Yaris Hybrid - Engine Vibrations

[yarisHybrid]

Never used 91... And dont't really know is it OK to use 98... i think it is :) but never did...

You can use 98 if 95 is not available, it won't provide any benefit and is usually more expensive.

I'm sure that there were no any vibrations when used fuel from INA, but that was before this cold winter... maybe the whole thing may be caused by low temperatures, around +5 to -8 C

And to say once more, I can feel vibrations only after some time during driving (30 to 45 mins). When it's started and after it's warm-up cycle, it works very smooth...

I'm leaning towards it being temperature related, it sounds like it is just taking longer to warm up and so spending longer in the first two warm up stages. In stage 1 particularly, the engine is set in a reasonably inefficient state which runs a bit rough, to warm up the engine and catalytic converters quicker.

See The Five Stages of Prius Hybrid Operation to learn more about the warm up stages of a hybrid. Even though it is based on a Gen II Prius most of the information is applicable to all Toyota hybrids, just some of the finer details might be different, e. g. speed thresholds.

HTH

Tnx :) This is interesting article! Tommarow I will pick up another - just like mine car - on a drive for two hours and finally see is there any difference.

I'm trusting Croatian 98 isn't leaded. But if it isn't, then use it for a few fill ups. A lot of countries are increasing the use of ethanol in petrol and I understand that higher concentrations can cause cold running issues. What are the chances of the fuel being diluted with extra ethanol to maximise profits?

But if the car is starting to run rough at cold, then it sounds like it is coked up. Run fuel system cleaner with the expensive 98 unleaded for a full tank and see if that improves things. If it does - and it will be pretty instant, then you know the problem. If it isn't, then running the fuel cleaner and 98 unleaded won't hurt things - far from it.

Useful info :) Tnx very much

[Grumpy Cabbie]

May I just pick up on the EGR point?

I notice the 1.5 is a VVTi engine.

Assuming it has variable valve timing on both camshafts, my guess is it may not have an EGR assembly as it would use valve overlap on the exhaust cam to draw exhaust gas back into the cylinders and thus reduce NOx that way.

It's a hybrid engine. It runs on the atkinson cycle and one of the down sides of this is high compression and high NOx. The benefits of the atkinson cycle is much improved fuel economy. The EGR system will reduce the NOx.

Comparison of atkinson engines compression ratios against a diesel and a 1.3 petrol engine. You can see why they need EGR.

Yaris HSD compression ratio: 13.4:1

Prius HSD " ": 13.0:1

Avensis DIESEL ratio: 15.8:1

Ford Fiesta 1.3 petrol: 9.5:1

http://en.wikipedia.org/wiki/Atkinson_cycle

http://en.wikipedia.org/wiki/Hybrid_Synergy_Drive

[Joseph D]

I'm trusting Croatian 98 isn't leaded. But if it isn't, then use it for a few fill ups. A lot of countries are increasing the use of ethanol in petrol and I understand that higher concentrations can cause cold running issues. What are the chances of the fuel being diluted with extra ethanol to maximise profits?

But if the car is starting to run rough at cold, then it sounds like it is coked up. Run fuel system cleaner with the expensive 98 unleaded for a full tank and see if that improves things. If it does - and it will be pretty instant, then you know the problem. If it isn't, then running the fuel cleaner and 98 unleaded won't hurt things - far from it.

While I have great respect for a lot of what GC has to say on all things Prius, I do not really buy into this fixation about using RON 98 fuel in a car that is spec'ed for RON 95. I have read a lot of GC's experiences that led to the conclusions he has come too, but my analysis of the information presented is that it has much more to do with using fuel that is possibly inferior rather than the RON rating of said fuels. The argument for using higher RON rated fuel, has "better" detergents so cleans your engine better, does not make any commercial sense to me either (I also cannot find any official data to corroborate this assertion, but find data that says the opposite--hence my viewpoint). I can't see a business prospering by selling an inferior product that destroys the consumer's car. All fuels have detergents. Detergents are a valid commercial marketing tool and will keep a customer coming back if the consumer finds a particular brand works well to keep their engine running smooth. At the end of the day, I'm not about to tell anyone not to put RON 98 in their car, if they have a firm belief that that's what they need, then they are welcome to spend the extra money to do that. I just like to offer my experience of having no such problems using exclusively RON 95 fuel.

Another thing to consider, this information is UK specific and I do not believe it translates internationally. Each country has their own standards and processes which are tailored to the market and geography of the target country. My personal experience is that I got better (sometimes much better) performance on European sourced fuel--Croatia being one of the places.

