US 5,406,483 A · Engine variable transmission control system

Abstract

An electronic transmission control system for a self-propelled off-road vehicle having an internal combustion engine and multiple gear powershift transmission. The control system controls the powershift transmission and provides at least one control signal to the engine for selecting the speed at which the engine is to operate. The system includes a first electronic controller that provides transmission control signals required to command the powershift transmission to shift to and operate in any particular one of its forward gears, and second electronic controller that provides at least one engine control signal required to command the engine to operate at one of a number of different desired engine speeds and to monitor the actual engine speed. By use of gear ranges which overlap slightly, and a throttle that is infinitely adjustable within a range of engine speeds, any given ground speed within the range of possible vehicle speeds can be achieved and maintained, as long as engine is operating within its overall power envelope. Once the desired ground speed is specified by the operator, the control system automatically selects the specific transmission gear and engine speed required to achieve the desired ground speed. The control system also performs automatic upshifts or downshifts, as required, to achieve the desired ground speed. The system has a comfort mode, fuel economy mode, and a maximum horsepower mode, all selectable by the operator. The system also supports a pseudo-gear mode where the operator interface indicates there are more gears in the transmission than actually exist.

An electronic control system for a self-propelled off-road vehicle having an internal combustion engine and a powershift transmission with a plurality of forward gears, said control system being for controlling powershift transmission and providing at least one control signal to said engine for specifying a speed at which said engine of said vehicle is to operate, said control system comprising:

mode selection means for allowing an operator of said vehicle to select a desired one of a plurality of operating modes including a maximum fuel economy mode, a comfort mode and a maximum horsepower mode;
speed selection means for allowing said operator to select a desired vehicle ground speed;
first electronic controller means responsive to said mode selection means and said speed selection means and operable under stored program control for providing transmission control signals that specify in which specific one of said plurality of forward gears said powershift transmission is to operate in accordance with said selected operating mode;
and
second electronic controller means operable under stored program control for providing at least one engine control signal required to command said engine to operate at one of a plurality of different engine speeds within a predetermined range in accordance with said desired vehicle ground speed,
said first electronic controller means including first electrical output means for commanding said powershift transmission to operate in a controller selected one of said plurality of forward gears in response to said gear as specified by the current transmission control signals, and communications means for sending and receiving digital signals to and from said second electronic controller means,
said second electronic controller means including second electrical output means for commanding said engine to operate at a particular one of said plurality of engine speeds indicated by said engine control signal, and communications means for sending and receiving digital signals to and from said first electronic controller means;
and
when in said maximum fuel economy mode said electronic control system selects particular ones of said plurality of forward gears and particular ones of said engine speeds to minimize fuel consumption of said engine, said electronic control system further allowing said engine speed to vary slightly to help achieve minimum fuel consumption while attempting to maintain an operator selected vehicle ground speed;
when in said comfort mode said electronic control system selects particular ones of said plurality of forward gears and particular ones of said plurality of engine speeds to maintain an actual vehicle ground speed approximately equal to said operator selected vehicle ground speed while simultaneously reducing the number of shifts of said powershift transmission by varying said engine speed as necessary to compensate for changing loads experienced by said vehicle;
and
when in said maximum horsepower mode said electronic control means selects various ones of said plurality of gears and varies said engine speed in an attempt to maintain said operator selected vehicle ground speed approximately equal to said actual vehicle ground speed while simultaneously maintaining said engine operating at one of said plurality of engine speeds that produces a maximum horsepower at said operator selected vehicle ground speed.

9 more elements

Facts

Application

08/216,250Filed 22 Mar 1994 · continuation

Priority

15 May 1991

Granted

11 Apr 1995

Term ends

Not estimatedThe source records don’t support an estimate.

Classification36 codes

B60W 10/06
Including control of propulsion units: including control of combustion engines
B60R 16/0315
For supply of electrical power to vehicle subsystems or for: using multiplexing techniques
B60W 10/04
Conjoint control of vehicle sub-units of different type or different function: including control of propulsion units
B60W 10/11
Including control of change-speed gearings: stepped gearings

Engine variable transmission control system

Life of this patent

Engine variable transmission control system

Life of this patent

Abstract

Claims23