Renault-Geely Amorfo motor reaches 98.2 per cent efficiency

A new powertrain boasting 98.2 per cent efficiency is causing a stir in the automotive industry. The technology comes from Horse, the joint powertrain company established by Renault and Geely. Called “Amorfo”, the motor is intended chiefly to make hybrid vehicles more economical; the manufacturer says it cuts energy consumption in day-to-day use by around one per cent.

Why this motor matters so much to the automotive industry

For years, manufacturers have been competing to develop more efficient powertrains. Japanese and European brands were long regarded as the benchmark, but Chinese groups are now advancing through intensive research. Dongfeng and Changan have reported record figures for combustion engines, while BYD has done so for electric powertrains. Renault and its partner Geely have now entered this environment with an electric motor that claims a new best-in-class figure.

The Amorfo motor is not expressly aimed at pure electric cars with huge battery packs. Instead, it is designed primarily for hybrids and range-extender vehicles. Every percentage point of efficiency carries twice the weight here, as the combustion engine, electric motor and battery all have to work together.

“With 98.2 per cent efficiency, the new Renault-Geely motor is approaching the physical limit of what currently appears realistic for high-volume production.”

The key lies in the stator material

The name “Amorfo” comes from the central feature of the concept: amorphous steel in the stator. Motors normally use crystalline electrical steel laminations. The atoms in this steel are arranged in a regular pattern, which is well understood in conventional machines but also makes certain losses unavoidable.

In amorphous steel, the atomic structure is disordered, much like glass. This irregularity is far from a marketing gimmick: it offers physical advantages. Its magnetic properties are different, and Horse uses this to reduce losses in the motor’s magnetic field.

Thinner than a human hair

The thickness of the steel laminations that form the stator is particularly striking. They measure just 0.025 millimetres. By comparison, laminations in many common electric motors are ten times thicker.

• Stator lamination thickness: 0.025 mm
• Comparison with standard motors: around 10 times thinner
• Reduction in motor losses according to the manufacturer: around 50 %
• Maximum efficiency: 98.2 %

These ultra-thin laminations reduce so-called eddy currents. They form in the metal as the magnetic field continually changes while the motor runs. They heat the steel and consume energy. The thinner the laminations, the less space there is for these currents, meaning less energy is lost as heat.

What 98.2 % efficiency means in practice

For electric motors, manufacturers typically quote efficiency figures of between 93 and 97 per cent, depending on the operating point and rotational speed. At first glance, 98.2 may appear to be only a small advance. Yet in a field already operating close to physical limits, achieving that increment is technically demanding.

Horse combines this high efficiency with respectable output figures: 190 PS and 360 Newton metres of torque. That is sufficient for medium-sized SUVs, saloons or vans, and suits modern plug-in hybrids well, where the electric motor covers a substantial proportion of driving.

“One per cent more efficiency across millions of vehicles adds up to enormous energy and CO₂ savings over the years.”

One per cent lower consumption may sound small, but it is noticeable

Across a complete hybrid system, Horse expects real-world energy use to fall by around one per cent. This is because the electric motor represents only one element of the overall system: the battery, power electronics, transmission and combustion engine all have their own losses.

A brief calculation illustrates this:

• A modern mid-sized hybrid uses around 15 kWh of electricity per 100 km in plug-in operation, or equivalent energy in combustion-engine mode.
• One per cent of this equals 0.15 kWh per 100 km, or a very small quantity of fuel.
• Over 200,000 km, however, this already amounts to 300 kWh; multiplied across hundreds of thousands or millions of vehicles, it becomes a major lever.

Seen in this context, the seemingly modest gain becomes far more significant. Manufacturers pursue tenths of a percentage point in every component. Securing one per cent in a key part of the powertrain at a single stroke creates a genuine fleet-consumption advantage.

Laboratory figure or real-world win? Where caution is justified

The 98.2 per cent figure comes from laboratory testing. Temperatures, speeds and load points can all be optimised to produce an ideal dynamometer result. On the road, however, a motor constantly faces changing conditions: cold starts, stop-start traffic, high summer temperatures, and ageing insulation and bearings.

Anyone who has compared test-bench data with later real-world measurements will recognise this issue. Official figures and actual consumption are often different. The gap is generally smaller for electric motors than for combustion engines, but it does not disappear completely.

Horse has also yet to reveal which production vehicle will be the first to use the Amorfo motor. No timetable has been given either. The motor currently appears in the joint venture’s catalogue, meaning it is in principle available to Renault brands and other Geely subsidiaries such as Volvo, Lynk & Co and Zeekr.

Technical obstacles associated with amorphous steel

Amorphous steel has drawbacks as well as benefits. Producing it is complicated because the steel must cool extremely quickly to retain its disordered structure. This limits formats and manufacturing processes, while pushing costs higher.

For series production, efficiency is not the only consideration; manufacturability matters too. Manufacturers must determine how the exceptionally thin laminations can be stamped, stacked and insulated precisely at high volumes without scrap rates and costs spiralling.

Why hybrids benefit in particular from the Amorfo motor

In everyday use, hybrids often operate at partial load: frequent pull-aways, regenerative braking, short electric-only journeys and then renewed combustion-engine running. The electric motor therefore rarely works at precisely the point where it achieves its theoretical peak efficiency.

When a motor reaches 98.2 per cent at its optimum point, the wider operating range generally benefits too. Average losses are lower. This is particularly important for plug-in hybrids, whose electric motor may handle 50 to 80 per cent of the daily distance depending on the driving profile.

Renault and Geely are expanding their hybrid strategy while many manufacturers simultaneously promote fully electric models. Efficient hybrid systems help them meet fleet targets and serve transitional markets where pure electric cars have not yet gained wide acceptance or become affordable.

What this development could mean for future electric cars

Although the Amorfo motor is primarily intended for hybrids, parts of the technology can be transferred to pure battery-electric cars. Every mile of range gained without increasing battery size saves weight, costs and resources.

For example, if an electric car needs two to three per cent less energy per kilometre thanks to a more efficient motor, the manufacturer can slightly reduce the battery size while retaining the same range. This not only lowers material use, but also makes rapid charging easier and reduces costs for buyers.

What motorists should take from this development

For drivers in Germany, Austria and Switzerland, the new motor is initially a technical signal: the race for efficiency is far from over. While much discussion centres on range and battery chemistry, substantial progress is taking place behind the scenes in powertrain components.

Anyone buying a new Renault, Volvo or another hybrid from the Geely group in a few years’ time could already benefit indirectly from this development, without it being explicitly mentioned in the brochure. Manufacturers often introduce such technologies quietly during model-year updates.

Terms such as efficiency, internal losses and amorphous steel may sound cumbersome, but they help determine whether a car suddenly consumes substantially more in winter or whether consumption remains stable even after many years. The more efficient the underlying motor, the easier it is to limit all these effects.

When reviewing specification sheets for new models, buyers should therefore look beyond headline system output. Details on efficiency, motor technology and hybrid architecture offer clues to how economical a vehicle will be in real life, regardless of how optimistic the official consumption figure may sound.