Compression ignition engine with low load rapid warm up strategy
AssigneeCaterpillar Inc.
InventorsMatthew Wolk, Gurudutt Nayak
Life of this patent
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Abstract
An electronically controlled compression ignition engine includes an electronic engine controller in control communication with fuel injectors, a high pressure exhaust recirculation system and a variable geometry turbocharger. The controller is configured to execute a low load rapid warm up algorithm that generates control signals to reduce turbine efficiency, set an air fuel ratio in a predetermined range, set the exhaust gas recirculation in a predetermine range and supply fuel in a split injection in each engine cycle that includes a main injection initiated before top dead center and a post injection initiated after top dead center. These settings allow for rapid warm up to the aftertreatment inlet in excess of 300° C.
Claims20
An electronically controlled compression ignition engine comprising:
- an engine housing that defines a plurality of cylinders;
- electronically controlled fuel injectors positioned for direct injection into respective ones of the plurality of cylinders;
- an electronically controlled high pressure exhaust recirculation system attached to the engine housing;
- an electronically controlled variable geometry turbocharger fluidly connected to the engine housing;
- an electronic engine controller in control communication with the fuel injectors, the high pressure exhaust recirculation system and the variable geometry turbine;
- the electronic engine controller is configured to execute a low load rapid warm up algorithm that generates control signals for a turbine efficiency below 26%, an air fuel ratio in a range between 20:1 and 30:1, an exhaust gas recirculation in a range between 28% and 36%, and a split fuel injection in an engine cycle that includes a main injection initiated before top dead center and a post injection initiated after top dead center.
A method of rapidly warming up an aftertreatment inlet temperature at low load conditions for a compression ignition engine equipped with a variable geometry turbocharger, electronically controlled fuel injectors and a high pressure exhaust gas recirculation loop, comprising the steps of:
- setting turbine efficiency below 26%;
- setting an air fuel ratio in a range between 20:1 and 30:1;
- setting an exhaust gas recirculation in a range between 28% and 36%;
- injecting fuel in a split injection with a main injection and a post injection in a same engine cycle, with the main injection being initiated before top dead center, and the post injection being initiated after top dead center.
Dependencies are inferred from the claim text.