Range anxiety is genuinely a more cumbersome problem in heavy haulage than in passenger cars. Stuttgart supplier Mahle thinks the answer is not bigger batteries but a compact generator where some of those batteries used to sit. The concept will be presented at the next IAA Transportation in Hannover, next month.

In the truck sector, electrification is materializing much more slowly than in the passenger car market. Battery-powered trucks account for roughly 4% of the market, leaving the overwhelming majority with diesel drivelines. Often touted as a better-suited solution than faster refills and longer range, hydrogen fuel cells remain stuck in pilot phases.

One small unit to cover it all

Mahle is thinking outside the box and proposes giving up roughly one-third of your battery capacity to gain an onboard combustion engine that keeps the electric drivetrain fed for an additional 400 kilometers.

Could this be the ideal bridging solution, awaiting the moment when batteries provide better range at lower cost, or when hydrogen steps out of the shadows?

 Mahle’s unit houses a high-voltage generator, a compact internal combustion engine, thermal and fluid management, a fuel tank, AdBlue storage, and exhaust aftertreatment in a single enclosure. OEMs can drop it into the standard battery installation space. 

The company’s press release quotes a continuous output of 110 kW, peaking at 130 kW, from a small diesel-powered ICE. An oil-cooling system pushes power density beyond 7 kW per kilogram, keeping weight reasonable.

An extra 400 kilometers

The good news is that the rear axle sheds about 400 kilograms. So, the total vehicle weight drops by roughly 600 kilograms as the remaining battery is smaller. Range lands north of 800 kilometers: roughly 400 kilometers on battery alone, then another 400 kilometers once the generator kicks in.

European truck charging infrastructure remains patchy on long-haul corridors. Equipped with Mahle’s diesel generator, trucks can easily fill up when the charging station is busy or out of reach and continue without much hassle. The truck would still be driving electric, as the diesel engine doesn’t drive the wheels directly. 

80% less emissions

But emissions are the obvious catch. Range extenders don’t run without a battery, as battery-driven vehicles do. According to Mahle, an 80 percent CO2 reduction versus a conventional diesel truck is achieved when operating in range-extender mode.

And, better still, running on advanced HVO100, which is perfectly feasible for the range extender, the tailpipe figure drops to “virtually zero.” However, both the real-world emission gains of range extenders and HVO-diesel are contested.

This is not the first attempt at a truck range extender either. DHL and Scania have already trialed similar technology in the field. Mahle wants to offer a production-ready, fully integrated kit for truck makers.

As a tier-one supplier already present in every battery-electric and fuel-cell truck in Europe, Mahle isn’t exactly an aftermarket tinkerer, but possesses the credibility to make it work. It needs it. Currently, there are no EREV trucks on the market.

Politically, they don’t enjoy any perks like road toll exemption or incentives, condemning them as carriers of the worst of both worlds: the pollution of an ICE and the weight of a BEV.  

Still, carrying a small diesel engine as a safety net is an asset many fleet managers will embrace. Charging issues such as poor coverage, out-of-service stations, and connection hiccups remain a challenge for the heavy-duty sector, but tenders from customers, especially in the public sector, increasingly push for electrified solutions.