NOx mitigation strategy in methanol internal combustion engine
AssigneeCaterpillar Inc.
InventorsKenth I Svensson, David Todd Montgomery
Life of this patent
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Abstract
Operating an internal combustion engine system includes feeding a stream of pressurized intake air to a plurality of cylinders in an engine for combustion with a methanol fuel. An engine parameter indicative of at least one of an exhaust NOx level or a change to the exhaust NOx level of the engine is monitored, and water injected into an intake conduit for the engine based on the monitored engine parameter to limit the exhaust NOx level of the engine. Related apparatus and control logic is disclosed.
Claims20
A method of operating an internal combustion engine system comprising:
- feeding a stream of pressurized intake air from a compressor through an intake conduit to a plurality of cylinders in an engine;
- admitting a methanol fuel to the plurality of cylinders by way of a plurality of methanol admission valves fluidly connected to a methanol fuel supply;
- igniting the methanol fuel in each of the plurality of cylinders;
- combusting the methanol fuel and the pressurized air in the plurality of cylinders;
- monitoring an engine parameter indicative of at least one of an exhaust NOx level or a change to the exhaust NOx level of the engine;
- injecting water, for reducing or limiting temperature in the plurality of cylinders, into the stream of pressurized intake air, based on the monitored engine parameter;
- and
- limiting the exhaust NOx level of the engine based on the injecting water;
- and
- heating the water prior to the injecting the water into the stream of pressurized intake air.
An internal combustion engine system comprising:
- a methanol fuel supply;
- an engine having a plurality of combustion cylinders formed therein, and a plurality of methanol admission valves fluidly connected to the methanol fuel supply;
- an intake conduit including a water port, and extending to the engine to feed a stream of pressurized intake air to the plurality of cylinders;
- a water injector coupled to the water port;
- a sensor structured to monitor an engine parameter indicative of at least one of an exhaust NOx level of the engine or a change to an exhaust NOx level of the engine;
- a NOx control unit coupled to the sensor and in control communication with the water injector, the NOx control unit being structured to:
- receive data of the monitored engine parameter produced by the sensor;
- and
- output a water injection command to the water injector based on the data, to limit the exhaust NOx level of the engine via injection of water into the intake conduit.
A NOx control system for an internal combustion engine comprising:
- a water supply conduit;
- a water injector fluidly connected to the water supply conduit;
- a heater coupled to the water supply conduit and structured to heat water conveyed to the water injector sufficiently for injection as steam into an intake conduit for the engine;
- a sensor structured to monitor an engine parameter indicative of at least one of an exhaust NOx level or a change to an exhaust NOx level of the engine;
- and
- a NOx control unit coupled to the sensor and in control communication with the water injector, the NOx control unit being structured to:
- receive data of the monitored engine parameter produced by the sensor;
- compare an exhaust NOx level indicated by the data to a target NOx level;
- output a water injection command to the water injector based on a difference between the indicated exhaust NOx level and the target NOx level;
- and
- limit the exhaust NOx level of the engine based on an injection of water as steam produced in response to the water injection command.
Dependencies are inferred from the claim text.