Navigant Research Blog

Upcoming U.S. Fuel Economy Standards Achievable

David Alexander — August 6, 2015

In July, the International Council on Clean Transportation released a new technical briefing paper entitled Hybrid vehicles: Trends in technology development and cost reduction. It is a good read and covers a lot of interesting information about light duty hybrid vehicles. The document points out that the two current hybrid vehicle market leaders, Toyota and Ford, both use a system that has two large electric motors and a planetary gear system in place of the conventional transmission. This is known as a power-split hybrid system. Most other manufacturers with recently introduced hybrid models have chosen to go with variants of a single-motor, twin-clutch hybrid system, commonly referred to as a P2 hybrid.

There are also other approaches in production today. A third option was chosen by General Motors (GM), which has implemented a simpler mild hybrid technology based around a powerful belt-alternator-starter. Honda has its Integrated Motor Assist and Mazda has i-ELOOP in production, which uses ultracapacitors rather than batteries to capture regenerative braking energy.

The message from the paper is that the incremental costs of adding hybrid drive are expected to continue falling as the systems are refined, by as much as 5% per year, thus making the technology more affordable. Some examples of how small changes have produced these improvements in the past are shown (for example, replacing a separate hybrid cooling system by expanding the existing engine cooling system). OEMs and suppliers are also expected to be able to improve efficiency in increments so that the return on investment (ROI) becomes more attractive for buyers.

Also mentioned are some of the topics that Navigant Research has covered in recent studies, such as 48-volt systems and fuel efficient technologies such as lightweighting and turbocharging. There is a lot of incentive to improve fuel economy as new government regulations on the horizon will require tough targets to be met or fines will be assessed.

Not All Gloom and Doom

But it is not all gloom and doom. The National Research Council has also recently published a report on the Cost, Effectiveness and Deployment of Fuel Economy Technologies for Light-Duty Vehicles. One interesting chart shows that many manufacturers already are selling vehicles that meet future standards. The Corporate Average Fuel Economy (CAFE) standard sets targets for fuel economy based on vehicle footprint so that the mile-per-gallon number is higher for smaller vehicles.

Some vehicles available today already exceed the targets for 2021 and 2025, including hybrids from Toyota, Ford, and Hyundai. The conventional 2015 Mitsubishi Mirage with a 1.2-L engine and continuously variable transmission (CVT) is close to meeting the 2023 target. Already close to meeting the 2021 target are non-hybrid vehicles such as the Volkswagen Golf diesel, Honda Civic HF, Toyota Corolla LE Eco, Mazda3, and Dodge Dart.

As Navigant Research’s Automotive Fuel Efficiency Technologies report discusses, there is no single quick solution for meeting emissions targets. The goals will be met by a combination of lower weight, better aerodynamics, and more efficient powertrains. The challenge for the automotive industry is to accomplish this at the lowest cost.

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