Non-hybrid fuel efficiency
 

Hi All,

I'm new to the forum and have always been interested in increasing fuel efficiency on the road. I'm currently driving a 2005 Honda Civic 4cyl 1.7L manual (5 speed) (sorry, non-hybrid - but at least I carpool to work!). Recently, after reading up on some tips to increase fuel efficiency that I read in this form, I started to be more mindful of my driving... especially being careful of quick acceleration and making a true effort to go sub-70 MPH on the highway (usually I drive about 74MPH). I also did my best to 'coast' (when appropriate and safe) down major hills/exit ramps by putting the car in neutral.

I did this for an entire tank and was excited to calculate my MPG upon filling up my tank. When I filled up, I found I was only getting 31.5 MPG when the previous few tanks I had achieved 34.5 or 35 MPG.

So the question I pose is... Do you feel that doing things like coasting in a traditional non-hybrid car increases gas mileage, or is this technique most appropriate for hybrids? I know more tempered accelerations will always save gas, so I think that did not play into my decreased mileage on this most recent tank - but am curious about your thoughts into this situation.

As a scientist, I understand that this is obviously a flawed 'experiment' as there aren't any replicates and it was very cold last week in New England where I live, but can't help to think that the coasting caused this marked decrease in MPG as this was one of the lowest MPG ratings I've received in this car. (The best was an all-highway round trip over several states in the summertime where I earned 49MPG for a full tank).

Any input into this question would be appreciated.

Thanks.

Re: Non-hybrid fuel efficiency
 

Hi,
I would suggest you might start by getting instrumentation for your vehicle that would give you a record or instant feedback on your performance. As you pointed out, the experimental conditions were not well controlled but instrumentation to record and sample critical vehicle parameters would help.

As for experts in driving non-hybrid cars efficiently, I would recommend CleanMPG.com that has that as their charter. Many of my techniques exploit the unique characteristics of hybrid electrics and don't translate well. For example, driving 38 mph and slower so the car can automaticly switch between electric and gas powered modes.

GOOD LUCK but I think the folks at CleanMPG.com would be an source for non-hybrid driving techniques.

Bob Wilson

Re: Non-hybrid fuel efficiency
 

tbarry,

You are definitely on the right track by cruising at a steady speed and going easy on acceleration. Monitoring with www.scangage.com will also be helpful.

Some people use cardboard in front of the radiator - including truckers. Short of that, turning the temperature to the coldest settings with the heater off mimimizes the draw on the coolant heat.

Re: Non-hybrid fuel efficiency
 

Hello, tbarry, and welcome to GreenHybrid!

I think coasting will help no matter the vehicle. For additional tips, check out CleanMPG, a site dedicated to optimal fuel economy in any type of vehicle. They have a mileage database similar to GreenHybrid's in which you'll see several Civics, even with auto trans, averaging in the upper 30s and low 40s.

Re: Non-hybrid fuel efficiency
 

Given the information you have provided, the only thing we can really say is that temperature may have had something to do with the drop. There is no reason why coasting in a non-hybrid car wouldn't have saved you gasoline. Ditto for the slower driving- air resistance and drag by themselves make a relatively big difference in the amount of gas it takes for the car to move forward. Without more specific data, I can't really give you much advice, sorry.

As for the 'coasting' in neutral, I don't know if this makes any difference or not, but when I'm talking about coasting, I don't shift my car at all. I just mean that I have my foot off the gas and off the brake, and I let the car coast. I keep my foot near the brake, of course, in case I need to slow down, but usually the car begins to slow slightly on its own (more quickly on a hill going up and less quickly downhill) and I move my foot back to the gas, gently.

I've done this in my mom's (non-hybrid) Prism and find that I can coast even more easily in a non-hybrid, because there's no regen. that kicks in to slow me down, and even leaving aside regen., the car doesn't seem to slow as quickly when coasting.

Re: Non-hybrid fuel efficiency
 

Thank you all for the replies - I've just registered on CleanMPG.com and will read their forums for more tips.

