Bosch (www.bosch.com) is electrifying semi-trailers (a trailer without a front axle), thereby making electro-mobility possible for today’s semi-trucks.

At the IAA Commercial Vehicles exhibition in Hannover (20-27 September), the company will be presenting an electrified axle that can be integrated into a semi-trailer; and instead of simply allowing this to roll freely, as has been the case up to now, it can generate electricity during braking and feed it into the trailer’s power units.

Bosch estimates that in the case of a refrigerated trailer, the saving could be as much as 10,000 euros a year (if the cooling unit is operated using the power generated in this way).

The company also says that this system can save up to 9,000 litres of diesel a year; an electrical start and acceleration boost function help to save fuel and reduce CO₂ emissions.

A further advantage — especially for deliveries by urban supermarkets — is that electric cooling units make significantly less noise than diesel-powered ones.

Bosch also says its electric axle is an important step in automated trailer parking on logistics companies’ parking lots.

Adding a powertrain to the axle means that the trailer can be shunted around the parking lot without a tractor.

Moreover, the company says this technology is available for new trailers or as a retrofit solution, adding that the potential demand is huge.

“In Europe alone, about a quarter of a million trailers with a gross vehicle weight of more than 10 tonnes are newly registered every year; and one in five of these is equipped with a refrigeration unit.”

In contrast to many other commercial-vehicle projects, Bosch engineers are relying on passenger-car parts for the electrified axle.

For example, the SMG180 electric motor already features in hundreds of thousands of hybrid and electric cars world-wide; and unlike in electric cars, the motors in the electrified axle work intermittently, operating only if they can recuperate energy — such as when going downhill or braking.

Such demand-driven application has a further advantage; because the electric motors are inactive most of the time, significantly less costly production parts from passenger cars can be used in this trailer application.

That said, the motors are still powerful enough to move the trailer or to provide start assistance to construction vehicles.