Navigant Research Blog

Electric Turbochargers: The Next Big Thing in Fuel Efficiency

— October 23, 2014

The key to the next major advance in internal combustion engine fuel efficiency could well be the electric turbocharger.  At a recent fuel economy technology showcase at the U.S. Environmental Protection Agency (EPA) National Vehicle Emissions and Fuel Lab in Ann Arbor, Michigan, Valeo showed off the motor-driven turbo it will supply to an unannounced automaker.  The first production applications are scheduled to begin arriving in 2016, according to the company.

The aggressive expansion of fuel efficient technologies, such as electrification, multi-speed automatic transmissions, and engine downsizing, has played a major part in increasing miles per gallon.  The average fuel economy of the American new light duty vehicle fleet has improved by almost 25% over the past decade.  Meanwhile, gasoline direct injection and turbocharging have enabled engineers to cut engine displacement by 30% or more without sacrificing the performance that drivers have come to expect.  As of the 2014 model year, approximately 75% of Ford gasoline and diesel engines globally are turbocharged while 85% of Volkswagen engines are boosted.

Response Time

Part of the concept behind boosted engines is to use smaller engines with turbochargers that provide performance on-demand.  There has always been an inherent time lag, however, between the time the driver presses the accelerator and the generation of enough extra exhaust gas to spin up the turbo and provide boost.  Mechanically-driven superchargers eliminate much of the lag at the cost of substantial friction at higher speeds.

Replacing the exhaust-driven turbine side of the turbocharger with an electric motor provides a number of advantages, most notably in packaging, responsiveness, and operational flexibility.  One of the fuel economy benefits Valeo highlights is the combination of an electric turbo with the cylinder deactivation – i.e., the ability to shut off multiple cylinders under light loads in order to improve fuel efficiency.

The fuel savings achieved by shutting off unneeded cylinders can be quickly lost when driving on roads that aren’t completely flat.  Even a mild grade can cause an engine to switch back to running on all cylinders in order to produce enough torque to maintain speed.  “With an electric turbo, the engine management system can request small amounts of boost on-demand to increase torque while climbing a grade while keeping as many as half of the cylinders inactive,” Ronald Wegener, application engineering manager with Valeo, told me.  “This can yield up to a 10% improvement in efficiency.”

Valeo has developed versions of the device for both 12V and 48V electrical systems so that the turbo can also be used as part of a mild hybrid system during off-throttle conditions.  Intake air flowing through the compressor drives the motor to generate electricity, charging the battery.  Audi is using this as one of the two forms of energy recovery on its Le Mans-winning R18 e-tron race car.  Many of the current crop of Formula One cars have also adopted this approach.  Earlier this year, Audi announced that the next-generation Q7 TDI, scheduled for model year 2016, would be its first production application of the technology.

Shrinking Engines

Electric turbochargers also provide packaging benefits to engine designers.  Traditional turbos require complex plumbing to route exhaust gases to the turbine side of the turbo and feed the boosted intake charge to the other side of the engine.  Disconnecting the turbo from the exhaust allows designers to place the turbo wherever it fits best for packaging and performance.

Executives and engineers agree that while electric vehicles will gain market share in the coming years, internal combustion engines will likely remain the dominant powertrain choice in the transportation space at least through the 2020s.  With engines continuing to shrink, it seems likely that electric turbochargers will account for a growing share of the boosted engine market in the next decade.

 

Car-Free in Colorado: Living with an E-Bike

— October 20, 2014

After years of vehicle ownership, I decided about 3 months ago it was time for a change of pace.  Literally.  Tired of the plethora of (and seemingly continually rising) costs associated with owning a vehicle (parking, maintenance, insurance, repairs, registration fees, gasoline, etc.), I sold my car and used part of the funds to purchase an E3 Vibe electric bicycle (e-bike)  for $1,500 from Currie Technologies.  An e-bike is a traditional pedal bicycle with a battery pack that stores electricity, an electric motor for propulsion, and a user control attached to the handle bars for modifying the level of electrical assistance.

(Source: Currie Technologies)

Living in Boulder, Colorado certainly makes this transition much easier than in most U.S. cities.  An excellent bicycling infrastructure, a local carshare program, and comprehensive transit system all contribute to an excellent environment for going car-less.

