Lifetime MPGe

I believe my gen-1 Insight was the only Honda that maintained lifetime stats on fuel economy. They did away with that feature when they designed the Civic Hybrid and gen-2 Insight.

 

The trip measurement (like mine, not reset since it was new) is MPGE, is a combo of gas and electric.
Electric MPG seems to be set at a flat 199.9 MPG. "Normal" driving gas only MPG is in the low 40's (like the EPA ratings). So, if I have driven 50% gas 50% electric since the beginning, that works out to 120 MPG.
If you drive one trip today on electric only, you will see the current trip registering as 199.9.
If you drive gas only for the next week, you will see the 125 declining.
I haven't seen this specifically written anywhere, but from my observation, this is how I believe it works.

 

I just track mileage myself. The computers in any vehicle are never accurate. My most recent fillup on the Clarity at 33895 miles, total 356 gallons over time. Average on gas trips was 48-ish, so 17000 of those miles have been gas. Average "MPG" including both gas and electric travel is 80.24 so far. I have never had any kind of "smart" EVSE so I can't say how many kWh were involved on the electric miles, but if n1+n2 / 2 = avg(n), then the advertised MPGe of 110 is close.

 

The MPGe figure is just an estimate, and I would not take it to the bank. I look more at the direction, rather than the number itself. I don't track gas mileage, but am very pleased with this vehicle compared to my old SUV's. The only aspect I am really negative about is HV engine noise.
The electric miles are purely guess-o-meter, even given they are backwards looking.

 

Doesn't bother me much, but that is the single biggest complaint of my wife and why overall she doesn't like driving it...

 

[QUOTE="d99, post: 174915, member: 14123" The only aspect I am really negative about is HV engine noise.[/QUOTE]
Apparently not everyone experiences "angry bees" but my Clarity has done this since day one. And since others in the forum seem to think the sound is minor, I suspect we're not hearing the same thing. As in, every passenger in my car since day one that heard this, asks if my car is going to be OK. It's LOUD.

Anyway, for my Clarity, if I keep EV > 0, I literally never hear the bees. Simple answer in my case. And if EV estimated range goes below 10, I hold down HV charge and am back in business. And ironically HV charge never sounds as loud as angry bees, not even close. So this might be something that some Clarity owners experience differently. But either way, at least in my Clarity, you just be careful to not let EV range go to zero, and all is well.

For uninformed people who just need to drive my car, I make sure EV range is full, and I tell them to get in, start the car and press EV before driving. So 100% of their driving is HV. (and if I need to do this, I also put a sticky-note on the D button for them). i.e. "HV press?" to remind them. Then all is well.

 

In EV mode, it's great. I hear the sound of NOTHING.... However, it's not always possible to have sufficient EV miles for every trip.

On a relatively flat freeway at higher speeds, and without stops, great in HV mode at constant freeway speed. The wind noise drowns out any engine noise.

In the city on flat streets in stop and go HV, way too much engine noise as the car accelerates from a light or stop sign. Very unrefined.

On a hill in HV (the engine automatically is supplemented with electric power), bad and very unrefined noise as the car chugs up a hill. I sometimes wonder if I'm doing damage to the car.

If you are in EV in the city and are driving to a nearby freeway and will be using HV, get the car prepared. I think it runs better in HV if it has a mile of HV at gentle speeds, before it's forced to quickly accelerate on the freeway. It's almost like I am "warming" up the car. Maybe I'm deluding myself but I think it works better.

 

MPGe is simply an energy conversion calculation. It is a fixed number for each individual alternative fuel vehicle based on the distance the vehicle will travel, under certain test conditions, while consuming 33.7kWh’s of energy. It is not a combined average using both gas and electricity as fuel sources, which would be infinitely variable between vehicles.

 

We're on a tangent to the original question. Arby asked for the lifetime fuel economy of the vehicle, a miles per gallon measure combining gas and electric.

