Meaning Of Power Instrument?

[YarisHybrid2016]

Hi,

Is there any real meaning behind the power instrument beyond generalities?

I know engine RPM is *loosely* coupled to what it shows, but is there any way of approximating engine RPM from position of the power needle and vehicle speed?

It seems if the needle is at or below the center of the ECO band that the engine sounds to be idling (in fact it feels to be "decoupled" or zero-torqued - just going slightly over the center of the ECO band when the engine is running, you can feel a very slight bump as the engine starts pulling).

Entering the lower part of the power band the engine distinctly starts to make a noise, but I have no idea of what it means? My last car started "screaming" at much over 4000 RPM; before then it was quite quiet, but there is no way to tell what the engine RPM is on this.

Looking at the specs it says that peak torque is achieved around 4000 RPM, and peak power around that point as well, so given the setup of the engine/electric combo I would have thought the engine would be held around that RPM until it was required to run faster (high vehicle speed) for flat-out acceleration, meaning anything less than maximum would require less than this RPM.

I did find a video recently on YT showing what various parts of the system are doing, but without knowing the roads/terrain, and how hard the driver is accelerating, it is pretty meaningless, though it gives a broad overview of how everything is operating.

The main thing I'm looking for is a way to "ball park" engine RPM vs. what the power instrument is showing.

[Wayne2015]

I only use it when I want the needle to be in the ECO bands ....beyond that I think its pretty useless and do prefer the REV counter back.....

But as I start to get used to my Auris, I think the less will I need for the use of the POWER instruments......

[Joseph D]

If you wish to monitor the RPM this can be easily done by installing either a ScanGauge II, the android phone app Torque or the iPhone/iPad app Engine Link.

However, I don't think it will help you in the way you think it might, as engine RPM is a little different in an HSD.

Personally, I think the "Power Instrument" is very useful.

[CPN]

Hi,

Is there any real meaning behind the power instrument beyond generalities?

I know engine RPM is *loosely* coupled to what it shows, but is there any way of approximating engine RPM from position of the power needle and vehicle speed?

It seems if the needle is at or below the center of the ECO band that the engine sounds to be idling (in fact it feels to be "decoupled" or zero-torqued - just going slightly over the center of the ECO band when the engine is running, you can feel a very slight bump as the engine starts pulling).

Entering the lower part of the power band the engine distinctly starts to make a noise, but I have no idea of what it means? My last car started "screaming" at much over 4000 RPM; before then it was quite quiet, but there is no way to tell what the engine RPM is on this.

Looking at the specs it says that peak torque is achieved around 4000 RPM, and peak power around that point as well, so given the setup of the engine/electric combo I would have thought the engine would be held around that RPM until it was required to run faster (high vehicle speed) for flat-out acceleration, meaning anything less than maximum would require less than this RPM.

I did find a video recently on YT showing what various parts of the system are doing, but without knowing the roads/terrain, and how hard the driver is accelerating, it is pretty meaningless, though it gives a broad overview of how everything is operating.

The main thing I'm looking for is a way to "ball park" engine RPM vs. what the power instrument is showing.

I think you are misunderstanding what you are hearing? The ICE (internal combustion engine) does not run all the time even whilst motoring along and there is no way you can equate the power gauge to the ICE's RPM at all... If there is enough power in the Battery to power the traction (electric) motor with enough torque to maintain the speed you are going at, then the ICE will not even be used at all at that given moment...

As someone else has suggested, the only way to see if the ICE is actually running (never mind what rpm it is doing!) is to use the Android Torque app or similar (which is what I do all the time...). BTW, the ICE's RPM is not even "loosely" coupled to the power meter indication at all. It bears no relationship.

[Wayne2015]

Colin @2:43am

[CPN]

Colin @2:43am

Lol... just call me an insomniac... ;)

[Wayne2015]

Colin @2:43am

Lol... just call me an insomniac... ;)

Live, sleep and die TOC

[Cyker]

Yeah, it's not helpful; At the same place at the same speed at the same pedal pressure the ICE could be doing any RPM - The computer decides depending on the temperature, the state of charge in the Battery, and probably other factors. On a cold day with a low Battery, the ICE might be red lining to put out enough power to charge the Battery AND keep the car moving at the requested speed. On a warm day with a full battery in the same situation, it might be idling or even off as the leccy motor does all the work! (These are woeful exaggerations as it's rare you'd get such a wide gamut, but you get the point! :)

The RPM in a HSD has practically no bearing on how fast you are going, and only a slight relationship with the amount of torque demanded.

