Can we clear up Serial vs Parallel drive?

[jaapv]

On top of that the engine has been adapted to the intended use by adjusting tolerances, coatings, engine management, etc. In fact, straining an engine at low revs is far worse that it running at speed; the pressure on the main bearings gets rather high.

 

[Fjpod]

I still can't reconcile claims made here that parallel is more fuel efficient. My mpg measurements indicate that parallel uses more fuel.

 

[kpetrov]

I still can't reconcile claims made here that parallel is more fuel efficient. My mpg measurements indicate that parallel uses more fuel.

Did you start your test with same battery level?
Did you finish both test with equal and less than 50% battery remaining charge? Do you disengage the parallel - CHARGE mode once battery reaches 60% - 70% charge?

 

[mellobob]

you're being overly worried about nothing. the engineers knew what they were doing when they programmed it.

not if you listen to the "engineers" on this forum.

But, I completely agree: Just drive the car. It works great!

 

[ThudnBlundr]

I read somewhere that the engine is limited to 4,500rpm, which is hardly head-shattering speed for an engine which runs far higher in a Lancer. Is it the same basic engine as the EVO?

 

[jaapv]

AFAIK that is correct, it will attempt to run at its most efficient RPM, The max speed is limited to limit the revs. It is quite impossible to damage it this way - borne out by the fact that we never had any report of engine trouble on this forum.

 

[Fjpod]

I still can't reconcile claims made here that parallel is more fuel efficient. My mpg measurements indicate that parallel uses more fuel.

Did you start your test with same battery level?
Did you finish both test with equal and less than 50% battery remaining charge? Do you disengage the parallel - CHARGE mode once battery reaches 60% - 70% charge?

Not exactly. I am basing my observation on monitoring a ScanGuage while I am driving. During parallel drive, over a few minutes, the mpg readings are definitely lower than in series. I do make allowance for level grade, similar speed, etc.

I don't seem to find a certain driving condition which favors parallel over series.

 

[kpetrov]

I still can't reconcile claims made here that parallel is more fuel efficient. My mpg measurements indicate that parallel uses more fuel.

Did you start your test with same battery level?
Did you finish both test with equal and less than 50% battery remaining charge? Do you disengage the parallel - CHARGE mode once battery reaches 60% - 70% charge?

Not exactly. I am basing my observation on monitoring a ScanGuage while I am driving. During parallel drive, over a few minutes, the mpg readings are definitely lower than in series. I do make allowance for level grade, similar speed, etc.

I don't seem to find a certain driving condition which favors parallel over series.

Of course the instant fuel consumption when you use the engine in parallel will be higher.
What you should measure is the average fuel consumption once you have used that extra power stored in the battery pack during parallel mode.

 

[Fjpod]

Did you start your test with same battery level?
Did you finish both test with equal and less than 50% battery remaining charge? Do you disengage the parallel - CHARGE mode once battery reaches 60% - 70% charge?

Not exactly. I am basing my observation on monitoring a ScanGuage while I am driving. During parallel drive, over a few minutes, the mpg readings are definitely lower than in series. I do make allowance for level grade, similar speed, etc.

I don't seem to find a certain driving condition which favors parallel over series.

Of course the instant fuel consumption when you use the engine in parallel will be higher.
What you should measure is the average fuel consumption once you have used that extra power stored in the battery pack during parallel mode.

I will pay more attention to that... but I have noticed that when in Parallel mode, sometimes there is nothing going to the battery.

 

[littlescrote]

Rather than trying to measure it in a completely unscientific way, just think about it.

There are 2 options to generate enough power to make the car move at a given speed against the wind and rolling resistance:
1) Series mode where an engine drives a generator that drives a motor to turn the 'axle'
2) Parallel mode where an engine drives the 'axle'

Given that nothing can be 100% efficient, that already tells you the answer.

 

[ThudnBlundr]

Indeed. Just plugging something in that gives you fuel consumption tells you nothing about how much power is being used to actually move the car and how much is being used to recharge the drive battery. And driving in Parallel will usually be at a different speed to Series mode. So you're not even comparing apples with pears; you're comparing apples with pizza

 

[kpetrov]

Also if charging the battery while the engine is moving the car was less fuel efficient then the complete idea of hybrid vehicle would have been an nonsense.
Serial (SAVE) is a kind of intermittent Parallel (CHARGE) when performed on lower speeds. Once over the speed (like ThudnBlundr mention) when the engine is coupled with the wheels and the actual parallel kicks-in then the ICE is used in most efficient way.

I never use SAVE actually. It doesn't make sense. Why should ICE start and stop when it can do what's needed in one shot?