Look at the fuel economy screen and the MPG figure shows for the entire "trip" as well as your last trip. That number is a combo of gas and electric. The combination in Arby's case is 125MPG. Since the trip stats have never been reset, it's for the life of the vehicle. That 125 number represents just over half electric miles.

Mine is currently 120.2 and recalculates constantly, taking into account the current trip. When I was driving primarily HV, the reading two years ago was about 55. Since I am driving primarily EV over the past two years, I have watched the number rise steadily from 55 to the current 120. That's based on electric at 199.9 and a gas calculation. Directionally correct.

If the current trip is all EV, notice the current trip mileage shows as 199.9. Depending on conditions, if the current trip is all HV, mileage could be in the 30's to 40's.

 

A tangent, perhaps. Clarification on the terms being used is essential to the discussion.

Combining electricity and gas as fuel sources to determine an average MPG is futile, in my opinion. We’ve driven the past 2000 plus miles on nary a drop of petrol. That’s infinite MPG. Last year we went roughly 8000 miles on 15 gallons of gas. That’s 533mpg.

A mile traveled on batteries is not a mile traveled on gas. Why would we include the electric miles if we’re trying to determine a Miles Per Gallon figure?

 

Arby asked a question, and I explained how the car calculates the combo MPG number. Agreed, the EV MPG of 199.9 the Clarity shows is arbitrary, but with that number, the 125 MPG number he is seeing indicates just over half his life to date mileage is electric. That should be an interesting statistic, and one to watch directionally.

 

The flaw I see in this calculation is that the car is using 199.9 for EV mileage which isn’t accurate. EV mileage does not consume 1 gallon of gasoline every 199.9 miles. It actually consumes no gasoline at all. You’ve suggested that a lifetime fuel economy figure of 120mpg is based on the assumption that half the miles were driven on gas at 40mpg and half the miles were driven on batteries at 199.9mpg. That may be how the car calculates the number, but the result is inaccurate and meaningless.

Driving 50% of the miles on gas at 40mpg and 50% of the miles on batteries is always going to give you a result of 80 miles traveled for every gallon of gas consumed.

It’s been discussed before that the easiest way to determine the distance the vehicle has traveled for every gallon of gasoline used, is to keep a record of fuel purchases and divide the total miles traveled by the number of gallons consumed. That will tell you, with a much greater degree of accuracy, the number of miles the vehicle has traveled, using a combination of gas and electricity.

 

This is not answering his question. He did not ask for a measure based on gallons used.

To me, I don't see any value in saying "I drove x thousand miles on Y gallons of gas, without some sort of attribution to electricity. The attribution part is hard. There is also no value in telling friends and family that you are getting 125MPG, except that in Honda Language calculations, it means you are driving about half half gas and electricity. The direction of that number is important -- is it going up or down.

I think just about the only thing you can tell friends and family is that the car gets approx low 40's MPG on gas in warm weather. An electricity fillup of about 47 miles costs $x and that takes care of most of your daily needs. Also, you can plug the car into a regular plug if you charge it overnight. If you need to go on a long trip, you can always fill up the tank. That will make them insanely jealous at today's gas prices. Isn't changing peoples' behavior the real point, rather than a technical answer that will cause most eyes to glaze over?

 

This is the original question. It asks for a MPG number based on both gas and electrical consumption. Gasoline is doled out in gallons, electricity in kWh’s. To calculate a MPG number, the only thing measured in gallons is the gasoline. Mixing in the miles traveled on batteries does not add an ounce of gasoline to the formula.

I believe it is pointless to say our car got 533 MPG last year, but it did travel 533 miles for every gallon of fuel that it consumed. It also consumed a large number of kWh’s. To answer the original question, it’s just a simple matter of dividing miles traveled by gallons consumed. It isn’t an answer that should cause anyone’s eyes to glaze over.

 

Everything that can be said on the topic has now been said. Hopefully, Arby can comment back on what he got out of this.

 

Try as we might to control the discussion, there will likely be more theories and opinions on the subject. One thing that many Clarity owners seem to enjoy is analyzing the wheels off the car.