Technical Paper
Development of 4D95 Engine Series Meeting Tier3
Masaki Tanaka Keisuke Inoo Jun Oshima Masaki Shinohara
The ecot3 engine has been developed and sold on the market as a Komatsu engine series that complies with the Tier3 exhaust gas regulation. Komatsu has recently completed the development and market entry of its 4D95 engine series as the anchor engines in the series. Not only exhaust gas regulation, but also low noise and a high fuel consumption efficiency are the important missions in engine development as social demands. The 4D95 engine series accomplishes these missions and features a good balance without sacrificing the engine placement property in the vehicle and versatility, which are other missions of the small engine, by incorporating the state-of-the-art technology to clear the exhaust gas regulation. Four models in the 4D95 engine series are overviewed and their technical features are introduced. Key Words: Diesel engine, environmentally friendly, Tier3, electronic control, common rail system, swirl current chamber system
1. Background
Komatsu has successively developed and commercialized its engine ecot3 complying with the Tier3 exhaust gas regulations. The production of an engine series with a piston displacement of 4.5 to 23 liters covering an output range of 75 to 560kW had been completed by early 2006. Subsequent to the production of this engine series, the production of the 4D95 engine series (piston displacement of 3.3 liters) representing the smallest piston displacement in the engine series of Komatsu has recently been completed. The 4D95 engine series complying with the Tier2 exhaust gas regulation has covered the output range of 40 to 75kW by a combination of three aspirations (NA [naturally aspirated engine], T [with turbo] and TAA [with turbo and air-cooled aftercooler]) and a mechanical fuel injection pump. To comply with the stricter Tier3 exhaust gas regulation, however, a specification to equip an electronically controlled high-pressure injection system (common rail system) has been added, to cover the output range of 82kW maximum. Taking the installability and versatility into consideration, the specification that covers the same output range as that of the Tier2 exhaust gas regulation continuously uses the mechanical fuel injection pump. To comply with the emission regulation, the combustion system of the NA and T specifications has been changed to the swirl current chamber system (IDI - indirect injection). This paper overviews the 4D95 series, which is regarded as the anchor engines in the Komatsu ecot3 series, and describes its technical features.

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