Cummins Engine Company, Inc.

John P Kresse

Matthew W Workman

W Patrick Niehus

Steven M Bellinger

Stephen West

Charles E Goode

Ross B Mursell

John Shoemaker

A system is disclosed for determining an effective throttle value of an internal combustion engine for controlling automatic transmission shift points. In one embodiment, the system is operable to determine an effective throttle value as a function of commanded fueling and engine speed under operating conditions wherein engine torque is requested by a system/component other than manual throttle control to thereby provide a throttle value indicative of what throttle position or percentage would be under present operating conditions if engine torque was being requested via manual throttle control. The present invention accordingly overcomes deficiencies in known automatic transmission shift point control systems by continuously computing an equivalent throttle percentage whenever fueling or requested torque values are not dominated by actual throttle (e.g. accelerator pedal) percentage. The equivalent throttle parameter value is approximately what the throttle percentage would be if manual throttle percentage was the dominant source of requested torque. Transmission shift point logic may resultantly be simplified by basing transmission shift points on the equivalent throttle parameter during non-manual fueling control just as transmission shift points are based on throttle percentage during manual fueling conditions.

System for determining an equivalent throttle valve for controlling automatic transmission shift points

A road speed control system for a vehicle driven by an internal combustion engine includes a control computer operable to control engine fueling based on inputs from at least an accelerator pedal position sensor, a vehicle speed signal, and at least one control signal. According to one aspect of the invention, the control computer is responsive to a first control signal to decrease the maximum road speed limit value and to a second control signal to increase the maximum road speed value, to thereby provide a road speed limiting system operable under manual engine fueling conditions. According to another aspect of the invention, the control computer is responsive to at least one control signal to activate a maximum road speed limit override feature for temporarily increasing the maximum road speed limit value to, for example, facilitate passing attempts.

System for temporarily increasing maximum road speed of a vehicle driven by an internal combustion engine

System for controlling road speed of a vehicle driven by an internal

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.

Vehicle/engine acceleration rate management system

An electronic throttle pedal nonlinear filter. During throttle control of a vehicle's all speed governor, a nonlinear prefilter is used to modify the reference command. This prefilter can be used to heavily filter small throttle corrections, while allowing large throttle changes to have little or no filtering. By heavily filtering small throttle corrections, throttle sensitivity can be reduced, helping the throttle 'feel' when driving over bumpy roads or when making small throttle changes. Little filtering when making large throttle changes helps to give a fast governor response when a large acceleration or deceleration is desired. The filter works by comparing the past value of the all speed governor reference speed (or throttle position) to a rate limited value of the current reference speed (or throttle position). This difference is used to look up a filter coefficient in a table. This coefficient is used in a conventional first-order digital lag filter to produce the filter output. The table can be calibrated such that if the difference was small (a small change in throttle position), a large filter coefficient (large time constant) can be selected. If the difference was large (a big change in throttle position), a small filter coefficient (or none at all) can be used to lightly filter the throttle.

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Shelbyville, IN, United States of America

John P Kresse