The Toyota hybrid systems are very unique in that although the ICE technically connected to the wheels through the power split device, it cannot send any power directly to the wheels - Any drive from the ICE to the wheels has to go through the MG1, which kinda acts like a CVT gearbox for it.

The power display is just an efficiency meter - I don't know how accurate it is, but keeping it in the eco zone does seem to deliver noticeably higher MPGs than even creeping a bit into the power zone. (I do wonder if the engine goes into some sort of 'sport mode' or different valve timings when you cross over from the Eco to Power zone as I found even being at the bottom of the power zone seemed to use noticeably more fuel than being at the top of the eco zone?? Have people that actually own HSDs found that too??)

[Wayne2015]

Yeah, it's not helpful; At the same place at the same speed at the same pedal pressure the ICE could be doing any RPM - The computer decides depending on the temperature, the state of charge in the battery, and probably other factors. On a cold day with a low battery, the ICE might be red lining to put out enough power to charge the battery AND keep the car moving at the requested speed. On a warm day with a full battery in the same situation, it might be idling or even off as the leccy motor does all the work! (These are woeful exaggerations as it's rare you'd get such a wide gamut, but you get the point! :)

The RPM in a HSD has practically no bearing on how fast you are going, and only a slight relationship with the amount of torque demanded.

The Toyota hybrid systems are very unique in that although the ICE technically connected to the wheels through the power split device, it cannot send any power directly to the wheels - Any drive from the ICE to the wheels has to go through the MG1, which kinda acts like a CVT gearbox for it.

The power display is just an efficiency meter - I don't know how accurate it is, but keeping it in the eco zone does seem to deliver noticeably higher MPGs than even creeping a bit into the power zone. (I do wonder if the engine goes into some sort of 'sport mode' or different valve timings when you cross over from the Eco to Power zone as I found even being at the bottom of the power zone seemed to use noticeably more fuel than being at the top of the eco zone?? Have people that actually own HSDs found that too??)

On my current test - yes, with needle above ECO bands my Auris is doing 10mpg less....EEK!

PS: Hi Colin :)

[MEP's Yaris GS]

As others have said really, as a user of a ScanGauge II in my PiP, I can confirm RPM has little to do with powerband and cars speed. I can be quite happily motoring along at 80-90MPH at 1000 RPM if conditions allow

[CPN]

As others have said really, as a user of a ScanGauge II in my PiP, I can confirm RPM has little to do with powerband and cars speed. I can be quite happily motoring along at 80-90MPH at 1000 RPM if conditions allow

That's been exactly my experience...

[CPN]

Yeah, it's not helpful; At the same place at the same speed at the same pedal pressure the ICE could be doing any RPM - The computer decides depending on the temperature, the state of charge in the battery, and probably other factors. On a cold day with a low battery, the ICE might be red lining to put out enough power to charge the battery AND keep the car moving at the requested speed. On a warm day with a full battery in the same situation, it might be idling or even off as the leccy motor does all the work! (These are woeful exaggerations as it's rare you'd get such a wide gamut, but you get the point! :)

The RPM in a HSD has practically no bearing on how fast you are going, and only a slight relationship with the amount of torque demanded.

The Toyota hybrid systems are very unique in that although the ICE technically connected to the wheels through the power split device, it cannot send any power directly to the wheels - Any drive from the ICE to the wheels has to go through the MG1, which kinda acts like a CVT gearbox for it.

The power display is just an efficiency meter - I don't know how accurate it is, but keeping it in the eco zone does seem to deliver noticeably higher MPGs than even creeping a bit into the power zone. (I do wonder if the engine goes into some sort of 'sport mode' or different valve timings when you cross over from the Eco to Power zone as I found even being at the bottom of the power zone seemed to use noticeably more fuel than being at the top of the eco zone?? Have people that actually own HSDs found that too??)

On my current test - yes, with needle above ECO bands my Auris is doing 10mpg less....EEK!

PS: Hi Colin :)

I'm awake! What more do you want?!

