What is BYD DM-i extended-range hybrid and how does it work?
DM-i changed the Chinese hybrid market overnight when it launched in 2021. Here's how it differs from a conventional Toyota or European PHEV.
Series-dominant, parallel-capable
In city: pure EV mode drawing from the ~18 kWh battery.
In highway cruise (>70 km/h): the engine can lock direct-drive to the wheels through a single-speed reducer for efficiency.
In battery-low: engine runs as a generator, charging the battery, which drives the wheels. Similar to Nissan e-Power but with plug-in capability.
Efficiency of the Xiaoyun 1.5L generator engine
Peak brake thermal efficiency: 43%. Toyota's best Dynamic Force 2.0L: 41%. This is world-leading.
Achieved via Atkinson cycle, 15.5:1 compression, cooled EGR, split cooling.
Range and consumption
Seal U DM-i (2024): 125 km EV + 1,125 km total on 60 L tank. Combined 21 kWh + 4.5 L/100 km battery-empty.
Song Plus DM-i: 100 km EV + 1,200 km total.
- 01Series-dominant hybrid — engine mostly generates power.
- 0243% thermal efficiency is world-leading.
- 03Great answer for buyers without home charging.
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