Engine start stop frequency

[Roker]

I'm into my 3rd day with my hybrid Coroller 

Thank you to all those answering my silly questions.

One more question. 

When I am driving along at any speed, the engine is constantly switching on and off and to electric approx every minute depending on load, suggesting the Battery is below charge.

I can only tel by watching the rev meter or EV indicator

Is this normal, it's a lot of engine starts per journey 

[AndrueC]

It depends on the journey. Toyota's HSD system will mix and match choosing whatever combination of ICE and Battery is most appropriate for the driving conditions.

The Battery is limited by capacity and power so frequent ICE on/off is only likely at low speeds.

If the ECU thinks it can meet the demands of the driver using just the Battery then it will switch the ICE off. As long as you always have what you need under your right foot all is good😉

[Red_Corolla]

Perfectly normal. The engine should be predominantly running while you're on the move, but it'll stop every time you lift off (unless it's still warming up). The engine is not just a generator, it's usually also providing some or all of it's output to the roadwheels, and you'll only find yourself running on pure electric when the power demand is very light (low speeds or downhill). There's also rare occasions where it finds itself unable to do any more energy harvesting and then runs up the engine purely as a compressor for decelaration - this can happen on long descents.

[Cyker]

I find once up to speed and cruising at any speed less than about 60mph, my Yaris will frequently shut off the engine as I lift off slightly to stop accelerating, and run on just the electrics. However, if I'm accelerating at anything other than very very lightly, or if there's increased load like from a car full of passengers, an incline or even if it's raining, the ICE will almost always fire up to provide more power.

 

[newda898]

You can minimise engine starts and stops by being gentle on the accelerator. Press it too hard and the engine will start anyway, regardless of the speed you end up doing, before then stopping once you're up to speed. Might need some practice and changing your driving style.

[AndrueC]

That's a good point about managing the ICE. If you switch the dashboard to show the eco gauge you can keep the car in full electric mode by ensuring that the power band stays in the ECO section.

Be aware however that there is a school of thought that says forcing the car into electric mode at every opportunity and for as long as possible can be counter productive. The idea is that it might mean that Battery power is not available to help out the ICE when it would do the most good. By forcing EV mode you risk limiting the ECU's choices. It might have to charge the Battery at a time when it would be better not to.

The point of Toyota's HSD isn't an either-or situation. The Battery is there to help the ECU keep the ICE at it's most efficient. Sometimes that can mean switching the ICE off but often it just means helping the ICE.

[Rosgoe]

I just let it do it’s own thing although I do admit to backing of the accelerator pedal to get it into ev.

I have been in ev at 65 mph on the motorway before now with a reasonable amount of charge in the traction Battery and with the cruise control on although only briefly about a minute.

[Cyker]

1 hour ago, AndrueC said:

That's a good point about managing the ICE. If you switch the dashboard to show the eco gauge you can keep the car in full electric mode by ensuring that the power band stays in the ECO section.

Be aware however that there is a school of thought that says forcing the car into electric mode at every opportunity and for as long as possible can be counter productive. The idea is that it might mean that battery power is not available to help out the ICE when it would do the most good. By forcing EV mode you risk limiting the ECU's choices. It might have to charge the battery at a time when it would be better not to.

The point of Toyota's HSD isn't an either-or situation. The battery is there to help the ECU keep the ICE at it's most efficient. Sometimes that can mean switching the ICE off but often it just means helping the ICE.

That's much less of a problem with the newer ones because they have a near-pathological desire to keep the SoC around 50%  

It's one thing me and my colleague noticed with my Yaris - It cycles between EV and ICE *much* more frequently than his Auris does.

It's partly because the Battery in the Yaris is tiny, but it's also a very smart strategy - It stops the engine cooling down too much, which is the biggest source of inefficiency it has, but also never lets the SoC drop too much. If you go above 50%, it'll use the electrics much more to bring it back down to 50%. If you go below, it'll use the engine more - It's almost self-balancing.

99% of the time, I'm around 3-5 bars of charge - I've rarely seen higher and only seen 2 bars once (Going up a long hill fully loaded to Goodwood!), while his Auris regularly sees much bigger swings. It's also why the EV mode button is almost useless in the Yaris, while in the Auris it can actually stay on for a useful amount of time - The Auris allows a bigger swing, while with the Yaris as soon as it starts to dip it immediately turns it off, saying there isn't enough charge!

