Relooking at warm-up

Hi everyone

I do agree with much of the posts of this thread that match with my records posted here: HSD behaviour during S1a & S1b warming stages | PriusChat

In that thread, for stationary warm-ups you may find several graphs like those below:







If we look at the ICE exhaust and catalyser temperatures, there are two probes; #1 probe is located before the catalyser and its temperature chart is the following:



Click here for zoom in

From my point of view there is nothing remarkable about #1 probe temperature.

Let's see #2 probe which is located behind the catalyser. Its chart is:



Click here for zoom in

In the #2 probe temperature chart there is a common inflection point of all curves at 55 seconds, which indicates that the amount of heat coming from the exhaust is much less after 55 seconds (S1b) than before (S1a) This is the effect of the ignition timing change designed by Toyota.

I hope you like them

Big hugs from Frank

 

I have started using a different cold morning fuel saver technique. This works on non hybrids too.
10-15 minutes before leaving home on cold mornings I put a little space heater on the drivers seat facing the windshield. Let it run on low for 10-15 minutes. I drape the cord out of the bottom of the door and shut the door.
The seats , windshield , steering wheel, even back window are warm and clear. Now I don't need to use front and rear defrost, saving significant fuel. It is also nice and warm inside. I consider it a crude form of a plug in hybrid. A few hundred watt hours stored in the form of heat in the cabin seats and windows.
I want to add a block heater to the regiment when I get a chance.

 

thanks...great stuff.......
at the speeds your suggesting...the car would use a lot traction battery automatically?
even your hypermiling record technique requires a lot of use of battery by cruise control at the speeds you suggest!

so where does the traction battery fit in? [hope it doesnt send this to much off topic]

 

In this thread I posted some charts of the ICE behaviour with different coolant temperature ranges that supports Bob's suggestions. The average power Vs RPM for each coolant temperature range is:



From 1450RPM with coolant temperatures lower than 70ºC (158ºF) the ICE provides some 2kW more than with warmer coolant temperatures.

The average torque Vs RPM for each coolant temperature range is:



The 8 Nm increase of torque with lower than 70ºC coolant temperatures is noticeable above 1450 RPM.

The average efficiency reported by OBD parameters Vs RPM for each coolant temperature range is:


As Bob says above, the higher the coolant temperature, the higher ICE efficiency at any RPM.

Please note that real ICE efficiency is 7% lower than the one reported by OBD parameters, which is the same amount that the fuel mileage indicated by the dashboard cheats.

Big hugs from Frank

 

getting it as warm as possible as quick as possible is the key.....
engine block heater.....grill blockiing...
what about power mode for start,

just trying to bring to real life use of these graphs

 

but ultimately heat will come from engine.....not n...?

 

Well, technically PWR will leave the engine idling (if no power is required) at speed more than 35 km/h (real) so, if a fast warming up is the the topic, it should give some contribution on faster warming.

I've got the problem of a 6 km slight descending slope just on leaving home, which means an engine still cold after the first 6 km, a good part of it with ICE off.
Testing the descent in PWR, i've got 10° more at the end of the stretch. Altough i'm still lacking of a precise FE comparison, FE seems to be affected in a negative sense.
Another data is that idling in PWR with a cold engine, its a variable affair depending on cooling temperature: for example, at 40° ICE spin (unloaded) @ something as +1400 rpm, going down to 1200 only approaching about 60° .


But PWR is an area worth investingating IMHO, particularly on the basis of such big influence of Temp over efficiency. Without a grill blocking strategy, i found its not uncommon to remain below 65° in a whole trip...

 

At what condition will PWR mode depend on speed this way? ... I do use it nothing like this I EVER seen. I monitoring RPM no way PWR mode does this. The only thing is happening is that in ECO mode the ICE will turn off at about 120F rather than the 145F or so in NORMAL/PWR

Can you quote some sources ??

That is correct it depends on temp not speed (as far as anyone reported) so it is WORTH WHILE to start with ECO if you expect stopping early (lights/stop sign etc or in your case no need power).

