Anyone else using Premium fuel in the Phev?

[Trex]

Hi,

I am using a Premium fuel called Premium 98 in my Phev mainly for the benefit of a cleaner fuel system, ie carbon deposits buildup, and it appears to give a slightly better fuel consumption than regular.

I should clarify this with I had problems with our previous car, a Prius, where the fuel injectors would clog up with carbon deposits and would "misfire" on 3 cylinders (and that would shake the car and sound bloody horrible) not long (about 4 or 5 months) after we bought it new. This was using Regular petrol . Anyway got the fuel injectors replaced under warranty, after our dealer went into bat for me, and the head mechanic at dealer suggested using additives (from Toyota), which I did once at about $30 a bottle (does 2 tanks of fuel), but from then on started using Premium petrol. Never had a problem again in the 4 years after we had this experience.

In the Phevs case seeing I am not using much fuel anyway ( about 90% ev ), but it is 8 cents a litre dearer, I have kept using Premium petrol.

Anyone else? Or am I just wasting my money?

Regards Trex.

 

[Titan]

I've not put it in the PHEV but I did run it for a year in my VW. I ran a spreadsheet for a while and saw that although more expensive at the pump, the extra mpg I gained from using it actually made it cheaper on a cost per mile. I think the price differential could be more than 6p/litre before the saving was lost.

As for not putting it in the PHEV, I haven't got round to thinking about it yet, as I've only filled up twice in the 1500 miles I've travelled.

 

[simonrh]

I put premium in my kit car and lawn mower as they have the fuel sitting in the tank for so long.

I have never put it in my daily driver before I got my PHEV last week but I did this time as it could be in there for a while.

I figured a decent drop of fuel with plenty of solvents and detergents could well last better?

....and also it is a small tank and I am not paying (being entirely mercenary)

 

[Hypermiler]

This has been discussed somewhere on here before...

I used it quite a lot in my VW as I had problems with it getting gunked up and stalling a lot (fsi engine).

I tend to use it in the PHEV as I put petrol in so rarely and I usually have a Tesco money off voucher. thought I would try to keep my new engine clean and get the most out of it.

H

 

[Kaboom]

Anyone else? Or am I just wasting my money?

Regards Trex.

Hi Trex

No you're not wasting your money!

Yes! I'm using Shell VPower for a couple of reasons:
1 - I really do think it works and keeps the important bits clean including the sensors - and there's bound to be loads of them.
2 - I'm using so little fuel that it really doesn't make any major difference that it costs just a little bit more.
3 - Liquid fuels can and do suffer from oxidation and the "additives" in the more expensive fuels will help keep the fuel healthier for longer.
4 - Do I need a forth?

Thanks!

 

[Trex]

Hi everyone that has replied,

Some good points especially about the longevity aspects of fuel going stale which I did not consider.

Premium fuel is the way to go.

Regards Trex.

 

[karl]

...are there some actual data to back up the claim that "premium" fuel lasts longer?
I try to avoid too much biodiesel in my boat to avoid growth - isn't there a risk that it'sthe additatives that crap up after a while. I think that most if not all of the extra "octane" is additatives, rather than better petrol.

I also doubt that a direct injected normally aspirated engine benefits from a higher octane rating in any detectable way.

 

[maby]

...are there some actual data to back up the claim that "premium" fuel lasts longer?
I try to avoid too much biodiesel in my boat to avoid growth - isn't there a risk that it'sthe additatives that crap up after a while. I think that most if not all of the extra "octane" is additatives, rather than better petrol.

I also doubt that a direct injected normally aspirated engine benefits from a higher octane rating in any detectable way.

Don't assume that fuel sold as "premium" is higher octane. We discussed this several months ago here and it seems that in Australia "premium" implies 98 octane, but if you read up on the manufacturers' documentation, you will find few, if any, premium fuels in Europe that claim anything higher than 95 octane. They generally just contain additives that claim to reduce deposits and, possibly, improve mpg.

 

[anko]

As I wrote earlier, the engine of the PHEV seems not to be maxed out when you are pulling a caravan. I mean, it will max out, when driving conditions dictate, but it will not go for the max for charging purposes. You can see this easily:

When driving on a flat road under ideal conditions, you may see the orange arrow from engine to wheels + a blue arrow from engine to battery. When the driving conditions become a little bit less optimal (little head wind, small incline) the blue arrow from engine to wheels disappear. But it takes even worse conditions before a blue arrow appears from battery to wheels. To me, this says there is some power reserve in the engine that will be used for driving, but not for charging when driving doesn't require it.

