Gear and mode selection for transmissions using a single input device

A transmission of a vehicle has a first gear and a second gear that corresponds to a lower gear ratio than the first gear. A transmission management system for the transmission comprises an enabling module, a shift control module, and a disabling module. The enabling module enables a second gear start mode of the transmission when a vehicle speed is less than a predetermined speed. The shift control module commands operation of the transmission in the second gear when the second gear start mode is enabled. The disabling module selectively disables the second gear start mode when a user commands a gear shift to the first gear while the second gear start mode is enabled and prevents the enabling module from re-enabling the second gear start mode after the second gear start mode is disabled.

FIELD

The present disclosure relates to vehicle systems and more particularly to vehicle transmissions.

BACKGROUND

Referring now toFIG. 1, a functional block diagram of an engine system100is presented. Air is drawn into an engine102through an intake manifold104. A throttle valve106varies airflow into the intake manifold104. An electronic throttle controller (ETC)108actuates the throttle valve106, thereby controlling opening of the throttle valve106.

The air mixes with fuel provided by a fuel injector110to form an air and fuel mixture. The air/fuel mixture is combusted within cylinders of the engine102, such as cylinder112. Combustion may be initiated by, for example, a spark from a spark plug114. Exhaust gas resulting from combustion is expelled from the cylinder112to an exhaust system116. Combustion of the air/fuel mixture generates torque.

Torque output by the engine102is transferred to a transmission118via a coupling device120. The coupling device120may include, for example one or more clutches and/or a torque converter. The transmission118transfers torque to one or more wheels of the vehicle.

An engine control module (ECM)130controls torque output by the engine102. For example only, the ECM130may control torque output by the engine102based on driver inputs, such as an accelerator pedal position and/or a brake pedal position. A driver input module132receives the driver inputs and transmits the driver inputs to the ECM130.

The driver input module132also receives an indication of the position of a park, reverse, neutral, drive, low (PRNDL) device134, such as a lever. The driver manipulates the PRNDL device134to request operation of the transmission118in a desired manner. For example, the driver may manipulate the PRNDL device134to operate the transmission118in park, reverse, neutral, drive, or low (drive).

Additionally, the driver input module132receives gear shift commands from the driver via a gear shift device136. For example, the gear shift device136may include two steering wheel mounted devices (e.g., paddles) that the driver may use to command a gearshift. The driver may command a downshift using one of the devices and an upshift using the other of the devices.

A transmission control module (TCM)150controls operation of the transmission118. For example, the TCM150may control shifting of gears included within the transmission118and/or operation of the transmission118in the desired manner. The TCM150may also control the coupling device120to allow smooth gear shifts and/or operation of the transmission118.

SUMMARY

A transmission of a vehicle has a first gear and a second gear that corresponds to a lower gear ratio than the first gear. A transmission management system for the transmission comprises an enabling module, a shift control module, and a disabling module. The enabling module enables a second gear start mode of the transmission when a vehicle speed is less than a predetermined speed. The shift control module commands operation of the transmission in the second gear when the second gear start mode is enabled. The disabling module selectively disables the second gear start mode when a user commands a gear shift to the first gear while the second gear start mode is enabled and prevents the enabling module from re-enabling the second gear start mode after the second gear start mode is disabled.

In other features, the transmission is one of an automatic transmission and a semiautomatic transmission.

In still other features, the disabling module disables the second gear start mode when the user commands a predetermined number of gear shifts to the first gear while the second gear start mode is enabled, wherein the predetermined number is greater than one.

In further features, the disabling module disables the second gear start mode when the user commands the gear shift to the first gear for at least predetermined period of time.

In still further features, the disabling module prevents the enabling module from re-enabling the second gear start mode until the user commands a shift to the second gear while the second gear start mode is disabled.

In other features, the transmission management system further comprises an input module and a mode control module. The input module receives gear shift commands for the transmission from a selection device and receives mode of operation commands for the transmission from the selection device. The mode control module selectively enables one of an automatic mode of operation, a tap mode of operation, and a manual mode of operation for the transmission based on at least one of the gear shift commands and the mode of operation commands.

In still other features, the enabling module enables the second gear start mode when the automatic mode of operation is enabled and the vehicle speed is less than the predetermined speed.

