| Fuel pump delivry is controlled by suction and spill valves. As plunger moves down, the suction valve is open and fuel-oil is drawn in to barrel. As plunger moves up fuel is displaced through still open suction valve and delivery commences as suction valve closes and commences till spill valve open. |
Since very small needle lift is obtained in the test equipment result in an unequal pressure distribution in the cut off shaft resulting in a hard contact in a small area along with high frequency oscillations, low lubricity of test oil will increase the chance of seizure. Full lift and high lubricity of heavy oil eliminates this risk of seizure during normal operation.( Always open and clean slide type valves before testing as cold sticky heavy oil along with small clearances can cause restriction in the movement of the spindle).
Comments