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Indeed! One good strategy is starting off with the car pointing downhill and choosing a relatively downhill route without straying off too much from the general direction of one's destination. Doing the warm-up at speed with less load is a tough balancing act but very rewarding when you see your mpgs are acceptably high in the first 5 - 10 mins.

That's the strategy i use in my afternoon commute as i can't use the EBH because I park on the side streets. However, i position my car pointing downhill and start off rolling down the hill (while the ICE starts its warms up routine) and taking the sea level route rather than the hilly route of about the same distance in the first 1.5 miles before joining part of the hilly route again going towards the uphill freeway. On a warm day (like 28C /82F coolant start temp), and an SOC above 52%, the resulting mpg is around 55-57 mpg in the first 5-min segment already.

 

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Sources? You have just to push a button in your car, you don't need a source And even when i don't turn on Torque Pro, in the 2013 Auris we have the Engine off light in the dashboard!

I see you have a 2012 Prius, so you should have my same software. Anyway, beeing a moderator on a Toyota hybrid forum, as per my signature, i know this feature is present also in 2009-10 EU Prius.

But i'm sure you're beeing sincere saying that, in your car, PWR does'nt leave the engine on above 35 km/h. On our EU cars its like this in any condition, its just a standard feature regardless : that means that your side of the pond, Toyota choosed different settings for PWR. EU cars have it, since 2009.

 

Bob, sorry for the OT, can you kindly give me a reference were the graph above has been discussed? I presume Ken@japan supplied it, is'nt it?

 

Sources? You have just to push a button in your car, you don't need a source And even when i don't turn on Torque Pro, in the 2013 Auris we have the Engine off light in the dashboard!

I see you have a 2012 Prius, so you should have my same software. Anyway, beeing a moderator on a Toyota hybrid forum, as per my signature, i know this feature is present also in 2009-10 EU Prius.
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This is my 3rd Prius starting in 2007 with a Gen II

I think I was not clear you said this is only in PWR. I tried to say that it isn't pwr (not that it will NOT keep it about 992 RPM) ... In our car I believe it is 42mph ... when the ICE will NOT shut off. BUT that has nothing to do with PWR/ECO that is basically protecting the overspeeding MG1. In ALL mode this will happen. I could not find any difference (neither heard anyone yet saying this) that.

So just to clarify you were arguing against using PWR during warm up by saying (or not) that this will not let the ICE shut off at the given speed but ECO or NORMAL will. And my question was under what other condition only during warm up or otherwise ??

I could only find so far btw ECO vs PWR regarding the warm up that in ECO it will allow the ICE shut off at a lower cooler temp (today it was about 105F for ECO) then I changed to PWR on purpose and ICE started up. The next stop somewhere about 130F or so at the stop in PWR mode ICE shut off ... I have several STOP sign before I can reach full warm up (unfortunately).

You maybe right (during warm up) but I can not replicate this .. I am certain that there is NO difference btw ECO and PWR btw 20mph (35kmh) and 42mph (~70kmh) ICE shuts down in glide in PWR mode under 42mph

 

Sorry, it must be my freaking horrible english.

1) Between 20 mph and 42 mph, EU Prius and Auris, in glide in PWR keeps ICE turned on, not matter what cooling temp or cat temperature is.
HOT or COLD always ICE ON in PWR for speed above 20 mph. Are you saying this is not the case on USA Prius? Interesting. If is confirmed, you should be interested in knowing how power is managed in PWR btw 20 and 42 mph in our cars.

2) Of course above 42 mph ICE is always on for protecting MG1 from overspeeding, altough PIP demonstrate that this is a bit conservative.

3)

Sort of.
PWR let the engine to stay on above 20mph (EU at the least), and you'll warm up faster, as i do measure, which is good. But if you're on top of a slope from the very beginning, like me, you'll not save the fuel of the engine off during the glide. So i ended up with a warmer engine but worse FE than the glide in Normal with ICE off.