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Engines: Perfecting the Status Quo
Thom Cannell

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Perfected Precision

In the next few years we'll see computer control of direct injection engines (diesel and gasoline) for near-perfect measurement and delivery of fuel. Benefits include less emissions and better economy.

Peter Schulmeyer, manager and head of Strategy and Advanced Systems Laboratory, Motorola, says "The current problem is such a low percentage (less than 10 percent) of
energy from the fuel is actually used to move people and cargo. One step up is to operate the engine to (its) most efficient state. VVT, camless engine, hybrids are steps in that direction."

According to Schulmeyer, that combination starter-alternator/generator-flywheel represents an early step to hybrid gas or diesel electric vehicles now beginning to come online. Think about it. When decelerating, the flywheel-generator pushes energy in the battery, to steal "about 30 horsepower" back for added acceleration. Regenerative braking adds a few more ponies, but at a higher cost.

Or what about the often-hyped Continuously Variable Transmission, the CVT used by Honda and some Europeans? Combined CVT, electronic control, and engines could be run
continuously at optimimum. Less waste, less size, less fuel.

Bye, bye belts

The most radical idea I've heard came from Wilkie and Schulmeyer both. "The trend is, over (the) next five years, to gradually get rid of the hydraulic system. Even if we don't dramatically change the engine architecture, you'll see moves towards 42-volt electrical systems, things like air conditioning and power steering...changing to electrical activation...not being powered by belts and hydraulics," according to Wilkie. Schulmeyer said "the generator/alternator becomes direct driven by the actual drivetrain. There's a maximum limit to how much power you can transmit over a belt."

Everyone agrees that cleaner fuels, particularly in the U.S., are a necessity. Lowering the sulfur content of gasoline and diesel fuel offer immediate benefits. Older vehicles run cleaner and new-generation vehicles can use a technology called "lean burn" to significantly lower exhaust emissions. ("Lean burn" engines use a higher proportion of air than current stoichiometric ratios of 14,7:1.) Adding more air to fuel increases fuel efficiency and lowers hydrocarbon and carbon monoxide emissions. Unfortunately nitrous oxide emissions increase and current high sulfur fuels reduce the effectiveness and longevity of catalytic converters designed for lean burn engines. Clean fuel is simply necessary. And it's doable at any refinery, it just costs money.

Are you wondering why we stick with familiar diesel and gasoline instead of the glamorous alternatives? Gasoline and diesel pack lots of energy into a small size. It's called energy density, sometimes methanol, compressed natural gas, hydrogen, and the latest lithium-ion batteries lack. So liquid hydrocarbon fuels are here to stay. Having said that, the final part of our vision is a synthetic compression-ignition (diesel) fuel currently championed by DaimlerChrysler.

Diesel fuel is normally pretty dirty stuff, compared with environmental standards and regulations. It contains sulfur, aromatics which produce particulates (soot and smoke), and all kinds of nasty chemical components. So nobody in the U.S. likes diesels except truck drivers. In Europe, where it routinely costs $40 to $80 U.S. to fill the tank, high-mileage diesel engines make up a quarter of the fleet.

A Clear Solution

In 1923, a process called Fischer-Tropsch made it possible to convert natural gas into clear fuel. A company called Syntroleum has developed cost-competitive methods of producing this fuel. Their two-step conversion process changes natural gas molecules into liquid hydrocarbon molecules. The result: synthetic crude oil.

Why is this good? Diesel engines are 40 percent more fuel efficient than gasoline engines, but sulfur bearing pump-grade diesel fuels poison catalytic converters. No converter, no more diesel. Syntroleum fuels have no sulfur. So manufacturers get clean exhaust, reliable engines, more fuel economy. Parenthetically, DaimlerChrysler has a synthetic fuel development program for it's newest generation highly efficient, single rail, direct injection diesel engine. In a demonstration, Dodge uses Syntroleum-type fuel in its Power Wagon concept vehicle.

Beyond the technological are some significant geopolitical considerations. North America has abundant natural gas and could lessen crude oil imports. World-wide, "stranded" natural gas wells located far from market could become economic fuel producers. Plants could be built near the field and liquids transported by pipeline or tanker to market. Synthetic fuel could be a new commodity, like crude oil but cleaner.

More pertinent, in many locations crude oil is mixed with natural gas, like the air trapped in a chocolate mousse. Some of this gas is burned off or "flared" from production wells. Some gas is vented directly to the atmosphere. Flares create greenhouse gases and the unburned methane is among the worst greenhouse gases known. If this were profitably convertible, there would be valuable clean fuel and reduced greehouse gases. Plus we would retain crude oil for other valuable chemical processes.

If this happens - and six large petrochemical companies have licensed the technology - synthetic fuel could be a transition fuel to the future. Original capacity might be used as a blending stock to make regular diesel fuel cleaner. Municipal buses, trucks and taxi fleets (in San Diego, Los Angeles, Chicago or Denver for example) could burn pure synthetic fuel to achieve clean air standards. In 10 years, when capacity comes on line, it would be available at the local pump and require no change in the fuel delivery infrastructure.

Synthetic fuels can be made into naptha, and naptha has twice the hydrogen density of methanol. That makes it a great fuel for fuel cells, completing the circle - from current internal combustion technology, to advanced electronically controlledl IC engines, to the electric fuel cell powered electric vehicle of 2020 or beyond.

-- Thom Cannell

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