d. Operation of the Supply Pump ‡ As shown in the illustration below (in case of HP3 pump), the rotation of the eccentric cam causes the ring cam to push Plunger A upwards. Due to the spring force, Plunger B is pulled in the opposite direction to Plunger A. ‡ As a result, Plunger B draws in fuel, while Plunger A pumps it to the rail. In the case of the 4-cylinder engine used with the HP3 pump, each plunger pumps fuel in a reciprocal movement during the 360 cam rotation. ‡ Conversely, in the case of the 6-cylinder engine used with the HP4 pump, 3 plungers pump fuel in a reciprocal movement for each one rotation of the cam. (IPMZIV]:EPZI 7YGXMSR:EPZI 4PYRKIV% )GGIRXVMG'EQ 6MRK'EQ 7':
4PYRKIV& 4PYRKIV%'SQTPIXI'SQTVIWWMSR 4PYRKIV&&IKMR'SQTVIWWMSR 4PYRKIV%&IKMR-RXEOI 4PYRKIV&'SQTPIXI-RXEOI 4PYRKIV&&IKMR-RXEOI 4PYRKIV%&IKMR'SQTVIWWMSR 4PYRKIV%'SQTPIXI-RXEOI 4PYRKIV&'SQTPIXI'SQTVIWWMSR 5() There are 3 plungers for the HP4. -12-