Heavy on the lightweighting

  • 19-Oct-2012 01:05 EDT
2013 Cadillac XTS.jpg

Lightweight structural materials will have the most impact in helping automakers meet fuel-economy targets, according to survey respondents. (Cadillac)

The U.S. government finalized in late August a regulation establishing 54.5 mpg as the average fuel economy required of cars and light trucks in MY2025. The newest set of CAFE (corporate average fuel economy) regulations begins with MY2017 products; a prior set of regulations covers MY2012 through 2016, the final year of which the CAFE requirement is 35.5 mpg.

To make the almost 20-mpg leap in less than a decade—and to meet similar upcoming mandates in other regions of the world—automakers and their suppliers must develop and deploy a variety of fuel-saving technologies.

Two main technology trends—lightweight structural materials (72%) and engine downsizing (65%)—will have the most impact in helping automakers meet fuel-economy targets, according to SAE members responding to an online survey conducted for 3M and Automotive Engineering International by independent research company Signet Research in mid-July to early August—just prior to the finalized CAFE announcement.

Other areas ripe for achieving fuel-economy gains include design optimization (45%), vehicle downsizing (38%), vehicle electrification (34%), aerodynamics (19%), and intelligent electronics (18%), with “other” receiving 5% of the respondents’ votes.

In line with these findings, 95% of respondents consider lightweighting efforts to be important in their company’s product development work, with 59% considering lightweighting to be very important and just 4% saying it’s not important. Nearly three-quarters (72%) of the respondents believe that the level of commitment to lightweighting within their organization is greater than it was five years ago. Only 4% said the level of commitment is less than it was in 2007, and 24% say it’s about the same.

Not surprisingly, regulations such as the new CAFE rules are an impetus for this. Ninety percent of respondents believe that government mandates are an important consideration in their organization’s lightweighting initiatives, with 53% believing them to be very important. In an open-ended portion of the survey, one respondent wrote, “Most customers don’t care about lightweighting; it’s only driven by government requirements.”

Fuel economy was overwhelmingly selected as the top driver behind industry use of more lightweight materials at 85%, with cost a distant runner-up at 8%. When allowed to select up to three top drivers for lightweight materials usage, nearly all respondents (98%) chose fuel economy, followed by cost (52%), technology leadership (47%), and green image (42%).

This in-depth look at lightweighting is the first such study conducted for 3M and AEI, and indeed is a timely topic. Of the 516 respondents, a majority classified themselves as engineering management (28%) or product, design, and manufacturing/production engineers, at 25%, 15%, and 5%, respectively. Sixty-three percent of the respondents work for an OEM, 24% for a Tier 1 supplier, and 6% for a Tier 2. More than 7 out of 10 (72%) respondents are located in the U.S., with Asia-Pacific (9%), Europe (8%), Latin America (7%), and Canada (4%) also represented.

No reduction too small

A half pound shed here, a pound saved there—it all adds up. That’s the mindset for 80% of the survey respondents who agreed with the statement, “We are open to any solutions offering weight reduction.” Others are in search of weight savings in chunks: 16% said that they “primarily target areas for large weight reduction,” while 4% said they “only target areas for large weight reduction.”

Powertrain and body are the two development areas that will be most impacted by companies' lightweighting efforts in the next five years, according to the survey, both with 66% of the vote. Chassis also is a significant target area, at 60%, followed not so closely by interiors (26%), batteries (23%), manufacturing (15%), and electronics (11%).

These findings make sense, considering that powertrain, body, and chassis are larger, heavier systems that offer more opportunity for weight-shedding. The results also align fairly closely with the areas of responsibility of the respondents. More than half (51%) of the 3M/AEI survey respondents are directly involved in powertrain, 30% exterior/body, 25% interior systems/seating/trim, 19% materials, and 4% electrical.

Batteries jumped to the top of the list, at 75%, when the same question was posed specifically for electrified vehicles. Powertrain (58%), body (57%), and chassis (52%) are still expected to be big beneficiaries of lightweighting efforts, and electronics, at 18%, jumps ahead of interiors (15%) and manufacturing (8%).

Design optimization and downsizing are key strategies to lightweighting, but advanced materials are critical to companies’ efforts to achieve further weight reductions. Eighty-six percent of respondents believe advanced lightweight materials to be important for the advancement of electrified vehicles, with 44% believing they are very important; 5% said they are not important. With electrified vehicles, stretching the all-electric driving range is a major goal—and challenge—for automakers and their suppliers. As is generally the case with conventionally powered vehicles too—the lighter a vehicle is, the further it can go on a tank of fuel or a battery charge.

So, what materials will provide the most benefit to industry’s efforts to reduce component/vehicle weight during the next five years? Aluminum and composites are the runaway choices, virtually tied at the top with 78% and 77% of the vote, respectively. Plastics (49%) are next, followed by steel at 34%, structural adhesives at 26%, magnesium at 23%, and other 2%.

