Patent Application
20180058575
This application generally relates to a system for managing driver-requested gear changes (modes of operation such as park, neutral, etc.) in a vehicle powertrain.
Shifting a transmission into various modes (e.g., Park, Reverse, Neutral, and Drive) has been traditionally accomplished by mechanical links to put the vehicle in the drive modes via a lever mounted on the steering column or a gear shifter near the center console. More recently, vehicles have become equipped with shift by wire (SBW) systems in which the transmission modes are engaged/changed via electronic controls without any mechanical linkage between the gear shifting lever and the transmission. SBW systems eliminate space required for housing the mechanical linkages between the shifter and the transmission.
One type of SBW system includes a push-button panel in which multiple buttons are provided, each button corresponding to a desired transmission mode. For example, if the operator depresses a button corresponding to a Park mode (e.g., “P”), a request would be sent to the control system to place the vehicle in park. The request is fulfilled assuming other conditions are met, such as the vehicle being motionless and the brake pedal being applied. Another type of SBW system includes a rotary shifter in which the operator rotates a knob to the desired transmission mode.
According to one embodiment, a vehicle includes a shift by wire (SBW) module configured to output requests to shift a transmission into various operating modes. A sensor is configured to output noise-vibration-harshness (NVH) signals during operating mode changes. At least one controller is programmed to, in response to the requests, command operating mode changes after a delay. The at least one controller is further programmed to modify a duration of the delay based on the NVH signals associated with previous operating mode changes.
In another embodiment, a method includes the following steps: shifting a transmission into various operating modes based on requests received from a shift by wire (SBW) module, outputting NVH signals during changes in operating modes, performing a first change in operating modes after a first delay from receiving an associated request from the SBW module, and performing a second change in operating modes after a second delay that is reduced based on NVH signals received during the first change.
In yet another embodiment, a powertrain includes a transmission configured to shift operating modes in response to a command from a shift by wire (SBW) module. At least one controller is programmed to request a mode shift in the transmission via a control area network (CAN) in response to receiving the command from the SBW module, and control a delay between receiving the command and requesting the mode shift based on received signals from an NVH sensor and CAN data.
Embodiments of the present disclosure are described herein. It is to be understood, however, that the disclosed embodiments are merely examples and other embodiments can take various and alternative forms. The figures are not necessarily to scale; some features could be exaggerated or minimized to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the embodiments. As those of ordinary skill in the art will understand, various features illustrated and described with reference to any one of the figures can be combined with features illustrated in one or more other figures to produce embodiments that are not explicitly illustrated or described. The combinations of features illustrated provide representative embodiments for typical applications. Various combinations and modifications of the features consistent with the teachings of this disclosure, however, could be desired for particular applications or implementations.
Many vehicles are used over a wide range of vehicle speeds, including both forward and reverse movement. Some types of engines, however, are capable of operating efficiently only within a narrow range of speeds. Consequently, a transmission may be capable of efficiently transmitting power at a variety of speed ratios. When the vehicle is at low speed, the transmission can be operated at a high speed ratio such that it multiplies the engine torque for improved acceleration. At high vehicle speed, operating the transmission at a low speed ratio permits an engine speed associated with quiet, fuel efficient cruising.
A transmission according to the present disclosure may be mounted to the vehicle structure, with an input of the transmission being driven by an engine crankshaft, often via a launch device such as a torque converter, and an output driving the vehicle wheels, often via a differential assembly which permits the left and right wheel to rotate at slightly different speeds as the vehicle turns. The transmission may be equipped with various subsets of the clutches and brakes to be engaged to establish the various speed ratios. The transmission may thus be referred to as a discrete step-ratio transmission as it is configured to shift between multiple, discrete, stepped gears that each has a different input-to-output speed ratio.
Referring now to the drawings,
The system 10 includes an actuator assembly 20 secured at any convenient place in the vehicle 10, such as in the underhood engine compartment, the interior of the vehicle, on the transmission 14 itself, or on the vehicle's chassis.
In one embodiment, longitudinal displacement produced by rotary movement of the actuator assembly's output lever is transmitted along a shift cable 26 to a manual valve 28 of the transmission's hydraulic control system to the position that corresponds to the selected transmission operating range. The position of manual valve 28 connects a pressurized portion of the transmission's hydraulic system to a circuit that produces the selected operating range.
One embodiment of a driver interface of the system 10 is a shifter switch 18, located in the passenger compartment on or near the vehicle's instrument panel. Shifter switch 18 produces a signal representing the selected transmission operating range (e.g., PRNDL), and the shift cable 26 moves the transmission's manual valve 28 in response to the signal produced as output by shifter switch 18. In one embodiment, the shifter switch 18 is push-button shift panel, as shown in
Sensors 56, 58 are Hall-type position sensors, which produce signals representing the presence and absence of the sensed component at a reference position. Sensor 56 is a position sensor on the outer member 74. A signal produced by sensor 56 and carried on line 66 is used by the microprocessor 44 to verify that the angular position of an output lever is correct relative to the desired, selected transmission operating range produced in response to the operator's manual control of the SBW module 18. A signal produced by sensor 58 and carried on line 66 is used by microprocessor 44 to verify that secondary output mechanism is functioning correctly.
