A lot has been made of late regarding high sulphur levels in diesel being a major problem with engine longevity, as well as contributing to exhaust emissions.Current levels of on-highway diesel fuel a...
A lot has been made of late regarding high sulphur levels in diesel being a major problem with engine longevity, as well as contributing to exhaust emissions.
Current levels of on-highway diesel fuel are legislated at 0.05 per cent or 500 parts per million (ppm).
With alternative fuels being encouraged from every direction, the oil suppliers are being forced into spending billions to take crude oil and extract much cleaner diesel fuel that contains only 15 ppm as of July 15th, 2006.
This will hit retail stations and fleets later that same year, probably by September.
The cost per liter to reduce the sulphur content is being quoted as anywhere between four to five cents U.S. per gallon.
At the same time, however, the American Petroleum Institute (API) says these new rules will probably result in a fuel price increase of at least 12 to 15 cents a gallon.
So why are regulators pushing so hard to see the price climb even further?
They now choose to view engines, particulate traps, NOx absorbers, the exhaust gas recirculation systems (EGR), and more importantly the fuel, as a single entity.
Without improved sulphur levels, the performance of most aftertreatment systems is adversely affected.
Many of these devices can not be effectively brought to market and function on high-sulphur fuel.
Couple these costs with the new vehicle price boosts of $1,200 to $1,900 per vehicle to pay for emissions control equipment, and you’re looking at a significant increase.
Alternative fuels, such as compressed natural gas (CNG), are now in use in day-to-day operation.
But the manufacturers seem to favor different fuel systems.
Caterpillar has backed the spark-ignition natural gas/diesel engine, while Cummins, Detroit Diesel and IVECO have backed a single-fuel, spark-ignition option.
Vancouver-based Westport Innovations, in conjunction with Cummins, have patented a high-pressure injector that allows natural gas to be burned in conventional diesel combustion chambers.
The gas is pre-ignited by a very small quantity of diesel fuel sprayed in at 3,000 psi from the same injector.
Exhaust particulates can be reduced by up to 70 per cent, NOx by 37 per cent, CO2 by 17 per cent and sulphur emissions can be reduced to virtually zero with the system.
Alternatively, fuel cells such as the Ballard model in Burnaby, are clean, silent alternatives to the internal combustion engine, but the method chosen to make the hydrogen to run them uses the very fossil fuels that they’re meant to replace.
Hydrogen made from natural gas at regional refineries or urban retail outlets would reduce exhaust emissions by approximately 70 per cent.
Using CNG has the drawback of storing the high-pressure gas in expensive fuel cylinders.
Plus there’s the problem of being able to carry enough fuel for long-haul trucks.
In-town vehicles are a more viable option for CNG.
Westport has projected that its natural gas/diesel system would add about $30,000 to $45,000 to the cost of a new rig, about the same price of buying a CNG engine direct from the factory from Cummins and Detroit Diesel.
And although exhaust emissions would decrease substantially, the cost of recouping this extra initial price for a CNG/diesel engine has been reduced lately due to the fact that the price spread between diesel and natural gas has decreased to about the same cost.
Low sulphur fuel
So although we have some great optional alternative fuels available, researchers still agree that using very low sulphur diesel fuel as described earlier will clean up the diesel exhaust emissions to the level where they are as clean as some of the alternative fuels currently being touted.
Eventually some form of happy medium will have to be found, and legislation will determine the result we have to live with in the future.
The diesel engine with its outstanding thermal efficiency will still be around for a while yet, even if it ends up running on an alternative fuel.
So don’t expect the cost of your monthly fuel bill to decrease anytime soon.
Accept as a fact of life that it will still be your most expensive running cost and do anything you can to become more fuel efficient. n