New Hybrid Engine Claims 71 MPG Without a Bigger Battery

From EV Retrofits to a New Hybrid Setup

Horse Powertrain first made waves with a simple but practical idea: let automakers convert their existing EV platforms into hybrids, rather than building new ones from the ground up. Last year, the company showcased compact, all-in-one hybrid modules that could replace a front electric motor, enabling a hybrid version with minimal additional engineering.

Now, Horse is back with a new product that aims for bigger efficiency gains from hybrid combustion. Teaming up with energy company Repsol, it has built a next-generation concept powertrain that gets more out of every drop of fuel – not by adding bigger batteries, but by reworking the engine’s internals.

Horse’s New H12 Hybrid Engine Concept

The Horse H12 hybrid engine concept focuses on improving combustion efficiency and reducing internal losses. Horse claims it reaches a peak brake thermal efficiency of 44.2 percent, putting it in the same league as some of the most advanced hybrid systems. That’s thanks to a high 17:1 compression ratio, better exhaust-gas recirculation, a tweaked turbo, and new hybrid transmission tuning.

The big number here is fuel consumption: under 3.3 L/100 km, or about 71.3 mpg. That’s based on WLTP testing, which is Europe’s standard and typically yields higher results than the stricter US EPA cycle.

Horse also designed the system to run on 100 percent renewable gas, which could cut annual CO2 output to 1.77 tons for a typical midsize car. Prototypes are already on the road, with a demo car coming soon and full-scale production as the long-term target.

Impressive Claim that Could Serve as a Benchmark

That 71-mpg claim blows past the most efficient mainstream hybrids you can buy in the US right now. Most top hybrids get EPA ratings in the mid-50s, with most strong sellers landing between 45 and 55 mpg combined.

Of course, that number comes from WLTP testing, so take it as a best-case scenario rather than a promise for the showroom. Still, it’s an impressive target, and it’s the kind of tech we’d like to see make it to production. Since Horse is a joint effort between Renault and Geely, expect to see this new hybrid approach show up in their future models.