Stop and Go in Heavy Traffic

You're not burning fuel while you moving a snails pace. That was the whole reason I bought a Prius... LA traffic.
Enjoy your new ride.

 

Curious why you think this traffic pattern will kill your new Prius? Did your last car suffer because of it?

The Prius is perfect for stop and go. No engine until it needs to move or recharge. The only concerning thing is Phoenix. It is hot, so you will want to keep the battery cool, just as you would want to keep the interior cool in any other car. If the car is too hot for you to be inside comfortably, the battery is uncomfortable. This is true of hot and cold. So keep the AC going if it is super hot

 

yes, keep your a/c blasting, it will protect your battery. airflow across radiators is unimportant when moving slowly. the ice has electric fan.

 

The annoyance will come when the traction battery is depleted & the ICE spins up just enough to get the battery over the minimum. Start, stop, start, stop, start, stop until you finally get moving fast & far enough for a longer charge. You'll see gaps in the consumption screen because you haven't gone far enough & your fuel economy will take a hit.

 

As everyone else said, you have nothing to worry about. Your Prius is easier to cool while sitting in hot traffic because your engine isn't always generating heat like if you had a conventional car. This kind of use is what your car is built for. Abiding heavy traffic with minimal wasted energy.

What's not to love?

 

That is where the Prius shines! You have electric fans to keep the engine temp. within specification, an electric "air conditioner" to keep you and the traction battery happy, electric steering so you can aim when the engine isn't running. What more would you want? As stated above, your mileage will drop in those situations, but not nearly as much as the other poor sods in "ordinary" cars!

 

What you'll see if you sit in traffic long enough is that your gas mileage will eventually drop. As another poster pointed out, so long as the traction battery retains charge, no gas is actually burnt while sitting there. The A/C does run off the traction battery so, eventually, the ICE will turn on when the traction battery charge gets too low. When it's running and the car is standing still, you can kiss 50 mpg goodbye.

However, having said that, the car still eats a lot less gas in that condition than a conventional engine which always has to run. So, while you'll be suffering a bit, all the other drivers around you will be suffering quite a bit more, at least in terms of MPG.

There's still plenty of cooling for the ICE in the electric fans that blow air through the radiators, so you're not going to overheat the engine. And, as a couple of posters above alluded, there's much less heat being blown about since, well, the ICE doesn't have to run all the time.

The Prius is built for this. Don't worry, be happy.

KBeck.

 

It's design for heavy traffic and city, here in DC/VA/MD area when I have my AC on you should see the SUV open their windows to save gas.

 

According to my ScanGauge display, my engine actually cools down in these situations. Most of the time it is shut down, not burning any fuel.

The ambient temperature in my region never reaches your 100s, so the cool down rates are not the same, but the concept should still be the same.

 

This.

In some cases the gas engine (ICE) comes on when you've been poking around slowly for a while and the hybrid battery depletes, but that's what it is designed to do. It will eventually turn off the ICE when sufficient charge is generated, repeating the cycle as necessary. Happens to me somewhat regularly here in the DC area but I've never been concerned. Annoyed that it's taking that long maybe, but that's about it.

 

My commute is 10 miles each way, 20 miles rt, same route to work and back home. On a just filled new tank of gas going to work I traveled at 45-50mph with hardly any traffic, when I reached work the display showed 60 mpg. Stoked! Then on the way home, several traffic accidents snarled traffic, average speed in traffic was less than 5mph, stop and go and sometimes a flat stop. It took me 1.5hrs to travel 10miles. Anyway when I finally get home, my record breaking morning commute of 60mpg dropped to 48 mpg. The EV mode didn't last too long in traffic so engine was running almost constantly, ac was on but just could not get the battery to recharge going 5mph. Bottom line: Heavy traffic is a mileage killer.

 

Just think how bad your mpg would be with a regular car of any make or model. 5-10 mpg?
Enjoy your Prius!

 

Yup. You can't always expect 50+ MPG for regular driving. But you can just about always expect the Prius to do it more efficiently than almost everything else.

 

Your 10 miles in 1.5 hours is an average speed of less than 7 mph, well below the Prius' most fuel efficient speed of about 15 mph, absent accessory loads.

But I suspect the biggest mpg killer was the AC. The same heavy slow traffic in cooler conditions not requiring AC should have boosted the MPG even higher than the morning commute.

 

Chicago is the same. Stop and go and get nowhere. It is not killing your new car. A hybrid car is designed for just that type situation.

 

Yes, you are slowly killing it.
If you use it that way all the time, I'd expect that after two or three times the distance at which a traditional car is dead or rebuilt, the Prius will likely be be in bad shape.
The Prius is better than traditional cars in many ways. I think that you should expect handling the conditions you describe to be one of them.

 

After fours years.... my personal exprience...