In further features, the gear shift commands and the mode of operation commands are generated based on user manipulations of the selection device.

A transmission of a vehicle has a first gear and a second gear that corresponds to a lower gear ratio than the first gear. A method for the transmission comprises: enabling a second gear start mode of the transmission when a vehicle speed is less than a predetermined speed; commanding operation of the transmission in the second gear when the second gear start mode is enabled; selectively disabling the second gear start mode when a user commands a gear shift to the first gear while the second gear start mode is enabled; and preventing the enabling from re-enabling the second gear start mode after the second gear start mode is disabled.

In other features, the transmission is one of an automatic transmission and a semiautomatic transmission.

In still other features, the selectively disabling comprises disabling the second gear start mode when the user commands a predetermined number of gear shifts to the first gear while the second gear start mode is enabled, wherein the predetermined number is greater than one.

In further features, the selectively disabling comprises disabling the second gear start mode when the user commands the gear shift to the first gear for at least predetermined period of time.

In still further features, the method further comprises preventing the enabling from re-enabling the second gear start mode until the user commands a shift to the second gear while the second gear start mode is disabled.

In other features, the method further comprises: receiving gear shift commands for the transmission from a selection device; receiving mode of operation commands for the transmission from the selection device; and selectively enabling one of an automatic mode of operation, a tap mode of operation, and a manual mode of operation for the transmission based on at least one of the gear shift commands and the mode of operation commands.

In still other features, the enabling comprises enabling the second gear start mode when the automatic mode of operation is enabled and the vehicle speed is less than the predetermined speed.

In other features, the gear shift commands and the mode of operation commands are generated based on user manipulations of the selection device.

DETAILED DESCRIPTION

A transmission management module (TMM) controls operation of a transmission and coordinates gear shifts within the transmission based on a desired mode of operation indicated by a driver and/or gear shifts commanded by the driver. The transmission may be, for example, an automatic transmission or a semiautomatic transmission. The driver indicates the desired mode of operation and commands gear shifts using a selection device located within the vehicle.

The transmission may be operated in an automatic mode, a manual mode, or a tap mode. The transmission management module controls gear shifts based on a shift map while the automatic mode is enabled. If the driver commands a gear shift while the automatic mode is enabled, the transmission management module enables the tap mode and commands the gear shift for a predetermined period of time. If the driver commands operation in the manual mode, the transmission management module enables the manual mode and commands gear shifts as they are commanded by the driver.

The transmission management module may also implement a second gear start mode. The transmission management module commands a second gear to be engaged during low vehicle speed events (i.e., when the vehicle speed is less than a predetermined speed) while the second gear start mode is enabled. Accelerating from the second gear instead of from the first gear increases fuel efficiency.

The vehicle, however, is likely unable to accelerate as quickly as possible while the second gear start mode is enabled. The transmission management module monitors the driver's inputs during low vehicle speed events and selectively disables the second gear start mode based on the driver inputs. For example, the transmission management module may disable the second gear start mode when the driver commands a downshift during a predetermined number of low vehicle speed events.

Referring now toFIG. 1, a functional block diagram of an exemplary engine system200is presented. The engine system200may be implemented in any suitable type of vehicle, including a hybrid type vehicle. The engine system200includes the engine102that combusts an air/fuel mixture to produce drive torque. Air is drawn into the intake manifold104through the throttle valve106. The electronic throttle controller (ETC)108controls the opening of the throttle valve106.

An engine control module (ECM)230regulates opening of the throttle valve106via the ETC108. In this manner, the ECM230controls airflow into the intake manifold104. Air from the intake manifold104is drawn into cylinders of the engine102. While the engine102may include multiple cylinders, for illustration purposes only, only the representative cylinder112is shown. For example only, the engine102may include 2, 3, 4, 5, 6, 8, 10, and/or 12 cylinders.

The ECM230also controls the amount of fuel injected by the fuel injector110. For example, the ECM230may generate a pulse for a predetermined period of time. The fuel injector110opens while the pulse is generated. Accordingly, the amount of fuel injected may be adjusted based on the length of the pulse (i.e., the pulse width). The fuel injector110may inject fuel into the intake manifold104at a central location or at multiple locations, such as near an intake valve that is associated with the cylinder112. Alternatively, the fuel injector110may inject fuel directly into the cylinders. In various implementations, one fuel injector may be provided for each cylinder.

