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PHEV - EV mode versus Auto EV/HV


nlee
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Curious really but does anyone use the Auto EV/HV mode? If so, do you notice much difference with EV mode?

I tend to just use EV mode which is what the car defaults to. The description says that it uses the electric motor but the ICE can kick in if required. Auto EV/HV mode says it will prefer to use the electric motor but the ICE will kick in when additional power is required for acceleration or going uphill. I presume it just brings the ICE in sooner?

Anyone see an advantage to this over EV mode? I never seem to require more power when in EV mode. I often wondered, why the "Auto" mode wasn't the default. If it is considered to be the best balance of power and efficiency you think it would be.

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I pretty much never use EV mode (for obvious reasons) and this comment is largely theoretical but if I had a PHEV I would use Auto EV/HV mode by default and only switch to EV mode when I was within <EV range> of my journey's end and access to a recharge point. This would mean that short journeys / commutes would be in EV mode, while longer journeys would be in Auto EV/HV mode until I was nearly 'home'.

My logic is that you clearly want to use EV power while you have a sufficient charge in the traction Battery - why burn petrol when you can run on electricity. But equally, you would want to avoid burning petrol solely to recharge the Battery - while the system does so as efficiently as it can, the conversion is fundamentally inefficient. So under circumstances where you are going to have to use petrol, you want to use petrol where it is most efficient to do so in order to provide motive power - say, cruising along the motorway - reserving electrical power for low speed and variable speed sections as well as burst of acceleration. And if Toyota have designed Auto EV/HV mode correctly I'd hope that is how it would work.

Just a thought ...

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I've tried it a number of ways and works best for me, is use the EV mode till it's exhausted, well down to the 30% the system receives for itself, then the car will switch to HEV mode to complete the trip.  If my trip is just likely to be over the EV range I still use it in EV mode and then if I'm a few miles from home and think the car would automatically switch to HEV mode before I get home I switch to HEV mode to run and warm the ICE then flick it back into EV mode ICE will cut out when it's fully operational and if needed run until I get home.

The 30% reserve will for 95%+ of the time always give you the spec'd acceleration and performance.  I get EV range and fuel consumption I'm very happy with so will continue to drive in a similar way, I'm sure there will be differences based of just who is behind the wheel. Mainly I just enjoy the drive and get as much benefit of the EV mode as I can.

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Having read many comments on the Forum, I, like Ernie, endeavour to make sure that the engine does not fire up just as I near home. I don't want an engine firing up 200 yards before shutting down as we reach home. 

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I think Ernie explains things well.

One additional thought is that in EV mode if you floor it you only get up to 220hp and which goes a little flat after 50mph, I assume to avoid draining the Battery so perhaps artificially constrained to a lot less than the c. 220hp as speed increases above 50mph. This is how it feels to me.

Where as the auto mode might be useful for people who want the full power on tap without button pressing twisting faff. That is to say, put your foot to the floor and the ICE will kick in, otherwise it will pootle in EV mode. This could be a safety advantage but to be honest there's a good amount of pulling out and overtaking power in all modes and eco to sport settings.

 

However, on my last Peugeot PHEV, setting the car to EV mode meant you had really set it to the equivalent of Auto EV/HV mode on the RAV. So if you push too hard on the accelerator pedal the ICE would kick in. There was no pure EV mode independent of throttle setting. Peugeot argued this was for safety reasons which was weird because in EV mode it was a quicker car than the RAV because of a 50 50 electric motor power split totalling 220+ hp so power went down better to the road. Fricking nuisance though because the car would frequently slip into ICE if you over did it on the gas pedal.

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Had a try with the Auto EV/HV mode yesterday. Only a short journey to the shops and back (about 8 miles) so not a thorough test. Result was the ICE wasn't used. Even up a hill. It was a 30 zone so wasn't a tough test but accelerated reasonably hard to get to 30 but obviously wasn't enough to trigger ICE. 

What I did discover, and I thought I'd tried this before, is the car will remain in Auto EV/HV after switching off and restarting. Previously I thought it defaulted back to EV mode.

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4 hours ago, nlee said:

Had a try with the Auto EV/HV mode yesterday. Only a short journey to the shops and back (about 8 miles) so not a thorough test. Result was the ICE wasn't used. Even up a hill. It was a 30 zone so wasn't a tough test but accelerated reasonably hard to get to 30 but obviously wasn't enough to trigger ICE. 

What I did discover, and I thought I'd tried this before, is the car will remain in Auto EV/HV after switching off and restarting. Previously I thought it defaulted back to EV mode.

Oh I didn't know it sticks with auto EV. That's good to know.

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3 hours ago, Nick72 said:

Oh I didn't know it sticks with auto EV. That's good to know.

