation module 328 determines the second TIS rotation 332 based on the timestamps generated by the second timestamp module 324 during the predetermined period before the generation of the update signal 308.

A third timestamp module 336 receives the TOS position signal 282 and generates a timestamp each time a pulse in the TOS position signal 282 is detected. When the update signal 308 is generated, a third angular rotation module 340 determines an angular rotation of the transmission output shaft 122. The angular rotation of the transmission output shaft 122 is referred to as a TOS rotation 344 and may predict an amount of angular rotation (e.g., in degrees) of the transmission output shaft 122 during the predetermined period of time correspond to the generation of the update signal 308. The third angular rotation module 340 determines the TOS rotation 344 based on the timestamps generated by the third timestamp module 336 during the predetermined period before the generation of the update signal 308.

A selection module 348 may select one of the first and second TIS rotations 320 and 332 and a selected TIS rotation 352 equal to the selected one th of the first and second TIS rotation set 320. The selection module 348 may select the first TIS rotation 320 or the second TIS rotation 332 based on which of the first and second clutches 202 and 204 is engaged. For example, if the first clutch 202 is engaged, the selection module 348 may select the first TIS rotation 320. The selection module 348 may select the second TIS rotation 332 when the second clutch 204 is engaged. A clutch control module 356 may generate a clutch signal 360 indicating which of the first and second clutches 202 and 204 is engaged.

wobei Ø die Drehdifferenz 368 ist, TIS die gewählte TIS-Drehung 352 ist, r_gr das vorliegende Übersetzungsverhältnis des Getriebes 120 ist und TOS die TOS-Drehung 344 ist. Während die Drehdifferenz 368 derart besprochen wird, dass sie auf der Basis der TIS-Drehung, der TOS-Drehung und des Übersetzungsverhältnisses des Getriebes 120 ermittelt wird, können Drehungsbeträge von einer oder mehreren anderen Wellen und das Verhältnis zwischen den beiden Wellen verwendet werden, wie etwa die Kurbelwellendrehung und die TOS-Drehung, oder irgendeine andere geeignete Kombination von Wellen. Die obige Gleichung kann allgemeiner umgeschrieben werden wie folgt: $$\varnothing =\text{Welle}1-\left(\text{Verh}\ddot{\text{a}}\text{ltnis}*\text{Welle}2\right),$$

wobei Ø die Drehdifferenz 368 ist, Welle1 die Drehung einer ersten Welle ist, die während eines vorbestimmten Zeitraums erfahren wird, Welle2 die Drehung einer zweiten Welle ist, die während des vorbestimmten Zeitraums erfahren wird, und Verhältnis das Verhältnis zwischen der ersten und zweiten Welle ist. In Hybridfahrzeugen kann eine Drehung der Ausgangswelle von einem oder mehreren Elektromotoren (z.B. unter Verwendung eines Resolvers oder eines Encoders) gemessen und verwendet werden.A difference module 364 determines a rotation difference 368 based on the selected TIS rotation 352, the TOS rotation 344 and the existing gear ratio of the transmission 120. For example only, the difference module 364 can determine the rotation difference 368 using the following equation: $$\varnothing =\text{TIS}-\left({\text{r}}_{\text{gr}}*\text{TOS}\right),$$

where Ø is the rotation difference 368, TIS is the selected TIS rotation 352, r _gr is the existing gear ratio of the transmission 120 and TOS is the TOS rotation 344. While the rotation difference 368 is discussed as being determined based on the TIS rotation, the TOS rotation, and the gear ratio of the transmission 120, amounts of rotation from one or more other shafts and the ratio between the two shafts may be used, such as such as crankshaft rotation and TOS rotation, or any other suitable combination of shafts. The above equation can be rewritten more generally as follows: $$\varnothing =\text{Wave}1-\left(\text{Marriage}\ddot{\text{a}}\text{ltnis}*\text{Wave}2\right),$$

where Ø is the rotation difference 368, shaft1 is the rotation of a first shaft experienced during a predetermined period of time, shaft2 is the rotation of a second shaft experienced during the predetermined period of time, and ratio is the ratio between the first and second shafts . In hybrid vehicles, rotation of the output shaft of one or more electric motors can be measured (e.g. using a resolver or an encoder) and used.

When the input and output gears of the selected one of gear sets 214-226 are in contact and no gear shifting occurs, the rotational difference 368 should remain approximately constant. Therefore, when no gear shifting occurs, a change in rotational difference 368 may indicate backlash between the input and output gears of the selected one of gear sets 214-226.

