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Question for hybrids acceleration/power/torque in general


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On paper we have specs of ICE power and torque, electric motor power and torque, and then combined max available to driver (which is never the sum of both sources, but less).
But then we know, that the max specs of electric motor are not really available because of limitations of the Battery.

So my question is:
When for example Toyota says acceleration time 0-60 is 8 sec., is this only possible with full Battery? Will this fluctuate a lot depending how many bars we see in the Battery on the dashboard? Please ignore the fact, that in real life stated acceleration times are not easily achievable and consistent, just focus on the question is EV power/torque consistent or dependent on the charge level.
Look at it this way - for regular ICE car, power/torque/acceleration is not dependent on how much fuel you have in the tank. But on theory for EV, this is not the case.
How is the behavior of the Toyota hybrids? For example if we make kickdown acceleration test with full Battery or above half bars and another acceleration test with 3-4 bars in Battery, will there be difference? I other words, if Toyota says you have 180hp and 250Nm, is this only achievable with full ( or more than half) Battery?

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2 hours ago, OXYGEN said:

On paper we have specs of ICE power and torque, electric motor power and torque, and then combined max available to driver (which is never the sum of both sources, but less).
But then we know, that the max specs of electric motor are not really available because of limitations of the battery.

So my question is:
When for example Toyota says acceleration time 0-60 is 8 sec., is this only possible with full battery? Will this fluctuate a lot depending how many bars we see in the battery on the dashboard? Please ignore the fact, that in real life stated acceleration times are not easily achievable and consistent, just focus on the question is EV power/torque consistent or dependent on the charge level.
Look at it this way - for regular ICE car, power/torque/acceleration is not dependent on how much fuel you have in the tank. But on theory for EV, this is not the case.
How is the behavior of the Toyota hybrids? For example if we make kickdown acceleration test with full battery or above half bars and another acceleration test with 3-4 bars in battery, will there be difference? I other words, if Toyota says you have 180hp and 250Nm, is this only achievable with full ( or more than half) battery?

0-62 or 0-100 km/h in 8 seconds is not possible with 152 horsepower only from a petrol engine. That's the 2.0 liters version.

Same thing for the 1.8 liters. It's not possible to accelerate 1500 kg. heavy car from  0-62 or 0-100 km/h in 11 seconds with only 99 horsepower.

The Ford Kuga PHEV however, has been tested with Battery + ICE, Battery only, and ICE only. There was no difference in acceleration if the car was running as plugin hybrid or "only" petrol powered car. 

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I haven’t tested that exactly with numbers to show however my experience makes me believe acceleration in Toyota hybrids depends on Battery state of charge since it’s a hybrid and when Battery is at lower levels the car uses its power from ice to propel the car and charge the Battery same time, which means extra load to the engine and lost of acceleration, similar to underpowered car with AC working. This can be felt on many occasions when hybrid Battery is drained and you are accelerating to join motorway for example or faster roads where more torque is needed. This is also the reason why auto journalists do not like our cars. On the other side when you have a good Battery charge and ice is at work temp you push it harder and the car pulls away nicely because has combined power available and no extra drag from the e motor. 

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Well, there's a huge difference in acceleration power under normal driving conditions, if the car's using the Battery or not.

If my Battery is down to 3 bars, the car will charge it, even if I accelerate. The ICE alone feels under powered compared to the feeling of "plenty" power when electric motor and IE are working together.

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Both the 1.8 and 2.0 have more than enough power for a sensible driver in normal conditions.

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It is an interesting question. My assumption has always been that you always have full power available when you want it. Same as a mobile phone, it discharges , but you still have full facilities from 100% charge to 15%. Then, depending on the model, and settings, it may go into power saving mode by shutting the screen off faster etc, but until 2% it works.

If you look at the Car Wow site, the reporter there tests several EV cars until total Battery exhaustion. Apart from alerts from the system urging him to go to a charge point, and at 5% the car started to shut off non essential systems like lane guidance to save power, he reported no loss of performance at all from the car, until well past "0%" charge when the car finally died.

