Torque Shop: Why EVs feel quicker than conventional cars
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An electric vehicle has maximum torque from the get-go, giving it a lead over an internal combustion engine car.
PHOTO: ST FILE
Lee Nian Tjoe
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I just went for a test drive in an electric vehicle (EV) with only 99kW, or 132bhp. Why does it feel faster than my 150bhp, turbocharged car?
Comparing the performance of an EV with an internal combustion-engine (ICE) car can feel a bit like the race between the tortoise and the hare.
Off the line, EVs have the benefit of instantaneous torque.
Both the MG 4 EV and Audi Q3 1.5-litre have a maximum torque of 250Nm. But the MG has access to all that twisting force from the get-go, while the Audi’s engine needs to be revved up to 1,500rpm before it delivers the maximum torque.
EVs typically have single-speed transmissions that take them from 0kmh to their maximum speed, so there is no interruption in the delivery of the motor’s performance, surging relentlessly while being pegged to the motor’s maximum torque level. On an ICE car, the engine revs drop at every upshift, affecting the amount of power going to the wheels.
The ICE car’s multi-speed transmission gives the flexibility to achieve higher road speeds when it needs to, while working with the inherent characteristic of the engine – like how it prefers to be within a certain rev range.
An EV, with its single-speed set-up, tends to be more optimised for use in the city, where the electric motor is also more energy-efficient than when driven at higher speeds. So, the steady tortoise ICE will likely catch up with the speedy EV hare.
As speeds increase, the ICE car will eventually overtake the EV that had the punchy initial acceleration. The specification sheets of the MG 4 and Audi Q3 show as much. While the 99kW EV maxes out at 160kmh, the Audi, with its 147bhp engine, will continue to pick up speed until it hits 204kmh.
The difference in top speed is academic on Singapore’s roads. What is more relevant is how lower-powered EVs – defined as those with up to 110kW – qualify for the cheaper Category A certificate of entitlement (COE), while ICE cars with a 1.5-litre engine making 147bhp have to contend with the higher Category B COE premium.