A change module 372 determines a change 376 in the rotation difference 368 based on the rotation difference 368 and a previous (e.g., last) value of the rotation difference 368. For example, the change module 372 determines the change 376 based on a difference between the rotation difference 368 and the previous value the rotation difference 368.

A backlash module 380 indicates, based on the change 376, whether there is backlash between the input and output gears of the selected one of the gear sets 214-226. For example, the backlash module 380 may indicate that there is no backlash between the input and output gears of the selected one of the gear sets 214-226 when the change 376 is within a first range of zero. The backlash module 380 may indicate that there is backlash between the input and output gears of the selected one of the gear sets 214-226 when the change 376 is greater than an upper limit of the first range or less than a lower limit of the first range. The upper and lower limits of the first range may be determined in advance and/or may have the same amount. In various implementations, an absolute value of the change 376 may be used, and the game module 380 may indicate that slippage occurs when the absolute value of the change 376 is greater than the upper limit of the first range. Alternatively, the backlash module 380 may anticipate whether the change 376 will increase or decrease as backlash occurs, and therefore whether the upper or lower limit to use, based on the throttle position, engine torque, and/or engine torque to detect game.

The game module 380 may determine the upper and lower limits based on an average of the change 376 over a predetermined period of time before the change 376 is determined. For example, the game module 380 may set the upper limit equal to a sum of the mean change 376 and a positive value of an offset. Similarly, the game module 380 may set the lower limit equal to a sum of the average change 376 and a negative value of the offset. The offset may be predetermined based on a maximum value of change 376 during a maximum amount of engine torque variation when there is no backlash between the input and output gears of the selected one of gear sets 214-226. For example, the offset can be determined in advance during calibration if the vehicle is equipped with instrumentation to detect backlash between the input and output gears of the selected one of gear sets 214-226.

In various implementations, the backlash module 380 may indicate that backlash exists between the input and output gears of the selected one of the gear sets 214-226 when an absolute value of a time derivative of the change 376 is greater than a first threshold value. The first threshold may be predetermined based on a maximum absolute value of the time derivative of change 376 when there is no backlash between the input and output gears of the selected one of the gear sets 214-226. For example, the first threshold may be predetermined during calibration if the vehicle is equipped with instrumentation that detects backlash between the input and output gears of the selected one of gear sets 214-226.

The backlash module 380 generates a backlash signal 384 indicating whether backlash exists between the input and output gears of the selected one of the gear sets 214-226. Game signal 384 may also indicate when game begins and ends. The game module 380 may determine that game ends when an absolute value of the change 376 is greater than a second threshold. The gaming module 380 may determine the second threshold based on a sum of the average value of the change 376 before a gaming event (e.g., accelerating or releasing the throttle) and a difference of the average value of the change 376 before and after previous gaming events. For example, the gaming module 380 may determine a first average of the change 376 before play occurs and a second average of the change 376 after play occurs. The game module 380 may then determine when game ends in a subsequent game event based on a sum of the average of the change 376 before the subsequent game event and the difference between the first and second averages.

The difference between the first and second averages may change depending on the gear ratio of the selected one of gear sets 214-226. Thus, the game module 380 may select the difference used to determine the second threshold based on the gear ratio of the selected one of gear sets 214-226. Additionally, the difference between the first and second averages is related to the amount of clearance between the input and output gears of the selected one of gear sets 214-226. This amount of clearance can change over time due to, for example, mechanical wear. Thus, the backlash module 380 may determine the difference between the first and second averages to account for changes in the amount of clearance between the input and output gears when determining starts and ends of backlash.

The ECM 116 may adjust the desired transmission input torque, such as a desired engine torque or a desired engine torque, based on whether backlash is detected. For example, during an accelerator application, the ECM 116 may increase the desired transmission input torque to a first torque level until backlash is detected and then maintain the desired transmission input torque at the first torque level. The first torque level may reverse the direction of relative movement of the input and output gears of the selected one of the gear sets 214-226 during throttle application and prevent final drive shock when the transmission input torque passes through the backlash zone. The first torque level can be determined in advance. Alternatively, the ECM 116 may determine the first torque level, for example during a previous throttle application, based on the transmission input torque at the beginning of backlash detection. The ECM 116 may maintain the desired transmission input torque at the first torque level when backlash is detected and then increase the desired transmission input torque to a second torque level when backlash ends. The second torque level may be a target torque level that corresponds to the amount of throttle application.

