PHEV-ICE starting unexpectedly

[ernieb]

11 minutes ago, Nick72 said:

So I think it is mismatch between displeyed rolling average range and actual remaining capacity, as mentioned. 

A way to understand if this could be the up to 5 miles displayed range is to understand the variance over time between the displayed rolling average at start up on full capacity and odometer readings. If this difference is circa 5 miles on any one occassion then that proves there can be up to a 5 mile mismatch thus ICE has to come on.

That could certainly be the answer but in my head it has only just started to exhibit this. When this has happened it comes on, runs, then switches back to pure EV so if what you're saying is correct the system then recalculates and decides there is enough to run on EV only?

[Nick72]

21 minutes ago, ernieb said:

That could certainly be the answer but in my head it has only just started to exhibit this. When this has happened it comes on, runs, then switches back to pure EV so if what you're saying is correct the system then recalculates and decides there is enough to run on EV only?

So the two algorithms will not be linked.

 

One algorithm says, how much actual juice is left thus what mode do I need to be in You can't see this algorithm but you can see the effect... ICE comes on.

 

The other algorithm (completely independent of the other) is used to display an EV range based upon the previous several trips as a rolling average. Display purposes only.

 

This means that if your past few trips have been pretty efficient a high rolling average remaining range is calculated. That may mismatch in some instances with your actual driving on a new trip so as you approach a low charge state there's a mismatch. This I think is something to do with how the remaining range (displayed) is calculated through use on a trip and based upon the initial rolling average estimate at full charge.

In a long winded way I'm saying if the above is the case (and I don't think this is a bad way of doing it btw) then there will on occassion be a mismatch between displayed remaining range and actual (empty). Thus forcing the ICE to kick in.

It's probably how I would have designed it. Batteries are notoriously difficult to determine actual remaining charge state as you know. Translating that into a vehicle range is even more challenging. Plenty scope for uncertainty. 

I'd see how you get on over a month. If it consistently does it over that time then that blows my theory out of the water and it might be worth a dealer visit.

Not sure this helps Ernie.

[Roger_N]

Could it be something to do with the introduction of E10 fuel?

I’ve been told this fuel does not last as long before it starts to degenerate and can cause issues with seals in the fuel system. If you are doing lots of short journeys and not using the ICE it may be perceived as a potential issue

I don’t know this for sure but as we are speculating on the cause, it may be worth considering.

Can these cars get an over the air update for the MCU?

[nlee]

I've not experienced the ICE kicking in towards the end of the range yet. In fact the opposite. Mine often gets to zero then dashes but continues in EV for a bit. I've travelled up to another mile with nothing indicated before the engine started. That could have been just those particular driving conditions though.

[ernieb]

Nick, that makes sense although I’ve done so many similar trips and it has never kicked in so maybe other influences are affecting situation.

Roger, I’m using Premium E5 fuel so not the issue in my case.

Nigel, I’ve had the same thing happen to me many time especially on a long continuous drive, display goes to zero, then three bars and still runs on EV but on most of those occasions it was a constant speed no acceleration.

[Roger_N]

8 minutes ago, ernieb said:

Roger, I’m using Premium E5 fuel so not the issue in my case.

Yes but if there is a possibility of it being used it would have to be allowed for. 

[Lawnmowerman]

I run Esso E10. So have always been E10 (purchased 30th Sept. - E10 introduced 1st September at the very latest). 

This is a very recent trend suggesting a change in programming (do they/can they reprogramme over internet?).

Now over 6,700 miles - so definitely recent.le dropped to one (still both modes of drive active - then miles available

Coming home tonight the ICE kicked in at 2 miles again. The energy monitor showed that the ICE and Battery were both driving the car (and Battery recharging on overrun etc. so much so the miles available increased to 2!).

All current cars are designed to use this fuel without harm, but the hygroscopic nature of the fuel absorbing moisture from the air and turning into water is one of the reasons for the reduced power and increased fuel consumption generally.

Edited March 4, 2022 by Lawnmowerman
Added info.