Electronic signals produced by SBW module 18 are carried on line 61 to the PCM 40. Electronic signals produced by the PCM 40 are carried on line 62 to the microprocessor 44 of the TRCM 42.
During normal operation, a secondary release motor 54 allows piston 48 to latch to a primary motor 50, thereby allowing piston 48 to move leftward and rightward among each transmission range in response to the signal produced by the SBW module 18. The transmission is shifted accordingly.
It should be understood that one or more of the control modules and processors described above can be referred to as a controller.
While
Referring back to
According to various embodiments of this disclosure, the control system of the vehicle controls the delay between a request to shift drive modes and the actual shift of drive modes based on signals that represent NVH from these (or other transmission) components.
A command to change gears is then issued from the TRS and TRCM via the CAN, illustrated at point P2. P2 is shown in
Once again, point P1′ represents the moment in which the SBW module commands a shift in operating modes. A mode shift command is not sent until point P2′, once the TRS indicates that the vehicle is not in Park, Reverse, or Neutral. The delay between the gear shift command being acceptable or issued at point P2′ and the requested gear shift from the paddle shifter at point P1′ is approximately t=0.6602 seconds. This is compared to a delay of t=0.461 seconds between points P2 and P1 in
The difference between point P3′ (i.e., the peak of the noise indicating the actual gear shift) and point P2′ (i.e., the issued command to shift gears) is t=0.177 seconds. This is compared to the similar delay between points P3 and P2 (
The overlap of the NVH signals and the data flowing through the CAN allows for a comparison of the optimum delay in requested mode shift and actual mode shift while still maintaining an acceptable NVH (sones). For example, as shown in
While the comparison between the NVH signals with the CAN data is shown can be from shifting from Drive to Sport, the comparison can also be done when shifting to any other gear or shift mode.
One or more algorithms can be programmed into the controller for controlling the gear or mode shifts described above. One example of an algorithm is as follows. The controller receives data regarding NVH observed over a plurality of shifts (e.g., from neutral to drive). During those shifts, the controller would alter the delay. During a first shift, after a first delay which produces a first NVH magnitude, the controller stores the information relating to that shift (e.g., the delay, the resulting NVH, etc.). Then, the controller alters the delay for a second shift. During that second shift with a second delay, a second NVH magnitude would result. The controller stores the information relating to that second shift. The process repeats for a third shift and subsequent shifts, with a plurality of data or information being stored with respect to each shift, showing different delays and different resulting NVH magnitudes. The controller can then determine which of the delays is the shortest possible delay while still yielding a NVH magnitude that is within a given specification or NVH threshold. The controller can then use that delay as the baseline delay for future shifts.
The processes, methods, or algorithms disclosed herein can be deliverable to/implemented by a processing device, controller, or computer, which can include any existing programmable electronic control unit or dedicated electronic control unit. Similarly, the processes, methods, or algorithms can be stored as data and instructions executable by a controller or computer in many forms including, but not limited to, information permanently stored on non-writable storage media such as ROM devices and information alterably stored on writeable storage media such as floppy disks, magnetic tapes, CDs, RAM devices, and other magnetic and optical media. The processes, methods, or algorithms can also be implemented in a software executable object. Alternatively, the processes, methods, or algorithms can be embodied in whole or in part using suitable hardware components, such as Application Specific Integrated Circuits (ASICs), Field-Programmable Gate Arrays (FPGAs), state machines, controllers or other hardware components or devices, or a combination of hardware, software and firmware components.
While exemplary embodiments are described above, it is not intended that these embodiments describe all possible forms encompassed by the claims. The words used in the specification are words of description rather than limitation, and it is understood that various changes can be made without departing from the spirit and scope of the disclosure. As previously described, the features of various embodiments can be combined to form further embodiments of the invention that may not be explicitly described or illustrated. While various embodiments could have been described as providing advantages or being preferred over other embodiments or prior art implementations with respect to one or more desired characteristics, those of ordinary skill in the art recognize that one or more features or characteristics can be compromised to achieve desired overall system attributes, which depend on the specific application and implementation. These attributes can include, but are not limited to cost, strength, durability, life cycle cost, marketability, appearance, packaging, size, serviceability, weight, manufacturability, ease of assembly, etc. As such, to the extent any embodiments are described as less desirable than other embodiments or prior art implementations with respect to one or more characteristics, these embodiments are not outside the scope of the disclosure and can be desirable for particular applications.
