Biodiesel contains about 9 percent less energy than petroleum diesel, but it has a higher cetane rating (which promotes more-efficient combustion) and better lubrication properties.
Instead of a wholesale switch to electric cars, with all their inherent range and charging problems, a seemingly easier way to wean ourselves off gasoline is to find alternate fuel that could be used in slightly modified internal-combustion engines. Unfortunately, there are some very real reasons — never mind what conspiracy theorists might tell you about oil companies and corrupt government officials — why most alternative fuels are not ready for prime time yet. Here's a look at the current status and near-term future outlook of the major alternatives to gasoline.
Modern turbo-diesels get about 30 percent better fuel economy than their gasoline counterparts, have gutsy low-rpm torque, and work well in vehicles with automatics and for towing; they're a seemingly perfect solution for the U.S.
Unfortunately, diesel emissions are far dirtier than gas emissions. Removing diesel's pollutants requires costly pieces of emissions equipment. Diesel also requires approximately 30,000-psi fuel-injection systems. These costs make diesels more pricey than even turbocharged, direct-injection gasoline engines, and those gas engines have the potential to achieve about two-thirds of diesel's fuel-economy advantage.
While diesel costs about the same as gas today, it has run as much as 30 percent higher — and it is taxed at a higher rate than gas. There's no easy fix to keep diesel prices low, relative to gas, because American refineries, in general, produce about 19.5 gallons of gasoline and 10.3 gallons of diesel from each barrel of oil. That means a gas-powered vehicle getting 20 mpg can drive about 390 miles on a barrel of oil, while a diesel, at 26 mpg, can go only 270 miles.
Since a barrel of oil doesn't go as far in a diesel car, a wholesale conversion to diesels is unlikely in America unless we suddenly figure out how to make diesel fuel from something other than petroleum. European refineries produce more diesel and less gasoline from each barrel of oil, but making that switch would essentially require building brand-new refineries. Don't hold your breath.
One approach is to transform animal fat or vegetable oil, via a transesterification process, into what is called "biodiesel." The resulting fuel doesn't contain sulfur and can be used in pure form, though many vehicle manufacturers recommend that it be blended with petroleum diesel in proportions between 5 and 20 percent. Biodiesel contains about 9 percent less energy than petroleum diesel, but it has a higher cetane rating (which promotes more-efficient combustion) and better lubrication properties.
Despite America's appetite for french fries, there isn't enough used cooking oil to make very much biodiesel. In fact, it has been suggested that to replace all of our petroleum needs with biodiesel would require the planting of soybeans on all of the arable land in the United States. New approaches for making biodiesel from algae are being explored, but they are likely decades away from mass production. Until then, biodiesel's limited availability and higher cost will keep it a bit player.
Another diesel alternative is synthetic diesel, made by a variety of chemical conversion processes that transform natural gas, methanol, or coal into diesel. The resulting fuel is usually sulfur-free and has a higher energy content than petroleum diesel, plus cleaner exhaust emissions. Converting natural gas to diesel fuel, also known as "gas-to-liquid," makes it easier to transport because it requires no refrigeration or compression.
The cost of synthetic diesel is also reasonable, although the environmental and energy-independence benefits are minimal. Converting coal to diesel creates much more carbon-dioxide emissions than simply using petroleum diesel. In fact, this is a problem, in varying degrees, with any of the synthetic-fuel processes. However, North America has plentiful natural-gas reserves, and this could be a simple way to convert it into an easy-to-use motor fuel.
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How is it that Mercedes, and VW can introduce Diesel cars here successfully, and not Ford or GM (or other manufacturers?). German car makers have no magic formula, they use their same technology on their European Diesels too. And yet, Ford, GM (Vauxhall/Opel), Toyota, Nissan, Honda Citroen, Renault, Fiat and every other manufacturer build mainly Diesel cars for Europe only!
Europe has long had a very stringent Eco Policy, just driving through France you will see fields of wind turbines to prove it. Recycling, is predominant everywhere and has been for decades. There is NO WAY that a European diesel is "dirtier" than a USA diesel and anyone that has traveled through Europe, especially servicemen, will testify to that!
A very important omission in this article is that the diesel technology being used in Europe is so good now that the low emissions from these cars are placing them in the same tax category as the Hybrids for low emissions ~ that is, Band "A", "B" or 'C" (Take the UK as an example, their diesel cars are cleaner than their gasoline cars!) If anyone doubts this just go to the Ford, or GM (Vauxhall/Opel) website in the UK. You will find Ford and GM Cars achieving 65-75 mpg and producing very few emissions!
