Powertrain torque control

A method for controlling a vehicular powertrain system (10) comprising a fuel-controlled engine (12), an engine controller for controlling fueling of the engine (40), a multiple-speed transmission (14) having one or more intermediate ratios, a direct drive ratio, and one or more overdrive ratios, means (44) for sensing an engaged transmission ratio, and a controller (26) for receiving input signals (24) and processing same according to logic rules to issue command output signals to system actuators including said engine controller, said method comprising the steps of:

• (i) sensing engaged transmission ratio;
• (ii) setting second (B), third (C) and fourth (D) torque limit values such that:
• B<C>D and
• B<D
• (iii)(a) if the transmission is engaged in an intermediate ratio, limiting engine output torque to said second torque limit (TE≦B), (b) if the transmission is engaged in the direct ratio, limiting engine output torque to said third torque limit (TE≦C), and (c) if the transmission is engaged in an overdrive ratio, limiting engine output torque to said fourth torque limit (TE≦D).

A control system for controlling a vehicular powertrain system (10) comprising a fuel-controlled engine (12), an engine controller for controlling fueling of the engine (40), a multiple-speed transmission (14) having one or more start ratios, one or more intermediate ratios, a direct drive ratio, and one or more overdrive ratios, means (44) for sensing an engaged transmission ratio, and a controller (26) for receiving input signals (24) and processing same according to logic rules to issue command output signals to system actuators including said engine controller, said logic rules including rules for:

• (i) sensing engaged transmission ratio;
• (ii) setting first (A), second (B), third (C) and fourth (D) torque limit values such that:
• A<B<C>D and
• B<D
• (iii)(a) if the transmission is engaged in a start ratio, limiting engine output torque to said first torque limit (TE≦A), (b) if the transmission is engaged in an intermediate ratio, limiting engine output torque to said second torque limit (TE≦B), (c) if the transmission is engaged in the direct ratio, limiting engine output torque to said third torque limit (TE≦C), and (d) if the transmission is engaged in an overdrive ratio, limiting engine output torque to said fourth torque limit (TE≦D).

A control system for controlling a vehicular powertrain system (10) comprising a fuel-controlled engine (12), an engine controller for controlling fueling of the engine (40), a multiple-speed transmission (14) having one or more intermediate ratios, a direct drive ratio, and one or more overdrive ratios, means (44) for sensing an engaged transmission ratio, and a controller (26) for receiving input signals (24) and processing same according to logic rules to issue command output signals to system actuators including said engine controller, said logic rules including rules for:

• (i) sensing engaged transmission ratio;
• (ii) setting second (B), third (C) and fourth (D) torque limit values such that:
• B<C>D and
• B<D
• (iii)(a) if the transmission is engaged in an intermediate ratio, limiting engine output torque to said second torque limit (TE≦B), (b) if the transmission is engaged in the direct ratio, limiting engine output torque to said third torque limit (TE≦C), and (c) if the transmission is engaged in an overdrive ratio, limiting output torque to said fourth torque limit (TE≦D).