Terrible MPG: What am I doing wrong?

I disagree with the "not hybrid friendly" phrase. I think, although I can't prove it, that the hybrid will get better mileage than any other internal combustion engine on the same route. If your car is cold, you still harvest braking energy and use it on take off or acceleration. So, if you were to drive the same route in the same conditions in another vehicle you would get worse mileage still.

 

Not only that, but the fact that Toyota's hybrids use the Atkinson cycle improves their thermal efficiency over the non-hybrid powertrains of similar system power, and the hybrid system will also tend to keep the engine from running in inefficient particularly low-load scenarios, instead charging the battery, and then avoiding inefficient high-load by using the battery to help.

 

Sure but both he and the OP are comparing their results to Prius EPA numbers (or what others here proudly post) not other cars.

 

I agree it gets better mileage, but not the regular 60+ mpg that @Coast Cruiser gets in California.

 

Not using engine braking mode should improve things allot. If you were using it all the time you may have to allow a few days of normal driving to retrain the computer. Please report back after a couple tanks.

 

I'd suggest DON'T do this - you could void your warranty. The Gen 4 does this automatically.

 

I bought mine in WINTER, and it initially would start the engine every time. The salesman (a mechanic too) said to turn the Climate Control to MIN temp (and the fan OFF so it didn't blow cool air on me) when I parked at night, that way it wouldn't try to warm the heater up. If I remembered to do that, the engine wouldn't generally start.

Now it's SUMMER, the engine almost always doesn't start up for ½ km or more.

 

Yeah this made more sense on previous gen's, done prudently. Depends on temp how much to block, and inverter coolant rad location is a factor. And regardless of ambient temp, I'd pull it all off if doing a protracted hill climb.

Here's the 3rd gen go-to thread on grill block:

2010 Prius Grill Blocking strategy | PriusChat

 

Nice link. I stand by my recommendation...block the freaking grill conservatively if not monitoring temps: improved areo, faster warm-up cycles and better heat retention when the engine is off...although less of a gain on gen 4. Get aggressive if monitoring temps.

But then I just bumped my tires up to 48 PSI and will go to low 50s in a few weeks. I ended up at 58 in my Civic..low 60s was finally too harsh with minimal loss of rolling resistance.

 

The Gen 4 already blocks the grill if it determines it is needed.
Are you smarter than a Prius??

BTW. The tires that came on my Gen 4 are rated at 44 psi maximum. What you did on your Civic would be dangerous on the Prius and void any warranty.

 

Short trips and temps below 40F are killers for gas mileage...

I can get 70 mpg on my 25 mile commute home from work, but when I go for my sunday shopping run (around 3-4 miles total), I can only manage about 32-42mpg. It's a short trip with a few stops in cold weather...

 

One thing you 2016'rs (with active shutters) can probably still do, is seal up the engine bay air a bit. This is on my third gen, there's no seal between hood and fender lip. I put these foam tubes in once temps start dropping:

 

2017 too ...

 

Some people have recommended a block heater but I wouldn't recommend using one (except in extreme cold environments where you might have a frozen engine otherwise). Using a block heater means turning electricity into heat, and while you can do that with 100% efficiency, if fuel (coal, natural gas, oil) was burned to get the electricity only about 50% of the fuel's energy went to generate the electricity; i.e. ~50% overall efficiency. That fact usually ends up built into the cost of electricity.

Meanwhile, when you start the engine, some of the energy goes to propel the car, and much of the remainder naturally goes to heat the engine, although some escapes out the exhaust. However, I believe the 4th generation Prius uses the exhaust gases to also help heat the engine. So, you get most of the energy either doing useful work or heating the engine. Finally, someone recommended pre-heating the engine for a couple of hours. But, that means a couple of hours for heat to escape, which costs even more energy.

Thus, from an energy perspective, it should be better to simply drive normally and let the Prius heat the engine than to pre-heat it with an engine block heater.

 

Depends on what the impact to fuel economy is, though. And, if you're actively letting the car sit to warm up the cabin, then you're wasting energy there, too, that would be better spent as electricity than gasoline.

 

I think Gregory is suggesting getting in and driving away to warm up, as opposed to letting the engine warm up before driving away. At least, that's how I interpreted it.

 

The truth is these toyotas will only ever hit the MPG numbers if you drive like a grandma in perfect conditions. Once you start putting in any meaningful number of short trips and/or use lots of cabin heat when it's very cold and/or don't drive like a grandma and/or the temps are low so the battery doesn't work quite as well,etc., you just will not match the numbers. My winter numbers on my 2010 prius were as much as 20% worse than the 50 MPG we were supposed to get; some tanks in the high 30's in harsh winter weather. My 2015 avalon rated at 40 MPG will give me as little as 33-34 MPG a tank in the winter. In the summer it will be high 30's.

 

Now, THAT isn't necessarily true either - with a moderate driving style, I can hit EPA city or better on short trips when it's at least 50ish F outside. On long trips, I usually beat EPA city in those conditions, even though it's highway, usually setting the cruise for 3-5 over. (We'll see what happens on longer trips in winter, though.)

 

The EPA tests changed. Most people easily exceed the 52 mpg combined for Gen 4 without driving like Grandma.
I regularly get over 50 & usually 55. Others in more level areas get over 60.

 

This grandpa drives more like a grandma than grandma.

Seriously: keep a generous following distance, keep your cool, keep to the limits.