Strange ICE behaviour when heating car

[Steepndeep]

This morning I started the car for the first time at cold temperatures (0 C). My normal commute is 15 km one way and I can charge the car at work so I do all I can to avoid having ICE start. My normal procedure is to always switch the heater to 15C when I park the car and have ventilation off. When I start the car I switch ECO mode on and drive away.

At temperatures around 5 C or above, if I wait 5 minutes or so after start before I slowly increase the temperature higher I can avoid ICE start and run on electrical heater. On the other hand if I immediately start increasing temperature at start, the ICE starts. I therefore assumed that excess heat from batteries were somehow used to heat the car, but that may be wrong.

This morning at 0 C I used preheat to warm the car, then drove away and waited five minutes. As soon as I increased the temperature setting to 15,5 C the ICE started. I continued and waited to see what would happen and also monitored the electrical heater power consumption. The electrical heater never went above 5 kW power and soon started to decline and after 1 minute the ICE stopped and never again started in 20 minutes. I also managed to increase the temperature setting to 20 C and arrived at work with warm car, heated by electricity only.

Running the ICE for 1 minute is absoluteley useless as it will not heat the car at all and just pollute the environment with coldstarts. HAs anyone else experienced the same thing?

And why on earth would anyone implement such a behaviour? Mistsu implementation seems to be, when it comes to using ICE to heat the car;

1 Always start the ICE when it is "cold"
2 Then start to figure out if it really was necessary to start the ICE
3 If not, shut down.

Anyone having an explanation or is this just another "Mitsu engineering mystery"?

As an alternate note. If one could turn the electrical heater on manually and leave the tempsetting at 15 C. Then the ICE would not start and you would have a warm car. Wouldn't that be nice

 

[anko]

An awful lot has been written about this phenomena. What you describe is kinda how it works, indeed. And I totally recognise your procedure ;-).

I believe it works like this:

In ECO mode, the car will only start the ICE for heating when the gap between requested and actual cabin temp is more than approx. 10 degrees C. Could be little bit less or more. In NORMAL mode, the car is supposed to be more comfy (and thus less eco) and it will decide to start the ICE for heating when the gap is much smaller. Maybe already at 5 degrees C difference.

So, if the actual cabin temperature is 6 degrees and you set the heater to 15.5, the gap is a little bit less then 10 degrees. In ECO mode the car will not start the ICE. But in NORMAL mode it will. Now, if the interior temperature is 4 degrees, the gap to 15.5 degrees is 11.5. ECO mode or not, you will not be able to run the heater without having the ICE started by the car.

So, the ICE goes to work. Engine slowly starts to warm up (why do both, you may wonder ... ;-)). Only when the ICE coolant reaches 70 degrees C the thermostatic valve between the ICE cooling circuit and the cabin heating circuit is opened and only then the ICE can contribute to warming the cabine. But before that happens, chances are the gap between the actual and requested cabin temperature has been reduced to less than 10 degrees by th electric heater. And the brain decides it doesn't need the ICE..... Total waste of fuel is the result. Quite annoying, I must agree.

There are two ways to prevent this:

- Preheat the car, so the gap is smaller when you take off.
- Install the Vtech tuning PHEV box with STOPheater function.

The last will manipulate the cabin temp sensor reading to make the car believe the actual cabin temperature is always 13 degrees or more. This means you can 'safely' set the heater to 19 or even 20 degrees, and then follow your procedure to get it even higher. That is, once your car is in ECO mode. So, you must still turn the heater off 'at night' and in the morning first select ECO and then turn the heater on again.

Vtech said he would provide an update to the box that manipulates the temperature sensor reading to be at least 17 degrees. I hope that would mean you can always leave the heater on. But I am still waiting for the update .....

,

 

[ChrisMiller]

My attempt (guess) at an 'explanation' is that the Mitsu software engineers didn't want to write two sets of software logic - one for models with electric heating and one for the base models without it (you can ascribe this either to laziness or a desire for elegant simplicity - your call ). So the versions with electric heaters don't 'know' there's an electric heater and just operate on temperature difference as anko has described.

 

[anko]

So the versions with electric heaters don't 'know' there's an electric heater and just operate on temperature difference as anko has described.

That can't be true, IMHO. Because if it was, how would you EVER be able to use the heater without the ICE firing up in a car with electric heater?

 

[ChrisMiller]

To clarify, I was thinking only of the logic that controls whether to start the ICE to warm the car (clearly there must be other software to control the electric heating, where available). I don't know what happens in models without electric heating, does starting the ICE to heat the car follow exactly the same logic, based on temperature differentials and moderated by selection of Eco mode?

 

[anko]

To clarify, I was thinking only of the logic that controls whether to start the ICE to warm the car ...

Me too ...

I don't know what happens in models without electric heating, does starting the ICE to heat the car follow exactly the same logic, based on temperature differentials and moderated by selection of Eco mode?

