First, lemme say it is good to be back. It has been a long time and it is good to see this message board still going strong! So my first question in a long time…
Given that many of the hybrids these days get much better gas mileage than traditional engines, at what point does the gas go bad and create problems with the engine? Also given the complexity of a hybrid engine, is it more sensitive to poor quality fuel? What is the size of the fuel tank?
And here is Cecil’s opinion on stale gas in general…
He says that gas can go bad but it can take anywhere from a couple months to a couple years. He also mentioned a stabilizer additive if long term storage is expected. And he does admit that poor fuel can reduce the performance of your engine in various ways.
Here’s a scenario…Let’s say I live in the mountains about 70 miles from the nearest town. I go to town once a month and buy all the supplies I will need. I know hybrids can go 45+ miles per gallon, so I am looking at ~3 gallons of fuel every month. With a 12 gallon fuel tank it would take me 4 months to use up all the fuel. Add that to the age of the fuel when I bought it (who knows?) and it sounds likely that this could be a problem. But I have yet to see the expose on the 6 o’clock news of the secret hybrid gas conspiracy…
If you only drive 70 miles a month, chances are you don’t own a hybrid. What’s the point? This isn’t something that would end up making a huge number of people have stale gas.
BTW…my old Civic Hybrid usually went a month or so between fuel ups. No issues. For really long stretches, sure, you might have some stale gas issues.
The thing is: if you drive so little, you’d probably have the same problem in any gas vehicle.
I’ve heard that if you have a hybrid, you’ve got the larger worry of the batteries getting screwed up if you leave the vehicle sit for too long. No idea if its true or not (we’ve got a few hybrid owners here who could answer the question for certain), but, at the very least, it seems plausible to me that a car maker would recommend such a thing as a CYA-type of thing, if nothing else.
Having worked at a few gas stations, I can say that it’d be pretty unlikely that the gas would be sitting around there long enough to go stale. You could have problems with gunk in the gas, but that would have more to do with the condition of the tanks than it would the age of the gas… (Every station I worked at generally got a delivery once a week, if not multiple times a week.)
What complexity?
I thought one of the advantages of the gasoline engines in hybrid cars was that they were simpler, being designed to run just at a single RPM to charge the batteries.
I can see that the charge/recharge system, and the motive system (with separate motors at each wheel) would be more complex, but the engine itself – isn’t that simpler?
No, the gasoline engines in the hybrids currently on the market is a conventional gasoline engine, with variable throttle response, etc. Effectively, once the engine is driving the car, the electric motor is helping, rather than the other way around.
The (hopefully) forthcoming Chevy Volt will use its gasoline engine solely to recharge the batteries, but no currently available car (in the US) works that way.