Engines
Maintaining the Life of Your Engine by Operating in a Waterless Capacity
Once in use, a waterless coolant can save significant fuel saving and maintenance, not to mention reduced down time. That’s an investment well worth looking into.
Mike Tourville
Engine manufacturers have been contending with heat transfer issues for more than 100 years with a multitude of modifications: powerful fans, larger radiators and applying engine performance limitations. The struggle to gain efficiency and meet tighter emissions standards, while controlling costs is an ongoing challenge. Despite the advances in engine cooling technologies, one aspect has remained relatively unchanged for over fifty years. The basic formula for coolant is still a 50/50 mix of ethylene glycol and water. Additives have improved and longer life coolants have evolved, but water has been a constant element. Water is a good thermal conductor, but it has its drawbacks and limitations: corrosion and a low boiling point, to be more specific. Cooling systems are designed to work within the limitations of water, and a lot of energy is consumed to keep the coolant from reaching its boiling point. A simple answer to consider has been developed to address these issues: To eliminate the problems associated with water, remove the water. The absence of water in a waterless heavy-duty coolant (HDC) prevents corrosion and avoids electrolysis. Perhaps the most important aspect is the high boiling point of 375° F, which translates into a large separation of the coolant operating temperature and the boiling point of the coolant.
What is good about water is it’s cheap and has superior thermal conductivity—as long as it remains a liquid. Water retains only 4 percent of its thermal conductivity when it changes into vapor. On the other hand, water is a poor choice because the boiling point of water is too low, and there is very little separation between the operating temperature of the coolant and the boiling point of water. If the coolant boils over, vapor pockets create an insulating barrier between the metal and the coolant. The low boiling point of water becomes the failure temperature of traditional cooling systems. With its high boiling point of 375°F, a waterless HDC has the capacity to safely operate at higher temperatures without overheating, resulting in less down time.
Maintenance Savings
Because this type of heavy duty coolant does not contain water, electrolysis and corrosion are eliminated. Water is the root cause of corrosion in engine cooling systems, and even the latest inhibitor technology often fails to prevent component failure. The most expensive corrosion problem is cavitation of cylinder liners. Cavitation erosion is caused by collapsing bubbles that cause erosion over the surface of the exterior of the cylinder liners. The resulting erosion eventually penetrates the wall of the cylinder and permits coolant to flow into the cylinder.
The large separation between the operating temperature and the boiling point of waterless HDC stops cavitation erosion of cylinder liners.
In a pressurized system, the water-based coolant must be maintained at a temperature below the boiling point of water to keep the system functional. The absence of water means that vapor will not be formed which can cause pressure in the system. Typically, cooling systems have up to a 15 lb. pressure cap to raise the boiling point. Each pound of pressure raises the boiling point by about three degrees, which means a 15 lb. cap would raise the boiling point to about 257° F. This is still dangerously close to the operating temperature of the coolant in an engine, especially under hot and dusty environments. The waterless HDC formula operates under a much lower pressure, decreasing stress on hoses and gaskets, reducing the likelihood of leaks. Additionally, a lower pressure brings an added safety element to the operator. Opening the cap on a hot radiator can result in injury to anyone within close proximity of the radiator.
Endurance of the engine is improved by maintaining control of engine metal temperatures at all times. The absence of cavitation erosion extends the life of cylinder liners and coolant pumps. Pump seals last longer because there are no abrasive additive deposits on the seals. Water also contributes to pump and cylinder liner cavitation and corrosion, as well as hot spots that can damage engines.
A waterless coolant can last forever, as long as it doesn’t become contaminated with water. With a waterless HDC, periodic coolant replacement and disposal is not necessary and supplemental coolant additives (SCAs) are not required. HDC additives remain stable and in solution during storage and use resulting in no abrasive additive deposits. The coolant will not evaporate which means the occasional topping off can be greatly reduced.
Fuel Economy
Most people wouldn’t associate coolants with fuel economy. The energy that it takes to maintain coolant temperatures below the boiling point of water is a huge waste of fuel. The huge separation between the operating temperature of the coolant and the boiling point allows an extra cooling capacity that your system already has. When the coolant temperature can be safely raised, the result is a more efficient heat transfer from radiator to the ambient air. This allows an engine to run continuously under harsh conditions using less fan power and saving fuel.
Independent evaluations and fleet testing have consistently demonstrated fuel economy improvements between 3 to 9 percent.
Due to the severe performance requirements refuse vehicles encounter daily, such as constant starts and stops, heavy loads and the lack of ram air to cool the engines, fuel savings is adversely affected. A waterless coolant allows a reduction of fan-on time by up to 40 to 50 percent. The fans on heavy-duty diesels draw considerable horsepower, therefore minimizing fan operation leads directly to significant fuel savings.
Along with reducing fuel consumption, decreasing emissions, maintenance savings are also achievable with a waterless HDC. The waterless formula does cost more per gallon than a traditional 50/50 ethylene glycol and water mixture. However, once in use, the fuel saving and maintenance benefits have demonstrated an ROI of 6 months or less; not to mention reduced down time. That’s a considerably short payback period, and an investment well worth looking into.
Mike Tourville is Sales and Marketing Director for Evans Cooling Systems, Inc. (Sharon, CT). He can be reached at (860) 668-1114 or via e-mail at [email protected].
Sidebar
John Deere Cavitation Test
In a recognized test (the” John Deere Engine Cavitation Test”) performed in April 2009 by a third party laboratory, the results showed that waterless coolants provided superior protection against cylinder liner cavitation erosion. The waterless coolant performed more than 70 percent better than any other coolant tested in preventing cavitation erosion. It is now approved as an ASTM standard test method.
Sidebar
SAE Type II Fuel Test
The SAE Type II Fuel testing using the waterless coolant and 215° thermostats and eliminating the fan time variable, still produced a 3 percent improvement in fuel efficiency. Recent emissions testing showed a reduction of 3.6 percent in CO2 emissions and a 4 percent fuel economy improvement in a test performed by Emisstar in August 2011. Emisstar provides independent third party testing services for the development of sustainable transportation technology strategies.
Sidebar
Case Study: Veolia Environmental Saves Fuel
Veolia Environmental Services in Florida was trying to reduce fuel consumption. They did a year-long evaluation using Evans Cooling Systems’ heavy-duty waterless coolant beginning in October 2009 and found that waste vehicles in Sheboygan, WI saved in the range of 4.4 percent fuel. Further testing in Apopka, FL demonstrated savings in excess of 9 percent due to reduced fan time when fan temperature is raised to 230° F. The coolant has paid for itself within a few months and no overheating issues were reported. Harold Graves, Regional Maintenance Manager, East North America says, “We’re very happy with the way Evans has presented their product and services. They are data purists, and the results are indisputable. Veolia is beginning to schedule the rest of the regional fleet and plans to continue to expand the conversions to other areas. We’re looking at converting off-highway equipment in the northeast, not only for fuel saving purposes, but to improve performance and productivity.”
Skip Webber, Area Maintenance Manager, Solid Waste, North America, agrees, “The waterless coolant is a great product and we’re seeing significant fuel economy improvement. We haven’t had a problem with any of the converted trucks, including overheating or maintenance issues.”