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Posted on 05/22/2012 1:43:00 PM PDT by Red Badger
Volvo Trucks unveiled last week its plans to launch a 13-liter heavy-duty natural gas engine featuring Westport high pressure direct injection (HPDI) technology. The engine, marketed under the “Blue Power” designation, is scheduled to launch for the North American market in 2014.
The engine’s advanced high pressure diesel ignition technology will provide significant fuel efficiency gains compared with current natural gas products. Combined with the company’s previously announced offering of compressed natural gas (CNG)-powered Volvo VNM and VNL model daycabs, the new engine will provide customers with a complete range of natural gas-powered transportation solutions. Volvo is also testing another fuel that can be produced from natural gas, DME (dimethyl ether), which has the potential to become an attractive alternative for the North American market.
Through advanced high pressure diesel ignition technology – using trace amounts of diesel to ignite the natural gas – Volvo’s LNG engine will deliver a 30-percent fuel efficiency improvement compared with spark-ignition (SI) engines, making it a viable alternative for demanding long-haul applications. The Volvo 13-liter LNG engine will also reduce greenhouse gas emissions by about 20 percent compared with current diesel products.
The engine will accomplish these savings without sacrificing power, torque or fuel efficiency, all of which are critical attributes for on-highway operations. The Volvo Group was the number one supplier of 13-liter heavy-duty engines to the combined U.S. and Canadian market last year, and the same vertically integrated approach that has made Volvo a global powertrain leader is being applied to the development of the new engine. The company’s proprietary Volvo I-Shift automated mechanical transmission also will be available for customers to specify.
North America’s abundant supply of natural gas, and the reduced emissions and minimal aftertreatment CNG engines offer, make the technology an ideal solution for customers operating in localized or closed-loop applications. To meet current demand, Volvo offers the CNG-powered VNM daycab equipped with a factory-installed Cummins ISL G engine.
The company also recently announced that it is operating natural gas-powered VNL demonstrator trucks. The larger, more robust VNL model features a 12-liter Cummins- Westport ISX12 G gas engine. Factory production of the natural gas-powered VNL daycab will begin in conjunction with commercial availability of the 12-liter gas engine in early 2013. These heavy-duty engines feature maintenance-free aftertreatment, requiring only a three-way catalyst to meet EPA 2010 emissions standards.
Hmmm. A Ford Escape TDI would be nice!
If I could be president for 1 minute, I would sign an executive order stating that “For national security reasons, every commercial vehicle using federally funded roads has to use fuel derived from natural gas by Dec. 31, 2112.”
Depends on the compression ratio :)
Ack!! just combined Depends and Burritos on the same thread.
Interesting. I wonder what makes this more efficient than a spark ignition?
If I could be president for 1 minute, I would sign an executive order stating that “For national security reasons, every commercial vehicle using federally funded roads has to use fuel derived from natural gas by Dec. 31, 2112.”
I don’t know the compression ratio required to light natural gas, but I would guess it is much higher than diesel compression ratios.
I figure they get diesel fuel efficiency by using diesel to light off the natural gas.
They also don’t say how the natural gas goes into the cylinder, either via a direct injector or through the intake manifold.
I would suspect that detonation could still be a big issue if there are any hotspots in the combustion changer, perhaps from buildup of carbon in specific areas, if the engine sucks in natural gas during the intake stroke.
I’m confused too because imo the gas would ignite before diesel would. If they use, however, hot and compressed diesel gas, then the diffusion of the gas throughout the mixture would make an efficient and complete clean burn as opposed to a localized burn to spread from a single spark point.
Also, you get a bump in efficiency, because you do not have to throttle a engine, you can burn super lean, since the diesel burns and lights the dispersed charge of natural gas, a mixture that probably would not otherwise burn.
Most of our car engines, unless you have one that has a throttle-less direct injection system, lose a gob-smack of energy because the engine is continuously pulling againt the artificial vacuum.
Weird, a little research on google, indicates that natural gas doesn’t like spark ignition at a compression ratio above 11.5:1.
I would not have guessed that..
It will be used for city bus and truck fleets. MARTA, the transit authority in Atlanta, has quite a fleet of CNG buses. They’ve been doing it for years, and are looking pretty smart for having done so at the moment.
“Ack!! just combined Depends and Burritos on the same thread.”
You say that like it is a bad thing. The combination could provide a measure of safety.
There are plenty of decommissioned former CNG Ford Rangers around here, the gas utility uses them. In the past they were converted back to gasoline for resale. Now, I don’t know but suspect there would be a market for them as is. A place to refuel them would be a challenge for most, setting one up in a home garage is fairly expensive.
A pro-American government would incent the opening of public fueling stations and go light on the taxation of it to establish a domestic alternative to Mideast oil. Heck, it’d go light on the taxation of gasoline produced from domestic crude for the same reason. Fungible my a**, loer transport cost, far less potential supply disruption, much more consistent price. Decouple that.
LOL, So True :)
Interesting discussion. However, technology is rapidly changing and what Ford and Volvo does today is obsolete tomorrow. I am in the process of raising capital to start a trucking company the uses hybrid technology to power class 8 tractors. This is a generator powered tractor with a diesel engine assist. It will get at least 24 mpg. Has a fraction of the carbon emissions of what’s on the market today. The prototypes have been built and tested and the results are conservative. Problem we have is getting funding and setting up a supply chain that the competition cannot derail. Bottom line is that tomorrow what I am seeking to do will become obsolete as well.
I saw a 100% electric Frito-Lay truck last week in Northern Va. It was bigger than the usual large size van. It seemed to accelerate the same as a regular truck. What was really strange was coming up along side, there was no noise other than the tires on the pavement.
Boston as well.
At Diesel compression ratios the peak cylinder pressure is so high that the voltage to initiate a spark discharge is so great and the amps so high spark plug life is well almost none existent, There has been some research work on using lasers to solve this problem, or as is done in large stationary NG engines of the megawatt class use plasma jet ignition but in the medium speed market i would think plasma jet would be horribly expensive to implement at a firing rate of +1600 hz. The simple solution is to “pilot” inject some diesel right before TDC this pilot fuel lights off and kicks off the stoichiometric NG gas burn, The good thing about NG is no particulates and you can go to stoichiometric mixing rates skip the fancy DPF filters and DOC + NOx after treatments using a simple 3 way conventional catalytic converter is possible if you run stotomietical mixtures.
Auto ignition temperature of natural gas is about twice that of diesel. The diesel is used to light off the NG. That idea has been around for many years.
Perhaps the increases in (thermal, I suppose)efficiency are coming from an elevated compression ratio, and perhaps staged injection to control cylinder pressures.
Seems like an answer to gov’t mandated lower emissions and utilization of a plentiful fuel as the means.
To liberals though, plentiful is bad, as that means lower cost, which means more consumption, and they want to control consumption. So costs will remain high, no matter what.
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