Method and system for controlling water injection
AssigneeFord Global Technologies, LLC
InventorsThomas G. Leone, Kenneth James Miller
Life of this patent
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Abstract
Methods are provided for optimizing usage of water from a water injection system that injects water into the engine responsive to engine operating conditions such as knock, exhaust temperature, and dilution demand. An amount of water selected for injection purposes, as well as an order of water injection responsive to the various engine operating conditions, is varied based on a current water level relative to a predicted future water level. The method allows water usage benefits to be maximized particularly when water availability is limited.
Claims20
A method for a vehicle engine, comprising:
- comparing a current water level in a water reservoir and a predicted water level in the reservoir over a vehicle drive cycle to a plurality of threshold water levels;
- and
- injecting water from the reservoir into the engine responsive to each of engine knock, dilution demand, and exhaust temperature based on the comparison.
A method for a vehicle engine, comprising:
- determining first, second, and third amounts of water to inject into the engine responsive to each of knock, dilution demand, and exhaust temperature, respectively;
- in response to water level in a water reservoir coupled to a water injector being higher than a first threshold, injecting the first amount of water responsive to knock, then the second amount of water responsive to exhaust temperature, and then the third amount of water responsive to engine dilution demand;
- in response to the water level being higher than a second threshold but lower than the first threshold, injecting the first amount of water responsive to knock, then the second amount of water responsive to exhaust temperature, and not the third amount of water responsive to engine dilution demand;
- in response the water level being higher than a third threshold but lower than the second threshold, injecting only the first amount of water responsive to knock, but not the second amount of water responsive to exhaust temperature or the third amount of water responsive to engine dilution demand;
- and
- in response to the water level being lower than each of the first, second, and third threshold, temporarily disabling water injection.
A vehicle system, comprising:
- an engine including an intake manifold and an exhaust manifold;
- an exhaust catalyst coupled to the exhaust manifold;
- an EGR passage including an EGR valve for recirculating exhaust gas from the exhaust manifold to the intake manifold;
- a water injection system including a water reservoir, a water injector, and a water collection system;
- a water level sensor coupled to the water reservoir;
- a knock sensor coupled to the engine;
- and
- a controller with computer readable instructions stored on non-transitory memory for:
- comparing a current water level in the reservoir to a predicted water level after a duration of vehicle operation;
- determining respective amounts of water to inject into the engine responsive to each of knock, dilution demand, and exhaust temperature;
- selecting an amount of water to inject from among the respective amounts based on the comparing;
- delivering the selected amount of water via the water injector;
- and
- adjusting an opening of the EGR valve based on the dilution demand relative to the selected amount of water.
Dependencies are inferred from the claim text.