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 Post subject: Re: ICE running unnecessarily?
PostPosted: Mon Jan 18, 2016 10:42 am 
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Location: Netherlands, Utrecht area
See it as a three-way junction, where three roads come together. One road leeds to the generator, one road leeds to the motors and one leeds to the battery. On each road, power can flow in only one direction at any given moment in time:

- From the generator to the junction, for example when:
-- the engine runs in serial hybrid mode and all power is converted into electricity by the generator
-- the engine runs in parallel hybrid mode and surplus power is converted to electricity by the generator
- From the junction to the generator, for example when:
-- the engine is being started up by the generator
-- the engine is idling in parallel mode and electricity is fed into the generator to eliminate E-drag in the generator

- From the battery to the junction, for example when:
-- driving in pure EV mode
-- the engine is being started by the generator
-- when coasting in EV mode, to eliminate E-drag in both E-motors
-- when coasting in serial or parallel hybrid mode, to eliminate E-drag in generator and both E-motors
- From the junction to the battery, for example when:
-- the battery is being recharged in Save or Charge mode
-- regen braking produces electrical power

- From the wheels to the junction, when:
-- regen braking produces electrical power
- From the junction to the wheels, for example when:
-- driving in EV or serial hybrid mode
-- driving in parallel hybrid mode with 4WD Lock engaged (rear wheels)
-- driving in parallel hybrid mode, when a very little power is applied to the rear wheels in order to maintain a 4WD characteristic

Unfortunately, the graphics do not show the junction as such. Only the path from engine (generator) to battery and the path from battery to wheels. Both paths lead across the junction. A graphic showing this junction with three paths would be so much nicer and clearer.

Picture this: while towing a caravan in parallel mode hit 4WD Lock. When this happens you will see this:
- Orange arrow engine to wheels
- Blue arrow engine to battery
- Blue arrow battery to wheels

It suggests the battery is being recharged. But this is totally not the case. In reality, a little amount of energy flows from the generator to the rear motor and a lot of energy flows from the battery to the same rear motor. The battery is being drained rapidly.

To make matters a little bit more complex, it is not exactly a 3-way junction, but more a 6 or 7-way junction (at least), with roads leading from the junction to:
- Battery
- Rear motor
- Front motor
- Generator
- Electric heater
- On Board Charger
- Rapid Charge Port

Where the junction is reality is connected to the generator and front motor via the same single road which splits near the end.

BTW: Kirchhoff laws say that the sum of currents on all roads connected to the junction (taking into account direction) must be 0.


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 Post subject: Re: ICE running unnecessarily?
PostPosted: Mon Jan 18, 2016 2:40 pm 
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Joined: Thu May 07, 2015 4:24 am
Posts: 469
Location: Doncaster, South Yorks
anko wrote:
See it as a three-way junction, where three roads come together. One road leeds to the generator, one road leeds to the motors and one leeds to the battery. On each road, power can flow in only one direction at any given moment in time:

- From the generator to the junction, for example when:
-- the engine runs in serial hybrid mode and all power is converted into electricity by the generator
-- the engine runs in parallel hybrid mode and surplus power is converted to electricity by the generator
- From the junction to the generator, for example when:
-- the engine is being started up by the generator
-- the engine is idling in parallel mode and electricity is fed into the generator to eliminate E-drag in the generator

- From the battery to the junction, for example when:
-- driving in pure EV mode
-- the engine is being started by the generator
-- when coasting in EV mode, to eliminate E-drag in both E-motors
-- when coasting in serial or parallel hybrid mode, to eliminate E-drag in generator and both E-motors
- From the junction to the battery, for example when:
-- the battery is being recharged in Save or Charge mode
-- regen braking produces electrical power

- From the wheels to the junction, when:
-- regen braking produces electrical power
- From the junction to the wheels, for example when:
-- driving in EV or serial hybrid mode
-- driving in parallel hybrid mode with 4WD Lock engaged (rear wheels)
-- driving in parallel hybrid mode, when a very little power is applied to the rear wheels in order to maintain a 4WD characteristic

Unfortunately, the graphics do not show the junction as such. Only the path from engine (generator) to battery and the path from battery to wheels. Both paths lead across the junction. A graphic showing this junction with three paths would be so much nicer and clearer.

Picture this: while towing a caravan in parallel mode hit 4WD Lock. When this happens you will see this:
- Orange arrow engine to wheels
- Blue arrow engine to battery
- Blue arrow battery to wheels

It suggests the battery is being recharged. But this is totally not the case. In reality, a little amount of energy flows from the generator to the rear motor and a lot of energy flows from the battery to the same rear motor. The battery is being drained rapidly.

To make matters a little bit more complex, it is not exactly a 3-way junction, but more a 6 or 7-way junction (at least), with roads leading from the junction to:
- Battery
- Rear motor
- Front motor
- Generator
- Electric heater
- On Board Charger
- Rapid Charge Port

Where the junction is reality is connected to the generator and front motor via the same single road which splits near the end.

