To meet challenging fuel economy targets, now carmakers will mainly use “start-stop” technology and lightweighting.

According to a new study from Lux Research (Boston, MA), auto manufacturers will need to meet aggressive fuel-efficiency targets over the next decade—54.5 miles per gallon in the United States and 95 grams of carbon dioxide emission per kilometer in Europe. While advanced technologies like all-electric vehicles, super-light carbon-fiber composites and hydrogen fuel cells will all be available, Lux Research’s analysis found that micro-hybrids will provide the most economical route to meeting 2025 targets.

Micro-hybrids automatically stop the engine when it would otherwise be idling, using an improved or additional battery (or another type of energy storage system) to quickly restart when it’s time to move. Some even capture braking energy and do propulsion assist. Nearly half of the improvements required to meet the stiff targets will come from micro-hybrid technology, notably through improved batteries; lighter structural materials will contribute 39% and improved fuels will add 13%.

Lux Research analysts built a data-driven model and evaluated the innovations necessary to meet ambitious 2025 fuel-efficiency targets, and determine their impact on automobile prices (an average of $1700 in increased vehicle cost). Their findings include:

• Micro-hybrids lead the charge based on energy storage advances. Innovations in micro-hybrid technologies will be the biggest factor in the march toward greater fuel efficiency, contributing 48% of the improvements required to meet 2025 targets. Falling prices of lithium-ion batteries, lighter and better-performing 12-V and 48-V batteries and better super-capacitors are among the changes powering energy storage.

• Lighter structural materials are at the heart of fuel efficiency and will contribute a hefty 39% of the targeted improvements for 2025. Carmakers such as Ford and GM have ongoing partnerships with companies like Alcoa and Nanosteel Co. to develop materials to reduce weight.

• A third, albeit smaller, factor driving fuel efficiency is innovation in alternative fuels. About 13% of the improved 2025 targets will come from increased research octane number (RON) content due to increasing biofuel blending mandates. Brazil has the highest target of 27.5% for ethanol, while the United States aims for 20% by 2022 of all renewable fuels. India and Thailand have set 20% targets, while Europe lags at 10%.

(According to Plastics Today)