The injected fuel mixes with the air and creates the air/fuel mixture. A piston (not shown) compresses the air/fuel mixture within the cylinder112. The spark plug114is energized, thereby igniting the air/fuel mixture. While the engine102is shown as including the spark plug114, the engine102may be any suitable type of engine, such as a compression combustion type engine. In other engine systems, the spark plug114may not be necessary to initiate combustion. The byproducts of combustion (i.e., exhaust gas) are expelled from the cylinder112to the exhaust system116.

Combustion of the air/fuel mixture causes the piston to rotatably drive a crankshaft (not shown). An engine speed (EOS) sensor236measures the output speed of the engine102and generates an EOS signal accordingly. For example only, the EOS sensor236may generate the EOS signal based on rotation of the crankshaft.

Torque output by the engine102is transferred to an input shaft of the transmission118via the coupling device120. For example only, the coupling device120may include a torque converter and/or one or more clutches. The transmission118includes one or more gears (not shown) that are selectively engaged to link the input shaft with an output shaft (e.g., a driveshaft) of the transmission118. The transmission includes any suitable number of gears and may be any suitable type of transmission. For example, the transmission118may be an automatic-type transmission. In other implementations, the transmission118may be a semiautomatic-type transmission, such as a dual-clutch transmission.

A transmission input speed (TIS) sensor238measures the input speed of the transmission118and generates a transmission input speed (TIS) signal accordingly. For example only, the TIS sensor238may generate the TIS signal based on rotation of the input shaft. A transmission output speed (TOS) sensor240measures the output speed of the transmission118and generates a TOS signal based on the rotation of the output shaft.

A current gear ratio (i.e., current gear engaged) may be determined based on the ratio of a number of teeth of a gear associated with the input shaft to a number of teeth of a gear associated with the output shaft. In other implementations, the current gear, or the current gear ratio may be determined based on the EOS to the TOS.

A label may be assigned to each of the gears or each of the gear ratios. For example only, a numeric label (e.g., first gear, second gear, etc.) may be assigned to each gear ratio, and the labels may be assigned such that the magnitude of the numerals increases as the gear ratio decreases. In other words, a first gear may correspond to a largest gear ratio, a second gear may correspond to a second largest gear ratio, and so on.

A transmission control module (TCM)250may be implemented to control operation of the transmission118and/or other vehicle components associated with operation of the transmission118. For example only, the TCM250may control the engaging of the gears within the transmission118(i.e., gear shifting) and operation of the transmission118in a desired mode or manner. The mode of operation of the transmission118may be, for example, automatic, neutral, reverse, park, and/or any other suitable mode of operation.

The ECM230controls torque output by the engine102. For example only, the ECM230may control the torque output by adjusting the airflow into the engine, the amount of fuel injected, the spark timing, and/or any other suitable engine parameter. The ECM230may control the torque output based on, for example, driver inputs. The driver inputs may include an accelerator pedal position, brake pedal position, and/or any other suitable driver input. The ECM230may also control the torque output based on inputs from various sensors (not shown), such as a mass airflow (MAF) sensor, a manifold absolute pressure (MAP) sensor, an intake air temperature (IAT) sensor, a coolant temperature sensor, and/or any other suitable sensor.

A driver input module232receives the driver inputs and transmits the driver inputs to the ECM230. The ECM230may transmit any received inputs to the TCM250. Likewise, the TCM250may transmit any received inputs to the ECM230. For example, the ECM230and the TCM250may be electrically connected via a bus.

The driver selects the desired mode of operation of the transmission118using a selection device252. The driver also commands gear shifts using the selection device252. The selection device252transmits signals indicating the desired mode of operation of the transmission118and gear shift commands to the driver input module232.

Referring now toFIG. 3, a diagram of an exemplary configuration300for the selection device252is presented. While the configuration300is presented, the selection device252may be configured in any suitable manner. The selection device252includes one or more sensors that generate signals based on the driver manipulations of the selection device252. The selection device252may include a mechanical device (not shown), such as a joystick, and/or one or more buttons. While the selection device252will be discussed as using the joystick, it should be appreciated that any suitable configuration can be used.