BTW: Kirchhoff laws say that the sum of currents on all roads connected to the junction (taking into account direction) must be 0.


Very nice explanation Anko :)

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 Post subject: Re: ICE running unnecessarily?
PostPosted: Mon Jan 18, 2016 6:05 pm 
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Joined: Thu Jul 31, 2014 5:25 am
Posts: 1102
Location: South Australia
Back to the original topic, The MMC design team have probably implemented some hard rules into the heating with ICE algorithm. It may be as simple as when heating is requested, and temp is cold, run ICE, but with minimum amount of petrol consumption, even when driving. This would possibly explain the apparent lack of surplus power for possible battery recharging and not running the ICE at the most efficient power level.

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 Post subject: Re: ICE running unnecessarily?
PostPosted: Mon Jan 18, 2016 9:55 pm 
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Joined: Mon Dec 01, 2014 11:30 am
Posts: 2587
Location: Netherlands, Utrecht area
Makes sense. Because, when the ice is started for heating, if means there is still sufficient SOC and it looks as if the design team (like myself) strives for maintaining an as low as possible SOC. Probably a smart decision. But then, why not use the SOC for heating instead of the ICE?


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 Post subject: Re: ICE running unnecessarily?
PostPosted: Mon Jan 18, 2016 10:15 pm 
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Joined: Thu Jul 31, 2014 5:25 am
Posts: 1102
Location: South Australia
Reading minds is on the same list with teleporting. :lol:

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PHEV Solar Recharging Station
1.7kW Solar Grid connect

Make the GRID your friend.


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 Post subject: Re: ICE running unnecessarily?
PostPosted: Tue Jan 19, 2016 12:23 am 
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Joined: Mon Dec 01, 2014 11:30 am
Posts: 2587
Location: Netherlands, Utrecht area
gwatpe wrote:
Reading minds is on the same list with teleporting. :lol:
True, This is why I thought this was a bad idea ....
gwatpe wrote:
I was trying to imagine myself in the Japanese design team.
;)


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 Post subject: Re: ICE running unnecessarily?
PostPosted: Tue Jan 19, 2016 1:37 am 
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Joined: Tue Aug 05, 2014 1:32 pm
Posts: 1352
iggys76 wrote:

A funny thing is that sometimes the ICE is fired but it does not increase in rpm when pushing the gas pedal, it only keeps the engine warm at constant low rpm, but mostly it sounds like it directly increases the rpms when I accelerate, resembling a normal gas driven car (very frustrating).


This (and anko's reply) don't make sense - unless you mean when not in Drive?

If moving, how can it not be acceleration when you push the gas pedal? Did you mean that sometimes when accelerating the ICE rpms increase and sometimes they don't? If so, surely this is the same as normal and depends on the rate of acceleration, i.e. the ICE will start to add power for quick getaways to assist the battery.


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 Post subject: Re: ICE running unnecessarily?
PostPosted: Tue Jan 19, 2016 2:01 am 
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Joined: Mon Dec 01, 2014 11:30 am
Posts: 2587
Location: Netherlands, Utrecht area
greendwarf wrote:
iggys76 wrote:

A funny thing is that sometimes the ICE is fired but it does not increase in rpm when pushing the gas pedal, it only keeps the engine warm at constant low rpm, but mostly it sounds like it directly increases the rpms when I accelerate, resembling a normal gas driven car (very frustrating).


This (and anko's reply) don't make sense - unless you mean when not in Drive?
This is what I assumed.


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 Post subject: Re: ICE running unnecessarily?
PostPosted: Tue Jan 19, 2016 4:34 am 
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Joined: Thu May 07, 2015 4:24 am
Posts: 469
Location: Doncaster, South Yorks
anko wrote:
greendwarf wrote:
iggys76 wrote:

A funny thing is that sometimes the ICE is fired but it does not increase in rpm when pushing the gas pedal, it only keeps the engine warm at constant low rpm, but mostly it sounds like it directly increases the rpms when I accelerate, resembling a normal gas driven car (very frustrating).


This (and anko's reply) don't make sense - unless you mean when not in Drive?
This is what I assumed.


I have had a situation twice, where the ICE starts for heating, and before I engage drive, I can rev the engine as you can in a petrol car with the car stationary. I have not been able to replicate it deliberately, so it might just happen at a certain SOC. I can't even work out why it would want to do that? :(

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 Post subject: Re: ICE running unnecessarily?
PostPosted: Tue Jan 19, 2016 5:49 am 
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Joined: Mon Dec 01, 2014 11:30 am
Posts: 2587
Location: Netherlands, Utrecht area
I think I mentioned this before: there is a difference between an 'idling' engine in Charge mode (car decides) and an engine 'idling' after being started up by a mechanic for maintenance / diagnostic purposes (throttle decides). I think an engine started up for heating behaves like the second.


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