Motor Car, any self-propelled vehicle with more than two wheels and a passenger compartment,capable of being steered by the operator for use on roads. The term is used more specifically to denote any such vehicle designed to carry a maximum of seven people.

The primary components of a car are the power plant, the power transmission, the running gear, and the control system. These constitute the chassis, on which the body is mounted. The power plant includes the engine and its fuel, the carburettor, ignition, lubrication, and cooling systems, and the starter motor.

HOW ENGINES WORK

Internal-Combustion Engine






The overwhelming majority of car engines still employ the four-stroke cycle (four piston strokes per cycle), invented by Nicholas Otto in 1876.
The first downstroke of the piston that is attached to a connecting rod at its top end and to the crankshaft at the bottom, draws a petrol-air mixture into the cylinder. This is then compressed, which is the second stage of the process. The volatile cocktail is then ignited by a sparking plug and the resulting explosion forces down the piston, so turning the crankshaft. The final phase of the operation is the stroke that expels the exhaust gases from the cylinder.

Drive Lines

In a front-wheel drive car, power is conveyed by gearing to a differential that is incorporated in the engine/gearbox unit. Its function is to permit cornering so that the outer-driven wheel turns faster and further than the inner one. Drive is transferred to each wheel by a constant velocity joint that can also absorb steering forces.On a rear-drive vehicle, power is transmitted from the gearbox to the rear-located differential via a propeller shaft. It is then conveyed to the wheels by half-shafts (in the case of a live rear axle) or universally jointed drive shafts (if independent rear suspension is employed).

Independent Suspension

The arrival of front-wheel drive saw an increase in the use of independent front suspension, in which each wheel is able to act in isolation to the other. One of its most important advantages is that it keeps the wheels vertical and the tyres on the highway, regardless of body roll, and therefore enhances the car’s road-holding ability. The most common version employs two unequal length “wishbones”, with coil springs providing the suspension medium. In the alternative MacPherson strut system there are no wishbones and the spring is combined with a shock absorber.

Brakes

Most cars use disc brakes on their front wheels; these are fitted on front and back wheels on more expensive models. When the brake pedal is applied, hydraulic power is applied to calipers that grip the disc and so contribute to arresting the car’s progress. Drum brakes, that use internally actuated shoes, are often fitted at the rear. An antilock breaking system (ABS) uses a computer, sensors, and a hydraulic pump to stop the car from moving forward without locking the wheels and putting the vehicle into a skid. Introduced in the 1980s, ABS helps a driver to maintain greater control over the car during emergency stops while braking on slippery surfaces. All cars feature a hand or parking brake that operates on the vehicle’s rear brake shoes or discs.

Steering

The most popular steering system is rack and pinion. Power-assisted steering, which is hydraulically activated by an engine-driven pump and previously the preserve of expensive cars, has become increasingly popular.

Bodywork

A body’s aerodynamic efficiency is measured by drag coefficient (Cd) and the lower the figure the greater the car’s wind cheating properties. Nowadays, most cars register a reading of 0.3 to 0.4 and such features as integrated bumpers, a tapered nose, and windows that are flush with the body sides are incorporated to keep a vehicle’s Cd as low as possible.As a result the Cd of a typical family car can be superior to that of some performance models. The Ford Mondeo and Vauxhall Vectra have Cd readings of 0.31 and 0.28 respectively, while the current version of Porsche’s long-running 911 sports cars registers 0.33.

Social Impact of the Car

Potentially, the motor car provided universal mobility for the population of the industrialized world. At first, only the wealthy could afford cars, although this began to change with the arrival of the Model T Ford. Mass-produced from 1913, its price fell and the beloved “Tin Lizzie” inspired a host of imitators across the globe. Nevertheless, during the inter-war years motoring remained a pursuit of the affluent.The increasing prosperity that followed World War II brought growing numbers of cars to the world’s roads that currently accommodate around 600 million motor vehicles. Britain accounts for 25 million of them. Traffic-related air pollution, traffic congestion and traffic control, and road safety are major issues in developed and other countries.

Early Development

The motor car first appeared in Germany in 1885 when Karl Benz and Gottlieb Daimler, each working independently of the other, produced self-propelled vehicles powered by rear-mounted, petrol-fuelled single-cylinder engines. These were based on the stationary gas engine that used the four-stroke principle.The replicas of the originals that each engineer produced gave birth to the world’s motor industry, although in 1896, France and not Germany became the world’s largest manufacturer of motor vehicles. In 1891 a French engineer, Emile Levassor, transferred the engine of the Panhard et Levassor car from its established rear location to the front of the vehicle, from where it drove the rear wheels via a clutch and in-line gearbox. Named Systeme Panhard, it rapidly overtook the original layout in popularity and survives, in essence, on large-capacity cars.The progressive Gottlieb Daimler soon produced, in 1893, a vertical two-cylinder in-line engine and Benz followed, in 1897, with a horizontally opposed twin in which the cylinders were in the same plane as the crankshaft. Panhard had introduced the in-line four in 1896 and this configuration soon outstripped all other types in popularity, most notably in the Henry Ford Model T, built between 1908 and 1927.Over 15 million of these Fords were produced and their success helped America to consolidate its position, attained in 1906, as the world’s largest manufacturer of motor cars. The United States dominated the industry until 1980, when it was overtaken by Japan.Britain had lagged behind France and Germany in introducing the motor car, as its industry was stifled by the presence of the Locomotive Act of 1865. This required self-propelled vehicles to be limited to a speed of 3.2 km/h (2 mph) in towns and 6.2 km/h (4 mph) elsewhere. Originally, motor cars were required to be preceded by a man carrying a red flag but this stipulation was usually set aside following an amendment to the act in 1878.As early cars were capable of at least 32 km/h (20 mph), Continental imports could not be practically or legally run on Britain’s roads until 1896, when the Locomotive Act was modified. The speed limit was raised to a blanket 19 km/h (12 mph) and increased again, in 1904, to 32 km/h (20 mph).Britain’s motor industry therefore dates from 1896, although most manufacturers were initially only responsible for their vehicles’ mechanical components. Bodywork, usually of the open type with only rudimentary weather protection in the form of a canvas hood, was the responsibility of coachbuilders, who had hitherto manufactured horse-drawn vehicles.In 1904 the English Napier company had built the world’s first usable six-cylinder car, although the costly straight-eight engine did not make any impact until after World War I. The more compact V8, in which four in-line cylinders were positioned in a V-shaped configuration, was popularized by the American Cadillac company in 1915. Its Lincoln rival was responsible for the world’s first successful V12-engined car that dates from 1915. However, the V6 unit, pioneered by Lancia, did not arrive until 1950.