My assumption is that the power from the Battery is managed for our hybrids in a similar way. The difference being that the ICE prevents the Battery from dropping below a certain level. If we run out of petrol, the car will still not allow us to totally drain the Battery.

Re "Full charge" I don't really know how we can get full charge under normal road conditions. I notice if you sit for a while in the driveway with the ICE running, you can sometimes get the Battery to within 1 bar of the top.  I have also managed it when I was in Devon and I descended a very long hill , and the car was on max bars for several minutes, ICE shut down. Mostly, I get to 2 bars from the top and the system will drain the Battery again via EV mode or EV assisting the ICE, no charging. So a full charge for our cars is not really possible except in certain circumstances. Again, leads me to believe we don't suffer from lack of power, unless the system has not reached operating temperature. I have never noticed fluctuating power levels myself.

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Hi Tim,

they do suffer and they are actually very different from full ev cars which also loose a bit of performance plus mobile phones too as it was the big scandal with Apple iPhones in recent years for throttling older devices. Back to the hybrids now. I believe you haven’t noticed big difference between empty and full Battery because you have 2.0 petrol engine much more powerful than 1.8 . The hybrid Battery when gets empty it’s about 40% and it’s got that much power just to keep e motors spinning at required speeds to much ratio with ice to keep car moving and to create a magnetic force to regenerate electricity. Toyota hybrids can not operate without charge in the 200v Battery, they will stop. I have been pleasantly surprised sometimes how quick my car can pulls away from traffic lights or roundabout just after I got off the motorway with long steep downhill like J3 on M40 towards Loudwater . I live in a bottom of a long downhill and my hybrid Battery is always full when arrive at home even sometimes I get ice spinning to discharge it., I mean properly full (where + and - symbols on top of Battery are full) never gets that full if you stay in ready mode only. Here I have picture of Battery not full but almost there and measure it was 67% 😊👍

CF98D695-4518-4ECD-B383-E5F3A53A08BA.jpeg

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31 minutes ago, TonyHSD said:

Hi Tim,

they do suffer and they are actually very different from full ev cars which also loose a bit of performance plus mobile phones too as it was the big scandal with Apple iPhones in recent years for throttling older devices. Back to the hybrids now. I believe you haven’t noticed big difference between empty and full battery because you have 2.0 petrol engine much more powerful than 1.8 . The hybrid battery when gets empty it’s about 40% and it’s got that much power just to keep e motors spinning at required speeds to much ratio with ice to keep car moving and to create a magnetic force to regenerate electricity. Toyota hybrids can not operate without charge in the 200v battery, they will stop. I have been pleasantly surprised sometimes how quick my car can pulls away from traffic lights or roundabout just after I got off the motorway with long steep downhill like J3 on M40 towards Loudwater . I live in a bottom of a long downhill and my hybrid battery is always full when arrive at home even sometimes I get ice spinning to discharge it., I mean properly full (where + and - symbols on top of battery are full) never gets that full if you stay in ready mode only. Here I have picture of battery not full but almost there and measure it was 67% 😊👍

CF98D695-4518-4ECD-B383-E5F3A53A08BA.jpeg

Thanks Tony, that's interesting. As you say, maybe the 2 ltr is less prone to power drop, and I have to say I don't thrash it, rarely using sport mode, possibly only once a month for a few seconds if I need to get past a tractor or something. Maybe that is why I notice no power drops. So back to the original question, maybe the 7.9 second 0 to 60 is achieved with the Battery full, Sport mode engaged, and the ICE not in charge mode. And probably with no lights, air con etc on.

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7 minutes ago, Timmon said:

Thanks Tony, that's interesting. As you say, maybe the 2 ltr is less prone to power drop, and I have to say I don't thrash it, rarely using sport mode, possibly only once a month for a few seconds if I need to get past a tractor or something. Maybe that is why I notice no power drops. So back to the original question, maybe the 7.9 second 0 to 60 is achieved with the battery full, Sport mode engaged, and the ICE not in charge mode. And probably with no lights, air con etc on.