The joystick defaults to a null position312, which corresponds to no driver input. In other words, the joystick returns to and remains in the null position312when the driver is not manipulating the joystick. The driver manipulates the joystick to indicate the desired mode of operation of the transmission118. For example only, the desired mode of operation of the transmission118may be reverse, neutral, automatic, manual, or park.

The transmission118may default to park when the engine102is started. The driver can thereafter indicate the desired mode of operation by manipulating the joystick to a specified location that corresponds to one of the modes of operation. For example only, the driver may indicate that the desired mode of operation is reverse, neutral, automatic, or manual by manipulating the mechanical device to a reverse (R) location302, a neutral (N) location304, a drive (D) location306, or a manual (M) location308, respectively. The driver may indicate that the desired mode of operation is park by pressing a park button310. In other implementations, the driver may indicate that the desired mode of operation is park by manipulating the joystick to a park location (not shown).

In some circumstances, the driver may operate the transmission118in the automatic mode. Gear shifts are controlled automatically during operation in the automatic mode. In some circumstances, however, the driver may command a gear shift. For example, the driver may command a downshift (e.g., shift from higher gear to lower gear) to execute a passing maneuver. The driver may command an upshift or a downshift by manipulating the joystick to an upshift (+) location314or a downshift (−) location316, respectively.

In other circumstances, the driver may operate the transmission118in the manual mode. The driver may command operation in the manual mode by manipulating the joystick to the manual location308. During operation in the manual mode, the driver controls gear shifts within the transmission118. For example, the driver may command an upshift or a downshift by manipulating the joystick to the upshift location314or the downshift location316. During operation in the manual mode, the driver may exit the manual mode and enter the automatic mode by manipulating the joystick to the manual location308.

Referring again toFIG. 2, the engine system200includes a transmission management module (TMM)260that controls the mode of operation of the transmission118and gear shifting within the transmission118. The TMM260controls the mode of operation and gear shifting based on the driver inputs.

More specifically, the TMM260controls the mode of operation and/or gear shifting based on the desired mode of operation indicated by the driver and/or driver commanded gear shifts. While the TMM260is shown inFIG. 2as being located within the TCM250, the TMM260may be located in any suitable location. For example only, the TMM260may be located within the ECM230, within any other suitable module, or outside of both the TMM260and the ECM230.

Referring now toFIG. 4, a functional block diagram of an exemplary implementation of a transmission management system400including the TMM260is presented. The TMM260includes a mode control module402, an automatic mode module404, a tap mode module406, and a manual mode module408. The TMM260also includes a shift control module410and one or more timers, such as timer412.

The mode control module402controls the mode of operation of the transmission118based on the driver inputs. For example only, the mode control module402may enable one or more of the automatic mode module404, the tap mode module406, and the manual mode module408based on the driver inputs. In other words, the mode control module402may enable one of the modules control of gear shifting. As stated above, the driver inputs may include the desired mode of operation and/or commanded gear shifts (i.e., taps). The mode control module402receives gear shift commands and transmits the gear shift commands to the appropriate module.

The mode control module402enables the automatic mode module404when the desired mode of operation is the automatic mode. The automatic mode module404then controls gear shifting within the transmission118. For example only, the automatic mode module404may control gear shifting based on a shift map. The automatic mode module404may use the shift map along with the driver inputs (e.g., accelerator pedal position), operating parameters, and/or any other suitable parameters to determine timing of gear shifts, which gear to engage, and/or any other suitable parameter.

During operation in the automatic mode, the driver may occasionally command a gear shift using the selection device252. When the driver commands such a gear shift, the driver may be said to be commanding operation of the transmission118in a tap mode (i.e., a tap range mode). For example, the driver may command a downshift (e.g., from a higher gear to a lower gear) when operating in the automatic mode to execute a passing maneuver. The mode control module402enables the tap mode module406when the driver commands a gear shift while the automatic mode is enabled. The mode control module402also transmits the commanded gear shift to the tap mode module406.

