Fuel economy in long traffic jam (data)

Thanks for the info

Just to note - I used to spend about 3 hours morning and 3 hours evening stuck in very heavy traffic and on a Friday it was gridlock pretty much all day. You can get good fuel economy in a Prius in those situations, though sometimes when the HV cycles between 2 & 3 bars with the engine on and off, it does drop a little.

In fact I logged an entire year on fuelly and my average was 49 mpg UK which is about 41 mpg US or 5.7 litres/100km, which is pretty good and matches your findings.

 

Not sure if you can monitor RPM (car will not tell you) from the condition you describe (44F outside) and you were using the heating ... right away. I would venture that your low MPG resulted from ICE never shutting down (OK this is not really winter condition but still) regardless of traction battery condition. In cold weather you can drive quite a bit before ICE will actually stop (if ever) if you have heating on (even moderate levels)....

This car (2010+) really doesn't like to retain heat I use full blocking all winter (just removed last Saturday the lower grill). That matters a lot especially when you need heating ... I monitor both RPM and water temp ...

I found that cold weather has a lot bigger impact than A/C in summer

 

I've seen similar graphs on my car when I've been unfortunate enough to be in a long line of Stop and Go traffic. The symptoms were similar, the battery would discharge (despite my best efforts to not use the battery or drive EV, it is unavoidable when you can't get your speed above 7 mph. I hate seeing my battery going down, because I know there is a massive penalty coming to recharge it.

 

Four minutes is quite long though .... that is for heating ... it should shut down a lot quicker in warmer days.

That is interesting ... my engine shuts down very smoothly almost unnoticable especially while driving .... even when stops after

I agree in my version (USA) the mpg actually read MPG so you would see the full scale .... but that is not the same as yours... highway over 45MPH often you can see the max but I can tell from scangauge that ICE is running 992 which is the lowest RPM ....

I think ICE could turn back up for both traction batter depleted ... engine temperature is dropped (used up by your heating)...

You mean blocking the grill ??? That should be a none issue !!! Volt and some other cars have it built into them .. .the cooling system is designed to cope with up to 120F ambient temp so blocking the grills during the winter is totally fine (engine block heaters are only make sense up north in Canada and some northern states in the US). No warranty issues at all ... but it is better if you can monitor the coolant temp (especially the inverter coolant) ... but using it sensible is a non issue.

Well agree on this when my brother-in-law (in Europe) said no big deal 5l/100km "your sistem car can do better" yes 1000cc no power steering no ABS no power-windows no A/C car sure can do 4.7 l /100km

Let's compare to 1.8L mid-size sedan

 

It think your car could/should give even a better result ....

And in Old Europe this is even a better pay-back then here in the New USA.....

What I usually do is to shut down the car (stops the ICE cold), and only bring up utility power (push start button without pushing the break) if you care for radio !!! that could save a lot ... and who cares sometime you maybe honked not jumping quick enough ... let the ICE only run when you are moving !!! and charge the battery ONLY when you actually moving... this works if you have 2-3-5 minutes waiting ....

Because with two bars you have plenty of juice to wait 5 minutes on auxiliary power, then when you move you use the ICE a lot more efficiently (move and charge ...)

 

Not sure that would work long term Szgabor. When it was a cab it had a lot of electrical equipment running - meter, dispatch computer, 2 way radio, sat nav etc. If I kept turning the car to ACC mode then I'd kill the 12v within weeks.

Also the traffic is more 3 mph rather than complete stop.

 

I am talking about complete stops .... and a predictable 1-2 minutes wait .... and NO I do not run much of anything other than the radio in those circumstances no ACC of course... if I do then will not stop the engine so all electrical is powered directly from traction battery or the generator/motor

I would say this is not for a cab not even in NYC ...

But in a cab scenario your running miles make the prius pay-back time a lot shorter (I assume). You probably drive as much in a month as I do in a year

 

I drive under very similar situation in my daily commute, usually at average speed around 15 km/h for total distance of 8km. My first 3km is usually smooth and the next 5km mostly slow crawl. Including engine warmup, I consistently get around 5L/100km after adjusting for 6% bias. Climate is warm here so that's not an issue and I apply moderate use of A/C. I've just started compiling more data to see how mileage can be affected by average speed.