I have a followup question based on leahbeatle's response. Does anyone have any insight into whether coasting in gear vs coasting in neutral would be more efficient in a 'gasser'?

Thanks.

Re: Non-hybrid fuel efficiency
 

Using a scangauge I can say that coasting in neutral is more fuel efficient than coasting in gear on my Tacoma, by a significant amount. I generally idle at .2-.3 gph (gallons per hour) but while coasting in gear it can be .4-.8 gph depending on rpm. The hills I hit on my daily commute allow me to crest at 10 below the speed limit and accelerate in neutral up to 5-10mph over the speed limit, with long coasts achievable. If I keep it in gear the engine braking kills the momentum.

It possible that some vehicles now shut of the injectors in engine braking situations, but my Tacoma doesn't appear to do this. The scangauge isn't intelligent enough to tell me for sure.

Re: Non-hybrid fuel efficiency
 

Good choice on CleanMPG.com but as to the transmission question.

I would recommend finding a shallow, down-grade and performing your own 'rolling' test. Starting from a known starting place, measure either the ending mph or a stopping point from each run. I would recommend at least three samples in each mode so you can average the results and remove minor noise. The following shows my Amsoil vs. OEM transaxle oil testing:
http://hiwaay.net/%7Ebzwilson/prius/pri_T_cold_01.jpg

Plotting the slope was a little over the top but I like to document as much as possible.

Did I mention 'walking the dogs' with a laser level and recording the paces between user measured height changes? The dogs were happy and soon learned the Alpha dog was interested in the funny 'red light'. The neighborhood was amused and the Paranoids, who live about eight houses down, came out to see what I was doing

Bob Wilson

Re: Non-hybrid fuel efficiency
 

Bob, you are so amusing. :) I hope your neighbors the Paranoids enjoyed the show!

Re: Non-hybrid fuel efficiency
 

tbarry

I think the scangauge will be a great help. We have one in our VW TDI and it shows exactaly what your mileage is instantly. I am going to guess your mileage is worse after coasting in netural then before because your car has a fuel cut system. If you coast in gear you use no fuel and when you coast in netural there is idle fuel consumption of .2 -.4 GPH. The scangauge on our VW will show a MPG of about 200 while coasting in netural and 9999 MPG while coasting in gear. The trick is to coast as far as possible, so start out in netural and about 200 MPG and when you know you will have to stop and you can get to the intersection at minimum speed, then put it back in gear and go the rest of the way at 9999 MPG. That should be good for 2 - 4 MPG over the whole tank....Louis

Re: Non-hybrid fuel efficiency
 

As Louis mentions, I think the problem is you put it in neutral, so the engine uses fuel to keep the motor running, hence using more fuel, not less. Instead do your "coast down" in gear, a higher one will let you go further with the throttle closed. Remember, the throttle has to be closed for the fuel cutoff to activate. Until the rpms drop below 1200rpm or so, the fuel should be cut off. I do this in my SAAB 9-5 all the time to maximize economy (2.3 LPT/5 spd) and get pretty good mpg with it.

Re: Non-hybrid fuel efficiency
 

Oh, one other thing - "tempered" accelerations help, but not as much as you think - the conventional ICE is more efficient with the throttle plates open a bit, so don't crawl up to speed in the lower gears. Also, shift up frequently enough to allow for the same moderate throttle opening as you gain speed, but with the rpms fairly low. This will minimize the high vacuum "pumping losses" from closed down throttle plates.

The ICE gets best mileage this way - low rpm/larger throttle opening, vs. higher rpm, throttle closed. As long as you don't open it so far as to go into acceleration enrichement. This is one reason that large engines are so inefficient around town - they go around with the throttle barely cracked open, creating huge pumping losses because of the displacement. And of course keeping your speed down on the freeway will show significant gains as wind drag goes up at the square of speed.

Re: Non-hybrid fuel efficiency
 

It has been my experience that temperature is the most important factor when it comes to mileage. My Prius went from 50 mpg in mild weather down to just below 44 mpg in cold weather. Those numbers are averages over a tank of fuel.

