This course lays a foundation for understanding and working with all machines.
Each lesson builds upon what you learnt in the previous ones, gradually expanding your awareness and understanding of how and where engines can be used to power machines, and how different types of machines function.
There are 8 lessons in this course:
Introduction to Engines and Motors -petrol, gas, electric
Machines and their parts
Drive Mechanisms -Transmissions, Gears, Belts
Optimising Function & Longevity
Brake Systems – Pneumatic Brakes, Hydraulic Brakes
The Mechanics Workshop – equipment, tools, safety etc
Each lesson culminates in an assignment which is submitted to the school, marked by the school's tutors and returned to you with any relevant suggestions, comments, and if necessary, extra reading.
Explain how different types of engines and motors work.
Describe the features that differentiate the quality and work capacity of engines; one from another.
Describe the scope and nature of components of a machine.
Explain different ways of converting the movement of energy to perform useful work tasks.
Describe how machinery can deteriorate over time, and responses to both prevent and repair deterioration.
Explain how engines and motors have their power output regulated.
Explain the mechanisms used to slow or stop any form of motion by applying force.
Describe machinery workshop tools and equipment, and explain their safe and appropriate use in maintaining and repairing machinery.
Machines are powered by engines (or motors).
Parts of a machine will usually include two types of parts, beyond the engine itself.
1. Parts that translate engine movement to a useful function (eg. the cutting blades on a lawn mower, the rotating wheels in a car)
2. Parts that support the operation of the engine (ie. allowing it’s speed and temperature to be controlled, and reducing negative effects such as exhaust fumes or power loss through friction).
Engines can need a variety of systems to support their operation, including: Cooling systems to stop the engine from overheating; lubrication Systems to prevent wear and tear on moving parts (reduce friction between parts and allow movement with less energy loss); ignition systems provide a spark of electricity to ignite petrol; and transmission systems transmit power/movement from the point of production to the point of use (e.g. Wheels of a car).
Where Does the Power Come From?
Motors or engines need energy to work. That energy may commonly come from burning something, or from electricity.Electric motors are run by electricity delivered to the motor. Petrol engines can be more complicated,requiring a system to deliver the appropriate quantity of fuel, in an appropriate way, and at an appropriate rate (ie. a fuel system).
The task of the fuel system is to supply clean fuel and air in the correct proportions, the correct form and at the correct point in the cycle. In diesel engines the fuel and the air are supplied separately, though in a petrol engine air is supplied as a mixture with the fuel. The fuel system consists of various components. These differ slightly depending on the type of engine.
For example in a petrol engine it is the job of the carburettor to provide the required mixture of air and fuel, to ensure they are properly mixed, and that the fuel is completely vaporised. The carburettor is replaced by a fuel pump in diesel fuel systems. The type of air cleaner also depends on the type of engine (also depends on what the engine is used for). Diesel powered tractors are more commonly used in agriculture today.
The diesel engine has no carburettor. It has a fuel injection pump and fuel injectors. A fuel lift pump is usually fitted to the fuel line. One or more filters may be used to filter the fuel as it travels through the system. The fuel injection pump is a sophisticated piece of equipment as it must accurately deliver small quantities of fuel, under high pressure, to the cylinder.
Two types of injection pumps are in general use in the industry:
1. The plunger pump
2. A distributor pump
The fuel injector is another highly accurate piece of equipment. It breaks up the fuel into a fine spray, by forcing the pressurised fuel through minute holes in the end of the injector.