DUAL FUEL COMPRESSION IGNITION INTERNAL COMBUSTION ENGINE SYSTEM EMPLOYING COMPRESSED NATURAL GAS AND DIESEL AND METHOD OF OPERATING THE SAME

摘要

Dual fuel compression ignition internal combustion engine system employing compressed natural gas and diesel and method of operating the same The engine system (1) includes an exhaust gas recirculation loop (27) having a catalytic converter (25) in the exhaust outline (11) of the engine (2) and passing through a gas cooler (28). The engine includes an exhaust plenum chamber (24) in the exhaust outlet line trailing the catalytic converter and a mixing chamber (26) in the air inlet line (8). The inlet of the exhaust gas recirculation loop is connected across the exhaust outlet line through a first bypass line (28) disposed before the catalytic converter and having a first bypass valve (29) and is further connected across the exhaust outlet line through a second bypass line (30) disposed after the catalytic converter and having a second bypass valve (31). A ring CNG injector (16) is coaxially located with the air intake manifold and has a row of nozzles (21) radially equally spaced from one another and directed towards the centre of the ring injector. The exhaust outlet line includes an exhaust outlet control valve (32) at the outlet end thereof past the second bypass line. Engine is operated in two modes. In mode 1, bypass line 30 is bypassed and in mode 2, bypass line 28 is bypassed (Fig 1).