The tap mode module406commands a gear shift according to the driver commanded gear shift. The tap mode module406then commands that the current gear (i.e., the gear engaged after the commanded gear shift is executed) be maintained for a predetermined period of time or until predetermined conditions are met. The tap mode module406may set the timer412based on the predetermined period. For example only, the predetermined period may be 2.0 s. Maintenance of the current gear may also be conditioned based on any suitable parameter, such as vehicle speed and/or accelerator pedal position. The vehicle speed may be determined based on any suitable measure of vehicle speed, such as from a wheel speed sensor (not shown) and/or the TOS.

During the time that the current gear is being maintained, the tap mode module406monitors the driver inputs for another gear shift command (i.e., a second gear shift command). The tap mode module406commands a gear shift based on the second gear shift command if commanded while the current gear is being maintained. The tap mode module406also resets the timer412when the second gear shift is commanded, and the predetermined period begins running again from the second commanded gear shift.

The mode control module402monitors the timer412and disables the tap mode module406after the predetermined period or upon occurrence of the predetermined conditions. In other words, the mode control module402re-enables the automatic mode after the predetermined period or upon the occurrence of the predetermined conditions.

In some circumstances, the driver may indicate a desire to enter the manual mode and manually control gear shifts. Operation in the manual mode may also be referred to as a tap gear mode. The mode control module402enables the manual mode module408when the driver indicates that the desired mode of operation is the manual mode. For example, the driver may indicate that the desired mode of operation is the manual mode by manipulating the mechanical device of the selection device252to the manual (M) location308.

The manual mode module408commands maintenance of the current gear and commands gear shifts when commanded by the driver. The mode control module402monitors the driver inputs and re-enables the automatic mode when the driver again indicates that the desired mode of operation is the manual mode. The mode control module402may also re-enable the automatic mode when the driver indicates that the desired mode of operation is the automatic mode.

The shift control module410receives gear shift commands from the automatic mode module404, the tap mode module406, and the manual mode module408. The shift control module410executes the commanded gear shifts within the transmission118. For example only, the shift control module410may control actuation of one or more mechanical devices (e.g., a solenoid and/or a series of clutches) that control engaging and disengaging of the gears within the transmission118.

The shift control module410may also determine current gear information, such as the current gear or current gear ratio engaged. Such information may be determined based on, for example, the EOS and the TOS. The shift control module410may also control the coupling device120to coordinate a gear shift.

The shift control module410module404employs one or more modes of operation for the automatic mode that are aimed at maximizing fuel efficiency. For example, the shift control module410implements a second gear start mode. The shift control module410commands operation of the transmission118in the second gear when the second gear start mode is enabled.

An enabling module414selectively enables the second gear start mode when the vehicle speed is low. In other words, the enabling module414enables the second gear start mode when the vehicle speed is less than a predetermined speed, such as 10.0 miles per hour, including times when the vehicle is stopped (i.e., vehicle speed is zero). If the second gear start mode was not enabled under such conditions, the shift control module410commands operation of the transmission118in the first gear. Fuel efficiency is increased when the vehicle accelerates from the second gear.

The increase in fuel efficiency that the second gear start mode provides comes at a cost—a decrease in the ability to accelerate as quickly as possible. Accordingly, under some circumstances, the driver may wish to disable the second gear start mode and accelerate from the first gear. A disabling module416monitors the driver inputs and selectively disables the second gear start mode based on the driver inputs.

More specifically, the disabling module416selectively disables the second gear start mode based on the driver inputs received while the second gear start mode is enabled. For example only, the disabling module416disables the second gear start mode when the driver commands a downshift (i.e., to the first gear) at least a predetermined number of times (e.g., eight) during a predetermined number of low vehicle speed events (e.g., ten).

The disabling module416also disables the second gear start mode when the driver maintains the selection device252in the downshift location316for a predetermined period of time (e.g., three seconds) while the vehicle speed is low. In other words, the disabling module416disables the second gear start mode when the driver commands a downshift for at least the predetermined period of time while the vehicle speed is low.

The disabling module416also prevents the enabling module414from re-enabling the second gear start mode after the second gear start mode is disabled. However, the driver may wish to re-enable the second gear start mode under some circumstances. The disabling module416prevents the enabling module414from re-enabling the second gear start mode until the driver commands re-enabling of the second gear start mode. For example only, the disabling module416may re-enable the second gear start mode when the driver commands one or more upshifts while the second gear start mode is enabled and the vehicle speed is low. The enabling module414thereafter enables the second gear start mode when the vehicle speed is low.