I must admit I have been puzzled by this thread - it seems pretty clear which mode it is in to me (ie AutoEV) and that is also the default. I am sure this has been covered in other threads? 

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2 hours ago, Flatcoat said:

I must admit I have been puzzled by this thread - it seems pretty clear which mode it is in to me (ie AutoEV) and that is also the default. I am sure this has been covered in other threads? 

So mine defaults to EV mode on start up even if you switched off being in HV mode. I hadn't realised that if I put it into Auto EV HV mode that it starts in that mode (albeit will start in EV).

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9 hours ago, Flatcoat said:

I must admit I have been puzzled by this thread - it seems pretty clear which mode it is in to me (ie AutoEV) and that is also the default. I am sure this has been covered in other threads? 

Strictly speaking there isn't an "Auto EV" mode. It's either EV, HV or Auto EV/HV?

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17 minutes ago, nlee said:

Strictly speaking there isn't an "Auto EV" mode. It's either EV, HV or Auto EV/HV?

Ok Auto EV/HV mode, i mis wrote. 

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Doesn't seem like OP's original question was answered sufficiently, IMHO.  Let me be more specific.  When exactly does the ICE trigger in EV mode vs. Auto EV/HV mode vs. pure HV mode?  Our Rav4 PHEV's in the US are called Rav4 Prime's, and mine never starts back up in Auto EV/HV or pure HV mode, even if I turn the car off in those modes -- it always defaults to EV.

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1 hour ago, NTheZone said:

Doesn't seem like OP's original question was answered sufficiently, IMHO.  Let me be more specific.  When exactly does the ICE trigger in EV mode vs. Auto EV/HV mode vs. pure HV mode?  Our Rav4 PHEV's in the US are called Rav4 Prime's, and mine never starts back up in Auto EV/HV or pure HV mode, even if I turn the car off in those modes -- it always defaults to EV.

In EV mode...

ICE triggers if...

Front defroster operated

Going down hill (steep) if additional engine braking is required

ICE hasn't run for a while

..........

In HV mode the ICE is running most of the time as at this point it is just a regular hybrid. So occassionally you get some EV.

..........

In Auto EV HV mode...

ICE starts as per EV conditions above plus, if you put your foot hard to the floor on the gas, and, I assume but not tried, if driving above a certain speed where ICE may be more energy efficient. Using the car in Auto mode is really for 2 reasons. 1. You can't be ubikd swapping modes and just want to trust Toyota. 2. You want the full power when you need it... gas pedal. 

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I always run mine in EV mode and when that runs out it switches to Auto EV/HV mode simple with the exceptions that's ben listed above.  I see the ICE start frequently in EV mode if the traction Battery is fully charged and I depend a steep hill as the regenerative braking runs out and it goes into the harder traditional braking the ICE will always cut in.

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Some further observations following a longer journey in Auto EV/HV mode last weekend.

Outward journey was in Auto EV/HV mode mainly along North Wales Expressway. 70mph ish, some hills with power down, the ICE never kicked in. Return journey, started already in Auto EV/HV mode. ICE didn't kick in until electric range expired and car switched to HV mode as expected.

However, next time I started the car after a charge, it started in EV mode. So, the car will stay in Auto EV/HV mode for multiple trips provided there is electric range remaining, but if it changes to HV mode, the next time it starts after a top up, it will default back to EV. That suggests to me the real default is EV mode and my conclusion is the Auto EV/HV mode is a bit pointless for my purposes.

Another observation was I only managed a disappointing 37 miles on EV from a full charge and starting with 48 miles indicated range. I'd guess that was due to driving at 70mph, rather than anything to do with mode. It was around 9C, light wind, in Eco mode, and Eco score of 92. Seems like no matter how steady you drive, 70mph will hammer the range, yet the ICE doesn't kick in to "optimise" in Auto mode.

No more playing now. Back to standard EV mode and letting it do its thing!

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Nigel, same as me EV mode and let the car sort it out for itself.

The range is very much dependent on speed and I’d think that when driving at 70mph the wind resistance makes a massive impact on EV range.  I’ve done some runs at 50mph and 60mph (gps real speed) and that makes an impact but if I run up to 70mph the impact is significant.

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51 minutes ago, nlee said:

Seems like no matter how steady you drive, 70mph will hammer the range, yet the ICE doesn't kick in to "optimise" in Auto mode.

Definitely not very "smart", which is what the Auto mode would suggest, and it is well reported and even documented in the user manual that HV mode is the right setting above ~45mph.

If I punch the pedal, the ICE will always start up even in EV mode.  That's the only way to get the full 306hp.

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53 minutes ago, nlee said:

Some further observations following a longer journey in Auto EV/HV mode last weekend.