During an accelerator pedal release, the ECM 116 may reduce the desired input torque to a third torque level before backlash is not detected and then maintain the desired transmission input torque at the third torque level. The third torque level may reverse the direction of relative motion between the input and output gears of the selected one of gear sets 214-226 during throttle release and prevent driveline shock when the transmission input torque passes through a backlash zone. The third torque level can be determined in advance. Alternatively, the ECM 116 may determine the third torque level, for example during a previous throttle release, based on the transmission input torque at the beginning of backlash detection. The ECM 116 may maintain the desired transmission input torque at the third torque level when backlash is detected and then decrease the desired engine torque to a fourth torque level gladly when the game ends. The fourth torque level may be a minimum torque level, such as zero, or a torque level that prevents engine stalling.

Detecting backlash and adjusting engine torque based on backlash detections may reduce torque delays and final drive shocks relative to adjusting engine torque in a controlled manner to avoid an abrupt increase or decrease in engine torque through a backlash zone. This reduction in torque lags, which is part of adjusting engine torque based on backlash detections, is in 4 illustrated. A reduction in torque lags associated with adjusting other transmission input torques, such as engine torque in a hybrid vehicle, may be achieved by adjusting the other transmission input torques based on backlash detections in a similar manner.

Now referring to the 4 An example graph illustrates the change 376 of the rotation difference 368, an output torque of the engine 404, a throttle position 406, an input shaft speed of the transmission 408 and a target torque of the engine 410 over time 412 after accelerating. At 414, the throttle position 406 begins to increase in response to throttle application. The output torque of the engine 404 is again adjusted in a controlled manner to avoid abrupt engine torque increases through a backlash zone. For example, the output torque of the engine 404 may be increased at a first rate for a predetermined period of time after throttle application. The first rate may be determined in advance and may be less than necessary to prevent the output torque of the engine 404 from increasing to a torque level that causes final drive shock when backlash occurs. The predetermined time period 416 then elapses. Thereafter, the output torque of the engine 404 may be increased at a second rate that is greater than the first rate.

In contrast, a system and method according to the present disclosure adjusts the target torque of the engine 410 based on whether backlash is detected. At 414, the system and method may begin to increase the desired torque of the engine 410 to a first torque level. At 418, the change 376 in the rotation difference 368 is greater than a first threshold 420 (ie, the upper limit discussed above with reference to 3 was discussed). Thus, the system and method detect backlash and may maintain the desired torque of the engine 410 less than or equal to the first torque level. At 422, the change 376 is greater than a second threshold 424 (eg, the second threshold discussed above with reference to 3 was discussed). Thus, the system and method determines that play is ending and increases the desired engine torque based on the throttle position 406. For example, the system and method may increase the desired engine torque at a second rate that is greater than the first Rate is to increase to the second torque level. By increasing the desired engine torque at 410 when the game ends rather than waiting for a predetermined period of time to elapse after throttle application, the system and method according to the present disclosure avoid a delay 426 in response to the output torque of the engine 404. The delay 426 is a period between 420, when backlash ends and engine torque can be increased without causing final drive shock, and 416, when the output torque of the engine 404 is increased at the second rate. Additionally, the system and method may record the level of engine 404 output torque and/or the desired engine 410 torque at 418 when backlash is initially detected. Subsequently, during subsequent throttle applications, the system and method may then increase the desired torque of the engine 410 at the second rate to the recorded level before backlash is detected.

Now referring to 5 An example graph illustrates the change 376 in the rotation difference 368, the output torque of the engine 404, the throttle position 406, the input shaft speed of the transmission 408 and the target torque of the engine 410 over time 502 after a throttle release. At 504, the throttle position begins to decrease in response to throttle release. In turn, the output torque of the engine 404 is adjusted in a controlled manner to avoid abrupt decrease in engine torque through a backlash zone. For example, the output torque of the engine 404 may be gradually reduced at various rates after throttle release until the output torque of the engine 404 is equal to a desired engine torque corresponding to the throttle position 406. The various rates can be determined in advance and may be less than necessary to prevent final drive shock, if that Output torque of the engine 404 passes through the play zone.

In contrast, a system and method according to the present disclosure adjusts the target torque of the engine 410 based on whether backlash is detected. At 504, the system and method decrease the desired torque of the engine 410 in response to throttle release. For example, the system and method may reduce the desired torque of the engine 410 to the third torque level and/or at a first rate. The first rate may be greater than the various rates at which the output torque of the engine 404 is reduced. At 506, the change 376 in rotational difference 368 is less than a first threshold 508 (e.g., the lower limit discussed above with reference to 3 was discussed). Thus, the system and method detect backlash and may maintain the desired torque of the engine 410 at the third torque level.