Now I was thinking: if the above observation is correct AND what if the car was not programmed to produce a specific amount of power at a given speed, but to consume a specific amount of fuel at a given speed (as long as driving conditions don't require more, that is)? Than I would have more power available for charging under normal driving conditions, by using premium fuels. Something worth trying on my next trip with caravan.

What I am not sure about: what would be the best fuel to test this with? Should I go for any premium fuel or should I go for real 98 Octane fuel?

 

[maby]

As I wrote earlier, the engine of the PHEV seems not to be maxed out when you are pulling a caravan. I mean, it will max out, when driving conditions dictate, but it will not go for the max for charging purposes. You can see this easily:

...
What I am not sure about: what would be the best fuel to test this with? Should I go for any premium fuel or should I go for real 98 Octane fuel?

I think you need to test with 98 octane - if you can find it. The 95 octane "premium" fuels are just too unpredictable - I suspect that many of them are little better than snake oil. That said, I'm not convinced that there is any benefit to be had from putting 98 into a car designed to run happily on 95.

When we bought out Prius and I was taking part in a forum similar to this one, it was widely believed that the Prius performed worse on most premium fuels than it did on regular unleaded. The claim was that the instrumentation controlling the hybrid systems is very sensitive to the type of fuel and could not adapt itself to anything other than plain petrol. These things are very subjective - I did try premium fuel a couple of times and got the impression that the car might not be totally happy. I didn't see any obvious benefits in terms of fuel consumption and went back to regular fuel on the basis that the premium was costing me 5p more.

It is true that hydrocarbon fuels degrade with age and a PHEV owner running almost 100% EV could hit a problem with fuel in the tank for months. We have a comparable problem on the boat where you can have many gallons of diesel sitting in the tank for months on end. This can result in "diesel bug" - nasty little bacteria that live in diesel, munching their way through it and clogging the fuel system up with their "waste products". We have to add chemicals to the tank to control them. I guess the same could happen to petrol - specially with the new biofuel additives that are being forced upon us. I've never seen any of the premium petrols claim to be longer lasting - it's not really an issue for the majority of drivers.

This weekend just past, I put the little Honda outboard onto the dinghy and started it for the first time in about six months. It had half a pint of regular unleaded in the tank which had sat there all winter - and the jets in the carburettor on a 2.3hp Honda outboard are tiny. It started after about a dozen pulls on the cord and ran perfectly well once it had warmed up, so I don't see any evidence of unacceptable degradation in petrol over the sort of periods that we are likely to experience in a PHEV.

 

[gwatpe]

Once you have some sort of direct reading output of instant mpg or L/100km you will be able to check the way the PHEV uses petrol and electrical energy. I have an OBD2 Heads up display and this shows ICE rpm as well as coolant temperature and petrol consumption. If you also have the energy dash display you will see the way the PHEV ECU loads the battery and petrol engine for varying vehicle loads from changes in road grade. I have typically seen in Save mode, on a flat road at 100kph, with parallel hybrid clutch engaged, petrol consumption, with no generator or battery energy consumption, at 8L/100km. As the grade changes to uphill I have seen the petrol increase up to 14L/100km before the battery helps out. And similarly with the grade tending to downhill, the petrol consumption decreases to about 5L/100km and then battery recharging occurs. With increased downhill, the ICE eventually drops to 1.8L/100km, and then eventually it will shut down. If the petrol is changed to a different grade, then there should be reductions in the L/100km as the octane is increased.

I have found the PHEV extremely difficult to get objective real time assessments of petrol performance due to the fast response of the ECU to driver inputs and road conditions changes.

Maybe with a MUT3 and computer logging, the data could be assessed.

Lap Time screen might even be of help if we could get access to it.

 

[Trex]

.

What I am not sure about: what would be the best fuel to test this with? Should I go for any premium fuel or should I go for real 98 Octane fuel?

Yep go for 98 octane if you can get it and please let us know how it goes.

Regards Trex.

 

[anko]

Thanks guys. I will try to get my hands on some 98. What's there to loose?

Once you have some sort of direct reading output of instant mpg or L/100km you will be able to check the way the PHEV uses petrol and electrical energy.
...
I have typically seen in Save mode, on a flat road at 100kph, with parallel hybrid clutch engaged, petrol consumption, with no generator or battery energy consumption, at 8L/100km.

I do have an OBD scanner that shows instant fuel consumption. As I said before, I would be totally flabbergasted to see an instant fuel consumption of 8 l/100 kph in Save mode @ 100 km/h. For average consumption? Sure. But for instant consumption? No way. Like I said before, at 100 km/h, I get 11.1 l/100 km at best (40% more than you get). I could also understand 8 l/100km if it somehow wasn't charging the battery at the same time. But driving 100 km/h AND charging the battery @ 8 l / 100 km? Please tell me your secret

Little voice in back of my head says: Could it be that the Save mode Down Under is a little bit different from ours? That it converts the PHEV into a normal car?

