Consumer Reports MPG Result For 2013 Fusion & C-Max Hybrids!

It sounds like a grudge to me. Did Toyota hurt your feeling when they decided to stay with NiMH?

Not sure what you've been reading but I have been following Toyota and Li-ion for a long time. They said after 3 years validation test, the durability, stability and safety were assured. However, the cost was still high so it wasn't ready yet to replace NiMH. Here is a post with more info, posted before you joined PriusChat.

My PiP has Li-ion and my previous Gen2 has NiMH. For hybrids, I think Toyota made the right call by staying with NiMH. Li-ion is better for those with tight spaces (Prius Alpha) when you need 3rd row or PiP (to retain flat cargo floor). Then, the higher premium is worth it.

The price of Li-ion is falling and the demand is raising and the long-term durability would be known when the Gen4 is rolled out.

Remember, Ford was using the primitive Cylindrical NiMH cells (like Honda). Toyota hybrids switched to Prismatic NiMH since 2004 models. So, it makes sense for Ford and Honda to switch to Lithium. There is no clear benefit for switching from prismatic NiMH to prismatic Li-ion, just some pluses and some minuses.

I agree with you that the difference is not much to talk about. Camry hybrid has a little more power 200hp vs 188 hp, a little lighter and with a little more trunk space but Fusion hybrid seem to get a few more MPG, due to smaller ICE displacement (2.0 liter vs 2.5 liter).

 

Ford has said that the difference of 65 mph and 75 mph in speed is 7 MPG for C-MAX hybrid. You are seeing 6 MPG in Fusion hybrid and it makes sense because Fusion's frontal area is smaller so less drag.

Once it is broken in and the outside temp raise to 70 deg F, you should see about 10 MPG boost. It seems Li-ion is very sensitive to cold temp.

Edit: Wait, you are already in 70 deg F weather right? Perhaps the non-LRR tires are taking 5 MPG hit?

 

That blurb was from the gen I fusion which uses prismatic.

Battery A nimh (camry hybrid) - 150lb, 44 hp peak, 1.6 kwh
Battery B lithium (fusion hybrid) - 106 lb, 47 hp peak, 1.4kwh
Battery B is also physically smaller. Lithium should allow battery B to use a broader SOC, but we don't know the details yet. Ford said they paying less for lithium than they were for prismatic nimh from panasonic. This likely is not true yet for Toyota.

Yes, Camry and Fusion take different trade offs. According to car and driver the fusion has the worst packaging of any of the midsized cars, Lithium would take less space not more in the camry.

The engine down sizing shouldn't really affect highway mileage with cruise control. It should help city mileage as will a slightly more powerful battery. If you are going under 60 mph and hypermiling the ford system should help also. Acceleration is much better with the camry hybrid at high speeds.

 

Trivia correction -- Toyota switched to prismatic in 2001. Only the NHW10 Prius sold in Japan between 1997 and 2000 had cylindrical cells.

 

A cruise control managed, constant speed too. That area of Florida and Georgia are fairly flat.

The flat MPG strongly suggests something associated with rolling drag is wrong. Dragging brakes is the most likely culprit but I would not rule out tire alignment . . . excessive toe would make it seem steering OK but be rubbing the rubber off. I had considered the wrong fluid in the transmission but that should have a non-linear effect . . . but I would not rule it out. If someone filled with a heavier grade transmission oil that would increase drag, heat, and possibly blow-out some seals depending upon the design.

Something is wrong and I would probably start with an IR thermometer and after driving the car around for 30 minutes, start measuring temperatures of everything that can be seen. Heat is the signature of energy waste.

I have not considered a major engine tuning issue but that would take an OBD scanner. If the spark failed to advance, the engine would be exceptionally inefficient. However, we should still see the aerodynamic effects between 55-65 mph even with a badly tuned engine.

Something is broke.

Bob Wilson

ps. Please do not set your 'hair on fire' but major energy losses like this are associated with excessive temperatures. This is the cool time of the year but when the weather gets warmer, one risks seeing some part get too hot and failing. There is time enough to diagnose what is going on but please don't put it off. If your dealer or mechanic blows you off, I know someone in Wisconsin who I would trust to do a through investigation.

 

Taking it in after work today. I drove it to work, just to verify that the MPG is the same as before my trip, and it is, got 39 MPG and should have been well in the 40's, if I drove my 2010, it would have been an easy 41. I havent felt the wheels or tires, but I do notice the rears have a bit of brake dust on them. Then again, so does my 2010, the Fords use more rear braking then front.

I'm leaning towards poor tire choice and possible alignment too.

 

While poor tire choice will increase rolling resistance, it won't have much to do with drag. The fact that you got the same mpg at 55 mph as 65 mph means something is wrong as drag should have a major impact at these speeds. Alignment could account for it, or bad software in showing you mpg, or lots of other things.

If your local dealer is not helping, I would contact ford corporate. If I were you I would not be happy unless they swapped in 17" low rolling resistance tires and gave me a n alighnment or gave me money to do so.