Part of my commute involves driving in stop and go traffic normally from 15 minutes to 45 minutes in the Washington DC area and traffic comes to a full stop for minutes at a time. It's a crawl and stop affair with me too - but maybe not as long as you. Is it killing my 2010 Toyota Prius? Not really. I lost my oil change access door when the clips fell off and the door drag along the superhighway until it fell off - that I fault on the Toyota Dealership which last changed my oil change for not putting in new clip to the oil change access door. My Prius' high voltage battery and power plant and transmission wise as well as my brakes pad on the my Prius are doing fine. I still have my original Yokohama Avid S33d tires but at 49800 miles - I am thinking may I should be replacing them since the tread looks mighty thin....3 of my tires were damaged and repaired last year from tread punctures but that was due to road hazards which were likely caused by road construction. The thing that hasn't worn very well in my Prius is the interior - the air rest for the driver and the labelling on the steering wheel controls.


Your Real Problem ...

My guess is that you have your air conditioner on full blast while you are waiting in traffic and your Prius periodically turns itself on to recharge the high voltage (HV) battery when the battery level goes lower than 3 bars - this causes your overall fuel efficiency to drop to somewhere 32 mpg to 42 mpg. Your primary question is whether this will eventually kill(prematurely age) your new car - the answer is no. The Prius turns itself on and automatically recharges the HV battery to protect the HV battery and extend its lifespan to +12 years. Running on the Air conditioner on a hot day, actually helps extend the lifespan of the air cooled HV battery whose air intake draws from the Prius passenger cabin so by keeping yourself cool you keep your Prius' HV battery cool - which is a good thing.


Can you answer the Question I was thinking but not asking?

My guess is now you are thinking - why isn't the Prius achieving the EPA mpg rating in stop and go traffic??? The answer is that no vehicle achieves their EPA mpg rating in stop and go traffic - conventional gas and diesel vehicle achieve much worst while hybrids don't do as bad.


Okay that begs the question - how can get better fuel efficiency in stop and go traffic in a brutal heat wave like in AZ???


for the rest of us.....

1) set your Prius in PWR mode - try to accelerate with the gas engine and avoid using battery-electric power - this will mitigate the frequency and need to recharge the HV battery which is a lossy conversion. How do you accelerate using the gas engine only? Set the Prius onboard computer display to the Hybrid System Indicator (HSI) display and press the accelerator so the bar goes pass the middle (pass the "C" in the "ECO" pill marker above) - this will automatically engage the gasoline engine. However, don't go too far pass the "O" in the "ECO" pill marker above when you accelerate if you want to keep your MPG up. Avoid go into the "PWR" mode or the "RCHG" mode - middle is good - outside is bad. Does this suggest a design flaw? Yes. The Prius is missing a only gas-engine power mode.

2) In a stop and go situation, don't start to accelerate until you have one or two car length in front of you. Wait for all if not most of the vehicles in front of you to be moving - so you can have a sustainable lengthy forward motion. The longer distance you travel before you have to do a full stop the better your fuel efficiency - but you knew this didn't you? While it is so obvious - it is so fundamental than it needs to be said over and over again.

3) Do a mini-pulse and glide, Accelerate to 5 -15 mph then coast (glide) on your momentum the rest of the way. What you want to do - is keep your top speed lower than 15 mph if you are going only 7 car lengths (about 100 feet) at a time - the glide cycle should be +1/2 of the distance you are travelling. When you eventually have to full stop - the Prius should not be going faster than 12 mph before you need apply the brakes If you are going over 15 mph when you need to apply the brakes you have accelerate way too fast and you are wasting fuel. A full stop is the biggest fuel efficiency hit - loss with regards to fuel efficiency - the lower your speed at the time you need to do a full stop - the less energy you will lose doing a full stop.

4) over inflate by 7 psi your tire so it rolls nicer


cooler ideas....

5) tint the Prius glass to the maximum your (AZ) local jurisdiction allows so your Air conditioner doesn't work as hard

6) set your air conditioner on auto with the temperature set at 80 or higher so it does not work as hard.

7) before you start the Prius drive on a hot afternoon day - open the doors for a minute or so and let all the hot air escape before getting in and turning on the air conditioner - this well lessen the work the air conditioner has to do.

8) buy a windshield sunshade (like one from the Prius Chat store that fits perfectly) and put it over the dash board of the Prius when it is parked outside during the day exposed to the hot sun - it works to keep your driver and front passenger seat cooler in the afternoon.

9) park in the shade when you can.


costlier options...

10) Get a Prius with the solar roof option

11) Get a plug-in Prius with an extended battery capacity.

12) To stay cooler - you can buy a cooling jacket - it is normally made for firefighter/fireman who need to go into a burning building to rescue somebody or a construction worker who has to work all day in the extreme heat. . It can be very expensive and you can't just buy it at the local big box retail outfit. The cooling jackets have pockets to put cooling elements in - the cheaper one use gel ice packs the more expensive ones use phase changing material (PCM) packs. Cooling jackets are rated by how long they keep you cool in a standard environment / temperature setting. Some professional cooling jackets are designed to be worn underneath a Nuclear power plant radiation suit or a fire fighting suit. Normally they keep you cool from 45 minutes to 3 hours with most designed to keep you cool for a little over 90 minutes.




hope this helps
Walter

 

Ignore that display. Albeit this is just a 2.2 mile commute from the gym to home after traveling from work to the gym but I get this in my display ALL THE TIME on the commute home of 7.7 miles. Not quite sure how my morning commute averages about 50mpg and I can get this on the way home and still not get over the low 50's on a tank.