[ernieb]

The car manual clearly states it's designed to run on E10 so can only assume the MCU has been set for this fuel as well as the cycle times to operate the ICE to circulate the fuel and lubricate the engine etc.

In previous cars I'd get through a tank of fuel every couple of weeks or so dependant on season, that's the retired life style for you.

In the RAV4 I filled up about a month ago and the ICE has literally only kicked in for these odd occasions or when I've triggered it to ensure it was warm if it was needed as I got nearer to home.  It's under these conditions that I feel the E5 might well be better for me with the lower amount of ethanol sitting in the tank,  I've decided that I will now drive using the ICE/HEV mode every couple of weeks to give the system a bit more activity and move the fuel around.

This car is a keeper for me so maybe being a bit OTT?

[Catlover]

Because I try to gain as much mpg from my Prius HEV if I had a PHEV and rarely used any petrol ie journeys mostly within the Battery range, I don’t think I would be inclined to run around with any way near a full petrol tank. That is a fair bit of weight to carry around doing nothing, and weight is a killer to mpg.

[ernieb]

Joe, totally agree with you and under normal circumstances I would not fill the tank this time of year.  But these are definitely not normal circumstances and I wanted the security of knowing that if fuel became an issue again I'd at least have some in reserve.

 

[AJones]

Is there any difference in behaviour between approaching 2 miles EV range remaining with a cold engine vs. a hot or warmed engine?

The engines have a warm-up sequence, I'm wondering if the control is anticipating that the EV range is almost used up but detecting the engine is cold, so going through a warming sequence to get the engine and catalyst up to temperature ready for it to pick up the full load of the car.

Maybe try going for an EV journey and forcing the engine on (force charge, defog) for a period to warm it up, drop back into EV and see how it behaves when you hit 2 miles.

[ernieb]

It's a reasonable thought Andy, but I've been travelling at 70mph on the M1 on pure EV and the ICE is off until the SOC reaches the three bars --- and then the ICE kicks in, so no anticipation just turns on the ICE.  I think even at that speed the ICE will run at around the 2K rpm and effectively just feeds the Battery with power rather than dive the wheels.

[jerryr666]

12 hours ago, ernieb said:

It's a reasonable thought Andy, but I've been travelling at 70mph on the M1 on pure EV and the ICE is off until the SOC reaches the three bars --- and then the ICE kicks in, so no anticipation just turns on the ICE.  I think even at that speed the ICE will run at around the 2K rpm and effectively just feeds the battery with power rather than dive the wheels.

On looking at my system / App (I’ve only had car a week/250 miles) the ICE cut in on a stretch of main road when on a 15 mile trip home on Thursday. I was using the Toyota Nav system & had noted that I’d run out of EV power about 3 miles from home, but appeared to have made it all the way on EV. It was only when I looked at the App I spotted the different coloured line. Does anyone know if it’s clever enough to link the range to the Nav & figure out range, then use ICE when speed is high, saving EV for the slow bit at the end?

[ernieb]

8 hours ago, jerryr666 said:

On looking at my system / App (I’ve only had car a week/250 miles) the ICE cut in on a stretch of main road when on a 15 mile trip home on Thursday. I was using the Toyota Nav system & had noted that I’d run out of EV power about 3 miles from home, but appeared to have made it all the way on EV. It was only when I looked at the App I spotted the different coloured line. Does anyone know if it’s clever enough to link the range to the Nav & figure out range, then use ICE when speed is high, saving EV for the slow bit at the end?

Don't think that happens Jeremy.  My experience is if I start in EV mode with a full charge and make a trip over the expected range of the EV, Sat Nav guidance or not, the car will use all the EV range then kick into HEV mode.  Unless I accelerate really hard, put on the front screen defrost etc., 

What I do see in the MyT app map when in HEV mode are stretches of EV mode operation that I can not remember being displayed in the car, they appear much more often than I'd assumed from driving the car.  When I first got the car there was no map display so it was a pleasant surprise to see just how well the car was recovering and using the EV mode when the app was updated to show the route and driving modes.

Remember the car will run at 85mph in EV mode.

