Measuring and testing – Vehicle chassis – Steering
Reexamination Certificate
1999-03-31
2001-05-22
McCall, Eric S. (Department: 2855)
Measuring and testing
Vehicle chassis
Steering
Reexamination Certificate
active
06234010
ABSTRACT:
TECHNICAL FIELD
This invention relates generally to a reciprocating internal combustion engine, and more particularly, to a method and system for predicting torque from crank speed fluctuations in an internal combustion engine.
BACKGROUND ART
Knowing the torque that an engine delivers when running is important for both a determination of engine starting power and total power loss for an engine. Power loss conditions in internal combustion engines present several problems, including increased down time and excess exhaust emissions. Excess exhaust emissions are extremely problematic since government regulations are making more stringent demands or limits on the exhaust emissions of internal combustion engines (diesel or spark ignited). Power loss can be caused by complete and/or partial misfires or clogged fuel injectors. Typically, on-line, crankshaft torque measurements require expensive measuring devices such as dynamometers.
The present invention is directed to overcoming one or more of the problems set forth above.
DISCLOSURE OF THE INVENTION
In one aspect of the present invention, a method for detecting torque of a reciprocating internal combustion engine is disclosed. The engine has a plurality of reciprocating components including, but not limited to, at least one cylinder and a rotatable crankshaft. The method includes the steps of sensing rotational crankshaft speed for a plurality of designated crankshaft rotational positions over a predetermined number of cycles of rotation for each crankshaft position and determining an average crankshaft speed fluctuation for each crankshaft position and determining information representative of crankshaft kinetic energy variations due to each firing event and each compression event in the cylinder and then determining information representative of crankshaft torque as a function of the crankshaft kinetic energy variations and the average crankshaft speed and responsively producing a representative crankshaft torque signal.
In another aspect of the present invention, a system for detecting torque of a reciprocating internal combustion engine is disclosed. The engine has a plurality of reciprocating components including, but not limited to, at least one cylinder and a rotatable crankshaft. The system includes an input mechanism that generates a signal, including a value for rotational crankshaft speed for a plurality of designated crankshaft rotational positions over a predetermined number of cycles of rotation for each crankshaft position and an electronic controller for determining an average crankshaft speed fluctuation for each crankshaft position and determining information representative of crankshaft kinetic energy variations due to each firing event and each compression event in the cylinder and then determining information representative of crankshaft torque as a function of the crankshaft kinetic energy variations and the average crankshaft speed and responsively producing a representative crankshaft torque signal.
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patent: 5878366 (1999-03-01), Schricker et al.
Schricker David R.
Zavarehi Masoud K.
Caterpillar Inc.
Kercher Kevin M.
Kibby Steven G.
McCall Eric S.
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