Diesel+Power

Diesel is an already readily available underutilized fuel oil that can be implemented fairly quickly in transportation. In 2007, the United States consumed more oil than China, Japan, Russia, India, and Germany combined accounting for over twenty billion barrels of oil or 840,000,000 gallons. Its not a clean alternative nor something that will replace our dependency on fossil fuels, but diesel is a cleaner burning than gasoline and can help extend our supply of fossil fuels. It must be realized that alternative energy cannot be implemented overnight and this can be one of the key stepping stones that will help reach our ultimate goal of near zero dependence on fossil fuels.
 * __Clean Diesel Power__**



To understand why a standard diesel engine is more efficient, first how a diesel engine functions and operate must be understood. There are thousands of different types of systems and configurations out there but here is the general construction of a diesel engine. A piston is cased inside a cylinder block. The piston is then connected to a crankshaft via connecting rods. When the gases inside expand due to spontaneous combustion due to high compression, the piston moves down. The connecting rods and crankshaft work in conjunction to transform the vertical motion into rotary motion which then can be connected to a drive shaft to move a car, truck, generator, or whatever you have the engine lined up with. At the same time, the crankshaft sets the timing for the opening and closing of the exhaust and intake valves via either belts, chains, or gears to camshafts which then in turn open and close intake and exhaust valves in the cylinder block. Typically, the standard diesel 4 cycle engine utilizes 4 strokes to extract the energy from the expanding gases into work. The first stroke is the intake stroke, this draws a mixture of air and fuel into the combustion chamber at a ratio of 15 parts air to 1 part fuel. The second stroke takes those gases and compresses those gases to generally a 20:1 ratio. This causes the mixture to self ignite under the heat of compression. The expanding gasses cause the third stroke known as the power stroke. This is where our work energy is generated by the downward movement of the piston. Finally, the kinetic energy of the crankshaft and flywheel drive the piston back up expelling the gasses through the exhaust valve completing the cycle.

Also, the difference between diesel and gasoline must be known. This leads to the refinement process of fossil fuels. The very condensed and simplified version of the refinement of crude oil is this: You take a big tank and heat up the crude oil, the crude oil will separate into different levels due to different densities. At the top of the tank is gasoline, the bottom of the tank contains basically tar, like the stuff used to pave roads and make roofing shingles. So, if diesel settles lower in the tank than the gasoline, this means it took less heat energy to refine it and separate it out from the crude oil and thus making the refinement process cheaper as we don't have to use as much energy to refine it. This is why it is cheaper to make diesel. Also, due to diesels higher density, it has a higher BTU content per gallon than gasoline. According to the National Institute of Standards and Technology (NIST), a gallon of gasoline contains 115,000 BTU's. Diesel contains 130,500 BTU's per gallon. This translates into a direct correlation of a diesel engine being more efficient and higher miles per gallon. However, there is one draw back to diesel fuel, because it is less refined, when burned it burns "dirtier" than regular gasoline, this is a catch twenty-two though. Remember when we did not use as much energy in the refinement process to make diesel compared to gasoline? Well, instead of us giving off NOx, CO2, and other greenhouse gasses refining the fuel, we are now giving them off when we burn the diesel fuel. The gasoline though emitted more NOx, CO2, and greenhouse gasses during the refinement process and less during the consumer use phase. We can overcome this though with technology.

Aside from changing the way we produce the energy to refine the crude oil (which just under 50% of Americas energy is produced by burning some sort of hydrocarbon) to nuclear power, hydroelectric power, or solar power, we can build engines that can better capture the harmful gasses and particulates along with lowering the amount of them in diesel to begin with. Something new on the market is Ultra Low Sulfur Diesel (ULSD). Previously, diesel contained 500 parts per million sulfur. Now, through better refinement techniques, we can produce diesel fuel that only contains 15 PPM Sulfur. In the United States, it is now mandatory that any diesel engine produced after 2007 to be compatible with ULSD. Advancements in filter technology is also helping make a come back in the American market. New filters are able to collect the soot commonly associated with diesel engines. The soot particulates (mostly sulfur) build up in the filter, when a sensor in the filter detects a pressure increase (back pressure in the exhaust system) it tells the engine to dump fuel into the combustion chamber thus raising exhaust temperatures further burning the soot particulate resulting in complete combustion which is safer for the environment than it previously was. These filters are also being implemented with a urea injection system. A water based urea (CH4N2O) liquid is induced into the catalytic converters where harmful NOx gases are passing through in hopes of being converted into water and nitrogen. Urea plus the heat of the combustion in the exhaust gases work to convert the NOx gases into harmless NO2 and H2O.

__**Real World Application**__

The United States is lagging in the world of clean diesels and actually using diesel engines to begin with, hence diesel is more expensive when we buy it at the gas station (See: Supply and Demand). However, some companies like Volkswagen and Daimler-Mercedes are leading the charge in small displacement, high compression, high mile per gallon, low emission diesel cars for the consumer market. For example, the VW Jetta TDI has 95% lower emissions than a standard diesel engine have had real world reports of them getting over 55+ miles per gallon. Also, when compared to the few cars on the road that have comparable gas mileage without saying any names (TOYOTA PRIUS) the horsepower and torque numbers blow the doors of the Toyota...I mean comparable car. The VW TDI boasts an impressive 236 ft/lbs of torque and 140 HP which is very respectable for it being only a 2 liter engine. The comparable car only gets 105 ft/lbs of torque and 98 HP. These numbers translate to the VW getting being more efficient when the engine is under strain such as climbing hills which lets face it, unless your driving in a dried lake bed, you will never see a perfectly level road where you will get optimal performance and lowest fuel consumption.

Also on the market for the commercial side is improvements in larger diesel engines used for towing. Newer engines are capable of producing larger torque numbers, more horsepower, and still have up to a 20% improvement in fuel economy.

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