Introduction; Definition Of Terms And Abbreviations; Principle Of Operation - Delphi YDT262 Manual De Funcionamiento Y Servicio

YDT262 Operating and Servicing Manual

1. Introduction

The Dynamic Timing Control Box (YDT262) is used to determine the timing position of diesel fuel
injection pumps. It is used in conjunction with a host test bench (to mount and drive the fuel pump), a
rotary encoder (providing angular position information), and a piezo pickup (giving the point of
injection signal).

2. Definition of Terms and Abbreviations

The following terms and abbreviations are used in this manual and/or in the YDT262 software.
SP Start Position. The box records a reference point for starting position (effectively
0 degrees). This is used later when calculating the Overcheck Angle.
Offset The angular offset to be applied from the point of injection to the locking position.
Trigger Level The piezo signal trigger level at which the angular position is recorded.
POI Point of Injection
RLP Required Locking Position. This is equal to POI plus/minus the Offset.
Overcheck Angle The difference between SP and RLP.

3. Principle of Operation

The rotary encoder is mounted on the pump drive coupling and the piezo pickup is connected to one
of the pump delivery valves. The piezo pickup provides a signal once every revolution at the point of
injection. By comparing this signal with the angular position information from the rotary encoder, the
point of injection angle is found.
The actual position is found by taking a number of samples at a given speed. The software then
calculates the average position and, once the drive has been stopped, provides you with an angular
countdown so that you can rotate the pump around to that position.
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DELPHI DIESEL AFTERMARKET
HL018, Issue 2