Power plants – System having plural motors or having diverse types of... – Having condition responsive control
Reexamination Certificate
2000-09-27
2001-05-22
Nguyen, Hoang (Department: 3747)
Power plants
System having plural motors or having diverse types of...
Having condition responsive control
C060S719000
Reexamination Certificate
active
06233943
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention is generally related to control of internal combustion engines, and, more particularly, the present invention is related to system and method for synchronizing engine speed in boats equipped with multiple engines.
Reciprocating internal combustion engines may create high acoustical noise and vibration during operation. Particularly in the case of vessels equipped with paired engines as their primary propulsion device, it is desirable to run such vessels with each engine operating synchronized relative to one another, that is, each engine should operate at the same or nearly the same speed. Lack of engine synchronization may cause annoying beat frequencies that would result in annoying discomfort to the occupants of the vessel. Under some known techniques, the engine synchronization may be attempted by manual adjustment of the throttle levers at the helm of the vessel. At best such techniques may only be partly effective since they may require human intervention, such as helmsman's observation of engine speed meters, e.g., tachometers, in conjunction with manual adjustment of the throttle levers. Under such techniques, the occupants of a multi-engine vessel with engines running at cruising speeds are often subjected to unpleasant noise and transmission and/or engine vibration when the respective speed or revolutions per minute (rpm) of the two or more propulsion engines are not held very close to one another, that is, when the engines are not synchronized.
As will be understood by those skilled in the art, most modern relatively large marine engines for pleasure boats and other marine vessels may be operated from a helm station using remote engine controls with throttle and shift engine control inputs conveyed to the engine by mechanical push-pull cables. Unfortunately, even relatively minor variations in control mechanisms, control cables, control cable routing, and engine throttle control linkages, and the adjustments thereof can collectively result in substantial differences in mechanical efficiency between the remote control lever and the engine's input signal device. Thus, in the case of known automated synchronizers, since these synchronizers generally rely on mechanically adjusting the respective throttle levers and throttle valves and associated cabling, these automated synchronizers tend to be expensive and unaffordable in small boat applications and subject to the above-described difficulties of having to provide mechanical control to a relatively inaccurate system. Engine control may be further complicated by routine engine operations, such as rotation of the engine about its steering axis or tilting (trimming) of the engine about its tilt axis, which operations can also affect mechanical throttle input to the engine's input signal device.
In view of the foregoing issues, it should be appreciated that remote control of throttle lever position by controlling lever or handle position relative to the other, either manually or automatically, can become unwieldy since such levers may become substantially offset relative to one another or have unpredictable relative position and often do not provide equal throttle control input and fail to provide appropriate engine synchronization even though the levers may be physically adjacent to one another. Thus, it is desirable to overcome the disadvantages of presently available remote engine control systems and to accurately synchronize engine speeds by utilizing microprocessor-based system and techniques to compare engine speeds and adjust engine power output electronically, thus achieving accurate and reliable engine synchronization by electronically controlling engine power independent of the respective primary throttle control input signal supplied to each engine.
SUMMARY OF THE INVENTION
Generally speaking, the foregoing needs are fulfilled by providing in one aspect of the present invention a computerized system for controlling a plurality of internal combustion engines. The system comprises a respective speed sensor coupled to a corresponding engine to supply a respective speed sensor signal indicative of each engine's speed. The system further comprises an electronic control unit coupled to receive each respective speed sensor signal. The control unit in turn comprises a comparator module configured to compare each speed sensor signal relative to one another and supply a comparator output signal based on the magnitude of any differences between the engine speed signals. A processor module is responsive to the comparator output signal to adjust one or more engine operational parameters of one or more of the plurality of engines. The one or more engine operational parameters are responsive to respective control signals from the control unit to affect engine speed to reduce the magnitude of the engine speed differences so as to maintain each engine speed within a predefined range from one another.
The present invention further fulfills the foregoing needs by providing in another aspect thereof a computer-readable medium encoded with computer program code for controlling a plurality of marine internal combustion engines. Each engine has a corresponding speed sensor coupled to supply a respective speed sensor signal indicative of each engine's speed. The program code causing a computer to execute a method that allows for comparing each speed sensor signal relative to one another to supply a signal based on the magnitude of any differences therebetween. The method further allows for processing the signal based on the magnitude of the engine speed differences to adjust one or more engine operational parameters of one or more of the plurality of engines. A generating step allows for generating respective control signals to cause the one or more engine operational parameters to affect engine speed of one or more of the plurality of engines so as to maintain each engine speed within a predefined range from one another.
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Beacom William Frederick
Manchester Arthur Gray
Duckworth Robert W.
Holland & Knight LLP
Mora Enrique J.
Nguyen Hoang
Outboard Marine Corporation
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