Source: CNET Green Tech
Last year, Lotus announced the development of its Omnivore engine, the name denoting flex fuel capability. Today Lotus released test results for the engine, along with the kind of detail on how it operates only an engineer could love. These test results cover the first phase of testing the Omnivore engine with gasoline. Presumably, testing with fuels derived from alcohol and other sources are in the next phases.
In Lotus’ lab, the Omnivore engine brought in 10 percent better fuel economy than current direct injection engines, which are the most efficient on the market.
Two-stroke engines have twice as many “power strokes” at any given RPM when compared to the common four-stroke engines, making them more powerful and naturally efficient. (The engine is not “wasting” as much energy moving the piston up and down in power-robbing intake and scavenging strokes.) Two-strokes are smaller and lighter when compared to four-stroke engine of similar horsepower, and have fewer moving parts that simplifies the inner workings, making them cheaper to build and maintain.
In the past, the problem has always been pollution – it was considered near-impossible to build a two-stroke engine that could meet modern emission standards. Apparently Lotus is solving this problem:
Omnivore also uses a two-stroke, rather than a four stroke cycle, but still manages to turn in emission levels equivalent to modern production engines.
This Lotus prototype engine uses an ignition system called “homogeneous charge compression ignition (HCCI), meaning that instead of igniting its fuel charge with a spark plug, the compression of the cylinder causes the charge to ignite, similar to a diesel engine.”
More good news – the prototype is a flex-fuel engine, which would allow the owner/operator to choose what kind of fuel preferred to power it with – fossil-fuel gasoline (and diesel?) or bio-mass alcohol (ethanol/methanol) or a combination of the two.
Flex-fuel engines already exist, the problem with the current crop is that they are engineered as gasoline engines, and re-programmed to also run on alcohol blends – meaning that mechanically they are still designed for the lower compression ratios required to run on modern gasoline blends. Alcohol fuels have “less energy” per gallon than gasoline, but can run at a much higher compression ratios, allowing a properly-built alcohol engine to “gain” additional efficiency and reduce the “MPG” gap with gasoline.
The Lotus engine can apparently modify it’s compression ratio thanks to what they call the “puck” – or the “variable compression mechanism…at the top of the cylinder which dynamically changes the displacement depending on running conditions.”
Once again innovative engineering is proving that there still are many ways to improve fuel efficiency with the internal combustion engines, and there are no technical reasons we can’t be driving cars that get 60+ MPG regularly. The “fuel efficiency flat-line” from the mid-1980’s until just recently was due to something else – not because it was “technically impossible” to build more efficient engines.
Fuelishness! Feed: Lessons in Fuel-Efficient Driving; Txting and driving film; New battery could change the world; Ethanol faces challenges ahead
- Lessons in Fuel-Efficient Driving — One of the interesting features of our Prius is that it keeps a running tab on your current gas mileage. You can see both the mileage at any given moment or the average over your trip. Having such easy access to this information while you’re driving subtly teaches you how to drive more efficiently. Here are a few things we’ve learned.
- This film that will stop you txting and driving — Gwent police is proud to have helped Brynmawr filmmaker Peter Watkins- Hughes in the production, which stars local drama students Jenny Davies as Cassie, and Amy Ingram and Laura Quantick as her friends, Emm and Jules. The film is a sequel to a previous documentary called ‘Lucky Luke’, made 14 years ago, which showed the devastating consequences of joy riding. It is hoped the film will become part of the core schools programme across Wales and ultimately the UK.
- New battery could change world, one house at a time — It promises to nudge the world to a paradigm shift as big as the switch from centralized mainframe computers in the 1980s to personal laptops. But this time the mainframe is America’s antiquated electrical grid; and the switch is to personal power stations in millions of individual homes.
- Ethanol faces challenges ahead — New technologies, supporting infrastructures, and greater demand will be needed to meet the country’s ambitious mandate to increase biofuel use.
Science continues to find better and more efficient ways to break down the sugars in inedible biomass feedstock for bio-fuels. A few years ago critics talked about cellulosic ethanol as if it was a myth that should be ignored. Today, with plants already in production, cellulosic ethanol is a reality – and with continued research finding natural processes to help convert the feedstock to energy, the future of cellulosic ethanol looks bright.
The latest bug helping to break-down bio-mass is our long-time nemesis, wood rot…
An international team led by scientists from the U.S. Department of Energy (DOE) Joint Genome Institute (JGI) and the U.S. Department of Agriculture Forest Service, Forest Products Laboratory (FPL) have translated the genetic code that explains the complex biochemical machinery making brown-rot fungi uniquely destructive to wood. The same processes that provide easier access to the energy-rich sugar molecules bound up in the plant’s tenacious architecture are leading to innovations for the biofuels industry. The research, conducted by more than 50 authors, is reported in the February 4 online edition of the Proceedings of the National Academy of Sciences (PNAS).
Among the challenges to more cost-effective production of biofuels from cellulosic biomass—the fibrous material of whole plants—is to find effective means to work around the polymer lignin, the scaffolding that endows the plant’s architecture with rigidity and protection from pests. By doing so, the organic compound cellulose—the long chain of glucose (sugar) units can be unbound, broken down, fermented, and distilled into liquid transportation fuel. This is where the destructive capabilities of rot come in.
“The microbial world represents a little explored yet bountiful resource for enzymes that can play a central role in the deconstruction of plant biomass—an early step in biofuel production,” said Eddy Rubin, Director of the DOE JGI, where the genome sequencing was conducted. “The brown-rot Postia placenta’s genome offers us a detailed inventory of the biomass-degrading enzymes that this and other fungi possess.”