3. Construction and Operation 3-1. Description of Main Components A. Supply Pump (HP3, HP4) a. Outline The supply pump consists primarily of the pump body (cam shaft, ring cam, and plungers), SCV (Suction Control Valve), fuel temperature sensor, and feed pump. ,4 7': *YIP8IQTIVEXYVI7IRWSV 5) ,4 *YIP8IQTIVEXYVI7IRWSV 7': 5) ‡ The two plungers for HP3 or the three plungers for HP4 are positioned vertically on the outer ring cam for compactness. ‡ The engine drives the supply pump at a ratio of 1:1. The supply pump has a built-in feed pump (trochoid type), and draws the fuel from the fuel tank, sending it to the plunger chamber. -6-