This section is a general introduction to the car as a whole. Over the years many unusual designs have been tried, some with more success than others. The most common is of course a rectangular vehicle with a wheel at each corner! To take this rather simple idea further, we can now put ‘light vehicles’ in one of five groups:
This is a term used to describe a set of related components on the vehicle. For example all the components used to make the brakes work, are described simply as the‘braking system’.
1. Front engine FWD
A design of vehicle with the engine at the front has a number of advantages.
• Protection in case of a front end collision • Easier engine cooling because of
the air flow • Cornering can be better if the weight is at the front • Front wheel drive adds further advantages particularly if the engine is mounted sideways on (transversely).
• More room in the passenger compartment • Power unit can be made as a
complete unit • Drive acts in the same direction that the steered wheels are pointing
2. Front engine RWD
Rear wheel drive from a front engine was the method used for many years. Some manufacturers have continued its use, BMW for example. A long propeller shaft from the gearbox to the finaldrive, which is part of the rear axle, is the main feature. The propshaft has universal joints to allow for suspension movement. This layout has some advantages.
• Weight transfers to the rear
driving wheels when accelerating.
• Complicated constant velocity
joints such as used by front wheel drive vehicles, are not needed. Four wheel drive combines all the good points mentioned above but does make the vehicle more complicated and therefore expensive. The main difference with four wheel drive is that an extra gearbox known as a transfer box is needed to link the front and rear wheel drive.
3. Rear engine
The rear engine design has not been very popular but it was used for the best-selling car of all time – the VW beetle. The advantages are that weight is placed on the rear wheels giving good grip and the power unit and drive can be all one assembly. One down side is that less room is available for luggage in the front. The biggest problem is that handling is affected because of less weight on the steered wheels. Flat type engines are the most common choice for this type of vehicle.
Fitting the engine in the mid position of a car has one major disadvantage; it takes up space inside the vehicle. This makes it impractical for most ‘normal’ vehicles. However, the distribution of weight is very good. This makes it the choice of high performance vehicle designers. A good example is the Ferrari Testarossa.Mid-engine is used to describe any vehicle where the engine is between the axles, even if it is not in the
As you learn more about the fascinating world of the automobile, you will keep meeting ‘new’ technologies. I have included a list of events and dates for you to see that some new ideas are not as ‘new’ as you first thought! By the way you don’t need to learn this bit, it is for interest only.
1769 Cugnot built a steam tractor in France.
• 1801 Trevithick built a steam coach. • 1860 Lenoir built an internal-combustion gas engine. • 1876 Otto improved the gas engine. • 1885 Daimler developed a petrol engine and fitted it to a bicycle. • 1885 Benz fitted his petrol engine to a three-wheeled carriage.
• 1906 Rolls-Royce introduced the Silver Ghost. • 1908 Ford also used an assembly-line production to manufacture the Model T. • 1911 Cadillac introduced the electric starter and dynamo lighting. 1938 Germany produced the Volkswagen Beetle.
• 1948 Jaguar launched the XK120 sports car and Michelin introduced a radial-ply tyre.
• 1955 Citroen introduced a car with hydro-pneumatic suspension. • 1957 Wankel built his first rotary petrol engine. • 1959 BMC (Rover Cars) introduced the Mini.
• 1966 California brought in legislation regarding air pollution by cars. • 1991 European Parliament voted to adopt stringent control of car emissions. • 2006 Satellite navigation systems are used on many vehicles • 2007 Telematics becomes more important and more
accurate satellite navigation is introduced • 2008 Combined active and passive safety systems • 2009 The story continues with you!.