So it's more than fine to 'force' EV-mode with 'the lifty trick' in the new ones - It won't let you do it for too long before it drops to 3 bars and wants to put the charge back in with the ICE.

[taxidriver50005]

Normal.. Thing to remember is the electric motor only really assists the ice motor.... It helps out when circumstances allow... I. E  low torque required or Battery has lots of power. 

[Bozz]

21 hours ago, Roker said:

I'm into my 3rd day with my hybrid Coroller 

Thank you to all those answering my silly questions.

One more question. 

When I am driving along at any speed, the engine is constantly switching on and off and to electric approx every minute depending on load, suggesting the battery is below charge.

I can only tel by watching the rev meter or EV indicator

Is this normal, it's a lot of engine starts per journey 

Feature of the product sir!!

[TonyHSD]

Toyota hybrids has always been a petrol cars with the best stop start technology that lets you “drive the car sometimes on electric power ”,  but recently they start calling them Self charging hybrids, then “HEV- hybrid electric vehicles”.  Where actually they should call them HEPV hybrid electric petrol vehicles 🔋⛽️

And the bigger the engine its more of a PV petrol vehicle, where the smaller engines stands for more HE hybrid electric vehicles as some owners has already noticed. 

[AndrueC]

Fixing my own post:

"..you can keep the car in full electric mode by ensuring that the power band stays in the ECO section."

Should be:

"you can keep the car in full electric mode by ensuring that the power band stays in the EV section."

[Cyker]

Does yours actually say EV for that section?? That would have been much better labelling.

Mine only has CHG' ECO and PWR, with ECO being the biggest band and split into two halves (Which I call ECO and ECO+ because that's what they used to be labelled).

If I keep it in the bottom half of the Eco band I can drive EV only, but as soon as I even breath on the 2nd half the ICE will immediately cut in!

[AndrueC]

My Corolla does. This is what the dash looks like when that mode is selected (apart from me preferring digital speedometer and mph).

Keeping the power gauge in the area marked with a yellow square (or the CHG section to the left) will keep the car in electric mode for as long as the Battery has sufficient charge.

In the rare event of the Battery being 'over charged' it's possible to drive with the the power band in ECO but that's uncommon.

My limited experience of a hybrid Yaris (a curtesy car) suggests it's not the same. It felt like it had a very much smaller Battery.

[Cyker]

Ah neat, I hadn't noticed that! (In my defence it's a lot smaller than the gauge on the Yaris, which takes up nearly a third of the dash  )

[Roy124]

39 minutes ago, AndrueC said:

My limited experience of a hybrid Yaris (a curtesy car) suggests it's not the same. It felt like it had a very much smaller battery.

I have the YX after my Corolla, I had a look at Battery sizes and i think the Corolla has several different HV sizes quoted against the Cross just one. IIRC the Cross had a 1.3AHr cf Cross at 0.8

I have been told the next Cross with Gen 4.5 will have a larger capacity Battery.  If 15% that will be 0.92AHr.

[Cyker]

The new Yarisuseieiesiees have the smallest high voltage Battery of any vehicle I know of - 0.7kWh! - so that seems about right about it having a much smaller Battery.

Even the Mk3's Battery was twice the capacity!!

It just makes it all the more impressive that it can get such ridiculous mpg with such a small traction battery!  

 

[AndrueC]

I will say that you don't get much power to play with on Battery. It can get you around a car park but it would take the patience of a saint (or !Removed! if vehicles were behind you) to attempt to accelerate purely on Battery on the open road.

On the open road it can maintain the car at 60mph on the flat but not much faster and not for very long at that speed. You do have to be fairly gentle on the accelerator to avoid going into the ECO band but when driving that Yaris is found it a lot harder to get the car into electric mode and almost impossible to keep there. The Corolla can easily be dropped into EV mode and will happily stay there for quite a while.

[Cyker]

It does depend on the speed, but at 60+ I find the electrics play very little part in propelling the car (Except maybe as an acceleration booster  )

Below that my Mk4 will happily trundle on MG2 alone for a surprising distance a lot of the time. I do have to do the lifty-trick to nudge it into turning the engine off otherwise it'll happily leave the engine running more than it should (Which is also partly why I can get better mpg than the cruise control can)