Cost Analysis

With an upfront cost of $1,500, the e-bike will pay for itself after one year of avoided car insurance and gasoline expenses.  My monthly gasoline and insurance charges were about $130 combined ($80 for insurance, $50 for gas), totaling $1,560 per year.  This is more than the brand new e-bike cost itself, without even delving into the additional avoided costs of vehicle registration fees, parking, maintenance, and repairs.  Just as an example of potential additional costs of owning a vehicle, it’s estimated that in Colorado, the average cost of a common car repair (parts & labor) was $348.17 in 2011.

What about the operating costs for e-bikes? While many organizations estimate the cost of fully charging an e-bike from $0.10 to $0.20, other conservative estimates project that it costs just under $0.25 to charge an average e-bike battery from empty to full.  For me, this would happen about twice a week, since I’m usually charging the battery from half to full power 4 times per week (a 6.3 mile commute round trip usually drains the battery to a little over half power).  Using the conservative estimate of $0.25 to fully recharge the battery, electricity for recharging my e-bike would run about $26 per year ($0.50 multiplied by 52 weeks).  This (wishfully) assumes no winter in Colorado.  With a more realistic projection of biking to work three-quarters of the year, this reduces the annual charging cost to under $20.

Electric Hum

When the weather isn’t suitable for biking to work, I take the bus with a complimentary bus pass from my employer.  However, since I do need access to a vehicle on occasion, I have become a member of Boulder’s carsharing program, eGo CarShare.  So far, I am averaging about $20/month in rental fees, amounting to $240 per year.

Overall, becoming an e-bike owner has not only provided significant financial relief, but has also been an incredibly enjoyable experience.  I bike more often and travel longer distances than I would typically go on a traditional bike.  In addition, I get to confuse other cyclists with the humming sound of a 250W electric motor.

 

Truck Fuel Economy on the Rise

— October 20, 2014

The U.S. Environmental Protection Agency (EPA) has just published its 2014 fuel economy trends report, and though the news is generally positive, some potential storm clouds remain on the horizon for manufacturers.  While the overall average fleet fuel economy hit a record 24.1 mpg for the 2013 model year, the monthly update from the University of Michigan Transportation Research Institute (UMTRI) showed a 0.5 mpg drop in September 2014, equal to the 2012 to 2013 annual increase.

The long-term trend has definitely been upward.  Last year represented the eighth increase in the past 9 years for the American new vehicle fleet.  Automakers will have to maintain this momentum if they expect to hit the 2025 corporate average fuel economy target of 54.5 mpg.  Fortunately, attendees at a fuel economy technology showcase at the EPA emissions testing lab in Ann Arbor were all publicly confident that the targets were achievable.

As for the sudden drop in September, that can be explained by what are likely temporary market conditions that led to a significant uptick in full-size truck sales at General Motors (GM) and Chrysler.  As the 2014 model year drew to a close, combined sales of the Chevy Silverado and GMC Sierra jumped 46%, aided by incentives of up to $4,500.  Ram sales were also helped along by retail incentives of up to $3,000, as well as the popularity of the new Ram 1500 EcoDiesel.

From Steel to Aluminum

Sales of Ford’s F-series trucks were essentially flat, as the automaker began the transition to its all-new, aluminum-bodied 2015 F-150.  It appears that GM and Chrysler are hoping to grab some market share in the financially lucrative big truck segment in hopes that Ford would stumble in the complicated transition from steel to aluminum trucks.

At this point next year, even if truck sales continue to climb, we’re unlikely to see a similar drop-off in fuel economy, thanks to new technology in the segment.  The weight savings and new power plants for the Ford trucks are projected to deliver up to 20% better fuel efficiency than the steel-bodied versions.

Chrysler and GM also have to meet the new fuel economy standards.  Ram pickups are already available with ZF 8-speed transmissions, and GM is adding its first 8-speed automatic transmission to 2015 pickups with a 6.2-liter V8.  As GM ramps up production of the new 8L90 transmission, it will probably get paired with other engines as well.  GM and Ford also have a joint development program to produce 9- and 10-speed transmissions for trucks and other vehicles in the next few years.