Referring now toFIGS. 5A-5B, method500depicting exemplary steps performed by the TMM260are presented. Control begins in step502where control enables the automatic mode. When the automatic mode is enabled the first time that step502is performed (after engine startup), the second gear start mode is also enabled. The state of the second gear start mode remains unchanged during later performances of step502.

Control continues in step504where control resets the timer. In step506, control determines whether the automatic mode is enabled. If true, control transfers to step508; otherwise, control ends. In other words, if the automatic mode is enabled in step506, control exitsFIG. 5Aand proceeds to step508ofFIG. 5B.

Referring now toFIG. 5B, control determines whether the driver has tapped M (i.e., the manual mode) in step508. If true, control continues to step510; otherwise, control transfers to step520. In other words, control disables the automatic shift mode and enables the manual shift mode when the driver commands operation in the manual shift mode. In step510, control maintains the current gear.

In step512, control determines whether the driver has tapped the selection device252(i.e., commanded a gear shift or a change in the mode of operation). If true, control continues to step514; otherwise, control returns to step510. In step514, control determines the type of the tap (of step512). If the tap was an upshift (+), control proceeds to step516. If the tap was a downshift (−), control proceeds to step518. If the tap was a manual mode (M) tap, control returns to step502and re-enables the automatic mode. In steps516and518, control commands an upshift and a downshift, respectively. After control performs either step516or518, control returns to step510.

Referring again to step520, control determines whether the driver has tapped the selection device252. If true, control continues to step522; otherwise control returns to step502and re-enables the automatic mode. If the driver has tapped the selection device252in step520, control enables the tap mode and disables the automatic mode.

In step522, control determines the type of the tap (of step520). If the tap of step520was an upshift, control proceeds to step524. If the tap of step520was a downshift, control proceeds to step526. In steps524and526, control commands an upshift and a downshift, respectively. Control continues to step528after control performs either step524or526.

In step528, control determines whether the vehicle speed is less than a threshold. If true, control transfers to step550; otherwise, control continues in step530. In step530, control starts the timer. The timer is set based on a predetermined period of time. This predetermined period of time may be calibratable and may be set to, for example, 2.0 s.

In step532, control determines whether the timer has expired. If true, control returns to step502and re-enables the automatic mode; otherwise, control continues to step534and the tap mode remains enabled. In step534, control determines whether the driver has tapped the selection device252again (i.e., commanded a second gear shift). If so, control continues to step536; otherwise, control returns to step532.

In step536, control determines the type of the tap (of step534). If the tap of step534was an upshift, control proceeds to step538. Otherwise, if the tap was a downshift, control proceeds to step540. In steps538and540, control commands an upshift and a downshift, respectively. In other words, if the driver commands a second gear shift within the predetermined period of time after the first gear shift command, control remains in the tap mode and commands the driver commanded gear shift. Control proceeds to step542after control performs either step538or540. In step542, control resets the timer. In this manner, control allows another predetermined period of time after the second gear shift command. Control then returns to step528.

Referring again to step550(i.e., when the vehicle speed is less than a predetermined speed and a gear shift is commanded), control determines the tap type of step520. If the tap of step520was an upshift, control proceeds to step552. If, however, the tap of step520was a downshift, control proceeds to step556.

In step552, control determines whether the second gear start mode is currently disabled. If true, control proceeds to step554; otherwise, control returns to step502and re-enables the automatic mode. In step554, control re-enables the second gear start mode, and control returns to step502. In other words, control enables the second gear start mode if the driver commands an upshift while the vehicle speed is low and the second gear start mode is disabled.

Referring again to step556(i.e., where the tap of step520was a downshift), control commands the driver commanded downshift. Control then continues in step558where control determines whether the second gear start mode should be disabled. If true, control disables the second gear start mode in step560; otherwise, control returns to step502and re-enables the automatic mode. Control also returns to step502after control performs step560. Control may determine that the second gear start mode should be disabled when, for example, the driver has commanded a downshift at least a predetermined number of times (e.g., eight) during the last predetermined number of low vehicle speed events (e.g., ten). Control may also disable the second gear start mode when the driver maintains the selection device252in the downshift location316for a predetermined period of time (e.g., 3.0 s).