On the subject of ethanol, I have found that, yes, there is a slight drop in fuel economy (comparing like for like) when compared to non-ethanol (E0) fuel. But the drop is not as large as the drop in using RON 98 E0. So, I'm not about to pay more for a fuel that gives me lower fuel economy. As I say, though, each to their own.

Finally, if you are going to use fuel system cleaner additives (i. e. your own custom added detergent package), you are just as well to add it to the correct RON 95. More is most always not better.

I haven't been as detailed as I might like to be so I hope that what I have said still makes sense, but I don't really don't want to a) repeat information I have already posted in other threads and b) this post is already long enough. If there is interest to discuss this subject matter further, I'd be happy to start a new thread to do this, rather that continue to hijack the OP's thread taking it on this tangent.

HTH

[cobh18]

" All fuels have detergents." Maybe. But EN*** makes no current requirement for detergency standards, so the field is open for a wide variation. Haven't ever seen a supermarket fuel blazoned with claims for cleanliness yet.....

[Joseph D]

" All fuels have detergents." Maybe. But EN*** makes no current requirement for detergency standards, so the field is open for a wide variation. Haven't ever seen a supermarket fuel blazoned with claims for cleanliness yet.....

I was hoping that this idea would come through. I do certainly think that different brands have different detergents and also that not every engine will work well on one particular brand of detergent package. So certainly there is going to be consumer preference for one or another, depending on what works for the customer.

However I don't believe that we need the EU to hold our hands to dictate to the N-th degree what we should or shouldn't do. I kinda believe that businesses want to make a profit and will sell stuff that works rather than damages, otherwise they are not in business for long.

While I have no opinion on supermarket fuels (I know others do) occasional tankfuls will not harm your engine and whether stated or not, they have detergents as well. I have seen plenty of people filling up at Tesco's Sainsbury's and ASDA, so methinks it can't be too bad, otherwise we certainly would be hearing about it. People need to get over their "big oil" conspiracy theories. LOL.

[Joseph D]

May I just pick up on the EGR point?

I notice the 1.5 is a VVTi engine.

Assuming it has variable valve timing on both camshafts, my guess is it may not have an EGR assembly as it would use valve overlap on the exhaust cam to draw exhaust gas back into the cylinders and thus reduce NOx that way.

It's a hybrid engine. It runs on the atkinson cycle and one of the down sides of this is high compression and high NOx. The benefits of the atkinson cycle is much improved fuel economy. The EGR system will reduce the NOx.

Comparison of atkinson engines compression ratios against a diesel and a 1.3 petrol engine. You can see why they need EGR.

Yaris HSD compression ratio: 13.4:1

Prius HSD " ": 13.0:1

Avensis DIESEL ratio: 15.8:1

Ford Fiesta 1.3 petrol: 9.5:1

http://en.wikipedia.org/wiki/Atkinson_cycle

http://en.wikipedia.org/wiki/Hybrid_Synergy_Drive

I don't know if this comes into the category of splitting hairs, but the ICE is not a true Atkinson cycle engine mechanically, but rather a a modified Otto cycle piston engine using the Atkinson cycle by way of computer controlled valve timing to achieve the Atkinson cycle. Mentioning just case anyone is interested.

[FROSTYBALLS]

Tesco do make improved consumption claims for their 99RON Momentum petrol, and also state that Momentum uses their largest additive package. Whenever our nearest Tesco Extra has a promotion on their fuel (eg spend x amount instore and get 5p off each litre of fuel, or their recent Fuel Save promotion), I use Momentum as the cost gets brought down to the price of their standard fuel. Otherwise I generally use BP regular unleaded or Shell FuelSave, which locally are as cheap as Tesco fuel (eg the BP station is opposite Tesco).

http://www.tescopfs.com/our-fuel/Our%20Fuel

[cobh18]

Ah yes, Tesco. Forgotten about them. Think the fuel is supplied by Greenergy, part owned by Tesco.

[Grumpy Cabbie]

OK, if it isn't the fuel that caused my car to coke up at 70k miles, then it must be a design issue or fault not found by Toyota who have serviced the car since new. :)

Historically I have always used Shell, for no other reason than it was the nearest branded petrol station to me. I have never previously had issues with coking up cars and my last petrol taxi was a Mondeo with 290k miles on it. I've read many reports where people say petrol is petrol and that they're all the same and to use the cheapest. So with my Prius, and the fact that in 2010 onwards petrol costs soured, I changed my usual habit and filled up from the local Asda station. The car ran fine - for about 65k miles, but then started to (with hindsight) suffer stuttering when cold, slight hesitation etc. Eventually the EGR failed at 70k miles due to being gummed up.

After this was replaced I changed to Shell again having learnt my lesson. You save £2 a tank going to supermarkets but good luck long term.

