Abstract: A system for controlling a vehicle drivetrain in a fuel-efficient manner includes, in one embodiment, a control computer operable to determine a number of engine load/engine speed boundary conditions as functions of brake specific fuel consumption (BSFC) contours in relation to an engine output characteristics map and define therefrom an undesirable engine operation region U. As long as the engine is engaged with at least one of the gear ratios of the vehicle transmission, the control computer is operable to maintain or encourage engine operation outside of the region U. In another embodiment, the control computer is operable to define a contour from substantially zero engine load to substantially full engine load, wherein the contour preferably corresponds to a fuel-efficient path from no-load to full-load engine operating conditions.

Abstract: A system for controlling an internal combustion engine in a fuel-efficient manner includes a control computer operable to determine a number of engine load/engine speed boundary conditions in relation to an engine output characteristics map and define therefrom an undesirable engine operation region U. As long as the engine is engaged with at least one of the gear ratios of the vehicle transmission, the control computer is operable in one embodiment to maintain engine operation outside of the region U, and in an alternate embodiment to allow operation within the region U but with decreased engine performance/response to thereby encourage operation outside of the region U. The system of the present invention further includes the ability to override, e.g. disable, such engine control based on, for example, certain transmission autoshifting conditions, current vehicle position, and/or information provided from a remote source via a signal transceiver.

Abstract: A system for controlling downhill vehicle operation includes an electronically actuatable engine compression brake unit associated with an internal combustion engine, an electronically controllable turbocharger boost pressure adjustment device, electronically actuatable service brakes and a transmission including a number of automatically selectable gear ratios, wherein each of these components are coupled to a control computer. In accordance with one aspect of the present invention, the control computer is operable to detect a potential runaway vehicle condition and control any one or combination of engine compression brake activity, turbocharger boost pressure, service brake activity and automatic transmission shifting to thereby provide for a controlled descent down a negative grade and thereby prevent a runaway vehicle condition.

Abstract: A system for controlling vehicle braking operation includes a mechanism for determining desired service brake force, a mechanism for determining vehicle deceleration, an electronically actuatable engine compression brake unit, an electronically controllable turbocharger boost pressure adjustment device and a transmission including a number of automatically selectable gear ratios, wherein each of these components are coupled to a control computer. The control computer is operable to activate the engine compression brakes whenever service brake action is detected, and to modulate the downshift engine speed points of the transmission as a function of the desired brake force. The boost pressure adjustment device and the engine compression brake may optionally be controlled to maintain a vehicle deceleration rate below a deceleration rate threshold. Alternatively, the downshift engine speed points may be controlled to maintain the vehicle deceleration rate below the deceleration rate threshold.

Abstract: A system for protecting one or more drivetrain components from excessive inertial torque includes an automated clutch disposed between an internal combustion engine and a transmission coupled thereto, wherein the automated clutch is responsive to computer control. Under conditions wherein driveline acceleration exceeds an acceleration threshold, wherein the acceleration threshold preferably corresponds to the weakest of the drivetrain components, a control computer is operable to actuate the automated clutch to thereby electronically disengage the engine from the transmission, and accordingly protect the various drivetrain components from damage due to excessive engine inertial torque. In an alternate embodiment, a control computer is operable to compute or otherwise estimate engine inertial torque and actuate the automated clutch as just described if/when the engine inertial torque exceeds a torque threshold corresponding to an input torque capacity of one or more of the drivetrain components.

Abstract: A system for controlling output torque characteristics of an internal combustion engine includes a control computer operable to control the output power/torque of the engine that is coupled to a transmission through a torque converter. The system is operable to determine an engine speed range of interest and limit engine output power/torque to a predefined maximum value if the current engine speed is within the engine speed range of interest when the torque converter is operating in torque converter mode (i.e., not in lockup mode). The predefined maximum value of engine output power/torque is preferably a maximum horsepower value that may be a constant value or a function of engine speed within the engine speed range of interest. Alternatively, the predefined maximum value of engine output power/torque is a dynamic function of a torque ratio of the torque converter and a predefined turbine torque limit.

Abstract: A system for controlling operation of an internal combustion engine includes a control computer responsive to a number of engine/vehicle operating conditions to control engine operation to thereby control engine speed and engine or vehicle acceleration. In one embodiment, the control computer is configured to determine an engine or vehicle acceleration limit value based on current engine or vehicle speed, and an engine speed limit value based on current engine load, and to control engine fueling and/or speed to thereby limit engine speed to the engine speed limit value and/or engine/vehicle acceleration to the engine/vehicle acceleration limit value.

Abstract: A system for controlling operation of an internal combustion engine includes a control computer responsive to a number of engine/vehicle operating conditions to control engine operation to thereby control engine speed and engine or vehicle acceleration. In one embodiment, the control computer is configured to determine an engine or vehicle acceleration limit value based on current engine or vehicle speed, and an engine speed limit value based on current engine load, and to control engine fueling and/or speed to thereby limit engine speed to the engine speed limit value and/or engine/vehicle acceleration to the engine/vehicle acceleration limit value.

