Eco Drive Ratio Confusion

[Trex]

............................................ my point is that you could take delivery of a brand new PHEV, never connect it to an external charger and a year later it will be telling you that you have driven 30% on EV. That is misleading as far as I'm concerned - all the distance you've driven has been achieved by burning petrol - just that 30% of that petrol consumption was deferred by a few minutes.

Now IMHO I like to see how efficient the PHEV has been and by seeing that EV ratio while burning fuel ie the closer to 100% that ratio is the more efficient the PHEV has been running ie better fuel consumption. Its showing just how much that bloody inefficient petrol motor (to me all ICE engines are inefficient when compared to batteries, electric motors etc) has been shut off.

So why do you think it misleading? Sure fuel, and some regen, has been used to make that EV ratio (once the grid charge has been used) but it was fuel used to generate electricity plus drive the front axle when in Parallel mode. Remember it is Hybrid Electric Vehicle (HEV). It tells us that that by putting the petrol engine in its efficient "zone" by generating electricity it can shut the petrol engine off approx 40% of the time for me on long trips ie it acts like a extreme overdrive ratio IMO. I use that EV ratio to tell me my average RPM of the petrol motor at certain speeds and at a certain SOC in the drive battery.

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I would not disagree that the proportion of the time running with the petrol engine off is an interesting figure, but I do think that describing it as "The EV ratio" is misleading. As has been demonstrated very strongly on this forum, a high proportion of PHEV owners seek to minimise petrol consumption - to the extent of pulling fuses to disable the engine and driving in multiple layers of clothing in order to avoid having to turn the heater on. While you have charge left in the battery from the last mains hookup, you have the potential to remain 100% EV provided you adopt the right driving style - that, I believe, is what most ordinary people would understand by "EV ratio". Once you have completely exhausted the charge that you took on from the mains, then you are driving a petrol car with an electrical transmission. The battery is providing a reservoir to buffer charge which was accumulated by running the engine at its peak efficiency rather than simply setting it to output the power level necessary to maintain your road speed but I maintain that recording those periods of consuming surplace energy from the battery on the same gauge that is also used to report the relative use of petrol and mains derived power is misleading.

Look at it this way - my normal pattern of usage is a round trip of about 250 miles each week with a few more miles done locally at weekends. As you know, I am unable to charge during that 250 mile round trip, so the car gets a mains charging once or twice per week. I get about 20 miles from a charge - perhaps 25 in the warm weather - so, in my book, the EV ratio of my car is around 10%, possibly a bit lower. Another driver with the same car, but a different lifestyle, could come close to never burning petrol at all. Greendwarf lives in London and uses his PHEV almost exclusively for short range commutes. My PHEV generally reports EV ratios between 30 and 40% - I guess that his generally reports something closer to 90%. Is his usage just two or three times more fuel efficient and ecological than mine? Of course not! My fuel consumption and carbon footprint are similar to what I would achieve with a similar sized pure petrol vehicle while his must be pretty close to zero.

Whoa hang on Maby I think we are getting mixed up here. You seem to be talking about a long term EV ratio compared to what I think most of us here are considering short term. The page I would consider most of us are using on trips etc is the short term page or auto reset page ie resets regularly either automatically or we can manually reset if we want and then on the old model PHEV we have a what I consider the long term or manual reset page. I never reset this page as I want long term fuel consumption etc.

Now the Op that started this thread has the Smartphone link Display Audio (SDA) system the same as my new PHEV and my old PHEV my son drives has a MMCS. So Keith the Op is showing us his short term or long term (can be both) Eco Information page and he has Auto Reset Mode turned on ie little yellow bar besides the touch screen Auto Reset Mode button. So the Op has short term turned on. With the SDA the PHEV now has a quite intricate history page showing graphs etc instead of the old long term or manual reset page from the MMCS from what I have seen.

So what I am trying to say is what most of us here have been saying is probably right including yourself for IMHO we are at crossed purposes.

Now as for comparing yourself and Mr Greendwarf Sir I think we can look at it this way on the short term screen. Mr Greendwarf Sir while driving around London will be showing 100% EV ratio and --- mpg fuel consumption while you on your trips away will be showing between 30 and 40% EV ratio and say 35 mpg. His is quite a bit better I think.

 

[greendwarf]

Look at it this way - my normal pattern of usage is a round trip of about 250 miles each week with a few more miles done locally at weekends. As you know, I am unable to charge during that 250 mile round trip, so the car gets a mains charging once or twice per week. I get about 20 miles from a charge - perhaps 25 in the warm weather - so, in my book, the EV ratio of my car is around 10%, possibly a bit lower. Another driver with the same car, but a different lifestyle, could come close to never burning petrol at all. Greendwarf lives in London and uses his PHEV almost exclusively for short range commutes. My PHEV generally reports EV ratios between 30 and 40% - I guess that his generally reports something closer to 90%. Is his usage just two or three times more fuel efficient and ecological than mine? Of course not! My fuel consumption and carbon footprint are similar to what I would achieve with a similar sized pure petrol vehicle while his must be pretty close to zero.

You are right, normally my EV% is 100 - unless I get over excited on the Park Lane race track :lol: - but when I slammed it at high speed (up to 85 mph) down to South of France in August, I seem to recall it was around 30%. Perhaps this is just a measure of the relative efficiency of the hybrid setup over a normal ICE and you will only see less than this if there is something wrong with the car. :idea:

 

[STS134]

Well I was playing around with this feature this morning, and I found something interesting. The "EV Drive Ratio" takes into account the following:

It is a ratio of the following: The amount of time the vehicle has spent moving without the ICE on, divided by the amount of time the ICE has been on (regardless of whether moving or stopped).

Yes, that's right, if I hit Charge while at a stop, I can watch the meter steadily decrease. But switching off Charge mode and standing still does not cause it to increase. I have to actually move the car in order for it to start counting time again.

Which makes me wonder if you can get a ratio over 100% by sitting still in Charge mode for a long time.

Interestingly, when it's doing the hysteresis in Save mode, or in Normal mode with the SoC at or below 30%, it counts the time the ICE shuts off and it briefly discharges the battery as "EV drive" time. Not too useful because as far as I'm concerned, those are ICE miles.