The 'perfect' hybrid...CNG?

Apparently, CNG vehicles are quite slow to fill. See http://priuschat.com/forums/other-c...atural-gas-vehicles-were-so-slow-fill-up.html.

I don't know the current status of Phill either. They were in limbo for awhile. Are there other reasonably priced home CNG fueling stations available?

 

natural gas will go way up in price when/if they put the proper safeguards on harvesting.

 

Pros:
- Clean burning. However, with a gasoline hybrid I suspect some of the advantage of CNG would be lost.
- Cheap.
- Replaces petroleum imports with a local resource.
- Potential for homes with mains NG to refuel at home, although I think that's pretty much been abandoned now.

Cons:
- Not much more efficient than a good gasoline engine: in fact, it's considered by many to be more efficient to burn NG in CHP plants and run EVs than to burn the NG directly in a combustion engine.
- Low energy density meaning either you have reduced range or a large tank that reduces space in the car. In a hybrid there would be a double whammy on space reduction.
- If CNG use spread to transportation on a large scale prices would likely rise and that would hit heating and electricity prices too.

Since NG isn't an ideal fuel for transportation I think it's best kept to specialized urban uses such as large taxis, buses and garbage trucks:
- low emissions have greatest value
- limited and predictable daily range allows for right-sizing of fuel tanks.
- doesn't require an extensive build-out of infrastructure
- replaces uses of gasoline and diesel where current efficiency is low.
- won't increase NG demand excessively

For now I'd prefer efforts to be concentrated on encouraging EV and improving bio- and synthetic fuel production with the aim of a future mix of diesel and EV.

 

It seems to me that weight and cost would be issues. For it's size the Prius is pretty heavy and a CNG tank would add a lot of weight and size and cost.
Remember the CNG Civic is about 5 grand more than the normal Civic. I doubt that a CNG Prius can be done for less than the price of a Volt.

 

GM's CEO was on CNN for an interview last Sunday (Fareed Zacharia's show I think it was). He said that CNG/Gasoline flex fuel vehicles make sense for USA (since we have nat gas). Got the impression GM is working on that concept. Sounds good to me.

 

200 + 13 = 213, not 350 to 400

You will get a minor improvement due to regen and start/stop in town.

 

Assuming similar tank size, you should see better-than-ICEV mileage. If it's a similar improvement over ICE, you might have a 333 + 13 = 346 for the 50mpge. 400 would be stretching it.

Cost and space issues combine to make it difficult, especially in an HEV.

 

1) 'most' of the Prius MPG improvement is going from Otto Cycle to Atkinson cycle, no such change in the NG ICE.

2) Packaging will be a bear, if you need 13 miles of batteries AND a high pressure vessel for a 400 mile fuel tank, you could look like a 2 seat Suburban.

 

CHP is 75% efficient. Burning CNG for home heating is efficient: modern furnaces can be 97% efficient. Burning CNG in an ICE is not efficient.

The Prius battery is a good size and is in the rear underneath the spare. If you add a larger natural gas tank there is a space issue.

In some markets there are stations. In most markets there are not. In order to make NG usable everywhere you need an extensive infrastructure, especially given the reduced range per fill.

I believe you are mistaken. US and European petroleum consumption has peaked and yet global prices are still high. It's growing demand from other nations that's causing high global prices. Gas prices would still continue their inevitable rise.

You're also ignoring the fact that any rise in NG price would hit people hard in home heating and electricity rates.

Reduced imports is the only significant argument for a full shift to NG, but simply having more HEVs would achieve the same effect at a lower cost.

 

NG is currently less than gasoline in part do to the fact that road taxes aren't applied to it.
Those fees will be added in addition to the price increases do to demand if it goes mainstream.

 

Keep in mind T Boone Picken's plan originally had the idea to convert cars to CNG. But the nat gas folks pointed out no infrastructure to support refills, so scope was narrowed to trucks. I would like to see move in this direction (as well as propane may have advantages). You can put propane in spare tire well, seen that in Europe.

 

Like this one? It would be sweet as it would qualify in CA HOV lane.

The compressed natural gas tank takes the room of the spare tire so sorry, no PHV CNG HSD for now.

 

The Prius with a CNG conversion would be a better "buy" or mod, than say upgrading to PHEV.
- cheaper to convert
- cheaper to run
- clean burning

There was talk of using NG as a catalyst in a fuel cell for producing pure hydrogen on demand. I wonder where that is at.

It would be cool to place a small fuel cell, a 20lb tank, and have this "system" top off to full the Prius HV battery, in a similar way the Enginer.us system works.

I wonder what the trade-off would be, energy wise. NG to Amps would have a loss & generate heat. NG in the ICE would be more, or less, efficient?

God I wish fuel cells / fusion cells weren't the stuff of science-fiction.

 

and expensive.