I don’t really know tbh how they test them for acceleration but very likely as you said in ideal conditions similar to efficiency test 👍

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The 2.0 ICE engine only produces around 145bhp (due to its Atkinson cycle setup), so the extra 40bhp of the combined output is provided by MG2. I’ve noticed mine isn’t as quick when hybrid Battery is down to 2 bars, compared to 4/5bars. 
 

The ‘feel’ of acceleration isn’t very noticeable on these hybrids (except pulling away from standstill), however they don’t hang about. You need to overtake someone to appreciate the rate of acceleration. After having 400nm for the last 5 years / 30k miles, having only 200nm is a very noticeable difference. 

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1 hour ago, TonyHSD said:

Hi Tim,

they do suffer and they are actually very different from full ev cars which also loose a bit of performance plus mobile phones too as it was the big scandal with Apple iPhones in recent years for throttling older devices. Back to the hybrids now. I believe you haven’t noticed big difference between empty and full battery because you have 2.0 petrol engine much more powerful than 1.8 . The hybrid battery when gets empty it’s about 40% and it’s got that much power just to keep e motors spinning at required speeds to much ratio with ice to keep car moving and to create a magnetic force to regenerate electricity. Toyota hybrids can not operate without charge in the 200v battery, they will stop. I have been pleasantly surprised sometimes how quick my car can pulls away from traffic lights or roundabout just after I got off the motorway with long steep downhill like J3 on M40 towards Loudwater . I live in a bottom of a long downhill and my hybrid battery is always full when arrive at home even sometimes I get ice spinning to discharge it., I mean properly full (where + and - symbols on top of battery are full) never gets that full if you stay in ready mode only. Here I have picture of battery not full but almost there and measure it was 67% 😊👍

CF98D695-4518-4ECD-B383-E5F3A53A08BA.jpeg

Tony after my brief spell in an Auris before my Corolla, I noticed the Battery management is so different on the Corolla. The Auris seemed happier to charge its Battery towards full, and then do a solid EV run (nearing 2 miles!) and run it right down to almost empty. The Corolla is much more reluctant to get near to the extremes of the Battery - you are lucky to get more than 2/3 of a mile on EV. The Auris charges the Battery more at speed too as the electric motor doesn’t contribute much and EV mode isn’t available over 47mph on the Auris. The Corolla will drop into EV at much higher speed, and allow the motor to contribute more too. 

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I thought I was imagining it at first but my 1.8 definately feels quicker off the mark with a full batt

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21 minutes ago, Timh21 said:

I thought I was imagining it at first but my 1.8 definately feels quicker off the mark with a full batt

On the occasions when I've got the charge higher than normal (ie;within one bar of full or all bars filled) the car definitely feels peppier. I think it's the ECU trying to discharge the Battery. My guess is that with more power being supplied by the batteries there is simply more torque available. Perhaps in this situation the car can't balance the two power sources like it normally would.

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16 hours ago, Gray86 said:

Tony after my brief spell in an Auris before my Corolla, I noticed the battery management is so different on the Corolla. The Auris seemed happier to charge its battery towards full, and then do a solid EV run (nearing 2 miles!) and run it right down to almost empty. The Corolla is much more reluctant to get near to the extremes of the battery - you are lucky to get more than 2/3 of a mile on EV. The Auris charges the battery more at speed too as the electric motor doesn’t contribute much and EV mode isn’t available over 47mph on the Auris. The Corolla will drop into EV at much higher speed, and allow the motor to contribute more too. 

Yes, these are my observations too, but I don't have any experience of the Auris. There is no doubt in my mind from what Prius and 1.8 Corolla owners have said, that the 2 ltr is set up differently to the 1.8, as it is aimed at different customers ( Performance higher priority, rather than economy in the 1.8). This is why comparison between the 2 power trains is difficult, and I prefer to compare with non hybrid 2 ltr ICE.  I wonder if the different type of Battery in the 2 ltr is also a factor? The 2 power trains are not really comparable.

