Method and device for controlling a standstill circuit of an automatic transmission

• US 8,078,369 B2
• Filed: 04/20/2006
• Issued: 12/13/2011
• Est. Priority Date: 05/11/2005
• Status: Active Grant

• Current Assignee: ZF Friedrichshafen AG (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Original Assignee: ZF Friedrichshafen AG (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Inventors: Reith, Ulrich, Groener, Wolfgang
• Primary Examiner(s): Algahaim, Helal A
• Application Number:
  US11/913,813
• Publication Number:
  US 20080221762A1
• Time in Patent Office: 2,063 Days
• Field of Search: 701/51, 701/58, 701/61, 701/70, 477/93, 477/114
• US Class Current: 701/51
• CPC Class Codes: F16H 2061/023 Drive-off gear selection, i.e. optimising gear ratio for drive off of a vehicle
• CPC Class Codes: F16H 2061/161 by checking feasibility of shifts, i.e. determine if requested shift can be successfully completed and post shift values are in an acceptable range
• CPC Class Codes: F16H 2312/022 Preparing to drive off
• CPC Class Codes: F16H 59/18 dependent on the position of the accelerator pedal
• CPC Class Codes: F16H 59/54 dependent on signals from the brakes, e.g. parking brakes
• CPC Class Codes: F16H 61/20 Preventing gear creeping ; Transmission control during standstill, e.g. hill hold control

Abstract

The invention relates to a method and a device for controlling a standstill circuit of an automatic transmission of the vehicle, comprising a decision unit for selection of the target gear, a low-speed monitoring unit and a standstill circuit, which, when the vehicle is standing still or when its speed falls below a predetermined limit speed, brings about or prepares the activation of a starting gear.

The method and the device are intended to enable a vehicle to start up safely even under the influence of considerable tractive resistance. Furthermore, they should be characterized by solutions which are as simple, inexpensive and easy to implement as possible by way of available methods and devices. To this end, the low-speed monitoring unit reads data concerning at least one state of the vehicle and, if necessary, additional data, and, on the basis thereof, as a function of decision rules, renders the standstill circuit ineffective.

Claims

1. A device configured to control an automatic transmission of a vehicle, the device comprising:

a standstill circuit configured to one of prepare and activate a starting gear ratio when the vehicle is one of standing still or at a speed below a predetermined limit speed,

a low-speed monitoring circuit configured to receive data representing at least one state of the vehicle in which the at least one state represented by the data is directly determined by a direct influence of a driver operating the vehicle, wherein

the data represents;

a deflection of a gas pedal,

an operation of a vehicle brake, including at least one of;

when one of the vehicle brake produces no braking effect and the braking effect is below a braking effect limit value,

a driver input indicating one of a requirement for the standstill circuit and a deactivation of the standstill circuit,

an operation of at least one of the transmission and a clutch, including at least one of;

a shifting state of the transmission,

and

a disengaged state of the clutch,

a direction of rotation of rotatable drive elements,

at least one of the standstill of the vehicle and when a standstill of the vehicle is not recognized within a defined interval of time,

an operation of at least one of a drive motor and a motor control device, including at least one of;

when a rotational speed of the motor exceeds a motor rotational speed limit value,

when a motor filling limit value is exceeded,

when a motor torque exceeds a torque limit value,

when a torque in a drive train exceeds a drive train torque limit value, and

an acceleration of the vehicle,

a decision unit implementing gear ratio selection rule and responsive to the standstill circuit and the low-speed monitoring circuit configured to select a target gear ratio for the automatic transmission, and

the low-speed monitoring unit emitting an output signal for rendering the standstill circuit one of ineffective and effective based on the data concerning at least one state of the vehicle and decision rules.