Engine hood design on trucks and buses

From top to bottom:
long-nosed, short-nosed, front-wheel drive

Lorries (lorries) and buses can be constructed with different hood designs. A distinction is made between long - nosed , short- nosed and front- wheeled vehicles (referred to in Austria as front seaters ). The hood design is closely related to the positions of the engine, cab and front axle (s) relative to one another.

Trucks that are used in agriculture, forestry and construction outside of populated areas as pure tractors are still built today as long-nosed vehicles, especially if they are equipped with powerful and therefore large engines.

Vehicles that require space-saving use of the road surface occupied by the vehicle for cargo or passengers are more likely to be built with a short or without a protruding engine hood. In this case, the engine can be located under the driver's cab, partially or completely behind the driver's cab or under the rear of the vehicle.

When it comes to vehicles for use in urban areas, a compromise often has to be found. A particularly compact design of the overall vehicle is often achieved in trucks by placing the driver's cab above the engine. This leads to a significantly higher seating position for the driver, which enables a good overview of the traffic situation. The raised position is disadvantageous if the driver has to get on and off frequently or has to communicate with other people at street level.

A compact design with a low seating position is achieved in city buses such as London's former Routemaster multi-storey buses by positioning the one-man driver 's cab on one side at the front so that there is space for the engine or the boarding area for the passengers.

Commercial vehicles such as heavy-duty dump trucks , truck cranes and other special vehicles also occasionally have a driver's cab on one side.

Overview of designs

Long-nosed

Long- hooded vehicles , including hood handlebars, are vehicles with a rather narrow, elongated hood that is positioned in front of the driver's cab. The engine - typically an upright in- line engine - protrudes only relatively little, especially with the attached gearbox, into the driver's cab, which can therefore be relatively low. You get in behind the front wheels. In front of the fenders there was often a platform that served as a side stand for engine maintenance. Rods with visor balls were also often mounted in front of the fenders, which protruded obliquely outwards and upwards, in order to be able to assess the front corners of the vehicle more precisely in cramped driving situations from the low-lying view of the driver.

Short-nosed

Short-nosed vehicles are vehicles with a longitudinally or transversely installed engine, whose driver's cab is partially placed above the engine compartment. The driver's cab is built as low as possible with the seat and foot position in order to facilitate frequent entry and exit as in urban delivery traffic. Sometimes it is accepted that parts of the housing of the motor-gearbox unit protrude so high into the driver's cab that there is no continuous footwell.

Forward control

As a forward-control (in Austria also: forehead seater ) cars are called, which does not have porch at the front of the vehicle for the engine, but it can for Windschlüpfigkeit, body stiffness, constructive desired curvature of the windshield slightly arched and be rounded at the contour edge.

In the case of the forward control, the engine is under the driver's cab (COE = American English “Cab over Engine”) or is located there as an elevation in the form of an engine tunnel. It is also possible to position the engine in the rear of the vehicle.

history

Both the first bus and ...

... the first trucks were front-wheel drive

The first omnibus and the first truck in the world were both front-wheel drive vehicles with rear or underfloor engines . The feature of the forward control was lost over time when the engine with the radiator was relocated in front of the driver's seat; this is how the long-nosed car came into being . With this design, the engine is at the front, followed by the driver's cab and the loading area or passenger compartment. The advantage of this design is the easy accessibility of the engine for maintenance and repair. The disadvantages of the long-nosed truck consist on the one hand in the fact that the vehicle is not clearly arranged for the driver and on the other hand in the fact that the front end with the engine increases the overall length of the vehicle considerably or reduces the available loading area.

After the legal regulations that limited the permissible total length became more and more restrictive, the commercial vehicle manufacturers had to think about optimized designs in order to improve the ratio of the length usable for the load to the total length. One step in this direction was the construction of short hoods in which the engine is pushed a little way into the driver's cab.

To make better use of the vehicle's length, it was even better to return to the front-wheel drive , where the cab is above or in front of the engine. This design finally established itself after the Second World War , in Germany mainly in the 1960s. The disadvantage of this design was initially that the engine was considerably more difficult to reach and could only be serviced and repaired through numerous flaps and openings. In many vehicles, the front axle or the entire driver's cab had to be removed to remove the engine.