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54 minutes ago, Timmon said:

Yes, these are my observations too, but I don't have any experience of the Auris. There is no doubt in my mind from what Prius and 1.8 Corolla owners have said, that the 2 ltr is set up differently to the 1.8, as it is aimed at different customers ( Performance higher priority, rather than economy in the 1.8). This is why comparison between the 2 power trains is difficult, and I prefer to compare with non hybrid 2 ltr ICE.  I wonder if the different type of battery in the 2 ltr is also a factor? The 2 power trains are not really comparable.

The 2.0 hybrid uses Ni Mh Battery similar to Auris and the 1.8 uses li Ion, I believe it’s down to software set up. Usually in Auris the screen when shows almost full its actual around 70-80% if measured. I had before Prius with NiMh and Prius + with Li ion Battery but don’t remember any difference in behaviour of car or battery, except the standard Prius was happier to stay in ev mode for longer perhaps because was lighter car. 

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Ok, thank you for the great discussion.
So indeed, there is a difference in power and acceleration depending on how full the Battery is.
And unfortunately, this means that Toyota hybrids are not like normal cars in terms of consistency of power available to user. I will make again the comparison with normal ICE car - if normal car has for example 100hp, it will always produce it no matter how much fuel you have in the tank. And user can use that power every time he needs it.
While we as hybrid owners, on paper should have the stated power (180hp in my case with 2.0), but it is rarely achievable and depends on Battery level.
So imagine situation with overtaking trucks on a busy road and starting with good Battery charge - first overtaking - lots of power and quickly doing it. Second truck - similar, third truck - starts accelerating slower, fourth - significantly slower, etc. And driver have to take this into consideration and wait for longer gap in oncoming traffic in the opposite lane. On theory this could be even dangerous in some specific occasions...
And again - this can never happen with normal ICE car.

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4 hours ago, OXYGEN said:

Ok, thank you for the great discussion.
So indeed, there is a difference in power and acceleration depending on how full the battery is.
And unfortunately, this means that Toyota hybrids are not like normal cars in terms of consistency of power available to user. I will make again the comparison with normal ICE car - if normal car has for example 100hp, it will always produce it no matter how much fuel you have in the tank. And user can use that power every time he needs it.
While we as hybrid owners, on paper should have the stated power (180hp in my case with 2.0), but it is rarely achievable and depends on battery level.
So imagine situation with overtaking trucks on a busy road and starting with good battery charge - first overtaking - lots of power and quickly doing it. Second truck - similar, third truck - starts accelerating slower, fourth - significantly slower, etc. And driver have to take this into consideration and wait for longer gap in oncoming traffic in the opposite lane. On theory this could be even dangerous in some specific occasions...
And again - this can never happen with normal ICE car.

Hi,

theoretically yes there is a difference, but in real world it’s not that bad to cause dangerous situation and once you floor it the car will pull to its best ability, but you need to press harder to the floor and ice needs to be at operating temperature. Especially you have 2.0 should not be a problem at all. I have older 1.8 gen 3 hybrid with 136bhp and never complain about power, a lots of motorway driving. Electric cars, bikes, scooters also suffer a bit but not that much, because they have only Battery as power source and we have petrol engine too, which actually is the main source of power, it’s not like 50/50 but 60/40 ice/electric average for example only figures. You can do some experiments though, take the car to a quiet road do some hard acceleration with full Battery and then with drained Battery and you will see the difference, I reckon 1 second difference. 👍

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8 hours ago, OXYGEN said:

Ok, thank you for the great discussion.
So imagine situation with overtaking trucks on a busy road and starting with good battery charge - first overtaking - lots of power and quickly doing it. Second truck - similar, third truck - starts accelerating slower, fourth - significantly slower, etc. And driver have to take this into consideration and wait for longer gap in oncoming traffic in the opposite lane. On theory this could be even dangerous in some specific occasions...
And again - this can never happen with normal ICE car.