 

[Trex]

Little voice in back of my head says: Could it be that the Save mode Down Under is a little bit different from ours? That it converts the PHEV into a normal car?

Nah like I have said before I see about 10.5ls/100ks at 100kph if I reset the computer when the petrol motor starts but I am using premium 98 octane..

Regard Trex .

 

[anko]

Ah, okay. So the 8l/100km is an average. That makes sense

If instant consumption is 10.5 on 98 and 11.1 on 95, that would mean that on higher octane it burns less fuel rather than produce more power (based on the totally silly assumption that conditions are the same for me and you :roll: ). At least it would suggest that there is no a preset burn rate. That is no to promising for my test. Ah well, we'll see.

 

[gwatpe]

Thanks guys. I will try to get my hands on some 98. What's there to loose?

Once you have some sort of direct reading output of instant mpg or L/100km you will be able to check the way the PHEV uses petrol and electrical energy.
...
I have typically seen in Save mode, on a flat road at 100kph, with parallel hybrid clutch engaged, petrol consumption, with no generator or battery energy consumption, at 8L/100km.

I do have an OBD scanner that shows instant fuel consumption. As I said before, I would be totally flabbergasted to see an instant fuel consumption of 8 l/100 kph in Save mode @ 100 km/h. For average consumption? Sure. But for instant consumption? No way. Like I said before, at 100 km/h, I get 11.1 l/100 km at best (40% more than you get). I could also understand 8 l/100km if it somehow wasn't charging the battery at the same time. But driving 100 km/h AND charging the battery @ 8 l / 100 km? Please tell me your secret

Little voice in back of my head says: Could it be that the Save mode Down Under is a little bit different from ours? That it converts the PHEV into a normal car?

The instantaneous petrol consumption is very dependent on how steady the accelerator is depressed. I never said that with the car driven on level ground that the battery was being charged with a petrol consumption of 8L/100km. With the clutch engaged at 100kph, the instant consumption can range between 5 and 14L/100km without generator or battery involved. The energy flow page on the dash is used in conjunction with the instant MPG, and with a steady pedal on a road with no traffic, you should see similar results. Hills and traffic will destroy any hope of seeing consistent instant MPG.

I will attempt to see if video evidence can be uploaded and linked to the forum some how.

 

[anko]

Now I am confused. After all of this, what is the significance of the 8 l / 100 km? Is it just a number that happens to come by?

Or, if that is what you meant to say, how do you establish the instant fuel consumption of "driving 100 km/h without charging the battery"? How can this be reproducible in a test with a different fuel type?

Thanks, Anko

 

[gwatpe]

On a flat road, driving at 100kph it is possible with the PHEV operating in parallel hybrid mode to ease back on the accelerator and find the point where speed is maintained with no generator and no electric motors.

This may be purely academic, as normally the car will have to be driven on a real road with pot holes and curves and undulations and the PHEV will load the petrol up and down in an attempt to get a programmed average best fuel usage.

BTW I use Premium fuel about every 3 tanks. I used a similar regime with a dual fuel [GAS] vehicle, when using petrol. Petrol was used 25% of the time and 33% of the petrol was premium.

 

[anko]

On a flat road, driving at 100kph it is possible with the PHEV operating in parallel hybrid mode to ease back on the accelerator and find the point where speed is maintained with no generator and no electric motors.

With all due respect, I have no idea what you mean. Best I can make of it is this: You are driving steady 100 km/h and the engine is propelling the car and charging the batteries. Than you gently lift the accelerator and instead of the car slowing down, the engine stops charging the battery? Is that what you mean? If so, next time I am in Australia, you will have to show me that trick :shock:

 

[maby]

On a flat road, driving at 100kph it is possible with the PHEV operating in parallel hybrid mode to ease back on the accelerator and find the point where speed is maintained with no generator and no electric motors.

With all due respect, I have no idea what you mean. Best I can make of it is this: You are driving steady 100 km/h and the engine is propelling the car and charging the batteries. Than you gently lift the accelerator and instead of the car slowing down, the engine stops charging the battery? Is that what you mean? If so, next time I am in Australia, you will have to show me that trick :shock:

Try running on cruise control and slowly popping the speed up and down while watching the power flow - you will find a speed around 50mph where the display shows the engine running, driving the front wheels and no other power flow.