Outward journey was in Auto EV/HV mode mainly along North Wales Expressway. 70mph ish, some hills with power down, the ICE never kicked in. Return journey, started already in Auto EV/HV mode. ICE didn't kick in until electric range expired and car switched to HV mode as expected.

However, next time I started the car after a charge, it started in EV mode. So, the car will stay in Auto EV/HV mode for multiple trips provided there is electric range remaining, but if it changes to HV mode, the next time it starts after a top up, it will default back to EV. That suggests to me the real default is EV mode and my conclusion is the Auto EV/HV mode is a bit pointless for my purposes.

Another observation was I only managed a disappointing 37 miles on EV from a full charge and starting with 48 miles indicated range. I'd guess that was due to driving at 70mph, rather than anything to do with mode. It was around 9C, light wind, in Eco mode, and Eco score of 92. Seems like no matter how steady you drive, 70mph will hammer the range, yet the ICE doesn't kick in to "optimise" in Auto mode.

No more playing now. Back to standard EV mode and letting it do its thing!

Good analysis. It does call into question the point of Auto mode. But, if you want to pootle in EV and have power available through gas pedal alone for the emergency overtake or whatever then perhaps that's really why it is there?

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4 minutes ago, NTheZone said:

Definitely not very "smart", which is what the Auto mode would suggest.

If I punch the pedal, the ICE will always start up even in EV mode.  That's the only way to get the full 306hp.

Now I've not found that. Must experiment. Foot flat to the floor on the gas pedal in EV mode does not start the ICE for me.

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32 minutes ago, ernieb said:

Nigel, same as me EV mode and let the car sort it out for itself.

The range is very much dependent on speed and I’d think that when driving at 70mph the wind resistance makes a massive impact on EV range.  I’ve done some runs at 50mph and 60mph (gps real speed) and that makes an impact but if I run up to 70mph the impact is significant.

Speed definitely kills EV range. Drag proportional to speed squared. Especially a boxy car.

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55 minutes ago, NTheZone said:

Definitely not very "smart", which is what the Auto mode would suggest, and it is well reported and even documented in the user manual that HV mode is the right setting above ~45mph.

If I punch the pedal, the ICE will always start up even in EV mode.  That's the only way to get the full 306hp.

To be honest, when I'm not experimenting, that's what I normally do on longer journeys. I only have a couple of miles before I'm on the expressway/motorway network to go further afield so as soon as I get on, I switch to HV and save EV mode until I get on smaller/slower roads towards the destination. It's a bit of manual intervention but so long as I've used all the electric juice by the end of trip I guess I feel I've made the most of the economy.

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2 hours ago, Nick72 said:

Speed definitely kills EV range. Drag proportional to speed squared. Especially a boxy car.

And weight even more so, you cannot beat Colin Chapman’s approach to car design. 

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1 hour ago, Flatcoat said:

And weight even more so, you cannot beat Colin Chapman’s approach to car design. 

The trouble with Chapman’s design is although they were very fast they collapsed if there was an impact to the detriment of the driver.

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  • 1 month later...
On 3/4/2022 at 10:24 AM, nlee said:

To be honest, when I'm not experimenting, that's what I normally do on longer journeys. I only have a couple of miles before I'm on the expressway/motorway network to go further afield so as soon as I get on, I switch to HV and save EV mode until I get on smaller/slower roads towards the destination. It's a bit of manual intervention but so long as I've used all the electric juice by the end of trip I guess I feel I've made the most of the economy.

Wasn't sure whether to start new post or revive this one, but was wondering if anyone has done some a few runs of the same (long, eg 100-200mile) journey to test this theory? 

 

I've got a ~250mile journey coming up soon for family holiday, mostly motorway & A-roads, and curious as to whether the advice in the manual (force car into HEV) bears out in real world mpg/range etc? I have noted when doing a journey to my parents', which is ~45miles of mostly 60-70mph, that changing to HEV when getting low-ish on Battery (to save for smaller roads at end of journey), the traction Battery is still gradually depleted in HEV mode, albeit very slowly. 

 

So my question is - does this mean that in a phev on longer motorway journeys, switching to HEV as soon as up to speed (as per manual) gives you a more efficient HEV drivetrain (than you would get at then nominal 30% phev/hev cutoff), ie will coast for longer with engine off where appropriate, will support acceleration more with ev motor than relying on ICE etc etc etc to give a better overall mpg/petrol+ev range? Does anyone have any rough numbers to share? 

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For context btw, I have a pair of mini-bladder midgets in the back, so there is zero prospect of doing the whole journey in one go, and there potentially is scope to plan a stop or two around a tesco with free pod point chargers, so I may go with one strategy on way out (ie deplete ev and recharge when available), and an alternative on way back, which is obv not scientific as not the same elevation etc, let alone traffic conditions different etc, but very curious to see whether there is a notable difference from following Toyotas's advice

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