Mitsubishi 4A9 engine
| 4A9 | |
|---|---|
| Overview | |
| Manufacturer | MDC Power |
| Production | 2004–present |
| Combustion chamber | |
| Cylinder block alloy | Aluminum die cast |
| Cylinder head alloy | Aluminum die cast |
| Valvetrain | Direct acting DOHC, 16 valves, continuously variable MIVEC intake valve timing |
| Chronology | |
| Predecessor | Mitsubishi 4G1 engine |
The Mitsubishi 4A9 engine is the newest family range of all-alloy inline four-cylinder engines from Mitsubishi Motors, introduced in the 2004 version of their Mitsubishi Colt supermini, and built by DaimlerChrysler-owned MDC Power in Germany (previously a joint venture).
The engine project was begun as a joint effort by Mitsubishi Motors and DaimlerChrysler (DCX), with Mitsubishi handling the development of the engines and MDC Power GmbH, a company previously jointly established by Mitsubishi and DCX, handling production. The 4A9 is Mitsubishi's first four-cylinder engine family to adopt a high-pressure die-cast aluminum block.
All engines developed within this family have aluminum cylinder block and head, four valves per cylinder, double overhead camshaft layouts, and MIVEC continuous variable valve timing (intake only).
For high output and low fuel consumption, the MIVEC system and other measures (including optimized shaping of the intake and exhaust manifolds and cylinder head) were used to promote intake and exhaust efficiency. Optimally shaped cooling passages in the cylinder head and optimal control of the flow of coolant into the cylinder head help to suppress engine knocking. Comprehensive measures to engine components were taken to minimize friction.
For lightness and compactness; design optimization, material optimization, and component integration were identified as effective means of minimizing weight and bulk, so they were comprehensively effected in combination with each other. With regard to materials, the cylinder block is made of aluminum; the cylinder-head cover and intake manifold are made of plastic; the exhaust manifold has a pipe-based structure and cams driven by a timing chain. Component integration was applied in many areas of the engine. Notably, the functions of engine accessories were integrated into the cylinder block.
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