At 510, the change 376 is less than a second threshold 512 (eg, a negative value of the second threshold described above with reference to 3 was discussed). Thus, the system and method determines that play is ending and again reduces the desired torque of the engine 410. For example, the system and method may decrease the desired torque of the engine 410 to the fourth torque level and/or at the first rate. It should be noted that the backlash is only detected during the period from 506 to 510. However, since the output torque of the engine 404 is controlled in a controlled manner independent of backlash detections, the output torque of the engine 404 is gradually reduced over the period from 504 to 510, which is greater than the period from 506 to 510. Therefore, by reducing the desired engine 410 torque at the first rate 504 rather than gradually decreasing the engine torque between 504 and 510, the system and method according to the present disclosure avoid a delay 514 in response to the engine 404 output torque Delay 514 is a period of time from 504 when the throttle position 406 begins to decrease and the engine 404 output torque is initially reduced to 510 when play ends. Additionally, the system and method may record the level of engine output torque 404 and/or the desired engine torque 410 at 506 when backlash is initially detected. Then, during subsequent throttle releases, the system and method may increase the desired engine 410 torque to the recorded level at the first rate before backlash is detected.

Now referring to 6 1 illustrates an example method for detecting backlash in a transmission and controlling the torque output of the engine 102 and/or the electric motors 103 based on backlash detections. The process begins at 602. At 604, the update module 304 resets a timer. At 606, the update module 304 may increment the timer.

At 608, the first timestamp module 312 generates timestamps based on the first TIS position signal 270, the second TIS sensor 274 generates timestamps based on the second TIS position signal 276, and the third timestamp module 336 generates timestamps based on the TOS position signal 282. At 610, the update module 304 determines whether the timer value is greater than the predetermined time period (e.g., 25 ms). If the value of the timer is greater than the predetermined time period, the method continues to 612. Otherwise the procedure returns to 606.

At 612, the first angular rotation module 316 determines the first TIS rotation 320, the second angular rotation module 328 determines the second TIS rotation 332, and the third angular rotation module 340 determines the TOS rotation 344. The first angular rotation module 316 determines the first TIS rotation 320 the base of the timestamps generated by the first timestamp module 312 during the predetermined period. The second angular rotation module 328 determines the second TIS rotation 332 based on the timestamps generated by the second timestamp module 324 during the predetermined period of time. The third angular rotation module 340 determines the TOS rotation 344 based on the timestamps generated by the third timestamp module 336 during the predetermined period of time. An exemplary manner of determining an amount of rotation of the shaft during a predetermined period of time that may be applied by the first and second angular rotation modules 316 and 328 is in the US patent US 8,457,847 B2 described.

The selection module 348 may select one of the first TIS rotation 320 and the second TIS rotation 332 as the selected TIS rotation 352 at 614. The selection module 348 selects one of the first TIS rotation 320 and the second TIS rotation 332 based on which of the first and second clutches 202 and 204 is engaged. For example, the selection module 348 selects the first TIS rotation 320 when the first clutch 202 is engaged, and the selection module selects the second TIS rotation hung 332 when the second clutch 204 is engaged.

wobei Ø die Drehdifferenz 368 ist, TIS die gewählte TIS-Drehung 352 ist, r_gr das vorliegende Übersetzungsverhältnis des Getriebes 120 ist und TOS die TOS-Drehung 344 ist. Obgleich wieder die Drehdifferenz 368 derart besprochen wird, dass sie auf der Basis der TIS-Drehung, der TOS-Drehung und des Übersetzungsverhältnisses des Getriebes 120 ermittelt wird, können Drehbeträge von einer oder mehreren anderen Wellen und das Verhältnis zwischen den zwei Wellen zum Beispiel unter Verwendung der folgenden Gleichung verwendet werden: $$\varnothing =\text{Welle}1-\left(\text{Verh}\ddot{\text{a}}\text{ltnis}*\text{Welle}2\right),$$

wobei Ø die Drehdifferenz 368 ist, Welle1 die Drehung der ersten Welle ist, die während eines vorbestimmten Zeitraums erfahren wird, Welle2 die Drehung einer zweiten Welle ist, die während des vorbestimmten Zeitraums erfahren wird, und Verhältnis das Verhältnis zwischen der ersten und zweiten Welle ist. In Hybridfahrzeugen kann eine Drehung der Ausgangswelle von einem oder mehreren Elektromotoren (z.B. unter Verwendung eines Resolvers oder eines Encoders) gemessen und verwendet werden.At 616, the difference module 364 determines the rotation difference 368. The difference module 364 may determine the rotation difference 368 based on the selected TIS rotation 352, the gear ratio, and the TOS rotation 344. For example, the difference module 364 may determine the rotation difference 368 using the following equation: $$\varnothing =\text{TIS}-\left({\text{r}}_{\text{gr}}*\text{TOS}\right),$$

