Electric creep torque control in vehicles having a manual/mechanical transmission

Abstract

A system for providing electric creep in a manual transmission vehicle having an accelerator pedal, a brake pedal, and an engine uses an electric motor configured to provide creep torque to a transmission output shaft when the manual transmission is in neutral, the electric creep mode is activated and the engine is auto-stopped. The system may provide forward or reverse creep torque. The system may cancel the electric creep in response to a vehicle door opening, a driver unbuckling a seatbelt, or depressing the accelerator pedal or the clutch pedal, or shifting the manual transmission out of neutral.

Claims

1. A vehicle comprising: an engine; an accelerator pedal; a brake pedal; a clutch pedal; a manual transmission having an output shaft; an electric machine configured to rotate the output shaft when the manual transmission is in neutral; and a controller programmed to: auto-stop the engine responsive to the accelerator pedal being released, the brake pedal being depressed, and the clutch pedal being released, responsive to the engine being auto-stopped, the brake pedal being depressed, and creep mode being requested, activate a creep mode, and responsive to the creep mode being activated, provide creep torque based on position of the brake pedal.

2. The vehicle of claim 1 wherein the controller is further programmed to cancel the creep mode responsive to the clutch pedal being depressed.

3. The vehicle of claim 1 wherein the controller is further programmed to cancel the creep mode responsive to a button being depressed.

4. The vehicle of claim 1 wherein the controller is further programmed to cancel the creep mode in response to depressing the accelerator pedal.

5. The vehicle of claim 1 further comprising a control button actuatable to request the creep mode.

6. The vehicle of claim 1 wherein the controller is further programmed to provide creep torque only when the manual transmission is in neutral.

7. The vehicle of claim 1 further comprising: a gear lever configured to place the manual transmission in neutral; and a button on the gear lever configured to request the creep mode.

8. The vehicle of claim 7 wherein the button is configured to select one of forward creep torque and reverse creep torque.

9. The vehicle of claim 1 wherein the controller is programmed to cancel the creep mode in response to unbuckling of a driver seat belt.

10. A controller for providing electric creep in a vehicle comprising a manual transmission, an engine, and an electric machine configured to be controlled by accelerator, brake and clutch pedals, the controller configured to: switch off the engine when the electric creep is activated; control the electric machine to provide the electric creep based on extent of depression of the brake pedal; and cancel the electric creep responsive to the clutch pedal being depressed.

11. The controller of claim 10 wherein the controller is further configured to cancel the electric creep in response to depression of the accelerator pedal.

12. The controller of claim 10 further configured to cancel the electric creep in response to opening of a vehicle door.

13. The controller of claim 10 further configured to cancel the electric creep responsive to the transmission being shifted out of neutral.

14. A vehicle comprising: an engine; a manual transmission coupled to the engine; a motor configured to power driven wheels of the vehicle; and a controller programmed to auto-stop the engine responsive to accelerator and clutch pedals being released, a brake pedal being depressed, and the transmission being in neutral, and responsive to the engine being auto-stopped and electric creep being requested, power the driven wheels via the motor based on position of the brake pedal.

15. The vehicle of claim 14 wherein the controller is further programmed to cancel the electric creep responsive to the clutch pedal being depressed.

16. The vehicle of claim 14 further comprising: a gear lever configured to place the manual transmission in neutral; and a button on the gear lever configured to request the electric creep.

17. The vehicle of claim 16 wherein the button includes a first position that corresponds to forward creep and a second position that corresponds to reverse creep.

18. The vehicle of claim 14 further comprising: a first axle including second driven wheels powered by the engine; and a second axle including the driven wheels.

19. The vehicle of claim 14 wherein controller is further programmed to cancel the electric creep responsive to the transmission being shifted out of neutral.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 shows schematically the constituent parts of an example of one embodiment of the disclosure;

(2) FIG. 2 shows the electric creep entry conditions of one or more embodiments of the disclosure;

(3) FIG. 3 shows the electric creep exit conditions of one or more embodiments of the disclosure; and

(4) FIGS. 4A-4B show schematically different powertrain configurations with manual or mechanical transmissions according to various representative embodiments of the disclosure.

(5) FIG. 5 shows a gear shifter with an e-Creep control switch.

DETAILED DESCRIPTION

(6) As required, detailed embodiments are disclosed herein; however, it is to be understood that the disclosed embodiments are merely representative and may be embodied in various and alternative forms. The figures are not necessarily to scale; some features may 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 claimed subject matter.

(7) FIG. 1 shows the integers that form part of a system 10 of a representative embodiment. The system 10 is implemented within a powertrain control module 40. The powertrain control module 40 is configured to receive data from a plurality of sensors positioned in different locations around the vehicle. Data received from some of the sensors can be used by the powertrain control module 40 to implement an electric creep functionality.

