Your car is a fine piece of engineering technology and design. It consists of some 15,000 individual parts and working units.

The basic principles have remained the same since its invention. It still uses an internal combustion engine, has four wheels with rubber tyres and a protective body.

To provide the energy required to make the car move, the engine needs a fuel, normally petrol or diesel; air and electric current. The engine's temperature is kept relatively low by both water and air. The major moving parts in the engine are the pistons that move up and down very quickly inside cylinders.

To reduce engine wear and prevent engine seizure the pistons are lubricated by oil. A 'four stroke cycle' occurs where the piston strokes go up and down. The stages are:

	Induction	Suck
	Compression	Squeeze
	Combustion	Bang
	Exhaust	Blow

Motor manufacturers are researching ways to power vehicles with zero pollution levels. The obvious choice has been electricity, but the technology for this choice still has a long way to develop.

Hybrid cars now in production use a halfway-house principle that combines the best qualities of both petrol and electric propulsion. These use a petrol engine and electric motor that work together to provide maximum power when required, with power coming from only one source in less urgent situations. Hybrids are ultimately complicated, expensive and heavy.

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Fuel Cells
One of the most attractive alternative power sources is the fuel cell. A fuel cell consists of a composite membrane, some wires, a box to store it in and a fresh supply of hydrogen. Chemically, the cell recombines hydrogen and oxygen with the aid of a catalyst.

This releases electrical energy with the only by-product being water. The hydrogen comes from a fuel tank, while the oxygen is simply extracted from the atmosphere.

The hydrogen is draw directly from another, more practical, fuel such as methanol. With Direct Methanol Fuel Cells (DMFC) devices, the catalyst itself both separates the hydrogen from the carrier (methanol) and encourages the fuel cell reaction as well.

Most current fuel cells operate at around 150°C upwards. Keeping the unit at an optimum temperature requires a coolant pump that lowers the efficiency somewhat. Efficiency is further impaired by the weight of crash protection for fuel cells.

Fuel cells may ultimately prove to be the most effective and cost-efficient alternative, not least because they extract energy from fuel extremely efficiently. They are very environmentally friendly too. Emissions, when using pure hydrogen, are minimal and harmless - just water.

All the major motor manufacturers have built and run prototypes successfully. They remain cagey about the purchase price of such a car.

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