The history of heavy transport — from steam wagon to AdBlue

The truck mechanic works with the vehicles that carry society's goods: trucks, buses, trailers and work machines. The field is closely linked to the history of transport, because heavy vehicles have always had their own demands — they must be able to carry a lot, drive far and brake safely again and again. Three inventions in particular have shaped the field: the diesel engine, the compressed air brake and electronics. To understand today's truck, it helps to know where it comes from.

§Before the engine — and the first heavy motor vehicles

Before the pots go on, the menu must be planned. You must think in variety, nutrition, season, budget and special needs. How many need food? How many diets are there? What needs to be bought? Good planning makes the busy production manageable and prevents both food waste and errors.

§The diesel engine — the driving force of heavy transport

The most important technical breakthrough for heavy transport was the diesel engine. It was invented by German engineer Rudolf Diesel in the early 1890s (patented 1892-1893 first functional engine 1897) with the goal of creating a more efficient engine that ignited fuel with compression heat instead of a spark. Initially diesel was mostly used for stationary and industrial purposes but during the 1920s the first diesel-powered trucks appeared on European roads. The diesel engine's combination of power durability and fuel efficiency suited heavy loads and long distances perfectly and it gradually became the absolutely dominant engine type in heavy transport.

For the mechanic diesel meant a trade with its own disciplines: injection pumps nozzles high compression and later turbocharging. Where the petrol engine had spark plugs and a distributor diesel work centred on fuel purity injection precision and the engine's ability to run for many hundreds of thousands of kilometres.

§The air brake — stopping many tonnes safely

A heavy vehicle cannot be braked properly with the same system as a car. The solution came from the railway: George Westinghouse invented the air brake for trains in the late 1860s, and the principle was later adapted for trucks. During the 1920s, as heavy truck traffic grew after World War I, air brakes spread to heavy vehicles and gradually became standard. With compressed air, braking force could be distributed throughout a large vehicle and further to a trailer, and the fail-safe principle of the spring brake—which brakes itself if pressure is lost—made heavy vehicles significantly safer.

§Standardization, legal requirements, and documentation

As truck traffic grew, so did regulation. Heavy vehicles weigh many tons, often drive far, and are used commercially, so a failure can have serious consequences. Therefore, through the decades increasingly strict requirements were placed on brakes, weight, equipment, and inspections. A particularly important step was the tachograph — the speed recorder — which records the vehicle's speed and the driver's driving and rest time. In the EU it became mandatory in the 1980s with the analog disc, and from the mid-2000s the digital tachograph was introduced. The purpose has always been the same: tired drivers should not drive heavy vehicles in traffic.

For the truck mechanic the regulation meant the trade became closely tied to legal requirements and documentation. It is not enough to repair well — the work must also be documentable and certain tasks such as calibration of the tachograph require special authorisation.

“A truck makes money when it runs and costs money when it sits still — that's why preventive maintenance became the core of the job.”

— About the conditions of transport

§Electronics and exhaust cleaning.

As with passenger cars electronics made its entry into heavy vehicles. Control units began to control engines and brakes and systems like ABS and later EBS distributed braking force electronically. At the same time environmental requirements drove development: to reduce emissions of particles and nitrogen oxides came the diesel particle filter (DPF) exhaust gas recirculation (EGR) and the SCR catalyst which uses the additive AdBlue. Where an old diesel engine simply let out exhaust an modern engine cleans it in several steps — and that has made aftertreatment a whole professional field in itself.

With electronics came also computer-controlled troubleshooting. The truck monitors itself stores error codes and can tell the mechanic where it fails. But just like in cars a code is a clue not a solution — and precisely because heavy vehicle systems are so interdependent overview and systematic approach has become a core competence.

§The truck mechanic today — and the future

Today the truck mechanic works with vehicles that unite powerful mechanics compressed air high-pressure hydraulics extensive electronics and emission control — all under strict inspection and environmental requirements. The trade also stands in the middle of a new transition where electrification and alternative fuels are beginning to make their entry into heavy transport exactly as the diesel engine did a hundred years ago. But the core of the trade is the same as when the first motor vehicles came: keeping the vehicles running that society depends on — safely legally and reliably.