This problem was solved by the construction of tilting cabs. The first forward control vehicles with a tilting cab appeared in the USA as early as the 1930s . European manufacturers, on the other hand, were quite hesitant, as security problems were feared. In particular, it was feared that the cab might tear off and hit forward in the event of emergency braking or an accident. In 1955, the German manufacturer presented Magirus-Deutz a cab- prototype with tilting cab at the Frankfurt IAA ago. However, this met with great skepticism from the audience and did not go into series. The first European truck with a tilting cab that was mass-produced was the L4751 Raske TIPTOP from Volvo from 1962. Krupp was the first German manufacturer to start series production of forward control arms with a tilting cab in 1965, followed by MAN that same year , Henschel and Faun . Mercedes-Benz , on the other hand, held on to non-tipping forward control cabs for a particularly long time. Because of their many maintenance hatches distributed over the entire cab, these trucks were quickly given the nickname “Advent Calendar” by drivers and mechanics. Mercedes-Benz continued to manufacture cab-over-engine models with fixed cabs until 1984.

Some forward control trucks received so-called underfloor motors , which were located behind the driver's cab below the loading area. However, this design could not prevail. The best-known manufacturer of such vehicles was the Büssing company . In buses, the engine was usually relocated either to the center of the vehicle (underfloor engine) or to the rear ( rear engine ).

Due to tougher competition in the 1970s, the advantages of the steering wheel increased in weight in terms of usable loading space length: With a maximum vehicle length of 12.5 meters, an 80 cm bonnet means almost 7% less usable loading space. In view of the many European ferry connections and billing based on vehicle length, front-wheeled vehicles had an advantage here.

In the course of the 1970s, the forward control vehicles almost completely replaced the hoods in Germany and Europe in medium to heavy trucks, and in buses as early as the 1960s.

In civil road traffic, long-nosed vehicles and, in particular, short-nosed vehicles were able to stay in the field of construction vehicles for the longest, up until the 1980s, before they had to make way for the front-wheel drive vehicles there too. The process of replacing fire engines took just as long .

The last long-nosed vehicles in Europe can still be found today as military vehicles (e.g. from Renault and Mercedes-Benz ): The frame here has already been raised significantly for maximum ground clearance, which is why a standard forward control cab would be too high for transport on normal flat railroad cars . Front control vehicles for the military, which should fit on normal flat cars, are therefore not equipped with the engine under, but behind the driver's cab. If military long-nosed vehicles are also in demand by civilian users in third world markets, they can offer significant price advantages compared to small series of special vehicles.

Short-nosed cars are still common today in light trucks and small vans (e.g. Mercedes-Benz Vario , Iveco Daily , Ford Transit ). In the van segment, short-nosed trucks have even pushed the front-wheel drive back on the European markets.

Outside Germany, hoods are sometimes much more widespread than in Germany. B. in the USA or Australia , where the traffic areas are generally much more generous. In the USA around 1980 the vehicle fleet consisted mostly of forward-hand drive vehicles, for which the same reasons were decisive as in Europe. As part of the deregulation under Ronald Reagan , the length restriction for trucks was lifted, only the length of the loading space remained limited. This led to a drastic shift towards long-haulers (mostly of the Freightliner , Volvo , Peterbilt , Kenworth , Mack and Western Star brands ). Frontlenker be there as a COE (for C from o ver e ngine ) or short Cabover referred. While they shaped the image of rest areas on US highways around 1980, they are very rare today.

gallery

Long-nosed
Heavy long-bonnet truck from the 1930s: Mercedes-Benz L 6500
Heavy long-nosed truck from around 1960: Magirus-Deutz A 6500
Saurer D330 three-way tipper
Modern long-nosed truck: Mercedes-Benz Zetros
Typical American long-nosed car:
Peterbilt

Short-nosed
Chevrolet 4600 short hood
Short-nosed cars from the late 1950s to the late 1960s ( MAN )
Short-nosed truck from the 1980s that can still be found today: Fire fighting vehicle 16 on the chassis of the Mercedes-Benz LAF 1113
Unimog 437.4 (2006)
Large transporter with a short hood: Mercedes-Benz Vario