Methods and systems for intake air filter diagnostics
AssigneeFord Global Technologies, LLC
InventorAed M. Dudar
Life of this patent
Estimating the term…
Abstract
Methods and systems are provided for diagnostics of an intake air filter during vehicle-off conditions. In one example, the engine may be reverse rotated, unfueled, and air flow via the exhaust manifold and the intake manifold are estimated and compared to a baseline air flow. A blocked intake air flow may be indicated based on the comparison between air flow via the exhaust manifold and the intake manifold and the baseline air flow upon opening a secondary flow path to atmosphere.
Claims20
An engine method, comprising:
- during unfueled cranking of an engine while the engine is spun in reverse, indicating a blocked intake air filter based on air flow through an exhaust system relative to air flow through an intake system and further based on a change in the air flow through the exhaust system upon opening a secondary path to atmosphere.
An engine method for an autonomous vehicle, comprising:
- during a first engine condition when the vehicle is operated without a human driver and when the vehicle is not being propelled by engine torque, reverse rotating an engine, unfueled, and recording a first baseline intake air flow and a second baseline exhaust air flow;
- during a second engine condition, when the vehicle is operated without a human driver and when the vehicle is not being propelled by engine torque, reverse rotating the engine, unfueled, and recording an updated intake air flow and an updated exhaust air flow;
- and
- diagnosing a presence or an absence of degradation of an intake air filter based on a correlation amongst each of the first baseline intake air flow, the second baseline exhaust air flow, the updated intake air flow, and the updated exhaust air flow.
The method of 13, wherein diagnosing the presence of degradation of the intake air filter is based on the updated intake air flow being substantially equal to the updated exhaust air flow, the updated intake air flow being lower than the first baseline intake air flow, and the updated exhaust air flow being lower than the first baseline exhaust air flow, and the presence of degradation of the intake air filter bring further based on an increase in the updated exhaust air flow upon opening an air flow path from downstream of the MAF sensor to atmosphere.
A hybrid vehicle system, comprising:
- a vehicle;
- an engine;
- an electric machine coupled to a battery capable of rotating the engine;
- an intake passage including an intake air filter and a compressor;
- an exhaust passage including a particulate filter;
- a manifold air flow (MAF) sensor coupled to the intake passage;
- a differential pressure sensor coupled across the particulate filter;
- a canister purge line and a ventilation path coupling the intake passage to atmosphere via a canister, the canister purge line including a canister purge valve (CPV) and the ventilation path including a canister vent valve (CVV);
- and
- a controller with computer readable instructions stored on non-transitory memory for:
- obtaining a baseline air flow via the MAF sensor by reverse rotating the engine with the electric machine when the intake air filter is first installed;
- and
- after usage of the intake air filter for a threshold duration since the intake air filter is installed and while the engine is rotated in reverse by the electric machine,
- obtaining a first intake air flow via the MAF sensor and a first exhaust air flow via the differential pressure sensor,
- comparing the first intake air flow, the first exhaust air flow, and the baseline air flow;
- and
- in response to the first intake air flow and the first exhaust air flow being equal to one another and being lower than the baseline air flow, diagnosing the intake air filter responsive to a change in the first exhaust air flow following opening of the CPV and the CVV.
Dependencies are inferred from the claim text.