Why does BYD DMI not have a transmission?

[VonTimothy]

Because BYD DMI uses a combination of differential and transmission to achieve the shifting function. Below is the relevant introduction of BYD DMI: 1. Body dimensions: The length, width, and height are 4765 mm, 1837 mm, and 1495 mm respectively, with a wheelbase of 2718 mm. 2. Powertrain: Equipped with a 1.5-liter naturally aspirated engine. This engine has a maximum power of 81 kW, reaching its peak power at 6000 rpm, and a maximum torque of 135 Nm, achieving peak torque at 4500 rpm. This engine features multi-point fuel injection technology and uses an aluminum alloy cylinder head and block. 3. Suspension: The front suspension uses a MacPherson independent suspension, while the rear suspension employs a torsion beam non-independent suspension.

[Lauren]

I was also curious about this at first. When driving my friend's BYD DM-i, I noticed how incredibly smooth the gear shifts were. Simply put, this system relies on the electric motor as the primary driver, with the engine mainly responsible for generating electricity or directly engaging the wheels at high speeds. The E-CVT (electronic continuously variable transmission) is sufficient—it uses a planetary gear set to distribute power, eliminating the need for the complex mechanical structure of a multi-gear transmission. Think about it: in stop-and-go city traffic, the electric motor delivers power directly with faster response, completely eliminating the jerky gear shifts of traditional transmissions. Not only is this more convenient, but it also significantly reduces maintenance costs since there's one fewer high-failure-rate component. Honestly, after getting used to it, driving a conventional fuel car feels like the gear shifts are holding you back.

[LeNorah]

As a researcher in new energy technologies, the core of BYD DM-i's transmission-free design lies in its power split strategy. This system assigns the primary driving task to the electric motor, delivering linear acceleration like a pure EV. The gasoline engine's role has transformed - it quietly generates electricity most of the time, only directly connecting to the drive shaft during highway cruising. The control module intelligently switches between pure EV, series charging, or parallel drive modes. Transmissions become fundamentally redundant in electrified systems. The electric motor itself can cover the entire speed range from 0 to high RPM, unlike internal combustion engines that require gear shifts to compensate. When I first tested the Qin DM-i, its mid-to-low speed electric motor torque response outperformed any AT transmission model.

[VanCayden]

Over the past two years of ride-hailing, BYD models have been my most frequently used vehicles. The reason for choosing the hybrid version is the absence of transmission-related issues, significantly reducing maintenance costs. What impresses me most during daily driving is the smoothness in traffic jams – the electric motor starts without any jerking. The most annoying part of traditional cars was the gearshift hesitation, but now with the transmission eliminated, even maintenance items are reduced. I heard the DM-i system uses a dedicated generator to directly drive the wheels, eliminating the need for complex gear-shifting mechanisms. This makes a real difference for commercial vehicles like ours – there's a noticeable cost difference in maintenance every 100,000 kilometers.