One key difference between electric cars and their conventional petrol/diesel counterparts is that electric models do not feature a manual gear shift; rather, they use an automated transmission which seamlessly changes gears as you accelerate or decelerate.
However, some automakers are beginning to reintroduce multi-speed transmissions into their electric cars; this trend can mainly be found among luxury brands and racecars such as Porsche Taycan and Audi e-Tron GT.
Single-Speed Transmissions
Electric cars differ significantly from their gasoline counterparts in that they don’t require multiple gears for transmission; rather, they rely on motors to convert stored energy from their batteries or fuel cells into mechanical energy for use by their wheels. Because this type of motor is easier and more energy-efficient than its gasoline equivalents, many manufacturers choose one-speed transmissions when developing electric vehicles.
One major reason EVs tend to feature single-speed transmission is due to electric motors’ wide power band, enabling them to accelerate at high speeds more efficiently than gas engines and reach top speed faster. Gas engine power bands start out low revs, meaning maximum torque production only occurs at certain engine speeds.
Most EVs utilize single-speed transaxles because it enables them to transfer power efficiently between the front and rear wheels, enabling the front motor to be designed for efficiency while power can be distributed equally between both motors when accelerating. This also enables efficient use of energy when shifting between them for efficient driving.
ZF, a German auto parts company, recently created an idea demonstrating how a two-speed EV transmission could work with an electric motor and provide powertrain solutions that could fit any car. They claim their design would serve as “the basis of an EV powertrain that could be implemented anywhere”.
ZF announced in its press release that they would share this technology with other automakers, while also noting how a multi-speed electric transmission could maximize performance and efficiency of electric vehicles (EVs).
Multi-speed transmissions may not yet be widespread among EVs, but they have made their debut in some luxury and race EVs like Rimac’s supercars and some Formula E cars. Over time they may become mainstream options as an alternative to single-speed transmissions found on most EVs; ultimately the decision rests with automakers.
Multiple-Speed Transmissions
Internal combustion engines rely on gearing systems to balance torque and speed, but this approach can add unnecessary weight and complexity while increasing friction levels in their powertrains. Electric motors don’t face this issue as they produce maximum torque from zero rpm with an expansive powerband across their rev range.
Automakers of electric vehicle (EV) autos can select a single gear ratio that provides an effective compromise between acceleration and top speed, such as Tesla’s Model S and X, which feature both front motor and separate rear motor that can be automatically switched between them.
An electric motor offers many distinct advantages over internal combustion engine (ICE) engines of comparable power ratings, including being smaller and more energy-efficient in design. This can save money in terms of manufacturing costs while simultaneously decreasing weight and increasing range.
Automakers are already designing electric vehicles (EVs) with multi-speed transmissions in mind; several luxury carmakers and Formula E racecars make use of this technology.
The Porsche Taycan uses a two-speed gearbox with different ratios to accommodate for different performance objectives. The first gear has a 15:1 ratio used for acceleration while its counterpart features an 8:1 ratio that makes cruising more efficient and reaches higher top speeds.
Other EVs, like the forthcoming Jeep Magneto, may utilize multi-speed transmissions to improve acceleration. Some of these systems are known as continuously variable transmissions (CVTs), which work by diverting power directly to wheels instead of gears.
This technology can boost efficiency by up to 4%, enabling carmakers to achieve faster acceleration and top speeds with lower energy use and optimal battery capacity for optimal performance. While most EVs don’t yet feature this technology, its adoption may increase over time.
Multi-Speed Transmissions
As most EV owners know, these vehicles are designed without transmissions in order to maximize efficiency, which reduces parts in the system, lowers weight, and makes servicing and maintaining easier. This makes EV ownership simpler!
So there are various technologies that can boost performance and efficiency of electric cars, with one such solution being continuous variable transmissions (CVT). CVTs adjust their speed according to driving situations so as to deliver desired power while decreasing energy use and fuel consumption.
CVTs do come with some disadvantages, including increased weight and production costs that can become costly for EV manufacturers.
Multi-speed transmissions provide drivers with more control and flexibility while improving performance, and are commonly found in high-performance vehicles ranging from luxury brands to racecars.
Electromagnetism can also help hybrid and electric vehicles perform more efficiently on the road, with benefits including faster acceleration, longer cruising distances and an extended battery lifespan.
Direct-drive transmissions offer another alternative to CVTs; these use a clutch to change gears. While more costly than their CVT counterparts, direct drives may provide significant advantages in certain situations.
Zeroshift has designed an innovative transmission concept for electric cars that requires no clutch and changes ratios without interrupting torque, thanks to electronic controls of electric motor shaft speeds and an integral damper in gear hubs that isolate vibrations during gear changes.
This technology features two small electric motors on separate shafts. Together they deliver incredible acceleration off of the line and sustained acceleration to higher speeds – almost as fast as an ICE vehicle – making this ideal for Formula E car applications and helping them achieve maximum speed and efficiency.
Manual Transmissions
Manual transmissions allow drivers to control engine gears directly, providing drivers with greater control and satisfaction than automatic transmissions do. Automatic transmissions make gear changes seamless with just the press of a button – and can even change gears at random intervals!
Gasoline engines use transmissions to deliver power at the optimal speed and torque to the wheels for any driving condition. A driver can switch their car between gears as needed – for instance if they want to maintain highway speeds without stalling out or need to make quick progress away from stop lines quickly.
Electric motors don’t experience the same limitations on power band as internal combustion engines do and thus don’t require gearboxes to keep them within their sweet-spot. There are still limited gear options, however; manufacturers have tested installing manual transmissions into prototype EVs like Tesla Roadster 2 speed version as well as six-speed Mustang display at SEMA 2019.
Toyota is also exploring ways to emulate manual gearboxes on electric cars by employing computer simulation that sends localised feedback to a clutch pedal and gear stick. Such a system could augment torque delivered from electric motors for replicating gear selection but may reduce engine performance as a result.
Lexus is also exploring methods of keeping manual transmission alive in electric cars, although this technology remains experimental. Recently, they announced they are developing an SUV powered by batteries and featuring manual gearbox for research and development purposes.
Manual electric vehicles (EVs) may never become mainstream vehicles anytime soon; but just having this option to provide clutch-based driving experience in an electric car is tantalizing. While likely never making much headway in mass market sales, Lexus and Ferrari have shown interest as potential ways of providing classic driving experiences to high-end customers.
Though a manual EV may not match up to conventional engined vehicles in terms of performance, it could be the perfect option for drivers unfamiliar with shifting gears and those wanting the ability to take their EV off the beaten path onto dirt roads or those who prefer an older-fashioned manual transmission over modern automatics.
