regen braking

[YarisHybrid2016]

Yes...some. Much is lost though.

Numbers are for illustrative purposes only:

Manual braking, 1 or 2 bars: 100% into the Battery.

Off-throttle only, D mode: 100%.

Off-throttle only, B mode: 50%.

Manual braking, B mode: 30%.

Hard/emergency braking, any mode: <30%.

Activation of ABS: 0% (regen cancelled).

Any engine braking is lost energy. Any application of the physical brakes is lost energy.

The above neglects the electron absorption rate of the battery's dielectric, which drops exponentially with current (max regen isn't as efficient at energy capture as moderate regen).

[anchorman]

4 hours ago, YarisHybrid2016 said:

Yes...some. Much is lost though.

Numbers are for illustrative purposes only:

Manual braking, 1 or 2 bars: 100% into the battery.

Off-throttle only, D mode: 100%.

Off-throttle only, B mode: 50%.

Manual braking, B mode: 30%.

Hard/emergency braking, any mode: <30%.

Activation of ABS: 0% (regen cancelled).

Any engine braking is lost energy. Any application of the physical brakes is lost energy.

The above neglects the electron absorption rate of the battery's dielectric, which drops exponentially with current (max regen isn't as efficient at energy capture as moderate regen).

Where have you got these figures from?  Hypothetical?  Lost how?  I think Colin is right, you can see it on the charge meter.  

[anchorman]

15 hours ago, Lawnmowerman said:

Hi Don - interesting. I know my RAV4 PHEV was Atkinson cycle but understood my YC was not.

Where did you get your information?

Cheers

All of the Dynamic Force engines are Atkinson or Miller (virtually the same but certainly not Otto) William.   If you scroll down to M15 here you’ll see it’s a 3 cylinder version of the M20;

https://toyota-club.net/files/faq/03-08-16_engine_eng.htm

….and here is a full description.  The writer isn’t keen on the concept of a 3 cylinder version but that’s a personal opinion.   All of this info comes off Toyota Techdoc which you can access for €4 an hour and a wonderful resource.  
 

https://toyota-club.net/files/faq/20-08-01_faq_df_r3_en.htm

https://toyota-club.net/files/faq/16-01-01_faq_miller_eng.htm

[anchorman]

…..and another thing, notice in those articles that problems with EGR valves were apportioned to poor fuel so this applies in this country to supermarket fuel which is devoid of additives.  Use branded or better still high grade fuel to avoid such problems.  

[Big_D]

I avoid supermarket fuel. While it may be slightly cheaper in the beginning, it can cause problems later on, which negate any original savings. 

[CPN]

10 hours ago, YarisHybrid2016 said:

Yes...some. Much is lost though.

Numbers are for illustrative purposes only:

Manual braking, 1 or 2 bars: 100% into the battery.

Off-throttle only, D mode: 100%.

Off-throttle only, B mode: 50%.

Manual braking, B mode: 30%.

Hard/emergency braking, any mode: <30%.

Activation of ABS: 0% (regen cancelled).

Any engine braking is lost energy. Any application of the physical brakes is lost energy.

The above neglects the electron absorption rate of the battery's dielectric, which drops exponentially with current (max regen isn't as efficient at energy capture as moderate regen).

Sorry, but I wouldn't describe it as "some". It is easily demonstrable in Hybrid Assistant's display which is sourced directly from the associated ECU's PID (process ID) and shows the power flow, in or out (in kW), of MG1.

As an example, when I come off the A1(M) and am going downhill down the slip road turnoff, if I switch to B mode at 50 mph, MG1's power (input) immediately jumps to between -10 & -15 kW (depending on the steepness of the incline - negative means it is acting as a generator) back into the HV Battery and its SoC rises accordingly. Add late braking into that mix and once I managed to get it to a reading of -25kW which, I believe, is the maximum it can manage... I once managed to get the SoC up to nudging 80% (78% actual) which is when the system starts to bleed off the charge...

I'll try and get some screen grabs the next time I am on a long run and you'll see what I mean.

[CPN]

3 hours ago, Big_D said:

I avoid supermarket fuel. While it may be slightly cheaper in the beginning, it can cause problems later on, which negate any original savings. 

