New Research Will Help Revolution In Diesel Motoring

[phantom power]

Using a new £1.6 million grant from the Government's Science Research Investment Fund and £350,000 from Ford, the University of Bath's Department of Mechanical Engineering is carrying out research into ways of significantly improving the fuel consumption of diesel engines and reducing harmful emissions.

These changes include making the temperature control and cooling mechanism of the engines more efficient and increasing the number of engine parts that are powered by electricity rather than mechanically.

Dr Hawley also said that research at the University of Bath was looking farther ahead. He believed that in the next five years vehicle electrical systems would switch from using a 12-volt system to 36 volts.

This would mean that car engines would have the capability within their starter system to cut out when drivers stopped the car at, say, junctions and traffic lights, and restart automatically when drivers put their foot on the accelerator. This would virtually eliminate pollution from standing traffic, making the air in cities such as Bath and London cleaner.
http://www.sciencedaily.com/releases/2004/08/040815232518.htm

[ewagner]

1. Interesting......

During the Oil embargo in the '70's, there was a lot of attention paid to diesel as an alternative but the research was tempered by the claim that a "diesel economy" was a false economy because in the cracking process of crude oil, less diesel can be produced than gasoline.

Do you know anything about that?

[phantom power]

2. My understanding is that it had more to do with emissions

At the time, diesel engines technology was such that it produced far more harmful emissions than gasoline. That's no longer true with modern tech.

I recently read a claim that diesel is preferable to gasoline, because there is more "diesel grade" oil than there is "gasoline grade".

Take that with a grain of salt. I'm a computer scientist, definitely NOT a hydrocarbon chemist.

[NNadir]

3. There are several low pollution diesel options.

Diesel fuels from petroleum are still very dirty, but the systems for ameliorating this pollution are more sophisticated than they were in the 1970’s. When the systems fail, the pollution from diesels can be profound, as one can often see on the roadways.

Two modern advances in diesel fuel offer the opportunity for significant progress.

The first approach uses "biodiesel" which is esters, usually of ethanol or methanol of fatty acids found in cooking oils. This biodiesel approach offers reduced particulates, lower CO, no sulfur pollution, but can under many circumstances result in higher NOx pollution. (NOx can be controlled with catalytic converters.) The real advantage of biodiesel is that it is greenhouse gas neutral, the carbon dioxide generated is merely that captured by plants. Moreover, biodiesels, especially those which are ethyl esters, are biodegradable, minimizing spill problems. Also Biodiesel, consisting entirely of straight chain compounds and no aromatics, produces none of the problematic PAH’s (polyaromatic hydrocarbons) that play a role in the carcinogenic properties of air pollution. (When mixed with conventional petroleum based diesel as in “B20” or other grades, the level of PAH’s can actually go up with biodiesel, especially those containing doubly unsaturated parent oils, depending on the aromatic content of the petroleum based products.) Biodiesel is commercially available in many parts of the United States and the world. Unfortunately this option will never be scalable to meet the worldwide demand for diesel fuels, although it can certainly be used to extend petroleum resources and reduce the greenhouse and other pollution impact of diesel engines.

A more scalable approach involves the chemical synthesis from carbon oxides (monoxide or dioxide) of dimethyl ether, via hydrogenation. Dimethyl ether is a commercial compound (used, for instance, as a propellant in hairspray where it replaced CFC’s) that is an excellent diesel fuel. Because it contains no carbon-carbon bonds, DME produces zero particulates when burned, vastly reduced NOx, no sulfur/sulfate pollution and no carcinogenic aromatics. It is non toxic, and as a high boiling gas, it is easy to remove from water. Because it burns so cleanly, very few pollution controls are required to use it, and the effect of failure of pollution systems will be at best trivial. Moreover, DME can replace natural gas and propane in many of the applications where these gases are used, particularly in heating and cooking. Although DME is a gas, like propane, it can easily be liquefied and stored as a liquid at ordinary temperatures. Unlike propane and the more problematic methane, DME, even though one would expect it to have Greenhouse properties based on its structure, is not much of a Greenhouse threat owing to its short atmospheric lifetime of about 5 days.

DME however can contribute to ozone pollution because, like methane and propane, one of its decomposition products is formaldehyde. Formaldehyde in the atmosphere plays a role in ozone chemistry. One would expect biodiesel esters, especially methyl esters would also result in some atmospheric formaldehyde, though hardly on the same level as would be the case with DME.

How DME impacts the Greenhouse situation is a matter of choice. DME can be made from synthesis gas, which in turn can be made from biomass, garbage or coal or sewage by supercritical water oxidation. DME can also be made by direct hydrogenation of carbon dioxide. In this sense, DME is a hydrogen equivalent, ie, a storage medium for other forms of energy, nuclear, electrical, biological or fossil in origin.

In any case, the diesel engine actually offers opportunities to provide low cost