Road trip results

@Pete H.
This is excellent.
I would not have expected 43 mpg at speeds of 70-75, but I believe you did the calculation exactly right.

I am curious about your modus operandi...
With most of the trip obviously in HV mode, did you let the EV range just go down to zero and automatically enter HV, or did you intentionally keep some EV range (in-between charges) by manually invoking HV?

 

It's not your imagination. I've had the same experience. It makes sense because the BMS is trying to protect the battery. The car doesn't know if you're on a long uphill stretch so it'll rely almost entirely on the gas engine when the battery is low. On a mountain grade near my home, if the battery is low (it doesn't have to be that low, I see the effect at 40%), the engine will scream and I'm basically in the slow lane behind the semi trucks. If I have over 50%, I can be in the fast lane and the engine will just purr as it gets a substantial amount of power from the battery. Thus, I never allow the battery to deplete before going to HV because you go from a 180 hp vehicle to maybe 100 hp and that's dangerous for a 2 ton car. I always have at least 50% in HV.

 

125.3kWh’s equates to roughly 9-10 full charges, or ~400-450 miles. In my experience, some range, 2-3 bars, will be used on long trips, provided that HV is engaged immediately after every stop.

Where do you believe most of the EV range was used?

 

I used to feel the same way about HV Charge and felt like it always had to be a hit on overall economics of operating the car. I've since changed my mind, at least somewhat. Running HV charge can at times allow the gasoline engine to run at a more efficient point (than if HV charge was not engaged), sometimes more than enough to make up for any electrical losses from charging and discharging the battery. I think it is best accomplished when the engine is not being stressed at all in HV mode, maybe pretty level ground at 45-65 MPH. Bottom line, I don't hesitate to use HV charge to gain back some bars on a long trip after I have forgotten to engage HV mode after a stop, especially if I'm in a stretch that isn't already stressing the engine at all.

 

Because of the way the car is programmed to operate, there really is no way to properly account for or separate electricity miles and gas miles. Even when in HV mode, the car will sometimes be powered only by the battery—and it will at least attempt at some later point get the charge level back up to where it started. Unless you are keeping a watchful eye on the power meter and keeping a detailed log of the distance traveled while the car chose only to use battery, you won't know how much electricity you've used. Just keeping track of how much you add in at a charging station doesn't give you the full story.

I'm going to guess that the EPA numbers have that voodoo cooked into them. Trying to account for electrons during a long trip that is predominantly in HV mode is basically fruitless.

 

Yes it does. There are only 2 sources of input energy - energy from the grid, and energy from gasoline. If you account for your gas, and you account for energy that enters from the wall, that is all there is. Yes, the HV battery gets charged sometimes from regen, or from the engine (gasoline) during HV operation, but that energy is not unaccounted for... It either came from gas, or wall power.

I do not believe there is any 'voodoo' in the EPA numbers at all. The EPA rating of 31 kWh per 100 miles is a measurement of EV operation (strictly EV mode with no gas being used - electricity in, and miles out).

You can separate the two. When you drive in EV mode, NO gas is used... You know kow many kWh you put in from the wall, and you know how many miles you got out. When you drive in HV mode, you burn gas. You now how many gallons you put in, and how many miles you got out. It doesn't matter that there is a complex dance going on behind the scenes alternating between EV and ICE. As long as there is no net change in SOC throughout the experiment, it is simply gas in, and miles out. HV is designed to hold the SOC constant. If it is not perfect (as some have found) you can account for any net change in SOC when determining your gasoline mpg.

 

The mere fact that in HV mode the car is deciding at any particular point in time whether it is using battery only or gas-assisted electricity makes it impossible to accurately separate the two. The only thing you can do is to agree to accept that if you drive 200 miles in HV mode, and you used 5 gallons of gas, you averaged 40 mpg even though some of those miles may have been on battery alone, even in HV mode. It could be that 12 of those miles were handled by battery alone, without the engine running. In that case, you only got 37.6 actual mpg on those 5 gallons. You simply don't know and there's no way to find out without staring at the power meter constantly and manually jotting down info instead of paying attention to your driving.

Also, although the car ATTEMPTS to maintain SoC in HV mode, it doesn't always do that accurately. Just yesterday on an HV drive home, at one point I noticed that the EV range had gone up above the starting point (not in HV charge mode). Straight EV miles are the only ones you can determine with accuracy. Unless the manufacturers are doing some VW-type of gimmickry, the EPA test cycle numbers for PHEVs have to have blended energy (battery & gas) involved in the MPG figures.