 

I drive into New York City Midtown everyday from about 25 miles away (not highway) the average speed IS a good indicator in traffic situation. Bad traffic means 13-14 avg MPH on the roundtrip ... good days like school vacation or similar 20-23 avg MPH ... and the mpg nicely reflect it slower avg speed yields about 50-52 mpg but higher easily around 60mpg !!! (

 

Sergio/grumpycabbie, if you don't already have it, you should get yourselves a tomtom with HD traffic. IT has saved me from a lot of traffic jams, especially in downtown Munich, and it is often meter-precise....HD traffic should be available in Poland as well now.
That said, to all, you might also want to read this thread and this post regarding commute time vs average speed vs temperature vs tires...

 

I have TomTom but not the HD traffic. Whilst good in that it shows you where the jams are, that doesn't help in a small city environment where the jams are usually on the only road/route. I know all the short cuts, side streets, rat runs, but they're no use if you can't actually get to the one you want because the arterial road is jammed up.

Unfortunately our motorway network is poor. Infact I remember having a politician in my cab a few years ago who was telling me about his time in cabinet. He said that he was getting held back on transport spending for expansion of the motorway network and got authorisation to build something like 50 miles. That same period Germany built an additional 1000 miles to their network of 4000 miles. The thing he stressed was that whilst we grumbled about 50 miles, that additional 1000 miles Germany was building was more than our entire motorway network at the time!

I don't think much more has been added to our since, though it is despirately needed. The 'Green' party lobby seems to win out every time, grinding our roads to a holt. It's all very well suggesting we all travel by bus, but those buses have to drive on something - a road.

Rant over

 

I read an article once that said why Ireland was the first place in Europe to get the Nissan Leaf.

Apparantly because the temperature is just right at 15-20c. Not -40c like Canada or +40c like Australia, just a nice happy 20c. It also added that electric cars don't mind rain.

 

Sergio/Grumpy - I understand what you say. I drove 9 years the streets of Munich and I thought I knew all possible ways to go from my place to the office everyday. Oh God was I wrong. I have discovered routes and roads I didn't even know existed. I discovered that cutting downtown is sometimes much faster, with all the pedestrians, traffic lights, bikes, garbage collection (always blocking streets at 8am when everybody is going to work....), etc. you name it, than taking the "usual route" around town.

My commute is a min. 13/max 17 km commute, depending on the route, and since I have the HD Traffic GPS, I consistently arrive at the office in 30mins or less. Before it was always 40min-45mins (at the very least).
The amount of fuel I am saving is amazing.

The good thing about the HD Traffic, is that you know exactly where the traffic is, before you even leave the place. So you can take a totally different route than expected, and adjust (it will do it for you) as you go.

This might not be practical in certain situations (as Grumpycabbie said for England: lack of roads), but I still could not imagine now going to work every day without it.

And I am also more relaxed because I exactly know when I am going to be home/office. The damn thing is precise +/-2mins max over a 30min trip with unpredictable city traffic. The only times I get there 5 mins later is because something totally unexpected happens - after all you are driving in town, not in the middle of the desert...

Maybe for Grumpycabbie this does not apply, but Sergio, before you leave home/office, try to check out the route home/office at the routes.tomtom.com webiste and see if what it proposes, with the current traffic situation is what you would do or not. It is also interesting to see traffic change as time goes by during the day... :roll eyes:

I take also the Navi in/out from my Prius each time, each day - I will continue doing it because the benefit of having the Navi each time with me far outweighs the continuous plugging in/out.

The problem with TMC/TMC Pro is that often it is outdated. HD Traffic, is very seldom, if at all, outdated and it is very often precise to the meter. Updates are done every 2 mins, which for a town might not be fast enough, so you might see a traffic jam on the map that is already gone (usually for less than 2mins delay traffic jams). It is based on Vodafone mobile phone positions, as well on sensors, other traffic information, position of other HD Traffic devices, all bundled together. What makes it different is exactly the information from mobile phones and that is what convinced me to get it.

PS: for all US/Canada readers, especially living in towns, HD Traffic is available also there!!! The website above shows also traffic in your towns/areas!