Method and system for determining knock control fluid composition
AssigneeFord Global Technologies, LLC
InventorsMohannad Hakeem, Gopichandra Surnilla
Life of this patent
Estimating the term…
Abstract
Methods and systems are provided for accurately determining the composition of a knock control fluid using sensors already present in the engine system. An intake or an exhaust oxygen sensor is used to estimate the water and the alcohol content of a knock control fluid that is direct injected into an engine cylinder responsive to an indication of abnormal combustion. A change in the pumping current of the oxygen sensor due to the water content of the knock control fluid is distinguished from a change in the pumping current of the oxygen sensor due to the alcohol content of the knock control fluid.
Claims20
An engine method, comprising:
- injecting an amount of a water-alcohol blend including no gasoline, the water-alcohol blend including water and alcohol;
- modulating a reference voltage of an exhaust oxygen sensor;
- monitoring a change in pumping current of the sensor during the modulating;
- learning a first portion of the change in pumping current due to a water content of the blend based on the monitored change in pumping current;
- and
- learning a second portion of the change in pumping current due to an alcohol content of the blend based on the monitored change in pumping current and the injected amount.
A method for an engine, comprising:
- operating the engine at a first condition, and, during operation at the first condition, injecting a water-alcohol blend including water and alcohol and containing no gasoline into an engine cylinder, and learning an alcohol composition of the water-alcohol blend based on a change in pumping current of an exhaust oxygen sensor and an injection mass;
- and
- operating the engine at a second condition, and, during operation at the second condition, injecting a gasoline-alcohol blend into the engine cylinder, and learning an alcohol composition of the gasoline-alcohol blend based on the change in pumping current.
An engine system, comprising:
- an engine including an intake manifold and an exhaust manifold;
- a crankcase coupled to the intake manifold via a crankcase ventilation valve;
- a first injector for injecting fuel into an engine cylinder;
- a second injector for injecting wiper fluid into the intake manifold downstream of an intake throttle;
- a canister configured to receive fuel vapors from a fuel tank, the canister coupled to the intake manifold via a purge valve;
- an EGR system including a passage for recirculating exhaust residuals from the exhaust manifold to the intake manifold via an EGR valve;
- an oxygen sensor coupled to the exhaust manifold;
- and
- a controller with computer readable instructions stored on non-transitory memory for:
- closing each of the EGR valve, the purge valve, and the crankcase ventilation valve;
- injecting an amount of wiper fluid via the second injector into the intake manifold, the wiper fluid including water and alcohol and no gasoline;
- modulating a reference voltage applied to the oxygen sensor between a first voltage and a second voltage;
- measuring a change in pumping current of the oxygen sensor during the modulating;
- and
- estimating a composition of the wiper fluid based on the injection amount and the measured change in pumping current.
Dependencies are inferred from the claim text.