Abstract: A system for overriding hold mode operation of an automated transmission coupled to an internal combustion engine is provided, wherein the transmission is operable in the hold mode of operation to maintain engagement of a currently engaged transmission gear. A control computer is operable to monitor at least one vehicle operating parameter and determine whether hold mode operation is inappropriate based thereon. If hold mode operation is inappropriate, the control computer is operable to either initiate an automatic upshift to a numerically higher transmission gear or limit engine or vehicle speed to a predefined speed value. In this manner, the system of the present invention is operable to allow hold mode operation only when a legitimate need therefore exists.

Abstract: A vehicle/engine acceleration rate management system includes means for determining vehicle acceleration rate and a control computer providing a fueling signal to an internal combustion engine fueling system. The control computer is responsive to a gear ratio signal indicative of one of a plurality of selectable transmission gear ratios currently engaged with the engine and a vehicle acceleration rate signal to control the vehicle acceleration rate by limiting the fueling signal whenever the vehicle acceleration rate signal exceeds a vehicle acceleration limit function. In one embodiment, such vehicle acceleration rate limiting is performed only for vehicle speeds above a threshold vehicle speed, and an identical engine acceleration rate limiting procedure is performed at vehicle speeds below the threshold vehicle speed. In either case, such acceleration rate limiting is preferably only performed under manual control of engine fueling via an accelerator pedal or the like.

Abstract: A system for controlling automatic transmission downshift points includes a control computer for electronically controlling an internal combustion engine and a transmission having at least one automatically selectable gear. The control computer is responsive to at least a throttle signal, provided by either a manually actuatable accelerator pedal or a cruise control system, to compute an engine load value, and is further responsive to either an engine speed signal or a vehicle speed signal to compute a deceleration value. The control computer is operable to compute a downshift engine RPM value based on the deceleration value and either the throttle signal or the engine load value, wherein the downshift engine RPM value is lower than a default downshift engine RPM if the deceleration value indicates a relatively slow deceleration rate and the throttle signal or the engine load value indicates high throttle or engine load.

Abstract: A system for managing engine retarding torque during coast mode operation includes a control computer operable in one embodiment to control boost pressure, engine compression brake setting and/or engine accessory deactivation upon detection of coast mode operation with the engine compression brakes enabled. In another embodiment, the control computer is operable to determine a current engine retarding torque value, based either on an estimation thereof as a function of current boost pressure and engine compression brake setting or based on a mass estimation technique accounting for the grade of the road, and control boost pressure, engine compression brake operation and/or engine accessory deactivation to thereby control engine retarding torque upon detection of coast mode operation with the engine brakes enabled.

Abstract: An engine control system is operable to provide an engine fueling rate equal to the larger of a first engine fueling rate at which the resulting engine torque is limited by a maximum input torque capacity of a presently engaged gear ratio of the transmission and a second engine fueling rate at which the resulting engine torque is limited by a nominal input torque capacity of the transmission. The foregoing technique can be enabled at all times, or alternatively only after determination that the vehicle is experiencing deceleration under heavy engine load conditions. The engine control system may be further operable to determine a third engine fueling rate at which the resulting engine output torque is limited by a maximum operating torque capacity of the transmission propeller shaft, as well as a fourth engine fueling rate at which the resulting engine output torque is limited by a maximum operating torque capacity of the drive axle connected thereto.

Abstract: The present invention allows the vehicle to be operated at higher than normally desired speeds during periods when there is a legitimate need for increased performance, such as downshifting in order to aid in climbing an uphill grade or accelerating with the goal of upshifting. Like the prior art systems, the present invention also imposes a maximum vehicle speed for all non-top gears, but only during steady state conditions (defined as a light engine load existing for a predetermined period of time). During transient conditions (discerned by recognizing gear changes and by high engine load conditions), the control system of the present invention provides lenience from the normal maximum vehicle speed limits for non-top gears. Such lenience provides for increased vehicle performance during periods when it is legitimately needed by the driver.

Abstract: An engine control system is operable to provide an engine fueling rate equal to the larger of a first engine fueling rate at which the resulting engine torque is limited by a maximum input torque capacity of a presently engaged gear ratio of the transmission and a second engine fueling rate at which the resulting engine torque is limited by a nominal input torque capacity of the transmission. The foregoing technique can be enabled at all times, or alternatively only after determination that the vehicle is experiencing deceleration under heavy engine load conditions. The engine control system may be further operable to determine a third engine fueling rate at which the resulting engine output torque is limited by a maximum operating torque capacity of the transmission propeller shaft, as well as a fourth engine fueling rate at which the resulting engine output torque is limited by a maximum operating torque capacity of the drive axle connected thereto.