[AJones]

2 hours ago, ernieb said:

What I do see in the MyT app map when in HEV mode are stretches of EV mode operation that I can not remember being displayed in the car, they appear much more often than I'd assumed from driving the car. 

In the Prius PHEV there's a real-time energy flow diagram and in HEV mode it is continually changing, you need to watch it like a hawk to know exactly what the car is doing at any given instant. In EV mode, at motorway speeds, it will sometimes bring in the engine for bursts even when in EV mode and staying in EV mode, so knowing whether the engine has run during a journey is almost impossible because it can cut in for a minute or two without any obvious indication.

[ernieb]

Similar to the RAV PHEV, I tend not to use that screen as much as when I first bought the car.  I found that if I was nit careful I’d OD on the display rather than keep fully focused on the road.  It is useful and I had thought of using that screen as the SOC reduced to see if the ICE cut in it might display what was going on in terms of power distribution.

[Lawnmowerman]

On 3/5/2022 at 7:43 AM, ernieb said:

The car manual clearly states it's designed to run on E10 so can only assume the MCU has been set for this fuel as well as the cycle times to operate the ICE to circulate the fuel and lubricate the engine etc.

In previous cars I'd get through a tank of fuel every couple of weeks or so dependant on season, that's the retired life style for you.

In the RAV4 I filled up about a month ago and the ICE has literally only kicked in for these odd occasions or when I've triggered it to ensure it was warm if it was needed as I got nearer to home.  It's under these conditions that I feel the E5 might well be better for me with the lower amount of ethanol sitting in the tank,  I've decided that I will now drive using the ICE/HEV mode every couple of weeks to give the system a bit more activity and move the fuel around.

This car is a keeper for me so maybe being a bit OTT?

Not OTT at all Ernie. I've said the last three were keepers!! But circumstances alter cases. My Yeti (Laurin & Klement) I adored but became disenchanted with VAG and the fall-out of diesel-gate. So not a penny more going in that direction (having 10 years as Aftersales Manager for the largest VAG group in Europe - that was how strongly I felt). After a lot of research my first RAV4 (4.4 Hybrid AWD). And it would have been a keeper - until the PHEV coming along with all the stars aligning.

👍

[philip42h]

5 hours ago, ernieb said:

What I do see in the MyT app map when in HEV mode are stretches of EV mode operation that I can not remember being displayed in the car, they appear much more often than I'd assumed from driving the car.  When I first got the car there was no map display so it was a pleasant surprise to see just how well the car was recovering and using the EV mode when the app was updated to show the route and driving modes.

Remember the car will run at 85mph in EV mode

I suspect that we need to be careful to distinguish between EV Mode and EV operation ...

Both the PHEV and the HEV have an EV Mode switch - it tells the car to draw motive power from the traction Battery rather than the ICE and the management system notes the driver's preference and then does what it thinks best. It is a very useful Mode in the PHEV (<50 miles or <85 mph) and rather less useful in a HEV (<1 mile or <20 mph).

What we seen in MyT trip history is periods of EV operation (ICE not running) and periods of non-EV operation (ICE running) - I guess calling them ICE and non-ICE wouldn't send quite the right marketing message but I think that is effectively what the labelling of sections of a journey really means. Obviously, when a PHEV is in EV Mode the vast majority of the journey will show as EV operation. Once in hybrid mode, a journey will show as non-EV and EV as the ICE cuts in and out.

When going on longer journeys, my wife and I share the driving. When I am driving I now use automatic cruise control as much as possible; my wife still prefers to control the speed manually. When automatic cruise is in operation MyT shows the bulk of any journey as non-EV - looking at the in car display we can see the ICE running continuously with the electric motors alternately providing assistance (up hill) or generating electricity (down hill). While my wife is driving we see far more EV sections in the journey - as she lifts off (presumably going down hill). Generally cruise control gives marginally better fuel economy despite having less time in EV operation. Obviously, I haven't done a proper side by side test and we have never driven the same section at the same time, but the observation holds over a number of such journeys.

