Science Fair Project Encyclopedia
- For further uses of the word truck, see Truck (disambiguation).
A truck is a motor vehicle for transporting goods. Unlike automobiles, which usually have a unibody construction, most trucks (with the exception of the car-like minivan) are built around a strong frame called a chassis. They come in all sizes, from the automobile-sized pickup truck to towering off-road mining trucks or heavy highway semi-trailers.
The term is most commonly used in American English and Australian English to refer to what earlier was called a motor truck, and in British English is often called a lorry or, for bigger vehicles, a Heavy Goods Vehicle (HGV). This type of truck is a motor vehicle designed to carry goods, with a cab and a tray or compartment for carrying goods.
"Pantechnicon" is a British word for a furniture removal van that has now fallen out of usage. It was originally coined in 1830 as the name of a craft shop or bazaar, in Motcomb Street in Belgravia, London. The shop soon closed down and the building was turned into a furniture warehouse, but the name was kept. Vehicles transporting furniture to and from the building, known as pantechnicon vans, soon came to be known simply as pantechnicons.
Trucks and cars have a common ancestor: the steam-powered "fardier" Nicolas-Joseph Cugnot built in 1769. However, steam trucks were not common until the mid-1800s. The roads of the time, built for horse and carriages, limited these vehicles to very short hauls, usually from a factory to the nearest train station. The first semi-trailer appeared in 1881, towed by a De Dion steam tractor. Steam-powered trucks were sold in France and the United States until the eve of World War I, and the beginning of World War II in the United Kingdom.
The first internal combustion engine truck was built in 1898 by Gottlieb Daimler. Others, such as Peugeot, Benz and Renault also built theirs. Trucks of the era mostly used two-cylinder engines could have a carrying capacity 1500 to 2000 kg. In 1904, 700 heavy trucks were built in the United States, 1000 in 1907, 6000 in 1910 and 25000 in 1914.
After World War I, several advances were made: pneumatic tires replaced full rubber, electric starters, power brakes, 6-cylinder engines, closed cabs, electric lighting. The first modern tractor-trailers also appeared. Touring car builders such as Ford and Renault entered the heavy truck market.
Although it had been invented in 1890, the Diesel engine was not common in trucks in Europe until the 1920s. In the United States, it took much longer for that type of engine to gain acceptance: gasoline engines were still in use on heavy trucks in the 1970s, while in Europe they had been completely replaced 20 years earlier.
Types of trucks by size
Light trucks are car-sized (in the US, no more than 6,300 kg (13,000 lb)) and are used by individuals and commercial entities alike. They are comprised of:
Medium (or medium-duty) trucks are bigger than light but smaller than heavy trucks. In the US, they are defined as weighing between 6,300 kg (13,000 lb) and 15,000 kg (33,000 lb). They are mostly used for local delivery and public service (dump trucks, garbage trucks).
Heavy trucks are the largest trucks allowed on the road. They are mostly used for long-haul purposes, often in semi-trailer configuration.
Highway-legal trucks are sometimes outfitted with off-road features such as a front driving axle and special tires for applications such as logging and construction. Trucks that never use public roads, such as the biggest ever truck, the Liebherr T 282B off-road mining truck, are not constrained by weight limits.
Anatomy of a Truck
Almost all trucks share a common contruction: they are made of a chassis, a cab, axles, suspension and wheels, an engine and a drivetrain.
A truck chassis consists of two parallel U-shaped beams held together by crossmembers. It is usually made of steel, but can be made (whole or in part) of aluminium for a lighter weight. The chassis is the main structure of the truck, and the other parts attach to it.
The cab is an enclosed space where the driver is seated. A sleeper is a compartment attached to the cab where the driver can rest while not driving. They can range from a simple 24″ (0.6 meter) bunk to a 120″ (3.0 m) apartment-on-wheels. Modern cabs feature air conditioning, a good sound system, and ergonomic seats (often air suspended). There are a few possible cab configurations:
- cab over engine or flat nose or COE, where the driver is seated on top of the front axle and the engine. This design is almost umbiquitous in Europe, where overall truck lengths are strictly regulated. They were common in the United States, but lost prominence when permitted length was extended in the early 1980s. To access the engine, the whole cab tilts forward, earning this design the name of tilt-cab.
- conventional cabs are the most common in North America. The driver is seated behind the engine, as in most passenger cars or pickup trucks. Conventionals are further divided into large car and aerodynamic designs. A Large car or long nose is a conventional truck with a long—68″ (1.73 m) or more—hood. With their very square shapes, these trucks offer a lot of wind resistance and can consume more fuel. They also offer poorer visibility than their aerodynamic or COE counterparts. By constrast, Aerodynamic cabs are very streamlined, with a sloped hood and other features to lower drag. Most owner-operators prefer the square-hooded conventionals, it has something to do with..."Take pride in your ride".
- cab beside engine designs also exist, but are rather rare.
- Slang terms
- "Tiltin' Hilton" :Cab-over with a sleeper berth.
- "Aardvaark" : The aerodynamically designed conventional.
- "Hood" : Any conventional that is NOT an "Aardvaark"
Trucks can use all sorts of Engines. Small trucks such as SUVs or pickups, and even light medium-duty trucks in North America will use gasoline engines. Most heavier trucks use four stroke turbo diesel engines, although there are alternatives. Huge off-highway trucks use locomotive-type engines such as a V12 Detroit Diesel two stroke engine.
In the United States, on-highway trucks almost always use an engine built by a third party, such as Caterpillar Inc. or Cummins. The only exceptions to this are Volvo trucks, which are available with Volvo diesel engines and Freightliner, which is built by Daimler/Chrysler and available with Mercedes-Benz diesel engines made by the parent company.
Small trucks use the same type of transmissions as cars. Bigger trucks often use manual transmissions, which must be built stronger to withstand the torque their engines make. Common North American setups include 10, 13 and 18 speeds. Automatic transmissions for heavy trucks are becoming more and more common, due to advances both in transmission and engine power.
Conduire un véhicule lourd, Société de l'Assurance Automobile du Québec, 7e édition, 2002 ISBN 2-551-19567-5
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