Thanks to all of you for submitting questions. Since the designated topic for this Q&A is Water-Methanol injection, I will begin by answering questions related to that subject, then move on to some of the other questions if time allows. First I think it would be prudent to discuss some of the basics of water-methanol injection. This technology is not new. It has roots in automotive use as far back as the 1920’s when it was used in taxi-cab fleets as an octane booster. Water-methanol injection offers benefits for both gasoline engines and diesel engines, but since this is a Cummins forum, I will limit my discussion primarily to the benefits available to diesels. The science is relatively simple, and speaks to a subject that I have been talking about for some time now: AIR DENSITY. If you are at all familiar with my products, you know that I focus heavily on getting air into the cylinder in order to effectively use/burn the fuel and therefore make power. The density of the air is a measure of its mass per unit volume; in other words, how many air molecules are packed into a given space… in this case, the space in the cylinders of the engine. The air density is affected by three things: The air pressure (usually identified as boost in diesel circles), the air temperature and the moisture content of the air (humidity). Air density is best when pressures are high and temperatures are low. The greater the density of the air entering the engine, the happier I am! Water-methanol injection is first about improving air density as a result of lower intake air temperatures. Whether we are injecting straight water, or a mixture of water and methanol, the fluid is introduced to the intake air in a very fine mist. This allows for a rapid evaporation of the water. As the water evaporates and converts to a gaseous state, it absorbs heat from the surrounding air, effectively cooling it down and consequently increasing its density. If the quantity of water is small, this evaporation may be complete before the air ever enters the cylinder; with greater quantities the process may continue right up until the combustion process. When methanol is also present, it also absorbs some heat and evaporates, but once it is present in the cylinder as either a liquid or a vapor, it will burn as an additive fuel. Because the auto-ignition temperature of methanol (875°F) is much higher than diesel (410°F), the diesel will always begin to burn first, and the burning of the methanol will contribute to the combustion process, increasing cylinder pressure moderately throughout the burn and increasing power. The amount of added power is, of course, dependent on the amount of methanol present, as well as the amount of oxygen available to combust it.
One of the nice things about methanol as a power adder is that it doesn’t advance the combustion timing and doesn’t result in cylinder pressure spikes due to its progressive burning with the diesel fuel. So to answer your question about long term issues, there are none that result from increased cylinder pressures within reasonable power limits (racing applications aside). However, methanol is a corrosive agent and therefore it is important to select system components that will withstand the effects of methanol. The injection lines that we use are nylon 6-6 and the fittings are nickel plated brass with EPDM o-rings, all methanol resistant and stable.
Automotive manufacturers rely heavily on fuel infrastructure, and this could be the reason that we have never seen widespread use of water-methanol injection in vehicles from the OEMs. However, the acceptance of secondary fluids/fuels is starting to change, particularly with the introduction of urea on late model diesels. Ford recently has been experimenting with methanol injection in a gasoline direct injected engine with some impressive results. In a vehicle application this would require two separate fuel tanks, which means that consumers would need to be comfortable maintaining two different fuel tank levels. With more attention given to alternative fuels, lower emissions, higher fuel economy standards, etc, it is possible that the OEMs will give more attention to features like water-methanol injection.