Method and apparatus for testing a gear-driven fuel pump on a fuel injected IC engine

Apparatus for testing a fuel pump in a fuel supply system on a fuel injected IC engine, the pump having a pumping element for supplying fuel injectors via a fuel rail, the apparatus comprising:

• a computer programmed with
• (a) software for providing a pump element pumping event;
• (b) software for disabling overlapping injectors during a test period that includes the pumping event;
• (c) software for measuring pressure in the rail at at least two engine crank angles surrounding the pumping event during the test period;
• and
• (d) software for determining a pump fuel delivery rate value based on the measured rail pressures, wherein the computer is operatively interconnectable to the engine.

A method for determining a quantitative leakage rate in a fuel supply system of a fuel injected IC engine, the fuel system including a fuel pump with one or more pumping elements supplying injectors via a fuel rail, the method comprising:

• (a) establishing steady state engine operating conditions with fuel rail pressure at a predetermined value;
• (b) disabling all injectors and all pumping events during a test period;
• (c) measuring rail pressure at preselected first and second crank angles during the test period, the first crank angle being advanced relative to the second crank angle;
• and
• (d) calculating the leakage rate based on a pressure drop determined from the measured rail pressure of the first crank angle relative to the measured rail pressure at the second crank angle.