As fuel prices continue to soar, most consumers are shifting their focus to vehicles that will deliver better fuel economy, power and durability – a trilogy of performance features that makes today’s clean diesel vehicles the new rising star across North America. Besides, technological advances in diesel engine fuel systems have made them quieter, sportier and, of course, up to about 40 per cent more fuel-efficient than their gas counterparts.
Currently, diesel vehicles represent about three per cent of the North American market, but automotive insiders are predicting that number to significantly increase in the near future – the U.S. market is already experiencing double digit monthly increases, according to the Diesel Technology Forum, a U.S.-based not-for-profit educational organization.
To answer such demand, European and North American automakers, which are being continuously squeezed by government to decrease emissions and meet strict fuel economy regulations, are adding more light-passenger diesel vehicle options in both Canada and the U.S. – there are 15 new diesel vehicles slated to arrive on the U.S. market in the next two years.
“The requirements handed down by the U.S. government for increased miles per gallon (MPG) has created an opportunity for new diesel technology to be introduced in passenger vehicles and light-duty trucks,” says David Pollack, marketing manager for Liqui Moly. “The new diesel technology can deliver MPGs equal to or exceeding hybrid vehicles on the road.”
Certainly, the fuel efficiency of the diesel is hard to resist, but to maintain that performance attribute it’s essential that the vehicle owners understand how these fuel systems work and what they require to maintain that efficiency. This is where additives come into play and give service stations the opportunity to educate consumers and offer additive services.
Although there are “all-in-one” additive products on the market, industry experts advise shops to focus their recommendations on diesel additives in concentrated dosages that target fuel system functions and issues, such as lubricity, detergents, anti-gel for cold temperatures and Cetane improvers.
Keep the Motor Running
When Ultra Low Sulfur Diesel (ULSD) was introduced at the pumps, the decrease in sulfur content removed a lot of the lubricity from the fuel, which fuel pumps and injectors relied heavily on to protect them from wear, according to Mark Nyholm, a mechanical engineer for Amsoil.
“The ULSD doesn’t play as well with cold temperatures,” says Nyholm. “There are naturally occurring waxes in diesel and when they stripped the sulfur out of the fuel, the desulphurization process drove the wax content up.” In cold temperatures this wax can solidify – known as fuel gelling – and plug the fuel filter, starving the engine. “If the temperature is cold enough the wax can solidify even in the fuel lines, the fuel pump and the fuel injectors, rendering the whole piece of equipment pretty much useless until you warm all that fuel back up to a temperature above the cold filter plugging point.”
In freezing winter temperatures, Jeff Torkelson, Valvoline’s technical director engineering tech services, says that diesel vehicle owners are going to need an anti-gel type of additive in the fuel tank at all times, otherwise if the fuel gels, the engine will simply stop working.
Getting a Boost
Unlike Octane values that are published at gas station pumps, the Cetane values of diesel fuel, essential to combustion efficiency, are not. Cetane values already in the fuel can be as low as 40, but this number varies from region to region. “It really comes down to where the crude oil came from and how it’s refined,” says Nyholm.
Some OEMs do publish necessary Cetane values for vehicles in the owner’s manual. So, if the standard is 40 and a truck, for example, requires a minimum of 48 Cetane, then a Cetane improver is needed. “Increasing the Cetane number can improve combustion efficiency and startability, as well as decrease the formation of soot and deposits,” says Torkelson.
But it’s also important to note that there is a saturation point in diesel fuel and it will only accept so much Cetane improver. For instance, if one ounce of the additive is good for five gallons of fuel, that will result in a seven point Cetane number increase – from a standard 40 Cetane value up to 47.
Some people think you can double that dosage and double the improvement. But Nyholm says, “It doesn’t necessarily work like that. You will see an improvement, however, there will be a saturation point in the fuel when it will no longer accept the Cetane improver and that’s likely going to be at numbers in the mid-50 range. Again, this all depends on the quality of the fuel and the crude the fuel was made from.”
Keep it Clean
One of the big issues with diesel fuel systems is the formation of deposits in the combustion chamber, on and in the injectors, pistons and rings, which will decrease the overall efficiency of the vehicle, and can eventually result in costly repairs.
“Today’s diesel engines are direct injection and the fuel is sprayed directly into the combustion chamber. Because that happens, even really efficient engines don’t burn 100 per cent of the fuel on a combustion cycle. What doesn’t burn forms into black, greyish carbon deposits,” says Nyholm. “If you add a detergent additive into your fuel tank, it will go through the fuel line, into the injectors and spray into the combustion chamber. Before it ignites, it starts to eat away at the deposits and it cleans up the injector nozzle and pintel to ensure that it can spray the right pattern and quantity of fuel that’s supposed to come out of each injection cycle.”
There are lubricity and detergent additives that vehicle owners can add to the fuel when they’re filling the tank, but service shops can also offer an injector cleaning service, which Torkelson recommends should be done every 8,000 km or every oil change interval. But he says that deposit formations do vary depending on how often the vehicle is used, driving style and environment.
During an oil change, Pollack points out that Liqui Moly’s Diesel Purge can be used to prime the fuel filter cartridge, rather than diesel fuel. “The best way to use Diesel Purge is by taking the intake and return lines of the fuel system and inserting them into the can of Diesel Purge and run the car on it,” says Pollack. “This allows the additive to bypass the fuel tank and focus the cleaning power on the fuel system.” A service, he suggests, can be offered as a part of a comprehensive package every 42,000 km.
Of course, one of the biggest game changers in diesel technology has been the introduction of the High Pressure Common Rail (HPCR) injector systems, which feature boosted pressure, smaller injector components and increased injection frequency. But with more HPCR systems entering the market a new line of deposits has been discovered, forming on the inside of the injector nozzle. “These are called Internal Diesel Injector Deposits (IDID),” says Nyholm. “Products of the past are not capable of removing this stubborn deposit. A new formula of chemistry is required.”
To target these deposits, Amsoil reformulated its diesel fuel additive line. Its Diesel Injector Clean and Diesel Injector Clean + Cold Flow additives work on both HPCR systems and older generation injectors. And similar to the more traditional injector deposit formations, those in a HPCR system can result in loss of power, loss of fuel economy, rough idle or engine operation and extra smoke.
Torkelson suggests that technicians and service advisors need talk to their customers to find out if there are any issues with the performance of the vehicle, such as loss of efficiency and power or hesitation when accelerating.
Using a diesel fuel cleaner (detergent) additive as part of a regular maintenance regime will also help slow down the rate at which the Diesel Particulate Filters (DPFs) might get clogged with soot. Although additives never make it past the combustion chamber to the DPF, drivers doing short trips, or those often in stop and go traffic are not getting the engine up to the proper operating temperature. And Torkelson says that this will increase the rate that deposits form on the injectors, which may produce higher levels of particulate or soot that will plug the DPFs.
“Additives can help delay clogging, but at some point the DPF needs to be cleaned,” says Pollack. “In most cases the two options have been to replace the DPF for about $3,000 or disassemble the exhaust system, remove the DPF, soak it for days and then put it back together.” With Liqui Moly’s new DPF Cleaner Kit, the service takes about an hour – without having to disassemble the exhaust system or remove the DPF – and the repair shop can charge $400 to $500 or more for the service.
Offering education on the benefits of diesel fuel additives will certainly help keep your customers on the road, but packaging additive based services with other regular maintenance offerings will help save your customers from costly repairs, while keeping the diesel fuel and the cash flowing into the shop.