 

[jaapv]

Actually, it does make sense. It allows you to adjust the battery level to the most efficient way of driving. You always want to arrive empty at your charge point, but at the same time you want to use your electricity as efficiently as possible. So assume you have a Motorway drive with a 10 km secondary road bit at the end. Run your battery down to 10 km range in the less efficient part and then hit "Save" to preserve exactly the right amount of electricity for the end of the run.

 

[kpetrov]

Actually, it does make sense. It allows you to adjust the battery level to the most efficient way of driving. You always want to arrive empty at your charge point, but at the same time you want to use your electricity as efficiently as possible. So assume you have a Motorway drive with a 10 km secondary road bit at the end. Run your battery down to 10 km range in the less efficient part and then hit "Save" to preserve exactly the right amount of electricity for the end of the run.

Or you can hit that CHARGE instead of SAVE using the maximum from your engine during this motorway section and switch to EV a little bit earlier and arrive with empty battery as well.
I find that by using "charge" I can control and estimate the remaining battery level much better than using "save" with it's fluctuations as well.

 

[jaapv]

Too much calculation and estimation involved for my taste -let the car do the legwork- and you have to be alert to push that button at the right moment.

 

[kpetrov]

Too much calculation and estimation involved for my taste -let the car do the legwork- and you have to be alert to push that button at the right moment.

Well, either save or charge involves this same calculation and both approaches are depended on the right moment to push EV.
The question was which one is more efficient.

 

[greendwarf]

kpetrov wrote -
I never use SAVE actually. It doesn't make sense. Why should ICE start and stop when it can do what's needed in one shot?

So you leave home with a low cost full charge from the grid, get on to a motorway, rapidly deplete the battery for few miles and then use expensive petrol to recharge the battery to use at your destination, rather than press Save? You must have, literally, "money to burn" :lol:

 

[kpetrov]

I never use SAVE actually. It doesn't make sense. Why should ICE start and stop when it can do what's needed in one shot?

So you leave home with a low cost full charge from the grid, get on to a motorway, rapidly deplete the battery for few miles and then use expensive petrol to recharge the battery to use at your destination, rather than press Save? You must have, literally, "money to burn" :lol:

So by pressing SAVE you are burning somehow less expensive "low cost petrol" than me by pressing CHARGE!?
Do you even realize what is happening when you press SAVE?

Hybrid drive train technologies for vehicles:
An advantage of a series hybrid is that the engine operates at its maximum efficiency point(s) thanks to the buffering of excess power; however, one disadvantage is the relatively low transmission efficiency at relatively high vehicle loads compared to other hybrid configurations. Unless the vehicle is used mainly for city driving.

The ‘parallel hybrid configuration’ (Fig. 18.2, bottom) has a higher transmission efficiency due to the mechanical connection between the engine, electric machine and vehicle wheels, and the engine and electric machine supply the propulsion power very efficiently. The ‘series-parallel configuration’ (Fig. 18.2, middle) is a combination of the parallel and series configurations, which benefits from most of the advantages of both configurations.

Fundamentals of Power Electronics Controlled Electric Propulsion:
In parallel... efforts are made to operate the electric motor alone at lower speed and ICE alone at higher speeds. Thus, at higher speed, ICE is operated at most efficient point, and hence, higher efficiency and better fuel consumption along with reduced tailpipe emission can be achieved.

Parallel mode is there for a reason and it's not to make the vehicle more complex.
Will let the others to add to the topic cause I'm already repeating myself.

 

[greendwarf]

Er what !!!!!!!!!!!!

I was asking if you use up your battery before using petrol at high speed, even if you will need it later? Where does "low cost petrol" come into it? I was referring to the difference between relatively cheap energy from the grid against generating it yourself from petrol - doh! :roll:

 

[ThudnBlundr]

kpetrov wrote -
I never use SAVE actually. It doesn't make sense. Why should ICE start and stop when it can do what's needed in one shot?

So you leave home with a low cost full charge from the grid, get on to a motorway, rapidly deplete the battery for few miles and then use expensive petrol to recharge the battery to use at your destination, rather than press Save? You must have, literally, "money to burn" :lol:

Whether you press SAVE or leave it till the battery is empty, the car will run in what is effectively CHRG for most of the time on a long journey, repeatedly refilling the battery with a mile or so of range before switching to EV to empty it again. There are 2 options: (1) use SAVE on the motorway and switch to EV with say 10km to go; (2) let the battery empty, then switch on CHRG to recharge the battery to be able use EV for the last 10km. It makes little to no difference to the fuel consumption to the fuel consumption which one you choose, as the car will run in CHRG for as long as it needs to so that you can reach your destination. The major difference between (1) and (2) is that you have a little more choice when it will run in CHRG