"Unfortunately, diesel emissions are far dirtier than gas emissions" Unfortunately for this writer above, this statement is just pure ignorance and is probably based on the EPA standard statement that they put out.
We see here on the US roads, smokey, noisy truck diesels when we sit in lines of traffic and somehow THAT passes emissions here!?
The rest of the world has already geared up for Diesel and Bio Diesel and it is thought that 75-85% of the worlds Power trains are diesel. While America drags its heels, the rest of the world enjoys low emission diesel cars that are fast, torquey, quiet, clean, environmentally friendly and most importantly, fuel efficient!
America continues to endure latest "improved fuel figures" of 40 mpg for cars and 28 mpg for trucks, (Europe was getting these figures 30 years ago!) and as a result retains its title of the worlds most oil consuming nation on the planet! When all they have to do is allow European Diesel technology over here and they could cut US fuel consumption by half overnight!
What a terrible shame for us Americans, that we only have the option to buy German cars to get a reasonable mpg when both Ford and GM build cars that will do 65-75 mpg for its European customers. A good analogy might be, while the rest of the world buys and uses Winchester repeating rifles, the good old USA is being sold old Flintlock muskets!Those that can should write to the EPA site, Ford and GM and ask for an explanation to this. You will most likely get the same response as me. Silence!
I know there's a simple solution to this complex problem especially if I ignore many of the issues involved.. Things like lack of infrastructure, ignoring the energy needed to produce all of these solutions, transportation problems, economic losses as whatever switch is made, lack of feasibility for some fuels in all types of vehicles, the economics of building a whole new infrastructure in a bankrupt nation, the inability of masses of our population to simply step out and buy the latest hot idea and the list is long of issues not thought about.
I've now been following the energy issue for, at least, two decades. In that time many things have come and gone. Different people come along with this or that agenda. What is really interesting is it's all about "how can I keep driving my car?" This narrow, simplistic perspective, in itself, displays a profound lack of knowledge about the scope of the problem. Where are we after decades of over a cup of coffee problem solving? Nowhere. I ride motorcycle a lot and, at sixty, I'm still getting passed by everything from loaded semis to oversized 4x4s pulling whatever to the small "fuel efficient" vehicle doing 80.
I suspect this "transition" will be extremely difficult, filled with problems we haven't even considered and be far, far more painful than most of us like to think about. And the longer we focus on "how can I keep on driving" the worse it will be.
I would like to add my opinion on the matter that this article looks to be written by someone who spent no more than a few hours brushing up on fuel types and corporate and governmental hype. Sure, call it a CT if you like, but the facts cannot be avoided.
I also believe diesle is a great option - but again, no re-tooling for known workign technologies, just putting bandaids on the exhaust (DPF, etc)
Interesting perspective on using diesel or gas or ethanol, ... in the same HCCI engine. My engineers and I researched and discussed this possibility and while there is always a margin for our error, do not get your hopes up.
The modern HCCI engines must tolerate higher temps than a traditional gasoline powered engine from higher compression ratios so have to be literally thicker skinned - heavier. It honestly makes little sense to capitalize an engine in this way AND have to engineer and maintain the necessary technologies to also provide the flex fuel capability. Frankly, the only motivation for this engineering migration was to increase MPG from gasoline. Just keep in mind that the trade off is higher manufacturing expense and a shorter engine life expectancy.
What is surprising to us is that HCCI engines made it past the prototype stage at all. This is an engine that is designed for high compression to burn a fuel that is unstable under pressure and has significantly less energy density than diesel fuel. Actually, with the EPA 15% ethanol blend announcement yesterday, this is even more concerning as the micro processors in these HCCI engines will be "challenged" to anticipate the still lower ignition point of this new blend.
Diesel engines rule and HCCI will likely be very short lived in the history books and in your garage. They have only been in production for 2 years, but I will suggest that very few drivers will achieve 200,000 miles form these engines. The majority will likely have major mechanical issues by 150,000 miles.
Get a diesel - treat it well and drive it past 300K, 400K, 500K miles. We are talking to people who are now past 1M miles on their diesel engines running B100 fuels. We have finally come around to what Rudolph Diesel envisioned when he first presented his invention back in 1890's. You will see $2 gallon at the pump for B100 within the next 6-7 years. Within 12 years you might even see $1 gallon.
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