Me also. I have never used anything other than Shell V-Power in my Mk4 and it is as smooth today as it was when I first got it 3 years ago.

I just don't experience all these "jerking", "clunking" or other funny noises when switching between ICE and EV that others have reported on here. I'm pretty certain (as I can be) that this is directly down to the constant use of quality fuel.

[Big_D]

While supermarket fuel may be cheaper, I would rather pay a few extra pennies for a better quality fuel

[CPN]

Absolutely Bob! 🙂

[Max_Headroom]

43 minutes ago, CPN said:

Me also. I have never used anything other than Shell V-Power in my Mk4 and it is as smooth today as it was when I first got it 3 years ago.

I just don't experience all these "jerking", "clunking" or other funny noises when switching between ICE and EV that others have reported on here. I'm pretty certain (as I can be) that this is directly down to the constant use of quality fuel.

 

 

Have you used Tesco Momentum 99? (E5)

I ask as there doesn't seem to be many threads/posts on the subject of modern Toyota cars running badly on premium unleaded  in fact i am sure i have read about members being happy using Tesco momentum 99 for smoother running than E10 and a big saving over V-Power.

 

Tesco Momentum 99 -

(Published: 22 November 2022 - Updated: 16 May 2023)

Our Momentum 99 petrol contains a special blend of additives to help keep a car's fuel system clean and working at its best.

Additionally, the higher octane level (99 compared to 95 for regular unleaded petrol) gives improved overall engine performance for cars that are able to take advantage of this (generally, sportier models).

Most Tesco Petrol Filling Stations across England, Scotland and Wales stock Momentum 99. We don’t currently have a supply terminal that is able to produce our high octane base fuel to blend with our exclusive additives in Northern Ireland.

[CPN]

6 hours ago, anchorman said:

All of the Dynamic Force engines are Atkinson or Miller (virtually the same but certainly not Otto) William.   If you scroll down to M15 here you’ll see it’s a 3 cylinder version of the M20;

https://toyota-club.net/files/faq/03-08-16_engine_eng.htm

….and here is a full description.  The writer isn’t keen on the concept of a 3 cylinder version but that’s a personal opinion.   All of this info comes off Toyota Techdoc which you can access for €4 an hour and a wonderful resource.  
 

https://toyota-club.net/files/faq/20-08-01_faq_df_r3_en.htm

https://toyota-club.net/files/faq/16-01-01_faq_miller_eng.htm

Wow! Excellent resources there Don! 🙂

[CPN]

9 minutes ago, Max_Headroom said:

Have you used Tesco Momentum 99? (E5)

No, I can't say that I have...

9 minutes ago, Max_Headroom said:

I ask as there doesn't seem to be many threads/posts on the subject of modern Toyota cars running badly on premium unleaded  in fact i am sure i have read about members being happy using Tesco momentum 99 for smoother running than E10 and a big saving over V-Power.

Yes, I've seen those posts too.

I've stuck with V-Power only because of my experience with it in my GT86 some years ago. That boxer motor was very sensitive to rubbish fuel and so I've steered away from cheap fuel ever since.

I guess you could just call me a V-Power fanboy! I realise I could save money by using Tesco's offering but I work on the principle that with the Yaris Hybrid, because of its excellent mpg figures, I am only topping up a smaller amount of fuel (typically 16-20 litres) half of the time compared to a conventional car and therefore I don't mind the bit extra for the peace of mind and preserving the car's resale value as much as possible.

[TonyHSD]

1 hour ago, CPN said:

Sorry, but I wouldn't describe it as "some". It is easily demonstrable in Hybrid Assistant's display which is sourced directly from the associated ECU's PID (process ID) and shows the power flow, in or out (in kW), of MG1.

As an example, when I come off the A1(M) and am going downhill down the slip road turnoff, if I switch to B mode at 50 mph, MG1's power (input) immediately jumps to between -10 & -15 kW (depending on the steepness of the incline - negative means it is acting as a generator) back into the HV battery and its SoC rises accordingly. Add late braking into that mix and once I managed to get it to a reading of -25kW which, I believe, is the maximum it can manage... I once managed to get the SoC up to nudging 80% (78% actual) which is when the system starts to bleed off the charge...

