Newly Development Lead Free Copper Alloy Bushing for Fuel Injection Pump 2006-01-1103
In a common rail type fuel injection system installed in recent diesel engines, a supply pump is needed to accumulate high pressure fuel. In this supply pump, a bushing is used for the outer cam system. The bushing is lubricated by diesel fuel with relatively low viscosity and unit load of the bushing is higher. Therefore, lubricating film thickness of the bushing is extremely thin. In order to ensure the bushing function under such severe sliding conditions, the bushing is required higher seizure resistance and higher fatigue resistance. Conventionally, lead bronze alloys are applied for the bushing material. We developed a new high performance copper alloy material without lead, which is one of substances of environmental concern. The newly developed bushing contains bismuth instead of lead for tribological component. By fine distribution of bismuth in the copper alloy matrix having high corrosion resistance, the bushing has achieved higher seizure resistance and higher fatigue resistance. In addition, by adding hard particles into the alloy, wear resistance and seizure resistance are improved.