Gas Engines to Remain Relevant

Special Coverage

SAE World Congress

DETROIT – Despite widespread calls for greatly improved fuel economy and vehicle emissions, the gasoline internal combustion engine (ICE) will continue as the dominant automotive powertrain of choice for the next 20 years.

Thisonclusion, reached by a panel of executive automotive engineers at the 2007 SAE International World Congress here, comes as a blow to industry watchers claiming the electrification of the vehicle and the proliferation of hydrogen fuel cells will revolutionize automotive travel in the near-term.

“We are in a period of unprecedented uncertainty (for the gasoline engine),” Michael Crane, director-gasoline systems, for Siemens VDO Automotive, says, noting it also is a time of great opportunity for advancements.

In North America, the penetration of clean diesels is expected to significantly increase in the mid-term, the panel says, with hybrid-electric drivetrains, hydrogen fuel cells and other alternative power sources playing ever-larger niche roles as their related technologies improve.

However, it will be the ICE – running on gasoline or some form of alternative fuel – that will continue to drive nearly half of all vehicles in 2030, Crane says.

More to the point, adds Uwe Grebe, executive director-advanced engineering, for General Motors Corp., the adaptability of the ICE will allow it to serve as a “bridge” to many alternative powertrains in the future.

The gasoline ICE has survived as long as it has because of its relatively low cost and high-power density, along with a robust and versatile design that operates on a cheap and widely available fuel source. Efficiency has been satisfactory and emissions are relatively low.

But as technology advances, the gas engine will continue to evolve.

Witness the 50% reduction in gas-powered vehicle emissions over the past five years, along with the 13% increase in power density over the same period, says Scott Bailey, general manager-Gas Engine Management Systems for Delphi Powertrain Systems.

Moving forward, the ICE will continue to improve in efficiency, emissions and power output through numerous advancements, including the increased use of direct fuel injection (DI) and turbocharging, advanced variable-valve timing and exhaust-gas re-circulation systems and lean-burn/homogeneous charge compression ignition technology, among others.

“DI will serve as an enabler,” Siemens’ Crane says, “similar to common-rail diesel injection systems 15 years ago.”

“It opens the door for the application of many new advancements.”

Among the likely scenarios in the future will be smaller gas engines approaching diesel-like efficiency, along with the elevated use of a varying array of alternative biofuels. In addition, the electrification of ICE drivetrain components will further improve micro-, mild- and full-hybrid systems.

This surge in technology will increase engine complexity and cost, the panelists agree, making investments in alternative drivetrains an increasingly attractive option.

Higher standards for corporate average fuel economy and carbon-dioxide emissions, combined with uncertain levels of alternative biofuel development and production, will dictate the viability of ICEs, as well.

However, the customer has the ultimate choice, Crane says, and the familiarity, fun-to-drive nature and well-established know-how of the spark-ignited ICE will allow it to remain relevant for a long time – regardless of what fuel source it runs on.

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