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The problem with oil is that it is an excellent source of energy. For instance, a single liter of gasoline contains more usable energy than a 53 kg NiMH hybrid battery pack.
However, amidst skyrocketing oil prices and a new generation of green-conscious consumers, fuel efficiency and environmental impact have become top design considerations for transportation. Engineers now face a new "green" challenge: How do you design an environmentally friendly product that also meets the traditional requirements of quality, cost, and time to market?
Armed with techniques such as hardware-in-the-loop (HIL) simulation and rapid control prototyping (RCP) as well as a new generation of measurement tools, engineers are taking advantage of new measurement and control capabilities to deliver new technologies to market and meet the accelerating demand for green transportation.
Consumers vote with their dollars, and the votes for fuel-efficient vehicles are in: Ford, GM, and even Toyota have closed or suspended SUV and truck plants in 2008. Legislative pressures are mounting as well—U.S. Federal Corporate Average Fuel Economy (CAFE) standards are proposed to rise to 35.7 miles per gallon in 2015, after remaining at 27.5 miles per gallon for the past 18 years. This combined with ever-stricter emissions requirements from both the California Air Resources Board and the U.S. Environmental Protection Agency makes delivering a vehicle to market that meets consumer expectations and these difficult requirements a daunting challenge.
After remaining relatively flat for 19 years, the Environmental Protection Agency has proposed that the Corporate Average Fuel Economy (CAFE) standards be raised beginning in 2011 with a goal of a 25% improvement by 2015.
Looking back several decades, today's vehicles, per kilogram, are more efficient than ever. Oil-powered engines have seen great strides in optimization, featuring elaborate emissions control systems and finely tuned calibrations. Hybrids have achieved consumer acceptance at realistic prices. Alternative fuel vehicles have been entering the market with engines capable of running on ethanol; mild ethanol-gasoline blends for use in normal engines can be found in gasoline supplies around the country. However, with all of these advancements, vehicles still emit many tons each of carbon dioxide over their lifetimes.
Role of the 'green' engineer in the automotive industry
While many industries have just started to practice green engineering, the automotive industry has been environmentally conscious for decades, becoming green to meet legislative requirements and handle competitive pressures during the first oil crisis in the early 1970s.
The role of the green engineer is more difficult than that of a traditional engineer because green considerations impact almost all aspects of a design. This includes everything from the operational impact of the product, a factor that is increasingly becoming relevant (especially for automobiles), to the end-of-life recycling of the product. Nearly every part of the design process is touched, affecting decisions in materials selection, manufacturing processes, electronics design, power train calibration, and vehicle testing.
These new factors can be difficult to justify from a business perspective. As recently as the 1990s, during the SUV boom, justifying extra development to increase mileage and reduce emissions beyond legislative requirements was a difficult task. It takes great discipline to look past the bottom line for a vehicle and take into account the big-picture life-cycle costs. Today's green engineer is aware of these issues and factors them into the design of the product.
Green automotive technologies have always been in development for a variety of reasons, ranging from complying with government standards to establishing goodwill with customers. A sense of urgency has gripped the automotive consumer as oil prices have nearly tripled in two years. Adam Smith's invisible hand is now accelerating advanced power train technologies into production at a new fervor not seen since the first oil crisis.
Optimizing the gasoline engine
Engineers are using a wide range of technologies to meet the challenge of the green automobile. It is impossible to cover them all here, but there are some notable advances that are showing both long-term and more immediate promise for improving transportation efficiency.
Advanced electronic control enhances going green
The vast majority of today's production vehicle fleet uses the venerable internal combustion engine. As it becomes more refined, realizing incremental gains is increasingly difficult because the technology is approaching its theoretical efficiencies. Early advances stemmed from mechanical improvements such as better materials, higher tolerances, and increased understanding of engine optimization. Most recent gains can be attributed to faster and more optimized electronic control of the combustion process.
Advanced control is enabling new efficiencies in engine technology that, mechanically, has remained fundamentally unchanged since the Model T. As engine controllers continue to benefit from increases in microprocessor power, more variables can be controlled in finer resolution at faster rates with higher-level modeling. With more reliable tool chains capable of taking mathematical models and converting them to production code, engineers can focus on new control strategies rather than debugging low-level controller code.
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