Diesel Debuts

Chrysler is also building on the success of the 28 mpg Ram 1500 EcoDiesel by doubling production to 20% of its total production volume of trucks in 2015.  Ford is still awaiting final EPA certification on the 2015 F-150, but the 2.7-liter EcoBoost V6 is also expected to get a highway rating in the upper 20s.  GM’s new midsize Colorado and Canyon pickups are already rated at up to 27 mpg with a gasoline V6, and a diesel version is coming some time in 2015.  Ford is also offering a diesel engine option in the new Transit full-size vans that replace the E-series this year.  Ford will likely be closely following the sales trajectory for diesel engines in the Chrysler and GM trucks, as well as the next-generation Nissan Titan and Toyota Tundra, which will both be available with a Cummins-sourced 5.0-liter diesel V8.

With the huge sales volumes of pickup trucks in North America, lightweighting, advanced powertrains, and automatic stop-start, trucks will make a big contribution to reducing fossil fuel use in the next decade.

 

Shakeout Looms in Fledgling E-Truck Market

— October 17, 2014

Despite significant government and private-sector investment over the past 10 years, the global market for hybrid, plug-in hybrid, and pure electric trucks has been slow to grow.  Although it’s challenging to get fleets to provide numbers on how many of these trucks  they are running – many companies view it as competitive information –the Navigant Research report, Transportation Forecast: Medium and Heavy Duty Vehicles, estimates that, in 2014, hybrid and plug-in technologies constituted well under 1% of medium and heavy duty (MHD) trucks fleets in North America and Western Europe.  This lack of progress matters, because MHD trucks account for 32.6% of U.S. fuel consumption.  Electrification could significantly reduce this rate of fuel guzzling.  Yet, as my colleague John Gartner noted in a recent blog, there is a real lack of PEV options in the trucking world.

Investment in these technologies has borne fruit, however, and will help the electric drive truck market grow.  Deployments have helped fleets determine the applications for which hybrid or plug-in trucks will work best, both in the sense of being able to meet the demands of the duty cycle, but also providing the greatest fuel savings benefit.  The range of MHD truck applications into which hybrid and plug-in technology can be integrated is broad, with widely varying performance requirements.

Filling the Gaps

First are vocational applications, including delivery and distribution trucks, such as refrigerated vehicles and service vehicles, especially those used by the utility and telecommunications sectors.  And within these segments, there is a multitude of usage patterns.  Delivery trucks may be long haulers, traveling at steady, high speeds; used for suburban delivery, operating with both high and low speeds; or used for delivery exclusively within an urban center, with stop-and-go driving and very low mileage.

All of these variances mean that there is no single technology that will meet all the needs of the trucking sector.  Thus, this sector will be highly segmented, with each technology option fitting into certain niches.  While hybrids have no range limitations, it can be challenging to achieve payback of the price premium unless the vehicle operates with some stop-and-go driving and accrues significant mileage – probably a minimum of 20,000 miles annually.  By contrast, while the range of a pure battery electric truck has proven too short for most applications, these trucks are ideal for deliveries within an urban center.  This application is likely to see more interest in the Western European market in particular, as cities are increasingly looking to limit vehicle access to the city center.

Winnowing Ahead

So, as the British say, it’s horses for courses for the trucking industry.  This will pose a challenge for the sector given the very high percentage of small firms supplying this market.  These are companies that may struggle to stay afloat in a market with low volumes in its early stages.

But pressure on truck OEMs and fleets to reduce the environmental impacts of their vehicles – a major theme of the Automotive Megatrends conference held by Automotive World in Brussels in September – is likely to increase.  A small company with a proven technology will find increased interest from fleets to trial new vehicles and perhaps interest from the major vehicle manufacturers in securing access to their technology through investment or acquisition.

 

Blog Articles

Most Recent

By Date

Tags

Clean Transportation, Electric Vehicles, Policy & Regulation, Renewable Energy, Smart Energy Practice, Smart Energy Program, Smart Grid Practice, Smart Transportation Practice, Smart Transportation Program, Utility Innovations

By Author


{"userID":"","pageName":"Electric Vehicles","path":"\/tag\/electric-vehicles","date":"10\/25\/2014"}