Diesel Motor Development
Diesel fuel motor development is progressing very swiftly, with incredible improvements in efficiency, economy, performance and emissions, but not as yet, in the direction of accurate multi fuel motors that can run on petroleum diesel fuel, biodiesels, SVO, or any combination of the three without alteration and under full manufacturer’s warranty. This is what the fast-growing international biofuels communal is pushing for.
There are millions of current ‘old-tech’ diesel vehicles that power the world’s transport. Transforming them to the clean, new technology will be a slow and costly process — and for the time being, they’ll continue gulping clouds of poisons from their exhausts.
But they are by far the most economical and efficient engines, and the world’s transport industries depend on them. Scrapping the diesel would increase the costs of just about everything and make everyone’s life a hard-hitter.
This is where biodiesel and other clean fuels have a part to play -biodiesel can cut diesel emissions now, at no extra cost, and without having to do anything except put it in the tank.
In the meantime, the Environmental Protection Agency in the US plans to reduce the sulfur levels in diesel fuel from the current 500 parts per million (ppm) to less than 15 ppm. But this will do away with the lubricity of the fuel — important in diesel engines since diesel engine parts are lubricated by the fuel itself. Only the latest motors will be able to use the new ultra-low-sulfur fuel. This is a chance for biodiesel since biodiesel is an excellent lubricity additive. Addition of one percent of biodiesel improves the lubricity up to 65 percent. And biodiesel contains no sulfur.
The future of diesel as a clean fuel
Due to fresh advances in technology, more vehicles are swapping to clean diesel. Conventionally, diesel engines have always been more fuel-efficient than their gasoline equivalents due to their capability to run very lean fuel mixtures and high compression ratios. Diesel also has additional heat energy per gallon than gasoline, but its heavier hydrocarbons yield more HC and soot.
“Diesel engines today are 500% cleaner than they were just 20 years ago.”- Chrysler
“Pollution from diesel cars has been cut by 80 to 90% over the past two decades.”- Union of Concerned Scientists
“Particulate emissions from diesel-fueled engines have been reduced by 90% over the past decade.” – Engine Manufacturers Association
They also have a greater combustion temperature, so they yield more NOX. These factors joined with engine noise, exhaust odour, cold start difficulties, and poor performance restricted diesel’s use in passenger cars until now.
Due to direct injection systems with electronic controls, today’s clean diesel engines drive and feel no poles apart than their gasoline equivalents but with 20-30% improved fuel economy.
An additional driving force for diesel is government regulations. The government is supporting the development of clean diesel. Even though diesel engines have been used in trucks for many years, there haven’t been many diesel choices for passenger cars since the 1980s. General Motors has proclaimed that it will be proposing more clean diesel options in 2019. Numerous European manufacturers are offering clean diesel choices. For now, Asian manufacturers are backing hybrids and direct injection vehicles to increase their fuel economy numbers.
Developments achieved so far in clean diesel
Today’s clean diesel engines yield 99% less NOX emissions and 98% less soot than diesel engines from 20 years before. Their fuel economy and performance are also much enhanced. The technology that makes all of this promising is common rail fuel injection at very high pressures and frequencies. Clean diesel usually use piezo injectors that can cycle as many as five to eight times during an injection affair to allow very accurate control over the combustion to decrease noise and improve efficiency. Clean diesel engines are planned to run on ultra-low sulfur diesel fuel, and B5, a 5% biodiesel mixture. Research is being done to discover if even higher mixtures of biodiesel are suitable for use. Future diesel fuels may even comprise of minute nanoparticles of metals, oxides, carbides, nitrides or nanotubes to increase combustion efficiency and fuel economy even more.
Clean Diesel Shortcomings
Current clean diesel technology requires some type of exhaust after-treatment to clean up soot and extra pollutants. Diesel catalytic converters require more platinum and other additives to handle the pollutants in diesel fuel. Also, a distinct Diesel Particulate Trap is needed to clip the soot. Many diesel systems add an after-treatment system to decrease the amount of EGR the engine needs. This helps to increase fuel economy. The vehicle that is equipped with an after-treatment system needs to have their Diesel Exhaust Fluid (DEF) refilled around every oil change. DEF freezes at 12 degrees Fahrenheit signifying that it needs to be heated in cold weather.
Next-generation after-treatment systems may remove the need for DEF and the intervallic maintenance requirements to keep the fluid level filled. Automakers are evolving and testing new diesel catalysts that use no platinum and do not require urea injection to control oxides of nitrogen.
Know more about fuel economy here https://www.yourmechanic.com/article/5-essential-things-to-know-about-fuel-economy
Peeking into the future: The upcoming fuels
Natural gas is cheaper and cleaner than diesel fuel, and it burns much cleaner in a diesel engine than diesel fuel. Natural gas yields about 20 to 25% less carbon emissions than diesel and comprises of no sulfur. Natural gas presently sells for a gasoline-equivalent price of $1.95 per gallon, making it a third less expensive to burn as a motor vehicle fuel. In Europe, Asia and even South America, natural gas vehicles are comparatively common. Many see natural gas as a chief component in our future energy plans, and an improved option than using food-based renewable fuels such as ethanol made from corn or biodiesel made from soybeans.
One application that may rapidly see greater use of natural gas as a substitute fuel is big Class 8 over-the-road 18-wheel heavy-duty trucks. According to the DOE, if all Class 7 and 8 trucks were transformed to CNG or LNG, it would decrease our nation’s appetite for oil by 14%.
Natural gas has long been used as a substitute fuel in stationary engines and off-road engines, but lately diesel engine manufacturers have been developing natural gas types of engines for highway use.
Cummins recently presented two advanced spark-ignited diesel engines that can run on either natural gas or diesel. After burning diesel, the engine can meet the emission standard without a diesel particulate filter or urea after-treatment. Cummins also has a 15-litre Westport ISX15G diesel engine that runs on a blend of 95% natural gas and 5% diesel. Volvo is also presenting a high-pressure direct injection natural gas/diesel option.
The variance in fuel mileage when burning natural gas compared to diesel can range from a 5% to 20% decrease to a 5% to 20% gain liable on the type of fuel system and the alterations to the engine that are made. When an engine is enhanced for natural gas, it can carry nearly the same fuel mileage as diesel or gasoline.
Natural gas has a very high octane rating and a small cetane rating but burns at a relaxed speed and lower temperature than diesel. Aggregating the engine’s compression ratio to take benefit of its high octane rating increases thermal efficiency, while cautious injection and ignition timing (when a spark is used) optimize combustion.
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