Many owners of diesel vehicles are installing water-methanol injection systems in their engines. Water-methanol injection systems provide a number of performance advantages when combined with the normal diesel fuel delivery system. Several manufacturers provide add-on kits for several applications, most of them designed for heavy truck and SUV use. There are several reasons why water-methanol injection systems provide additional performance. Any vehicle owner considering such a system should know why water-methanol injection can be a good thing.
A typical water-methanol injection system includes a reservoir tank, which holds a mixture of water and methanol in a prescribed ratio -- most often a 50-50 mixture. A high-pressure fuel pump siphons fuel from the tank and sends it to solenoids through a hose. The solenoids meter the amount of mixture and send it through aeration nozzles fitted in the intake manifold. An exhaust manifold fitting ties into the system to provide real-time pressure and temperature readouts, and sends the data to a digital controller, most often mounted in the dashboard area. Most systems are adjustable for peak performance tuning.
When a water-methanol mixture is introduced into the intake manifold, engine air charge temperatures can drop by as much as 200 degrees Fahrenheit. The fine mist of water, during atomization and injection, absorbs excess heat. The cooling effect lessens the head and valve temperatures by cooling the combustion chamber. Reduced engine heat causes less component friction and maintains oil viscosity much longer, extending engine life.
As the water-methanol mixture reduces the air charge temperature, it increases the density of the air charge by providing more oxygen molecules. The increased oxygen provides more efficient fuel combustion. The methanol, which acts as an additional burning catalyst, improves the ignition flash point, while the water, which has expanded into gaseous steam, acts as a secondary power source by using the "steam effect" to provide additional downward pressure on the piston during the power stroke. The result is increased horsepower and torque. For a 5.9-liter engine using a 50 percent mixture, a gain of 100 to 150 foot-pounds of torque and 50 to 100 horsepower is possible.
The water-methanol injection process, which acts as a supplemental fuel source delivered in small amounts, enhances the fuel mixture to derive all possible power from combustion process. Liquid or vaporous diesel fuel that might have passed unburned through the exhaust burns more completely and efficiently during combustion. Less fuel is wasted, which increases overall fuel economy. The cost of methanol can be as little as $1.50 per gallon. Gains in fuel economy of 10 to 15 percent are not uncommon.
Water-methanol injection burns much cleaner during the combustion process. Excess fuel is burned, keeping it from entering the exhaust system where it produces harmful soot and carbon buildup. The water-methanol combination also has a "steam-cleaning" effect on the exhaust flow passages, removing carbon buildup, varnish and soot. The increased air flow provides better engine intake and exhaust breathing. Less particulate matter exits the tailpipe, contributing to better environmental emission standards.
Due to the decreased air charge temperature and increased horsepower, water-methanol injection performs particularly well during heavy towing and load applications, where higher head and combustion temperatures are encountered. Turbo-diesel engines run much hotter than normal when towing heavy loads. Water-methanol injection helps to keep the air charge, component and oil temperature within safe limits.
