Start-from-stop engine torque limiting
AssigneeEaton Corporation
InventorDavid L. Wadas
Life of this patent
Estimating the term…
Abstract
A control for preventing damage to a vehicular driveline (10) during attempts to launch a vehicle from a stopped condition while engaged in an inappropriate start ratio. The control involves sensing engaged transmission ratio (GR) and vehicle speed (OS) to determine if the vehicle is being launched while the transmission is engaged in an inappropriate start ratio and, if such conditions are sensed, issuing command signals to the engine controller (36) to cause engine output torque to be limited to a predetermined value, preferably a value less than 50% of maximum engine output torque.
Claims21
A computer program product for controlling a vehicular transmission system comprising a multiple-speed transmission driven by a fuel-controlled engine having a maximum output torque, said transmission having a plurality of acceptable start ratios and a plurality of unacceptable start ratios, a manually operated shift selector for shifting said transmission in accordance with an established shift pattern, an engine controller for controlling fueling of said engine in response to command signals, said engine controller having a mode of operation effective to limit engine output torque, a system controller for receiving input signals and processing same according to predetermined logic rules to determine values of control parameters indicative of vehicle operating conditions, including vehicle speed and engaged transmision ratio, and to issue command output signals to system actuators, including said engine controller, said program having codes for:
- determining as a function of the values of said control parameters indicative of vehicle operating conditions if said transmission is engaged in an unacceptable start ratio when vehicle speed is below a predetermined speed value;
- and
- if said transmission is engaged in an unacceptable start ratio when vehicle speed is less than said predetermined speed value, issuing command output signals to said engine controller to limit engine output torque to a predetermined engine torque value.
A method for controlling a vehicular powertrain system (10) comprising a fuel-controlled engine (12) drivingly connected to a vehicular drivetrain system including a multiple-ratio, change-gear transmission (16), said engine having a maximum output torque, and an engine controller (36) responsive to command signals to control fueling of the engine and, in at least one mode of operation, effective to limit engine output torque, said method comprising:
- determining values of control parameters indicative of drivetrain operating conditions including vehicle speed and engaged transmission ratio;
- comparing the values of said control parameters to reference values corresponding to the value of said control parameters during drivetrain operating conditions wherein the vehicle is being launched from a substantially stopped condition and said transmission is engaged in a ratio deemed inappropriate for launching said vehicle from a substantially stopped condition;
- and
- if the sensed values of said control parameters are indicative of the existence of an attempt to launch said vehicle while said transmission is engaged in an inapproriate ratio, causing said engine controller to limit engine output torque to a value less than 50% of maximum engine output torque.
A method for controlling a vehicular transmission system comprising a multiple-speed transmission driven by a fuel-controlled engine having a maximum output torque, said transmission having a plurality of acceptable start ratios and a plurality of unacceptable start ratios, a manually operated shift selector, an engine controller for controlling fueling of said engine in response to command signals, said engine controller having a mode of operation effective to limit engine output torque, a system controller for receiving input signals and processing same according to predetermined logic rules to determine values of control parameters indicative of vehicle operating conditions, including vehicle speed and engaged transmision ratio, and to issue command output signals to system actuators, including said engine controller, said method comprising:
- determining as a function of the values of said control parameters indicative of vehicle operating conditions if said transmission is engaged in an unacceptable start ratio when vehicle speed is below a predetermined speed value;
- and
- if said transmission is engaged in an unacceptable start ratio when vehicle speed is less than said predetermined speed value, issuing command output signals to said engine controller to limit engine output torque to a predetermined engine torque value.
A control system for controlling a vehicular transmission system comprising a multiple-speed transmission driven by a fuel-controlled engine having a maximum output torque, said transmission having a plurality of acceptable start ratios and a plurality of unacceptable start ratios, a manually operated shift selector, an engine controller for controlling fueling of said engine in response to command signals, said engine controller having a mode of operation effective to limit engine output torque, a system controller for receiving input signals and processing same according to predetermined logic rules to determine values of control parameters indicative of vehicle operating conditions, including vehicle speed and engaged transmision ratio, and to issue command output signals to system actuators, including said engine controller, said control system comprising:
- means for determining as a function of the values of said control parameters indicative of vehicle operating conditions if said transmission is engaged in an unacceptable start ratio when vehicle speed is below a predetermined speed value;
- and
- means effective, if said transmission is engaged in an unacceptable start ratio when vehicle speed is less than said predetermined speed value, for issuing command output signals to said engine controller to limit engine output torque to a predetermined engine torque value.
A method for controlling a vehicular powertrain system (10) comprising a fuel-controlled engine (12) drivingly connected to a vehicular drivetrain system including a multiple-ratio, change-gear transmission (16), said engine having a maximum output torque, and an engine controller (36) responsive to command signals to control fueling of the engine and, in at least one mode of operation, effective to limit engine output torque, said method comprising:
- determining values of control parameters indicative of drivetrain operating conditions including vehicle speed and engaged transmission ratio;
- comparing the values of said control parameters to reference values corresponding to the value of said control parameters during drivetrain operating conditions wherein the vehicle is being launched from a substantially stopped condition and said transmission is engaged in a ratio deemed inappropriate for launching said vehicle from a substantially stopped condition;
- and
- if the sensed values of said control parameters are indicative of the existence of an attempt to launch said vehicle while said transmission is engaged in an inapproriate ratio, causing said engine controller to limit engine output torque to a value less than said maximum engine output torque.
Dependencies are inferred from the claim text.