Patent ID: 9243533
Filing Date: 2016-01-26
CPC Classification: B01D,F01N,F02D,Y02T

Claim Text:
1. An engine system comprising: an exhaust path through which an exhaust gas from an engine passes; a urea injection valve that injects urea into the exhaust path; a catalyst that is provided in the exhaust path downstream of the urea injection valve, and that selectively reduces NOx by using ammonia acting as a reducing agent, the ammonia being generated by hydrolyzing injected urea from the urea injection valve; a heating portion that is capable of heating the catalyst and the injected urea; and a controller programmed to perform a first control and a second control, wherein in the first control, the urea injection valve injects urea, and the heating portion heats the injected urea to a first temperature at which ammonia is generated from the injected urea, wherein in the second control, the heating portion increases a temperature of the catalyst to a second temperature that is lower than the first temperature at which NOx can be reduced, and wherein the first control is performed based on an amount of ammonia adsorbed on the catalyst being smaller than a predetermined value, and the second control is performed based on the amount of ammonia adsorbed on the catalyst being equal to or larger than the predetermined value.