Composites become the clear leader when looking 10 years down the road, at 84%, while aluminum (59%) and plastics (53%) maintain the second and third spots. The outlook for steel is not as positive, according to the survey results; steel, at 19%, drops below both structural adhesives (36%) and magnesium (28%) in terms of providing the most weight-reduction benefit during the next 10 years.

Again looking ahead 10 years, two-thirds (67%) of respondents strongly agree that the average vehicle will benefit more from a mixed-materials design approach, for which different materials are chosen for specific applications, rather than from any one lightweight material. Thirty-one percent of the respondents somewhat agree with that notion, and 2% do not agree with it.

The advanced lightweight materials expected to benefit future vehicles are not necessarily innovations created by or for the automotive industry. Almost half (48%) of respondents indicated that their group/company has benefited from the transfer of lightweight material technologies from other industries. Only 15% said their organization had not benefited from technology transfer, while 37% were not sure. The aerospace industry has contributed the most (86%) to the auto industry, according to the survey, followed by motorsports (45%), military (22%), energy (11%), commercial vehicles (10%), and medical (7%).

Cost a hurdle

When the new CAFE regulation was announced, the U.S. Department of Transportation’s NHTSA (National Highway Traffic Safety Administration) unit and the U.S. EPA acknowledged the higher costs expected to be incurred by automakers to develop and deploy fuel-saving technologies, but the agencies also project that fuel savings will far outweigh those costs.

DOT Secretary Ray LaHood and EPA Administrator Lisa Jackson said the new regulation estimates that technologies used to meet the standard will add, on average, about $1800 to the price of a new light-duty vehicle in MY2025. However, consumers who drive their MY2025 vehicles for their entire lifetime are expected to save, on average, $5700 to $7400 in fuel. (This estimate assumes gasoline prices of $3.87 per gallon in 2025 with small increases most years throughout the vehicle’s lifetime.)

Convincing the buying public of this endgame net savings will be a challenge, as one 3M/AEI survey respondent noted to an open-ended question asking what is the number-one industry challenge to achieving lightweighting goals: “The play-off between increased cost for manufacture and how much the customer is prepared to pay up front considering the decreased future running costs.”

When asked the importance of cost in choosing a lighter-weight material over an incumbent material, 94% responded that it was important to some degree, with 45% indicating it to be very important and 3% not important. And cost was overwhelmingly cited as the top challenge facing the industry in terms of lightweighting. Some of the responses:

“Extensive lightweighting requires investment in plant and equipment tailored to new materials not substitutable as ‘drop in’ alternates.”

“The cost increase versus the added fuel economy must always be considered. In addition, when dramatically changing systems (more modular, etc.), there is significant development and testing which needs to be performed to minimize the risk of applying both new technology and new materials.”

“Overall cost is the biggest detractor. While lightweight materials may do the job, the OEM customer does not want to pay for them despite the obvious advantages.”

This last point—OEM unwillingness to pay for weight reduction—was a fairly common refrain among respondents, one of whom stated there’s “still a something-for-nothing logic.”

Even so, more than six out of 10 (62%) survey participants responded that their company is willing to pay more for weight reduction when selecting materials—15% agreeing to “Yes, definitely” and 47% to “Yes, probably.” Nineteen percent said their company is not willing to pay more, and 18% were unsure.

How much more will companies shell out? On average, respondents whose companies are willing to pay more for lightweighting materials will pay up to 7.5% more. Thirty-eight percent of respondents believe their companies will accept up to a 5% cost increase, and 30% indicated a 6-10% cost increase would be acceptable (see chart for full results).

For composites, in particular, cost again was chosen as the most significant challenge to more widespread deployment in the auto industry, at 86%, followed by manufacturing and assembly (57%) and durability/other performance characteristics (51%).

Another challenge is incorporating lightweighting initiatives early in the design cycle—a process some survey respondents believe is currently not happening. “It isn’t done early enough—at the architecture level,” one participant wrote. “Therefore, when the architecture shows up, weight drives weight—i.e., when the ‘arch’ is heavy, the chassis components upgrade to carry and stop it, the safety team adds gauge, doublers, and extra airbags to achieve performance targets, etc.”

Another respondent said the main challenge is an “inability to change the mindset and accept that the cost of more exotic materials can be offset by manufacturing process, etc., if the decision to consider weight is made early enough in a program’s life cycle.”

On average, the decision is made to target the vehicle for weight reduction 3.5 years from start of production (SOP), according to survey findings. Nineteen percent indicated that the decision comes less than two years from SOP, while 48% selected two to less than four years from SOP. More than a quarter (27%) of respondents believes the decision is made four to less than six years from SOP.

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