 

We will have to agree to disagree on this one. If we carry your arguement to absurdity, you could say that none of your miles are gasoline (because the Clarity is fundamentally a serial hybrid, and thus all the miles come from electricity, not gas). An exception of course, is the direct drive mode which departs from the serial hybrid paradigm.

Let's consider your example a little more carefully however. Let's say that you drive 200 miles in HV mode, and use 5 gallons of gasoline. I contend that you CAN precisely state that your averaged 40 mpg (as long as the SOC is the same before and after the experiment). During those 200 miles, it could very well have been that 12 of those miles were handled by the battery alone, but that does not change the fact that you really, really did get 40 mpg during that trip (as long as the SOC is the same before and after the experiment).

Now, if you want to address the fact that the SOC is not perfectly maintained, then I agree... Unless you account for the change in SOC, then your 40 mpg is wrong. Let's create an example that includes this effect - You start out with 50% SOC, and you drive 200 miles (using 5 gallons of gas). When you are done, the SOC has dropped to 30%. Now, I will agree with you that it is not possible to 'perfectly' know your gas mpg because indeed some of the 200 miles were taken from the battery (which was charged from the wall earlier). But, it is easy to get a very good estimate. Roughly speaking, you get 50 miles with a full charge. This means that the 20% SOC 'droop' that you experienced is equivalent to ~10 miles (20% of 50 miles). This means that you really only got 190 miles with 5 gallons, or 38 mpg.

If your EV range happend to drift up (as you experienced yesterday), then it would mean that you mpg was actually better. If the SOC were to increase by 20% during the 200 mile experiment, then you effectively got 210 miles with your 5 gallons, or 4 mpg. The only time I have seen the EV range drift up (while in HV mode) is during a sustained downhill where there is sustained regen. Eventually it comes back in my experience.

I actually think we actually agree more than we disagree. Yes, you can't know what your exact mpg is when in EV mode (unless the SOC is the exactly the same before and after the experiment). But you can get extremely close by including the change in SOC as an adjustment to your calculation.

 

If you’re anywhere close to being the average American, approximately 60% of the electricity that you use to charge the battery is generated from fossil fuels. There’s some debate as to the efficiency of that charging process. Regardless of the outcome of that debate, it is a handy feature to be able to charge the battery while traveling from point A to point B.

The manual recommends using HV Charge while driving at sustained high speeds. High speeds could be interpreted in different ways. For many, 45-65mph would qualify. It doesn’t take a great deal of horsepower to keep a car moving along at 60mph. As you’ve mentioned, it’s the ideal situation to use HV Charge.

 

I just got back from my first highway trip of 1000 miles. Used HV charge to bring the battery over 1/2 and travelled in HV mode over the rockies from Vancouver to Edmonton with a couple stops along the way. Cruise was generally set at 68mph(110 kph) and filled before leaving and when I got to my destination. Average fuel economy was an impressive 44.5 miles per US gallon (56 miles per imperial gallon). Although this is not the way the car is going to be primarily used now that I'm home it is good to see how relatively efficient it is in HV mode.

 

Thanks for sharing.

You could consider a move to Oregon, where regular gas is approaching $4/gal. I believe we’ve officially turned in to California although there’s been no formal announcement.

I was responding to your engineering sensibilities rather than your financial acumen. But, if you don’t care how the electricity is generated, why do you care how the electricity is generated?

 

Just for perspective I paid 1.90 per liter in Vancouver for the first fill. 1.90 X 3.78 = 7.18 Can$ X 0.79 exchange = $5.67 US $ per US Gal.

 

For additional perspective - What is the cost of electricity up north in Canada?

 

Varies from Province to Province. I pay approx: 11.5 cents a kwh in British Columbia with a $17.50 a month service fee. In Alberta I pay 6.8 cents a kwh but the service/delivery fees and rate riders are close to tripling that if you do the math. All in Canadian peso's

 

The first plug in Accord acted just like this. It would self charge when on level ground and downhill. Then use the battery on the to assist on uphills.

 

My old 2003 VW Jetta TDI got 49mpg.

Honda should had used the planetary gear dual motor design that the new Camary uses. It allows for a variable final gear drive.