Edit: and once again I am assuming that the PHEV and HEV behave in similar ways when operating in hybrid mode. It seems a reasonable assumption but has proved false on previous occasions.

[Nick72]

So if I'm in EV mode (not Auto HV EV), no matter how hard I press the gas pedal I stay in EV mode. Always.

If im in Auto EVHV mode and it is in EV operation, if I push hard on the gas beyond the soft stop then the ICE kicks in.

 

Just been up on the fells and a good run to try this.

[ernieb]

Take your point Philip my use of EV mode was shorthand but I guess most people would have understood it meant running in a non ICE mode.  

[Hayzee]

On 3/5/2022 at 7:43 AM, ernieb said:

The car manual clearly states it's designed to run on E10 so can only assume the MCU has been set for this fuel as well as the cycle times to operate the ICE to circulate the fuel and lubricate the engine etc.

In previous cars I'd get through a tank of fuel every couple of weeks or so dependant on season, that's the retired life style for you.

In the RAV4 I filled up about a month ago and the ICE has literally only kicked in for these odd occasions or when I've triggered it to ensure it was warm if it was needed as I got nearer to home.  It's under these conditions that I feel the E5 might well be better for me with the lower amount of ethanol sitting in the tank,  I've decided that I will now drive using the ICE/HEV mode every couple of weeks to give the system a bit more activity and move the fuel around.

This car is a keeper for me so maybe being a bit OTT?

Ernie

I'm pretty much in the same situation. In the 10 days since I had the car the ICE has only kicked in for just minutes as my average daily mileage is within EV range.

As my fuel sits in the tank for weeks is E5 better in terms of long term storage in the tank? Is there an MPG advantage in using E5?

[nlee]

I'm fairly sure that it is much more complex than the theory but the government figures claimed a 1% reduction in mpg. I don't believe that works in theory and previously (and being nerdy) did a calculation myself

Bioethanol gives around 33% of the energy of unleaded petrol. E5 has 5% bioethanol content, E10 has 10%.

On that basis, E5 gives the equivalent of 96.65% of the energy of pure unleaded and E10 93.3%. That's a 3.5% reduction in available energy for E10 compared to E5 rather than the 1% claimed. At 45mpg on E5, it works out at 43.4 mpg on E10. Not a huge amount but adds up. Over 10,000 miles it's about an extra 40 litres of fuel, or about £60.

Like I say, theoretical only and there:s probably lots more to take into account, including the question you pose on the effect of it sitting around.

[ernieb]

If those figures are somewhere near correct then the extra cost of the E5 over E10 would be worth a punt over the year. My last fill up of E5 was I think +5p per litre over E10 but in these crazy time I’m not sure what the cost might be the pump prices for E10 advertised as I drive by seem to increase daily.

[philip42h]

1 hour ago, nlee said:

I'm fairly sure that it is much more complex than the theory but the government figures claimed a 1% reduction in mpg. I don't believe that works in theory and previously (and being nerdy) did a calculation myself

Bioethanol gives around 33% of the energy of unleaded petrol. E5 has 5% bioethanol content, E10 has 10%.

On that basis, E5 gives the equivalent of 96.65% of the energy of pure unleaded and E10 93.3%. That's a 3.5% reduction in available energy for E10 compared to E5 rather than the 1% claimed. At 45mpg on E5, it works out at 43.4 mpg on E10. Not a huge amount but adds up. Over 10,000 miles it's about an extra 40 litres of fuel, or about £60.

Like I say, theoretical only and there:s probably lots more to take into account, including the question you pose on the effect of it sitting around.

Sorry Nigel - I need to challenge your nerdy calc. My understanding is that bioethanol has around 30% less energy than pure (100%) unleaded - so 70% of the energy.

Reworking your sum, E5 gives 98.5% of the energy of pure unleaded and E10 97.0% so a 1.5% reduction.

My source is: https://afdc.energy.gov/fuels/ethanol_fuel_basics.html

Do you have a better one? 😉

[Nick72]

Will my car go faster with E5?

I mainly only use fuel for long work trips (I don't pay) and if I'm at the traffic lights waiting for the green light on occasion.