In June 2006, Mitsubishi Motors Mitsubishi Heavy Industries and Renault announced a joint development project for a new generation of clean diesel engines to be used in cars exported to Europe with a target of beginning mass production in 2010[2] and later announced that the engines will be gradually phased into other global markets.[3][4]
The preliminary version of the 1.8 L (1,798 cc) engine was first seen in the Concept-cX test car introduced in 2007. The larger 2.3 L (2,268 cc) was first exhibited in the Concept-ZT test car introduced in the same year and later used in the Concept-RA test car introduced in 2008.[5][6][7][8]
Together with Mitsubishi's electric vehicle technology the new diesel engines are positioned as a core element in the Mitsubishi Motors Environment Initiative Program 2010 (EIP 2010) announced in July 2006.[3][9]
The 4N1 engine family is the world's first to feature a variable valve timing (intake side) system applied to passenger car diesel engines.[10]
Mitsubishi's new clean diesel engines use a 200 MPa (2,000 bar) high-pressure common rail injection system to improve combustion efficiency. The 4N13 1.8 L (1,798 cc) uses solenoid fuel-injectors. The larger 4N14 2.3 L (2,268 cc) engine uses piezo fuel-injectors that produce a finer fuel spray. Both engines feature a fast ceramicglowplug system. The engines are designed to operate at a lower compression ratio, thus lowering the combustion pressure, allowing the use of an aluminium cylinder block that reduces weight.[1][11]
The 4N13 1.8 L (1,798 cc) engine uses a variable geometry (VG) turbocharger with a variable vane turbine, which provides optimal boost pressure control for different driving conditions. The 4N14 2.3 L (2,268 cc) engine also uses a VG turbocharger plus a variable diffuser (VD) that uses both variable geometry vanes in the turbine housing and a compressor with variable vanes in the diffuser passage, further improving combustion efficiency.[1][11]
Within the engine, Mitsubishi used an offset angle crankshaft that reduces friction, therefore noise and vibration, allowing the engine to run smoothly and quietly at all engine speeds.[1][11]
