Diagnostic method for variable compression ratio engine
AssigneeFord Global Technologies, LLC
InventorMichael John Cullen
Life of this patent
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Abstract
A diagnostic method for a motor vehicle having an internal combustion engine operable in a plurality of compression ratio operating states includes the steps of determining a change in idle air flow of the engine as the engine is operated in selected ones of the compression ratio operating states, and evaluating operation of the internal combustion engine based at least in part on the change in idle air flow.
Claims23
A method for diagnosing operation of an internal combustion engine having a plurality of compression ratio operating states, comprising:
- determining a first idle air flow as the engine is operated in a first of the compression ratio operating states;
- determining a second idle air flow as the engine is operated in a second of the compression ratio operating states;
- and
- evaluating operation of the internal combustion engine based at least in part on the first and second idle air flows.
A diagnostic method for an internal combustion engine having a compression ratio setting apparatus, the compression ratio setting apparatus being operable to configure the engine in a plurality of compression ratio operating states, the method comprising:
- determining a first idle air flow at a first of the compression ratio operating states;
- determining a second idle air flow at a second of the compression ratio operating states;
- comparing the first idle air flow to the second idle air flow;
- and
- evaluating operation of the variable compression setting device based at least in part on said comparison step.
A diagnostic method for a motor vehicle having an internal combustion engine, the internal combustion engine having a compression ratio setting apparatus operable to configure the engine in a high compression operating state and a low compression operating state, the method comprising:
- commanding the compression ratio setting apparatus to operate the engine in the high compression operating state;
- determining an average idle air flow while operating the engine in the high compression ratio operating state;
- commanding the compression ratio setting apparatus to operate the engine in the low compression operating state;
- determining an average idle air flow while operating the engine in the low compression ratio operating state;
- determining a difference between the average idle air flow at the low compression operating state and the average idle air flow at the high compression operating state;
- comparing the difference to a predetermined limit;
- setting an operational status flag for the compression ratio setting apparatus based on said comparison step.
A system for operating an internal combustion engine having a plurality of compression ratio operating states, the system comprising:
- a sensor disposed within the engine for generating a signal representative of idle air flow into the engine;
- a compression ratio setting apparatus for configuring the engine in selected ones of the compression ratio operating states;
- and
- a controller in communication with said sensor and said compression ratio apparatus comprising computer program means for determining a first idle air flow of the engine as the engine is operated in a first of the compression ratio operating states, for determining a second idle air flow of the engine as the engine is operated in a second of the compression ratio operating states, and for evaluating operation of the internal combustion engine based at least in part on the first and second idle air flows.
Dependencies are inferred from the claim text.