I'll try and get some screen grabs the next time I am on a long run and you'll see what I mean.

This is spot on. 
I haven’t played with the app as much but because I live bottom of a long  downhill my hybrid Battery is always full those 78-80% in reality and if I use B mode in my last mile simply top ups quickly. 
One thing I noticed with age and mileage these traction batteries start to get full very easy and also does not hold charge as long as when the car was new, that’s normal. And this is the reason why I get my Battery topped up so quickly, thankfully still holds its charge ok and the car is still drivable, although the app shows Battery health at only 38% and change needs soon. How soon we will see. 
Now for the Tesco momentum.  We had been discussing this long ago and in many posts. Frosty recommended as fuel of his choice back then before the E10 standard but I haven’t tried since I had my worst experience with any petrol ever from one Texaco garage with theirs 99 premium, my engine almost got broken. Anyway since the E10 has come to the market here in uk I had tried the 99 momentum e5 from my local supermarket and the car felt completely different, smooth, quiet, responsive, and efficiency increased 3-5mpg. I exclusively use this ever since and even at my last plugs change they looked in very good condition. 
Tried others like bp, Shell, esso premium fuels but haven’t noticed anything better than my local Tesco . What I noticed though that not all Tesco premium petrol are as good and same other members reported this too. 
I stick with Tesco 99 momentum e5 instep of any top tier e10 for sure. 
Don’t mind Shell or bp premium bit these are way too expensive for me and filling up roughly about 80- 100 litres a week make a big difference. 

[Cyker]

I'm not sure with the B-mode on all cars, but on mine it only ever shows 1-bar of regen maximum, whereas if I'm braking manually I can get the full 3-bars of regen, so that might be what YarisHybrid2016 is basing his observations on; I have always been curious how much regen it can get in B-mode vs manual braking, but I have no way to get accurate figures alas.

That said, I think the older hybrids used maximum regen in B-mode, which is why everyone still thinks that's what it's for!

 

re. the EGR valve issues, that was a specific case in Italy due to chlorine-contaminated fuel; No amount of fuel additive is going to help with that!!

Remember, even supermarket fuel has to comply with the minimum standards, and that's one thing this country has been good at enforcing, so you're very unlikely to get any problems from it unless you drive very infrequently and the engine never gets hot, giving deposits the chance to build up.

The biggest draw for the 'super fuels' these days is not that the combustible part of the fuel is better quality, but that they have more cleaning additives and octane boosters. Oh, and less ethanol!

[CPN]

39 minutes ago, Cyker said:

I'm not sure with the B-mode on all cars, but on mine it only ever shows 1-bar of regen maximum, whereas if I'm braking manually I can get the full 3-bars of regen, so that might be what YarisHybrid2016 is basing his observations on; I have always been curious how much regen it can get in B-mode vs manual braking, but I have no way to get accurate figures alas.

That said, I think the older hybrids used maximum regen in B-mode, which is why everyone still thinks that's what it's for!

As I said, when I get the chance (probably Tuesday) I'll try and put this question to bed once and for all (at least for the Mk4) with a few HA screenshots...

[Cyker]

If you can get the kW figures for just letting B-mode slow the car, and then for manual braking to 3-bars of regen, from similar sorts of speeds, that would be very insightful.

Based purely on the CHG meter, I was assuming manual braking recovered more energy than B-mode in the Mk4, but it would be nice to have figures to show either way!

[CPN]

32 minutes ago, Cyker said:

If you can get the kW figures for just letting B-mode slow the car, and then for manual braking to 3-bars of regen, from similar sorts of speeds, that would be very insightful.

I'm sure I'll be able to do that...

32 minutes ago, Cyker said:

Based purely on the CHG meter, I was assuming manual braking recovered more energy than B-mode in the Mk4, but it would be nice to have figures to show either way!

I'm pretty sure your assumption will be correct from what I have seen already on occasion...

[MikeSh]

1 hour ago, Cyker said:

that they have more cleaning additives and octane boosters. Oh, and less ethanol!

