Even though my EV range took a nose dive in two distinct steps several months ago, and has recovered a little since, I still drive my P.Prime almost entirely on electric. I currently go to the gas station once every 2-3 months at which time I put in a couple gallons each time. My reasoning for doing that, instead of filling up all the way once per year, is to keep the gas from getting too stale. As with engine oil, gasoline can deteriorate gradually by thermal degrade and oxidation. This video, above, while mostly about damage to engine components between pure gasoline, ethanol, and methanol, made a few comments, right at the end, about the tendency of alcohols to separate from gasoline over time and to degrade into water. Recently I’ve been toying with the possibility of putting in 4-5 gallons and going 6 months between trips to the gas station, but I’m thinking this confirms my current 2 gallons per 2-3 month approach.
i used to fill up every 6 months, and force burn the extra using hybrid mode when unnecessary. after 6 years, i have decided to guesstimate my gas needs for the next 6 months, and only fill up that much. one member warned of condensation due to mostly empty tank all the time. another claimed it is not a problem in todays sealed fuel systems. toyota warns of 'stale gas', could that be layman terms for the ethanol issue?
As was mentioned, you need to keep the tank near to full.......to minimize condensation and because a large quantity of fuel tends to deteriorate at a slower rate than a small amount. Regardless of how much and how often you add to the tank, I suggest that it would be prudent to add the recommended amount of a fuel stabilizer along with your gas......especially if you can't find ethanol free gas which should be even better.
I suppose it’s fair to say that “stale gas” can mean anything that is less-good a product than straight out of the pump. So, yes, I suppose it could mean that. It could also mean oxidation and thermal breakdown (e.g., depolymerization), although obviously those degrade mechanisms are far more likely on engine oil than fuel.
A fuel system can NOT be completely sealed. It needs to vent pressure due to heat and allow some air IN to replace the gas used. The venting is a bit more sophisticated than it was years ago. ALL volatile fuels eventually go bad (stale). Ethanol mixes just tend to do it a bit quicker.
The problem with Ethanol is not mechanical, it's political. US government requiring E10, causes farmers to grow corn for fuel instead of other food crops. Ethanol has less energy density, yet we pay the same (or even more) for E10 than for pure gasoline. Ethanol takes more energy to produce than it outputs, which is bad for environment. All in the name of "saving environment". Basically, another government dysfunction in US. There are many big agricultural states that benefit from E10 mandate and they have sway in congress. But burning it in cars in not dangerous. Some early equipment suffered some material degradation (like plastic lines and reservoirs), but that has largely been addressed since E10 has been made mandatory in this country. My lawn mowers and grass trimmers still suffer from gas line degradation due to ethanol, but it's only because those manufacturers have opted to not change their materials and push anti-ethanol products (fuel additives that supposedly counteract the effects of ethanol) instead. I think your modern 21st century vehicle is absolutely fine with E10 and I would not worry about it, but your point about gas going stale is valid (and has nothing to do with ethanol), so if you are worried, put StaBil or similar product in the gas to stabilize it.
+1 ...With the non-automotive observation that corn in the US not really used as a food like people think that it is. Corn is mostly grown as sileage (used to make cows and pigs fat) converted into something called High Fructose Corn Syrup (used to make kids fat) and other kinds of alky-haul.....like burbon which, by law, must contain at least 51% corn. And then there's all of the high-carb fun food like chips, cereals. etc. With the global jihad against GMOs that's raging on the internet most hippies won't touch corn unless it's grown on some commune, and so I'm guessing that putting Ethanol in gasoline is one of the BETTER uses for it. Last time I was in the Middle East? I didn't see much corn growing.....
Ethanol separation is a pain in the butt for lawn mowers and portable gaso cans, but I am not expecting too much problem in a modern PHEV gaso tank which is designed to greatly control the gasoline. You can add something like Stabil if you want to enhance. What I would/not do if the gaso was sitting in the tank 6+ months: (1) I would use TopTierGas.com (2) I would not dump from a 5-gal gaso can sitting around into the tank (3) possibly use an additive such as Stabil designed to keep ethnaol in solution with the gaso (4) try to fill up once in a while I will not get into the politics here either
Only remark I can say about ethanol is it does burn cleaner and like others have said yields less power...The cars that used E85, when ran E85 get worse fuel economy and produce less horsepower. Anyway, yeah corn subsidies. Everyone thinks it's cheaper but they don't realize they're already paying for it with their taxes... Technically, if you fill up your Prius with ethanol free you should be able to go 0-60 faster!
Some of us don't have any choice about ethanol in automotive gasoline, due to state mandates. Yes, you can still get non-ethanol gasoline at non-automotive fuel stations (like marine), but it is difficult.
..and Federal regs....those of us in areas mandated to use EPA reformulated gasoline are mandated for 10% ethanol, and usually it is not possible to find E0 in the RFG areas. So the OP just happens to live in a state that is mostly non-RFG, but I think maybe Houston and some other areas in TX have it. But most Prime owners cannot get E0 so it is E10 for most, thereby proving E10 is OK by user experience to date (inlcuding Volts, Pips etc).
I would treat it as a piece of equipment, same a s a lawnmower, weed eater, etc. I would use non-ethanol fuel with a fuel stabilizer, as the gas can sit a while.
GM recommends against any fuel additive be used in the Volts fuel and claims all engine and fuel maintenance is automated. Further the manual specifically states to only fill the tank 1/4 if you won’t be using much gas and e15 is allowed. I have never read a Prime or PIP manual but would guess following the book wouldn’t hurt anything. Does Toyo for example recommend fuel additives? I would check, many cars specifically disallows fuel additives.
PIP manual only says to use up the gas every 6 months iirc. haven't read anything about prime, seems to be in absentia.
Methanol is the key to fuels derived from methane (natural gas) and even coal. The local BMW USA plant is using methane from garbage dumps to complementarily fuel their factory. Methanol was the "Gasohol" fuel of choice, before the Iowa lobbyist introduced ethanol as a fuel to supplement the farmers in the corn lobby. That's why one of the first presidential primaries is in Iowa. In China, it is illegal to grow food to be used as a fuel. China has embraced methanol as a transportation fuel, as well as EC's as the future. Before 2000, Ford spent hundreds of millions of dollars developing vehicles using Gasohol made with methanol. Methanol can be the future for coal. It is readily and easily converted to the liquid from methane. Methane is readily available from the abundant supply of natural gas transported everywhere by existing pipelines. Natural gas can be converted at a local plant and transported as a liquid to local "gas" stations and dispensed in the current method. Ethanol is a politically driven mistake.
Methanol is cheap but far more coorsive than ethanol and more dangerous in terms of physical exposure
