Posted on 10/17/2013 6:06:17 AM PDT by thackney
Capitalizing on America’s abundant supply of clean-burning, low-cost natural gas, General Motors said Wednesday it will build a Chevrolet Impala sedan that can operate on either gasoline or compressed natural gas and travel up to 500 miles between fill-ups.
The bi-fuel Impala, which goes on sale summer as a 2015 model, could be the start of something big. Honda Motor has been selling a natural gas-powered Civic since 2011 and while still modest, sales have been steadily rising. The Japanese carmaker is on track to sell about 2,500 CNG Civics this year, up from 1,900 in 2012 and 1,200 the year before. In July, Ford Motor said its most popular vehicle, the F-150 pickup, will be offered with a compressed natural gas engine starting in the 2014 model year.
“Natural gas will grow increasingly attractive as an alternative fuel source, as we’ve seen each year with natural gas Honda Civic sales, particularly in areas like California where HOV lane access is available,” said Alec Gutierrez, senior analyst for Kelley Blue Book. “The lack of infrastructure remains a hurdle, but if more automakers begin to offer CNG-powered vehicles, we could see a greater push for access to CNG in the years to come.”
The Impala’s bi-fuel powertrain is engineered to switch seamlessly from CNG to gasoline, which should reassure consumers worried about finding a place to refuel. For business fleet customers, whose drivers return to a central location, CNG refueling shouldn’t be a problem. GM did not announce the new car’s price, which is likely to be higher than the standard gas model, but savings at the pump could offset that extra payout quickly.
(Excerpt) Read more at forbes.com ...
You're so right! Years ago I bought a new VW Jetta with a diesel engine. It would go about 400 miles on a tankful.
But when we took trips, my wife and three young children found it expedient, nay, imperative to make a rest stop every couple of hundred miles. The kids hated that Jetta; they couldn't get dad to stop when they needed to.
I should have added, the manufactures web site linked above states the fill rate is 1.2 standard cubic meters per hour or 0.59 cubic feet per minute or 35.4 cubic feet per hour.
This allows 147,000 BTU/Hr. Within a couple percentage points, that is 147 standard cubic feet of natural gas.
I should have added, the manufactures web site linked above states the fill rate is 1.2 standard cubic meters per hour or 0.59 cubic feet per minute or 35.4 cubic feet per hour.
The most common (only US??) home refill unit (Phill by BRC) goes to 3,600 psi in their write-up. I think I’ve read the vehicle CNG tank code was 4 or 5,000 psi with a very significant safety factor on top of that.
Uh-huh.
That 100LL stands for “Lots o lead.” (^;
I tried running lawn equipment on 100LL to get around the alcohol/MTBE problem and the deposits got bad enough in the 4 strokes that the valves quit sealing. Not to mention the increase in octane is counterproductive on low compression engines.
What are minimum burst pressure for each type of cylinder?
http://www.iso11439.com/faq.php
ISO 11439 defines different burst pressure for each type of cylinder based on the raw material used
CNG-1 Metal:2.25
CNG-2 Type of fiber: Glass:2.75 Aramid:2.35 Carbon:2.35
CNG-3 Type of fiber: Glass:3.65 Aramid:3.1 Carbon:2.35
CNG-4 Type of fiber: Glass:3.65 Aramid:3.1 Carbon:2.35
These factors define the minimum burst pressure in ratio to working pressure. E.g. A 200bar working pressure cylinder of type 3 is made with metallic liner and wrapped with Carbon fiber. This means the cylinder should not be filled over 200bar of content gas and will have to be able to withstand minimum pressure of 470bar (The cylinder may burst above this pressure).
200 bar = 2,900 psi
470 bar = 6,187 psi
I need to quit doing these off my memory. After seeing the lower tank values I checked. It is 3,000 psi.
http://www.brcfuelmaker.it/en/phill-domestico-prodotto-brc-fuel-maker.aspx
The tanks are hydro-tested at 3,5, or 10 years intervals depending on composition to 5/3 of their working pressure.
It is a 220W compressor, or about 1/8 the size of my daughter’s hair dryer for power draw.
Sssslllllloooooowwwww fffllloooowwww.
No it does it at a lower volume. I have a 5K psi breathing air compressor that is pulling less than 30 amps single phase.
You need some 13:1 pistons for that Briggs and Stratton, LOL.
Think about comparing a high-pressure hydraulic pump on to a water pump. Pressure alone doesn’t describe power requirements.
I never tore down airplane engines before they went to “low lead” but the standard stuff must have been like syrup judging by the deposits left behind by “LL.”
And yea, that was a joke...
OK ...still it seems odd that 220 watts could generate 3000 psi even over a long period ...thanks for explaining it.
“You need some 13:1 pistons for that Briggs and Stratton, LOL.”
Many moons ago, I milled the head, a bit at a time, on my go-kart till the valves started hitting the head. I never could detect a lot of increase in performance.
I think the problem is a flathead engine can’t really respond to the improvement. Did you port the block to maintain the cross section between the valves and cylinder for gas flow? Not sure how much wall thickness there is in there also before you break thru.
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