Data processing: vehicles – navigation – and relative location – Vehicle control – guidance – operation – or indication – Indication or control of braking – acceleration – or deceleration
Reexamination Certificate
1998-12-23
2001-05-29
Cuchlinski, Jr., William A. (Department: 3661)
Data processing: vehicles, navigation, and relative location
Vehicle control, guidance, operation, or indication
Indication or control of braking, acceleration, or deceleration
C701S096000, C701S102000, C701S104000
Reexamination Certificate
active
06240356
ABSTRACT:
TECHNICAL FIELD
This invention relates generally to control systems for monitoring engine speed and energy absorption capability and, more particularly, to a control system which controls and manages the maximum ground speed of a work machine based upon the degree of slope or inclination of the terrain upon which the work machine is operating.
BACKGROUND ART
Work machines such as track type tractors and a wide variety of other types of mining and earthmoving equipment often work in environments which give rise to speed control problems. For example, many different types of work machines are subject to potential engine and brake damage when operating on terrain which slopes, that is, when operating at various angles of inclination. Typically, any movement or pass on a slope where the work machine is not dozing, ripping, or performing other earthmoving type operations provides the opportunity for that particular work machine to be affected by gravity and to reach much faster speeds than it would normally reach under similar no load conditions on level terrain. In potential overspeed situations, the engine governor associated with some work machines may be controlled to respond to such a situation by shutting off fuel to the engine thereby retarding the ground speed of the machine. The engine is also capable of providing increased braking torque as the engine speed is driven higher due to the fact that the work machine is accelerating on the particular slope or inclination. Depending upon the particular work machine, there is some slope or inclination at which the weight of the work machine can drive the engine speed, or ground speed of the machine, beyond the speed capabilities of the particular work machine thereby resulting in damage or failure to the engine or power train system, typically, damage to the valve train. Also, as the terrain slope increases, the work machine achieves higher levels of kinetic energy which can be more difficult to dissipate depending upon the particular work and/or environmental conditions existing at the time.
Engine valve trains and brake systems can be developed to improve their overspeed and energy absorption capability. There are, however, economic and physical limitations to the amount of improvement which can be realistically achieved in these areas if a marketable product is to be produced.
It would therefore be desirable if there were provided a control system that would monitor the ground speed or engine speed of a particular work machine as it operates on an inclined surface and that would both manage and control the speed limit of the work machine based upon its operating slope or inclination. It would also be desirable if such a speed control system could also output appropriate signals to various speed retarding systems associated with a particular work machine to maintain the speed of the machine within proper operating speed limits while performing work on an inclined surface.
Accordingly, the present invention is directed to overcoming one or more of the problems as set forth above.
DISCLOSURE OF THE INVENTION
In accordance with the teachings of the present invention, an engine or work machine speed control system is disclosed wherein the attitude or inclination of the work machine is sensed and, based upon that particular slope or inclination, the control system determines the maximum ground speed or track speed of the work machine and monitors such ground speed so as to prevent the work machine from exceeding such maximum speed. In accordance with the operation of the present control system, the maximum speed limit of the work machine is directly related to the degree of slope or angle of inclination of the terrain upon which the work machine is operating. In this regard, the control system interfaces with an electronic control module (ECM) which outputs appropriate signals to other systems of the work machine to retard the ground speed of the work machine when the predetermined maximum speed limit for the particular slope of inclination is approached during operation conditions. For example, the present control system may output appropriate signals to the brake control system to modulate the brakes in order to assure that the maximum speed limit determined for that particular slope or inclination is not exceeded.
In another aspect of the present invention, the present control system will output appropriate signals to the engine governor to control the delivery of fuel to the engine and, if necessary, to shut off fuel to the engine, in order to maintain the ground speed of the work machine below the predetermined maximum speed limit.
Still further, in another aspect of the present invention, the present control system will output appropriate signals to the transmission control system so as to select and downshift the work machine into an appropriate gear that will again retard the ground speed of the machine so as to stay below the predetermined maximum speed limit.
The present control system therefore determines a maximum ground speed of the work machine based upon its operating slope or angle of inclination and thereafter outputs appropriate signals to appropriate retarding systems so as to maintain such ground speed below the predetermined maximum speed limit. The present system therefore allows the various systems and electronic control modules associated with the work machine to automatically control what a machine operator does today to properly manage machine speed and brake energy.
REFERENCES:
patent: 5560431 (1996-10-01), Stratton
patent: 5731761 (1998-03-01), Sychra
patent: 6030314 (2000-02-01), Brooks et al.
Caterpillar Inc.
Cuchlinski Jr. William A.
Haverstock Garrett & Roberts
Marc-Coleman Marthe
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