where Ø is the rotation difference 368, TIS is the selected TIS rotation 352, r _gr is the existing gear ratio of the transmission 120 and TOS is the TOS rotation 344. Although again the rotation difference 368 is discussed as being determined based on the TIS rotation, the TOS rotation, and the gear ratio of the transmission 120, amounts of rotation of one or more other shafts and the ratio between the two shafts may be included, for example Using the following equation can be used: $$\varnothing =\text{Wave}1-\left(\text{Marriage}\ddot{\text{a}}\text{ltnis}*\text{Wave}2\right),$$

where Ø is the rotation difference 368, shaft1 is the rotation of the first shaft experienced during a predetermined period of time, shaft2 is the rotation of a second shaft experienced during the predetermined period of time, and ratio is the ratio between the first and second shafts . In hybrid vehicles, rotation of the output shaft of one or more electric motors can be measured (e.g. using a resolver or an encoder) and used.

At 618, the change module 372 determines the change 376 of the rotation difference 368 based on a difference between the rotation difference 368 and the previous value of the rotation difference 368. At 620, the game module 380 may determine whether the change 376 is outside the first range. Alternatively, the game module 380 may determine whether an absolute value of a time derivative of the change 376 is greater than the first threshold. If the change 376 is outside the first range or the absolute value of the derivative of the change 376 is greater than the first threshold, the game module 380 continues to 622. Otherwise, the game module 380 continues with 624. At 622, the backlash module 380 detects backlash between the input and output gears of the selected one of the gear sets 214-226 of the transmission 120. At 624, the backlash module 380 detects no backlash between the input and output gears of the selected one of the gear sets 214-226.

The desired torque output of the engine 102 and/or the electric motors 103 may be adjusted when backlash is detected. For example, the target torque output can be kept at a fixed value. Alternatively, the desired torque output may be adjusted at a first rate when no backlash is detected, and the desired torque output may be adjusted at a second rate that is less than the first rate when backlash is detected. The second rate can be selected to prevent final drive shock when contact is restored between the gears.

Claims (8)

A method of controlling a transmission (120) of a vehicle, comprising: determining a first angular rotation of a first shaft during a first predetermined period of time based on a first signal generated by a first sensor; determining a second angular rotation of a second shaft during the first predetermined period of time based on a second signal generated by a second sensor; and selectively detecting backlash between gears of the transmission (120) based on the first angular rotation and the second angular rotation; characterized in that the first shaft is a transmission input shaft (TIS), the first shaft sensor is a TIS sensor (274), the second shaft is a transmission output shaft (TOS), and the second shaft sensor is a TOS sensor (280); the method further comprising: increasing a desired torque (410) of the transmission input to a first torque level at a first rate before backlash between gears of the transmission (120) is detected during a backlash event, the first torque level being selected to provide a final drive shock to prevent when backlash occurs; maintaining the desired torque (410) of the transmission (120) at the first torque level when backlash between gears of the transmission (120) is detected; and increasing the target torque (410) of the transmission input to a second torque level at a second rate that is greater than the first rate when backlash between gears of the transmission (120) is no longer detected. Procedure according to Claim 1 , further comprising: determining a difference in rotation of the TIS and the TOS during the first predetermined period based on the first angular rotation, the second angular rotation and a gear ratio of the transmission (120); and selectively detecting play between gears of the transmission (120) based on the difference. Procedure according to Claim 2 , further comprising setting the difference based on the first angular rotation minus a value equal to a product of the second angular rotation and the gear ratio. Procedure according to Claim 2 , further comprising: determining a change in the difference based on the difference and a previous value of the difference; and selectively detecting backlash between gears of the transmission (120) based on the change. Procedure according to Claim 4 , further comprising: determining a first value based on an average of the change over a second predetermined period of time before determining the change; and selectively detecting backlash between gears of the transmission (120) when the change is greater or less than the first value. Procedure according to Claim 4 further comprising selectively detecting backlash between gears of the transmission (120) when an absolute value of a derivative of the change is greater than a predetermined value. Procedure according to Claim 1 , further comprising: determining a third angular rotation of a second TIS during the first predetermined period of time based on a third signal generated by a second TIS sensor; and selectively detecting backlash between gears of the transmission (120) based on the second angular rotation and a selected one of the first angular rotation and the third angular rotation. Procedure according to Claim 7 , further comprising selecting one of the first angular rotation and the third angular rotation based on whether a clutch is coupled to the TIS or to the second TIS.

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