 

Here is a data point from clean mpg - Wisconsin.
http://www.cleanmpg.com/forums/showthread.php?t=45224&page=4

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Its interesting that he is speculating that the car's software is doing something at 60-63 to make it less efficient. If that is so, I hope ford can fix the software bug, toyota did fix the braking software bug in my gen III prius. I am not saying there is a bug, but their is that possibility.

 

I don't think it is a bug but a feature.

C-MAX Hybrid doesn't have EGR (like Prius) to reduce pumping loss at low engine loads. Its ICE has higher displacement than Prius (2.0 liter vs 1.8 liter) so that makes it worse. I think what's happening is that ICE is recharging the battery with the excess power and then shutdown. ICE can't be shutdown above 62 mph so ICE would be forced to run with pumping loss.

Prius ICE can go as low as 13.4 hp (10kW) and maintain 230 g/kWh BSFC.

 

You bring up a very good point!

We're used to the Toyota Atkinson cycle but have almost no knowledge of the Ford version. If their variable valve adjustment was not working correctly, the engine could have a really inefficient, operating line. An Otto cycle would have a similar problems under low power conditions.

Now if someone could get a readout of the engine torque, rpm and mass-flow, they could generate BSFC charts for the engine. This would provide exactly the type of data needed to diagnose what is going on.

Diagnosis of a failing, valve adjustment system could be . . . difficult. If Ford uses a 'to the stops' adjustment, either ON or OFF, there would be no need for angular reading of the cam adjustment. One would almost have to put in a sensor to determine if the cam angle adjustment mechanism was really working. . . .

Great hypothesis!

Bob Wilson

 

+1

I've heard that a lot.

There are a lot of little things in the prius liftback that will make it more efficient than the c-max. The two big things are cdA and rolling resistance. The prius liftaback simply has a lower load, much lower because of cdA at high speeds.

cooled egr and ehr are little things that can make it more efficient. I doubt either of these have much of an effect at 60 mph.

The prius engine is lower displacement and has a greater expansion ratio 13:1 versus 12.3:1 in the Camry and ford hybrids. This may slightly reduce pumping losses and lead to slightly higher ice efficiency at 60 mph. At some higher power level I would expect the ford ice to become more efficient, but a hypermiler may not get to these power levels .

The ford hybrids should be able to shut off the engine and buffer in the battery to help keep the ice in the most efficient range. This requires good software that understands the trade offs. We only have anecdotal evidence that the software is not doing this well right now. We need to know the bsfc map of the 2L and how the software works to know for sure.

+1

Yes, and with cooled egr it is able to keep close to this level at lower power levels. This may help explain better city mpg in the gen III versus the gen II in spite of higher rolling resistance.

 

The guy quoted from cleanmpg.com seems to be validating the theory I posted earlier that Ford is doing charge/discharge cycles at speeds under ~63 mph much like the Chevy Volt.

So now the question in my mind is whether the reports of "low" mpg at 55 and 60 mph are accurate or if people are confused because they aren't accounting for the charge being saved in the battery while the ICE is running. At shorter test distances this can make a noticeable difference.

When properly accounted for, the Volt gets 45-50 mpg on flat roads at 55-57 mph around 60F.

I just joined volstats.net now that it is using the new OnStar web API to get their data. For various reasons, my lifetime MPGcs (hybrid mode) is not representative of my current driving pattern but if you click the Monthly Totals tab and scroll down to the raw data table you will see my last 2 weeks of driving since I joined in early December.

It currently shows that I got 46.78 MPGcs driving just more than 300 miles.

Volt Stats: Details for Volt #2011-00042 (Jeff N)

 

It will put extra stress on the battery pack for sure.

 

Really folks,

We need facts and data to test these hypothesis. My one visit to the Ford forum suggests they have the skills and resources to run this problem 'to ground.' Perhaps it is time to let them do 'the heavy lifting.'

Bob Wilson

 

And the Sonata hybrid. Cleanmpg.com reported that it does an automated pulse and glide while cruising(don't recall the speeds it did at).

 

That's hogwash. The Prius has no trouble getting EPA mileage at 70mph on the freeway. Drive a GenIII and a C-Max from LA to Sacramento with the CC set at 70mph and watch how much difference there is between the two despite similar EPA highway ratings.

 

Why do Ford's new hybrids ace the EPA fuel economy tests?

Seems like a partial retraction.

It should mention weather, HVAC, and other factors that are accounted for in EPA but not in CR.

It should also show city mpg, and include the prius c if they want to be fact based here. It is not as if other hybrids are normally within 2 mpg as they implied in the initial opinion piece.

Ford definitely seems to not do well at higher speeds. I wonder if CR got a fusion with 18" wheels which is not discussed here, we know from Car and Driver that the fusion tested there had the 18" wheels.

 

I would be willing to wager the difference in FE between the 17" Energy Saver A/S tires and those 18" LS-2 tires is at least 3mpg.