But ethanol is an octane booster ...

[Cyker]

I know, that is the stupidest irony of the Exx fuels - compared to pre-Exx days, they take the octane booster out of E10 and add more ethanol, but in E5 they take out the ethanol and add more octane booster  

They should have made E10 like, 100RON or something, and made E10 engines able to take advantage of it, then we could run higher compression ratios and more efficient engines; Instead they've hamstringed the advantages of adding more Ethanol so we end up with the worst of both worlds! (We get the water absorption and lower energy density, but can't use the higher knock resistance or increased power!)

[TonyHSD]

I think B mode should not be compared to braking by any means, especially by regenerative power, only been compared to free rolling aka released accelerator. 
B mode despite main function is engine braking always adds more power to the Battery because of the stronger regen from the electric motor.
At slower speeds even without engine ON still adds more power., the car  almost feels like one pedal drive ev although the ice will kick in sooner than if in D.  

[CPN]

6 hours ago, TonyHSD said:

I think B mode should not be compared to braking by any means, especially by regenerative power,

Why Tony? In Toyota's own words from the manual, "Applying moderate engine braking driving down hills". Also, it does create "regenerative power" back via MG1. It slows the car down, so they labelled it "B" (for braking)...

6 hours ago, TonyHSD said:

only been compared to free rolling aka released accelerator.

If you release the accelerator in a normal manual car (or even a conventional automatic for that matter) without dipping the clutch, you get engine braking and the car slows down. In my world, that's a kind of "braking" whichever way you slice it.

6 hours ago, TonyHSD said:

B mode despite main function is engine braking always adds more power to the battery because of the stronger regen from the electric motor.

Correct but I'm not quite sure that I understand what you mean by "despite main function"?

6 hours ago, TonyHSD said:

At slower speeds even without engine ON still adds more power. the car almost feels like one pedal drive ev although the ice will kick in sooner than if in D.  

Even at slower speeds, if you engage "B", the ICE will always get started up immediately. It doesn't "kick in" sporadically depending on what your right foot is doing so, again, I'm not quite sure I understand what you are saying?

[TonyHSD]

1 hour ago, CPN said:

Why Tony? In Toyota's own words from the manual, "Applying moderate engine braking driving down hills". Also, it does create "regenerative power" back via MG1. It slows the car down, so they labelled it "B" (for braking)...

If you release the accelerator in a normal manual car (or even a conventional automatic for that matter) without dipping the clutch, you get engine braking and the car slows down. In my world, that's a kind of "braking" whichever way you slice it.

Correct but I'm not quite sure that I understand what you mean by "despite main function"?

Even at slower speeds, if you engage "B", the ICE will always get started up immediately. It doesn't "kick in" sporadically depending on what your right foot is doing so, again, I'm not quite sure I understand what you are saying?

Hi Colin, 

I only meant to say that people who compare B mode for regenerative braking added power instead of using the brakes it’s wrong. 
Of course when we are using the brakes we will get higher or highest amount of recuperated energy but we have to keep on pressing the brake pedal, not always ideal or most convenient.  
If we don’t want to keep pressing the brake for long we can chose B and prevent unwanted acceleration downhill.
This is why B mode is to be compared to free rolling not braking. 
If we want to brake or slow down we gonna use the brakes, no doubt. 
Here we are looking at maintaining a steady speed while going downhill not how much energy we get or how we stop the car.
Similar to driving at lower gear in manual transmission.
But never mind really, it’s my bad English that causes misunderstanding., apologies for that. 👍

 

[CPN]

ok, I think I understand what you are driving at now...

[Cyker]

There are differences, as I found in my friend's Auris hybrid the B-mode seems to use a lot more regen than the Yaris Mk4 does. I'm not sure why they made that change between the two different versions.

The other noteable difference is, when you lift off the accelerator, the Auris regens less strongly than the Mk4 and can coast noticeably further. The Auris coast-regens like a manual car in 4th or 5th, while the Mk4 coast-regens like it's in 2nd or 3rd.

[CPN]

That'll probably be just a tweak in the ECU's software between the two...