That would mean you only get heat from the engine (in other words any heat at all) when the requested temperature is at least 5 (NORMAL mode) or 10 (ECO mode) higher than actual temperature, because otherwise the engine would not be running (unless you forced it to run). I don't have a car without electric heater, but I expect the engine will start as soon as the requested temp is higher than the actual temp. Don't you?

 

[greendwarf]

To clarify, I was thinking only of the logic that controls whether to start the ICE to warm the car ...

Me too ...

I don't know what happens in models without electric heating, does starting the ICE to heat the car follow exactly the same logic, based on temperature differentials and moderated by selection of Eco mode?

That would mean you only get heat from the engine (in other words any heat at all) when the requested temperature is at least 5 (NORMAL mode) or 10 (ECO mode) higher than actual temperature, because otherwise the engine would not be running (unless you forced it to run). I don't have a car without electric heater, but I expect the engine will start as soon as the requested temp is higher than the actual temp. Don't you?

My Gx3h (no electric heater) is controlled by the same temperature gap. I have to "force" the ICE to start to provide heat (esp. for demisting) by increasing the cabin setting well above the 15.5 where I usually leave it, down here in Tropical Sarf Lundun. :mrgreen:

 

[anko]

That is interesting. In well over 3 years of discussions on this same topic, here and in the Dutch forum, nobody ever mentioned this.to me this is very unexpected. A well, learn something new every day.

 

[Tipper]

I think there's more to it than just the heater setting/gap for the heater usage. I think it's more to do with running the engine gently in preparation for a real engine start when the engine is needed for drive-train power (and associated high revs because of the nature of the transmission/power control) when the ambient temp is low, ie below 10C. This must be essential in Scandinavia during the winter when temperatures are properly low. :lol:
This preliminary start gets oil around the engine ready for its later use in earnest. I think the heater setting bit is coincidental but has been used because it's convenient to do so.

 

[anko]

I think there's more to it than just the heater setting/gap for the heater usage. I think it's more to do with running the engine gently in preparation for a real engine start when the engine is needed for drive-train power (and associated high revs because of the nature of the transmission/power control) when the ambient temp is low, ie below 10C. This must be essential in Scandinavia during the winter when temperatures are properly low. :lol:
This preliminary start gets oil around the engine ready for its later use in earnest. I think the heater setting bit is coincidental but has been used because it's convenient to do so.

My car has never spontaneously started the ICE when the heater was off (set to 15 deg C or the fan turned off).

 

[user 816]

It seemed to me that the engine was starting when cold and running a little just to warm the oil.

Its annoying that pre-heating the car plugged in sets the alarm off so easily. I have switched my alarm off in MMCS to 'cure' it as no one takes any notice of car alarms these days anyway.

 

[jaapv]

This question came up in relationship to the 2017 model, which will fire up the engine from stone-cold when needed in EV mode. According to Mitsubishi the design of the engine is such that it will not be harmed by cold and stagnant oil.

 

[Claymore]

My car has never spontaneously started the ICE when the heater was off (set to 15 deg C or the fan turned off).

Not sure how having the temp set to 15 degrees is equal to 'off'.

JimB

 

[anko]

Simple. The electric heater will not consume power or provide heat when set to 15 degree Van. Not even when it is -10 deg C outside.

To me that constitutes "off"

 

[SolarBoy]

Timed Pre-heating didn't work for me on Monday morning, I had set the temp down to about 15 degrees C, I am now wondering if the two are related.

 

[Dusz]

Used my preheating for the first time today and did not have to scrape the car down.
You have to enabled the climate control timer and set the times. Mine came on even though I had turned the climate control off before I switched off on the previous journey.

 

[SolarBoy]

Used my preheating for the first time today and did not have to scrape the car down.
You have to enabled the climate control timer and set the times. Mine came on even though I had turned the climate control off before I switched off on the previous journey.

Had mine since Feb, this is the first time it's missed an appointment to pre-heat.

Just a tip, the headlights don't defrost ... when I say a tip, something I forget to de-ice.

 

[ps44]

My first defrost from the kitchen experience this morning too. Love it
And I just let the ICE do it's thing when I left as I had an hour to drive.
Bloody cold biking at Cannock this afternoon though

 

[Claymore]

Simple. The electric heater will not consume power or provide heat when set to 15 degree Van. Not even when it is -10 deg C outside.

To me that constitutes "off"

Does it actually say "off", mine only says 15 degrees.

You have to be careful making definitive statements Anko, because it bars other posters from entering the frivolous fray.

:lol:

JimB

 

[Claymore]

Timed Pre-heating didn't work for me on Monday morning, I had set the temp down to about 15 degrees C, I am now wondering if the two are related.

No, they are not.

Preheating operates without regard to the preset heater temperature and just blasts away at its max operating power for the period set.

JimB