PURPOSE: To nitrogen, maintain a stable quality assurance, and increase durability by providing a three way catalyst or NOx reduction catalyst and ammonia denitrogen catalyst.
CONSTITUTION: A cylinder 13 is operated at a theoretical air/fuel ratio or in rich fuel condition as a cylinder to generate ammonia by three way catalyst, and cylinders 14 to 16 are operated by lean burning. If injectors 5 to 8 inject the same amount of fuel, an unbalance of output torque is generated due to a difference in air/fuel ratio. To prevent this, a throttle valve 3 is throttled so as to control the output of the cylinders to the same level. Also the exhaust gas discharged from the cylinder 13 enters the three way catalyst 18 to generate ammonia. In the other cylinders 14 to 16, NOx is generated because lean burning is made in them. The ammonia and NOx thus generated enter an ammonia denitration catalyst 19, and NOx is reduced to nitrogen by ammonia.
KITAHARA YUICHI
EBISAWA MAKOTO
KURODA OSAMU
IIZUKA HIDEHIRO
HITACHI CAR ENGINEERING KK
Katsuo Ogawa (1 person outside)