Within the next 20 years, petroleum will become scarce enough and even more expensive that a hydrogen-based energy infrastructure will be needed in about 30 years for a sustainable energy future as well as environmental quality. That's the conclusion of a spirited discussion by a panel of automotive power train and electronics experts gathered at the Infineon Technologies Media Day this past Monday in Sonoma, Calif.
But on the way to such a new-technology-based economy, efficiency and emissions improvements to current engine technologiesgasoline internal combustion, diesel, and hybrid driveswill all be needed to stretch hydrocarbon fuel resources to get us there.
The greatest interest was stirred by John Pinson, engine systems group manager at General Motors Power Train Systems Research Lab. He described developments now under way on the Homogeneous Charge Compression Ignition (HCCI) enginea concept that looks to improve fuel economy in gasoline engines by 20% and allow diesel engines to achieve emissions comparable with gasoline internal combustion. GM and Bosch, along with Stanford University, have a joint program to unable HCCI technology through development of advanced control systems involving sensors, actuators, and algorithms.
"The challenge is the process is inherently unstable and difficult to control with sensors and software," says Pinson. Currently available technologies such as direct fuel injection into cylinders and variable valve timing will be adapted to make HCCI engines work, he adds.
The HCCI process does not use a spark for ignition but heating from compression, much like a diesel. It is superior, Pinson notes, in that there is no flame when burning for efficient combustion and low emissions. The combustion is similar to what happens with many old cars that are out of tune on a hot daythey experience "run on" or "dieseling," which is a very uncontrolled process. Thus sensors, particularly for in-cylinder pressure measurement, and processing power are key to keeping HCCI under control over automotive operating temperature ranges and for different quality fuels that might find their way into a car's tank, he adds.
Compared to a gasoline internal combustion engine (see below), an HCCI engine compresses part of the charge from the previous exhaust stroke in a recompression stroke as a "seed" for the next intake stroke, helping to initiate ignition of the fuel air mixture. Regulating this seed charge adjusts the combustion.View an animation of the HCCI process
Semiconductor developments will be vital in realizing such combustion improvements, noted Chris Cook, VP of Infineon's Automotive, Industrial, and Multimarket Business Group. He specifically cited the following:
Added sensor processing power and I/O
Advanced sensing requirements for higher resolution and ruggedness
Power control for energy efficiency within cars equipped with more and more electronic features
The drive to smaller chip feature sizes will allow more cost effective electronics, and efficient packaging will help in power conservation, Cook added.
Pinson expects to see HCCI technology introduced incrementally within a decade at a cost point that consumers will accept for the benefits gained. He adds that using HCCI in a hybrid power train further increases its advantages. But he and the other panelists concluded it still uses petroleum resources and only sustainable fuels such as hydrogen and renewable biofuels will be needed eventually.