Monday, 1 June 2020, 10:34 AM

Site: CP Fitters' Phase 2 Apprenticeship Training
Course: CP Fitters' Phase 2 Apprenticeship Training (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.

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.



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 12V electrical training boardDuring the electrical module, one of the suggested exercises is to construct various electrical circuits such as parking lamps, headlamps (including relays) and glow plug circuits (including solenoid control).

In order to facilitate this exercise, we use 12V electrical training boards. These are boards of steel construction, with a working tray and a base that can accommodate a 12V battery.

This set up allows apprentices to construct the various circuits, and connect the board to an engine fitted with an alternator.

This set up allows each apprentice to wire up all the basic electrical circuits and components found in a typical plant vehicle.


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.


Visual explanation of the dimensions of an 18650 battery

CAUTION: Li-ion batteries do not behave the same way as lead acid batteries do, when they are being charged and discharged.
Make sure you know how these batteries operate, how they are charged and how you can safely use and discharge them.
If this type of battery is mis-handled or abused in any way (physically damaged), there is an immediate and great risk of fire or explosion.

The number '18650' describes a battery, similar in size to an AA battery.

An 18650 is a lithium ion rechargeable battery. The correct name is “18650 cell”.

The 18650 cell has voltage of 3.7v and a capacity of between 1800mAh and 3500mAh.

The cell name is based on its dimensions: the cell is 18mm in diameter and 65mm in length.

For comparison purposes, an AA cell is a 14500 cell - 14mm in diameter and 50mm in length

Typical 18650 batteries


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.


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