How was an average fuel consumption of 6.7 L/100 km achieved during highway driving with a depleted battery? Isn't extended-range technology known for high fuel consumption when the battery is low?
A depleted battery is indeed the most unfavorable operating condition for an extended-range vehicle, as the battery cannot provide sufficient auxiliary drive, leaving the range extender to solely handle all propulsion power demands. Under highway conditions, the range extender's RPM and load often fall outside its most fuel-efficient range.
Our core approach can be summarized in one sentence: significantly broaden the coverage of the high-efficiency zone. Even if operation deviates from the optimal point, fuel consumption will not deteriorate sharply as long as it remains within this wide high-efficiency zone.
First, the range extender equipped in the Xiaomi Pengcheng series is deeply customized by Xiaomi EV in collaboration with Dong'an Power, achieving a peak thermal efficiency of 42% in actual vehicles, a 1.5 percentage point increase over the original version, representing an improvement equivalent to a major iteration in traditional engines. This is backed by a deeper Miller cycle, higher-efficiency turbocharging, higher exhaust gas recirculation rates, and synergy with custom Shell lubricants.
More importantly, the high-efficiency zone where range extender thermal efficiency exceeds 40% highly overlaps with the generator's high-efficiency zone exceeding 92%. When the range extender operates in its most fuel-efficient state, the generator simultaneously operates at peak efficiency, achieving a maximum oil-to-electricity conversion rate of 3.66 kWh/L. Therefore, even under the dual disadvantages of highway driving and depleted battery, fuel consumption does not significantly worsen.