(8) An accelerator pedal position sensor 21, brake pedal pressure sensor 22 and clutch pedal or clutch position sensor 23 provide data indicative of the extent of depression of the respective pedal. Whilst the data provided by the sensor will include data indicative of the extent of depression of the respective pedal, the electric creep system 10 requires only a subset of that data showing whether there is any depression of the pedal or not.

(9) Gearbox position sensor 24 provides data about the position of the gear lever, in particular whether the gear lever is in the neutral position or not.

(10) An e-Creep driver control switch 25 is provided. This can be a binary switch with on and off positions. Alternatively, it may be a rocker switch with forward, reverse and off positions. Of course, other combinations of an on/off and forward/reverse switches or buttons are possible.

(11) Further sensors 26 collate data indicative of the driver potentially leaving the vehicle. These can include a sensor monitoring engagement of the driver's seat belt and a sensor monitoring the opening of the driver's door, for example.

(12) It will be appreciated that the accelerator, brake and clutch pedals sensors 21, 22, 23 are configured to provide data to the powertrain control module 40 for the normal functioning of this module. Furthermore, a seat belt engagement sensor 26 is typically provided in order to provide a warning should the driver attempt to drive the car without fastening the seat belt. Additional sensors are not required at these locations for the deployment of the electric creep system. The powertrain control module 40 is also configured to receive and interpret the data appropriately for the deployment of the electric creep functionality.

(13) The deployment of the electric creep functionality is achieved via an electric motor 60 that is integrated into the propulsion system of the vehicle.

(14) The powertrain control module 40 additionally provides data to an e-Creep driver interface 62. This interface 62 may be embodied as a lamp, telltale, or message within the instrument cluster.

(15) In addition, the powertrain control module 40 provides data to a module 64 configured to control the reversing lamp. This ensures that when the e-Creep system is deployed in the reverse direction with the gear lever and transmission in neutral, the vehicle's reversing lights are deployed just as they would be if the vehicle was being reversed under power from the combustion engine with the gear lever in the reverse position.

(16) FIG. 2 summarizes the entry conditions for the e-Creep system 10 of a representative embodiment. The gear lever 34 must be in the neutral position; the accelerator (A) pedal 31 and clutch (C) pedal 33 must be fully released, i.e. not depressed at all or less than an associated threshold to account for variations across vehicles. This configuration results in the initiation of the auto-stop functionality 39. Once the combustion engine has been auto-stopped, then if the brake (B) pedal 32 is depressed and the e-Creep control switch 25 has been activated, the vehicle will enter an e-Creep mode. In this mode, the e-Creep torque is controlled solely by the modulation of the brake pedal. If the e-Creep control switch 25 includes forward and reverse options, then the creep torque will move the vehicle either forwards or backwards depending on the position of the switch 25.

(17) FIG. 3 summarizes the exit conditions for the e-Creep system 10 of a representative embodiment. The system 10 will be cancelled if any one of the following conditions is met: moving the gear lever 34 out of the neutral position; the accelerator (A) pedal 31 or clutch (C) pedal 33 is depressed or depressed beyond a threshold; or the e-Creep control switch 25 is pressed. If the control switch 25 is a slider or non-latching button with three positions, forward, reverse and off, then the system 10 is cancelled when the button or slider is moved to the off position.

(18) FIGS. 4A-4B show different manual transmission configurations to which the system 10 can be applied. In each of these representative illustrations the combustion engine is depicted as a series of four circles, effectively providing a top view of the cylinder block with the pistons. The other integers are the electric machine E/M, the battery B, the differential or final drive D, the transmission T, and the starter motor S.

(19) FIG. 4A shows a single clutch configuration with a small electric machine E/M. This configuration is optimized with the electric machine partially integrated into the transmission.

(20) FIG. 4B shows an alternative configuration that includes an electric rear axle drive (ERAD). The rear wheels are driven by an electric machine E/M while the front wheels are driven by the internal combustion engine.

(21) Referring to FIG. 5, the e-Creep control switch may be disposed on a gear shifter 80. In one embodiment, the control switch is a button 82. The button 82 may be a single button or a dual position button having first and second positions 84 and 86. The first position 84 is for forward creep mode, and the second position 86 is for reverse creep mode.

(22) It will be appreciated by those skilled in the art that although the invention has been described by way of example with reference to one or more embodiments it is not limited to the disclosed embodiments and that alternative embodiments could be constructed without departing from the scope of the invention as defined by the appended claims.

(23) While representative embodiments are described above, it is not intended that these embodiments describe all possible forms of the claimed subject matter. The words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the disclosure. Additionally, the features of various implementing embodiments may be combined to form further embodiments that may not be explicitly illustrated or described.