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 Trucks can use all sorts of engines. Small trucks such as SUVs or pickups, and even light medium-duty trucks in North America and Russia will use gasoline engines. Most heavier trucks use four stroke turbo intercooler diesel engines, although there are alternatives. Huge off-highway trucks use locomotive-type engines such as a V12 Detroit Diesel two stroke engine. North American manufactured highway trucks almost always use an engine built by a third party, such as CAT, Cummins, or Detroit Diesel. The only exceptions to this are Volvo Trucks and Mack Trucks, which are available with subsidiary of DaimlerChrysler, which are available with Mercedes-Benz and Detroit Diesel engines. Trucks and busses built by the Navistar International can also contain International engines. The Swedish truckmaker Scania claims they stay away from the U.S.-market because of this third party tradition. In the European union all truck engines must comply with Euro 4 regulations, the regulations will become more severe in 2008 with the introduction of Euro 5. |
Double
clutching allows the driver to control the engine and
transmission revolutions to synchronize, so
that a smooth shift can be made e.g. when upshifting,
accelerator pedal is released and the clutch
pedal is depressed while the gear lever is moved in to neutral,
clutch pedal is than released and
quickly pushed down again while the gear lever is moved to the
next highest gear. Finally, the
clutch pedal is released and accelerator pedal pushed down to
obtain required engine rpms.
Although this is a relatively fast movement perhaps a second or
so while transmission is in
neutral it allows the engine speed to drop and synchronize
engine and transmission revolutions
relative to the road speed. Downshifting is performed in a
similar fashion except the engine speed is now required to increase (while transmission is in neutral)
just a right amount in order to The so called skip
changing is also widely used, in principle operation is the same
but it requires neutral be held slightly longer than single
gearchange. Common North American setups include 9, 10, 13, 15,
and 18 speeds. Automatic and semi-automatic transmissions for
heavy trucks are becoming more and more common, due to advances
both in transmission and engine power. In Europe 8, 10 and 12
gears are common on larger trucks with manual transmission,
while automatic or semiautomatic transmission would have
anything from 5 to 12 gears. Almost all heavy trucks
transmissions are of a "range double H shift pattern and
split" type where range change and so called half gears or
splits are air operated and always preselected before the main
gears selection.
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Small trucks use the same type of transmissions as almost all
cars which have either an automatic transmission or a manual
transmission with synchronisers. Bigger trucks often use manual
transmissions without synchronisers which have less bulk and
weight although synchromesh transmissions are used in larger
trucks as well. Transmissions without synchronisers known as
"crash boxes" require double clutching for each shift, (which
can lead to repetitive motion injuries), or a technique known
colloquially as "floating," a method of changing gears which 
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