Tuesday, 28 March 2017, 08:50 PM

Site: CP Fitters, Phase 2 Apprenticeship Training, Ireland
Course: CP Fitters, Phase 2 Apprenticeship Training, Ireland (CP Fitters Homepage)
Glossary: Course Glossary



> means greater than -example 2 > 1

< means less than - example 1 < 2

≤ means less than or equal to.

≥ means greater than or equal to.


Lambda, a letter from the Greek alpahbet. In automotive engineering, it is used to represent the stoichiometric ratio of the amount of air required to burn a fuel. For example, for diesel, the value is approximately 14.5:1, meaning that it takes 14.5 parts of air to burn 1 part of diesel.

The stoichiometric ratio for petrol is approximately 14.7:1.


Animated image explaining Pi

Pi, Greek letter used to represent how many times the diameter of a given circle will fit into its circumference. This is constant at 3.142. Apprentice cp fitters use this figure for many calculations, for example: when calculating the capacity of an engine; when calculating centrifugal force and when calculating the peripheral speed of a cutting disk.

The Greek alphabet



1104D Perkins common rail engineThis is a Perkins designation, and refers to the 1100 series engine. The '4' refers to a four cylinder engine, and the 'D' refers to the common rail engine.

This engine has full electronic control of the fuel system - common rail with electronic injectors. 

As of April, 2012, we operate 3 of these engines.


The 1106C Perkins diesel engineThis designation refers to the 1100 series Perkins engine. The '6' refers to the number of cylinders, and the 'C' refers to the fuel injection system, which is mechanical, based around a rotary fuel injection pump. This engine is the forerunner of the 1100D common-rail engine. Currently, the section is equipped with 6 1106C engines and 3 1104D engines.


Typical 12 volt electrical test lampThis consists of a 12V lamp, with two different terminals. One terminal (the earth terminal) consists of a short cable and a crocodile clip. The other terminal is at the pointed end of the tool. It is used by fastening the crocodile clip to a good earth point, and then using the sharp end of the took to probe wires. If the wires are live, the lamp will glow.

During the induction phase of the course, you will be issued (at your own expense) with a 12V test lamp.

You can see the most current prices of this and all the other items issued on repayment here...


Typical diodeOne of a series of diodes (the 1N4000 series). They are popular, 1 amp, general purpose, silicon rectifier diodes.

During the Phase 2 course, we use these diodes to make half-wave rectifiers, full-wave rectifiers, and to suppress voltage spiking on 30 amp relays in circuits such as the time-delay circuit built as part of the Electrical Module.


1N5819 diodeFrom the data sheet:

"Axial Power Schottky rectifier suited for Switch Mode Power Supplies and high frequency DC to DC converters."

Because it is a Schottky diode, it has a relatively low forward voltage drop (0.2V compared to 0.6V for a signal diode such as the 1N4001.

This low voltage drop makes this diode suitable for use in rectifiers.


Crowsfoot injector removal toolCrow's foot tool that allows you to tighten injector pipe unions with a 3/8" torque wrench.



The 3 effects of electicity.

3 Effects of electricity:

  1. Chemical change  - For example, the electrolyte in a battery changes from sulphuric acid (H2SO4) when the battery is charged, to water, H2O, when the battery is discharged.
  2. Heat - For example, current passed through a bulb causes the filament to glow white hot. This is incandescent heat.
  3. Magnetism - for example, when we pass electrical current through the commutator and the field windings of a motor, like poles come into close proximity. These poles repel each other, giving us the motoring action.