For a start I'd question the need to overtake anyway. On most journeys it won't make much difference to your arrival time. You're unlikely to cut more than 10% off and what's 10% difference for a half hour journey? You could easily lose that much time at either end by unlucky set of traffic lights or congested roundabout.

I do overtake on occasion but I usually plan it such that I don't need to engage the Battery and that's with my 1.8. My generally laid back demeanour helps with that of course. Hybrids can recharge the Battery as they go along and I'd question the wisdom of performing so many overtakes and demanding so much power that you end up exhausting the Battery. As far as I'm concerned that's 'boy racer' territory and anything that helps deter that kind of behaviour is to be applauded.

I view getting additional power from the Battery as a waste of a valuable resource. It's nice to know it's there but as far as acceleration is concerned for me it's something to be kept in reserve. I prefer to keep the Battery available to take over from the ICE when the ICE would otherwise not be operating efficiently which is at low RPMs.

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I think it is a case of what different users need from their cars. Some want to see how much economy they can eak from their systems and perfect their Hybrid driving styles. Others have Hybrids for the lower business tax, but need to get to a customer or meeting, so overtaking is a must. On a short journey, the saving in time by over taking may be minimal, but on longer journeys and on some long A and B  roads, trundling at 40 mph or less behind a lorry on a 60 mph limit can make quite a difference. When I had my under powered 1.6 Cavalier, it was very difficult to over take some days, not others. Setting off to Cambridge at the same time, my arrival varied by 15 minutes many times, depending on what tractors or Tesco Lorries I managed to over take or not! Safely of course.

At the end of the day, however you need to drive your Hybrid, you will make a saving against a normal petrol ICE, and that is largely what owners buy them for, rather than a standard ICE. 

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That's a fair point, Timmon and yes we all have our own driving styles. But overtaking multiple vehicles by running round each one in turn (presumably heavy acceleration followed by heavy braking) in rapid succession is not sensible driving. It's dangerous and it disturbs me that someone would propose it as a possible scenario.

If you're trying to explain why a stock Corolla won't ever win the Touring Car Championship then fine but it should not be considered a reasonable criticism on the public road.

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Totally agree Andrue. Safe overtaking is a must. We have all seen the road hogs out there.  Safe overtaking with consideration to other road users is acceptable, taking risks that may endanger other road users is not.

 

 

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On 2/15/2021 at 11:23 PM, AndrueC said:

...But overtaking multiple vehicles by running round each one in turn (presumably heavy acceleration followed by heavy braking) in rapid succession is not sensible driving. It's dangerous and it disturbs me that someone would propose it as a possible scenario...

Don't take it literally.
It was just an extreme example (an edge case) to better and stronger describe what my point was.
Of course I am not at the age or the mindset to drive like this.  
Ok, let's try to use more realistic scenario:
Long uphill where Battery is used a lot to help the ICE and on the top there are only 3 bars left. And there you approach a tractor/slow lorry/something too slow for the speed limit.
Now imagine the same, but instead of uphill, it was long descend,  Battery is fully/almost fully topped and at the bottom you approach the slow vehicle.
Acceleration during the takeover in the first case should be slower than in the second...

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Yeah, on a long hill I can see how you could run out of Battery power. I guess the moral of the story is don't use your Battery to help with overtaking then you won't notice 😄

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Slightly sideways comment,  I have a long steady hill where the throttle can be kept steady and if starting with a fairly full Battery, some ev assists the engine which holds a steady medium revs. When the Battery runs low, there's no difference in speed or any throttle input but the ice revs considerably higher suddenly.  Now the ice is supplying most power to move plus recharge the Battery. Really,  if you're trying to accelerate hard while Battery is low, the engine revs much harder to make up the power. I'm always careful about overtaking, not because of a lack of power but because of the delay while the power kicks in. It's a slipping clutch type of feel but it's never a problem as long as you plan the overtake sensibly 

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