[Grumpy Cabbie]

May I just pick up on the EGR point?

I notice the 1.5 is a VVTi engine.

Assuming it has variable valve timing on both camshafts, my guess is it may not have an EGR assembly as it would use valve overlap on the exhaust cam to draw exhaust gas back into the cylinders and thus reduce NOx that way.

It's a hybrid engine. It runs on the atkinson cycle and one of the down sides of this is high compression and high NOx. The benefits of the atkinson cycle is much improved fuel economy. The EGR system will reduce the NOx.

Comparison of atkinson engines compression ratios against a diesel and a 1.3 petrol engine. You can see why they need EGR.

Yaris HSD compression ratio: 13.4:1

Prius HSD " ": 13.0:1

Avensis DIESEL ratio: 15.8:1

Ford Fiesta 1.3 petrol: 9.5:1

http://en.wikipedia.org/wiki/Atkinson_cycle

http://en.wikipedia.org/wiki/Hybrid_Synergy_Drive

I don't know if this comes into the category of splitting hairs, but the ICE is not a true Atkinson cycle engine mechanically, but rather a a modified Otto cycle piston engine using the Atkinson cycle by way of computer controlled valve timing to achieve the Atkinson cycle. Mentioning just case anyone is interested.

I know. That's why I put the links in, trying to keep it simple. The trouble with hybrids is that any explanation of how something works can never be simple. So yes, the hybrid engines are pretty much normal engines with one or two changes and controlled as you describe.

But NOx emissions are still high as you can see by the high compression ratios. The non hybrid Yaris petrol engine by comparison is only 10.5:1 instead of 13.4:1

http://media.toyota.co.uk/wp-content/files_mf/1351684804120330MTOYOTAYARISTECHNICALSPECIFICATIONS.pdf

[FROSTYBALLS]

For comparison purposes the compression ratios for the current Yaris according to the brochure are:

1.0, 1.33 manual, 1.33 auto petrols - 11.5:1

Hybrid - 13.4:1

Diesel - 16.5:1

Be interesting to see whether the new 1.0 litre and 1.3 litre Atkinson cycle engines are put in the Yaris later this year/next year.

[vanilla.coffee]

May I just pick up on the EGR point?

I notice the 1.5 is a VVTi engine.

Assuming it has variable valve timing on both camshafts, my guess is it may not have an EGR assembly as it would use valve overlap on the exhaust cam to draw exhaust gas back into the cylinders and thus reduce NOx that way.

It's a hybrid engine. It runs on the atkinson cycle and one of the down sides of this is high compression and high NOx. The benefits of the atkinson cycle is much improved fuel economy. The EGR system will reduce the NOx.

Comparison of atkinson engines compression ratios against a diesel and a 1.3 petrol engine. You can see why they need EGR.

Yaris HSD compression ratio: 13.4:1

Prius HSD " ": 13.0:1

Avensis DIESEL ratio: 15.8:1

Ford Fiesta 1.3 petrol: 9.5:1

Whilst I don't dispute the need for EGR, my question was does the 1.5 have an EGR assembly or does it use VVT instead by using the valve overlap on the exhaust cam to draw exhaust gas back in to the cylinders thus controlling EGR function without the need for an EGR solenoid valve assembly?

Sent from my iPhone using Toyota OC

[Grumpy Cabbie]

There is no simple answer. The info you need was in those links. All the hybrids have VVT by the very reason they exist and the Toyota hybrid system couldn't run without. The links explain. The Toyota HSD is simple to operate but very complicated to explain.

[vanilla.coffee]

I take delivery of my own Yaris HSD tomorrow so I shall have a look under the bonnet and see if I can spot an EGR solenoid.

Then we'll know for sure.

Sent from my iPhone using Toyota OC

[Grumpy Cabbie]

I take delivery of my own Yaris HSD tomorrow so I shall have a look under the bonnet and see if I can spot an EGR solenoid.

Then we'll know for sure.

Sent from my iPhone using Toyota OC

Indeed.

I've had a quick search on eBay and the EGR valve for the Yaris HSD second hand is just shy of £200.

http://www.ebay.co.uk/itm/2013-TOYOTA-YARIS-1-5-HYBRID-EGR-VALVE-25620-21020-ONLY-DONE-2328-MILES-/271314255054

[MEP's Yaris GS]

Out of interest where on the engine block is the EGR located on the 1.8?

Is it worth taking it off to clean periodically before it fails?

[Dancing Badger]

VBbc

[MEP's Yaris GS]

VBbc?

[Grumpy Cabbie]

I think just use good quality fuel and some fuel cleaner once in a while.