"Put the pedal to the metal" in the Yaris Hybrid and you'll easily see just 8-10 mpg instantaneous if you want!

[Wayne2015]

Yeah, it's not helpful; At the same place at the same speed at the same pedal pressure the ICE could be doing any RPM - The computer decides depending on the temperature, the state of charge in the battery, and probably other factors. On a cold day with a low battery, the ICE might be red lining to put out enough power to charge the battery AND keep the car moving at the requested speed. On a warm day with a full battery in the same situation, it might be idling or even off as the leccy motor does all the work! (These are woeful exaggerations as it's rare you'd get such a wide gamut, but you get the point! :)

The RPM in a HSD has practically no bearing on how fast you are going, and only a slight relationship with the amount of torque demanded.

The Toyota hybrid systems are very unique in that although the ICE technically connected to the wheels through the power split device, it cannot send any power directly to the wheels - Any drive from the ICE to the wheels has to go through the MG1, which kinda acts like a CVT gearbox for it.

The power display is just an efficiency meter - I don't know how accurate it is, but keeping it in the eco zone does seem to deliver noticeably higher MPGs than even creeping a bit into the power zone. (I do wonder if the engine goes into some sort of 'sport mode' or different valve timings when you cross over from the Eco to Power zone as I found even being at the bottom of the power zone seemed to use noticeably more fuel than being at the top of the eco zone?? Have people that actually own HSDs found that too??)

On my current test - yes, with needle above ECO bands my Auris is doing 10mpg less....EEK!

PS: Hi Colin :)

I'm awake! What more do you want?!

"Put the pedal to the metal" in the Yaris Hybrid and you'll easily see just 8-10 mpg instantaneous if you want!

LOL

Putting my foot down a bit and I swear to God, I can see the AVERAGE MPG drop like seeing the petrol gauge drop like I was driving a lamboguini on full power

[YarisHybrid2016]

OK - now I'm very intrigued. You can be cruising at a steady speed on level ground at 70 MPH and the ICE be idling????

From what I understood of the system, above 45 MPH the engine is running all the time, and will increase in RPM relative to vehicle speed in order to keep MG1 RPM in limits (MG2 being related to vehicle speed).

I've noticed in hard acceleration to 70 MPH the engine note hardly changes.

I know that as you lift off to maintain a steady speed, the RPM reduces, but to reach idle in such a state is both intriguing and surprising (note I'm specifically avoiding the case of coasting downhill).

Thinking about it, I'm surprised the engine RPM is not shown on the computer.

I agree that just slightly going into the power band seems to cause it to drink fuel. I've been doing some experimenting, and constantly found that acceleration with the needle just touching the power band gives both good acceleration and fuel economy vs. accelerating to the same speed (on the same road) but going to one tick mark short of it.

Hard acceleration at low speed is sure way to kill fuel economy. It seems totally disproportionate.

[Wayne2015]

OK - now I'm very intrigued. You can be cruising at a steady speed on level ground at 70 MPH and the ICE be idling????

From what I understood of the system, above 45 MPH the engine is running all the time, and will increase in RPM relative to vehicle speed in order to keep MG1 RPM in limits (MG2 being related to vehicle speed).

I've noticed in hard acceleration to 70 MPH the engine note hardly changes.

I know that as you lift off to maintain a steady speed, the RPM reduces, but to reach idle in such a state is both intriguing and surprising (note I'm specifically avoiding the case of coasting downhill).

Thinking about it, I'm surprised the engine RPM is not shown on the computer.

I agree that just slightly going into the power band seems to cause it to drink fuel. I've been doing some experimenting, and constantly found that acceleration with the needle just touching the power band gives both good acceleration and fuel economy vs. accelerating to the same speed (on the same road) but going to one tick mark short of it.

Hard acceleration at low speed is sure way to kill fuel economy. It seems totally disproportionate.

On a similar subject I am also intrigue why the Atkinson engine not more fuel efficient on its own....see my thread here:

http://www.toyotaownersclub.com/forums/topic/169614-atkinson-s-18-engine/

[MEP's Yaris GS]

OK - now I'm very intrigued. You can be cruising at a steady speed on level ground at 70 MPH and the ICE be idling????

Correct, if you're not demanding power from it, it'll always drop to its idle speed of approx 1000rpm.

[YarisHybrid2016]

Wow! Nice!!