For your experiments, make sure the temperature is close to the same when comparing driving methods.

Harry

Re: Non-hybrid fuel efficiency
 

I second Harry's remarks about temperature. But don't just take our word for it- the database asks you to track the temperature of your drives, so you can scan through a few people's results and see just how big a difference a little cold weather can make.

Re: Non-hybrid fuel efficiency
 

Actually non hybrid cars can give you pretty good gas mileage. Some of them give you 40+ highway mileage which is comparable to most hybrids.
Here is a list of non hybrid cars those are very good on gas:
http://www.whybuyhybrid.com/top-fuel...d-cars-in-2006

Re: Non-hybrid fuel efficiency
 

rahman15,
I see TWO on that list that would be expected to average 40 or so MPG overall.
The rest would get in the 30s.
Not any of these are "comparable" to the Prius, Insight or Civic hybrids. Pretty good MPG, yes. Hybrid-like, no.

Re: Non-hybrid fuel efficiency
 

Your facts and data are wrong:http://www.fueleconomy.gov/feg/sbs.htm
2007 is not available for sale in the USA.http://www.fueleconomy.gov/feg/sbs.htm
"2007 Volkswagen New Beetle (auto like our hybrids) 23/32"http://www.fueleconomy.gov/feg/sbs.htm
"2007 Volkswagen Jetta (auto like our hybrids) 25/32"http://www.fueleconomy.gov/feg/sbs.htm
"2007 Toyota Corolla (auto like our hybrids) 20/38"
"2007 Prius (auto) 60/51"http://www.fueleconomy.gov/feg/sbs.htm
"2007 Yaris (auto like our hybrids) 34/39"
"2007 Prius (auto) 60/51"http://www.fueleconomy.gov/feg/sbs.htm
"2007 Honda Civic (auto like our hybrids) 30/40"
"2007 Honda Civic Hybrid (auto) 49/51"

Bob Wilson

Re: Non-hybrid fuel efficiency
 

Pretty right about that.

Just click on my signatures to go on a short roller-coaster ride. By the way, the Winter FE I got could have been much lower - It just so happens that I made a few winter mods on both cars.

Cheers;

MSantos

Re: Non-hybrid fuel efficiency
 

Regarding non-hybrid efficiency, I originally bought my HCH as a car which gets great mileage driven normally, but especially one which has potential for much higher.
Take the Civic for example, the new EPA shows the standard Civic as 29MPG and the hybrid as 42. Most of us do a bit better than that in our HCH's. What is the highest a stock regular Civic gets? 40? 50? While the hybrid version is good for well over 60, even exceeding 70 for some drivers.
Today gas is just under $2.50 in our area, but when it exceeds 3 or 4 /gallon those driving cars with higher potential will be better off.

Re: Non-hybrid fuel efficiency
 

Actually Bob his facts and data are exactly correct and yours is somewhat skewed.

First the reasons Rahman15 is not wrong:

He said: "Actually non hybrid cars can give you pretty good gas mileage." which is true.

Then he says: " Some of them give you 40+ highway mileage..." Which is also true of about on third of the cars on his link's list.

Then he says: " ....which is comparable to most hybrids." This may seem incorrect if you cherry pick only the best mileage hybrids but if you include ALL the hybrids including the Accord, Camery and the Trucks and SUVs, it is completely true.

Bob the reason your facts and data are skewed are because you cherry picked the hybrids you used as a comparison. You also assume that everybody wants an automatic which may be true most of the time but isn't always true. I prefer and own a manual because I like to be in control and because I don't have a wife insisting that we get an automatic.

The list is titled "Top Fuel-Efficient Non-Hybrid Cars in 2006" so pointing out what is going on in 2007 is a nice update but that does not make the list wrong for 2006.

Re: Non-hybrid fuel efficiency
 

Actually Rahman15 had copied his list from an earlier, out of date article. Also, he left the hybrid vehicle comparisons open and only specified the gas models. Having been in that web site to look at the new EPA numbers, I knew some of his vehicle numbers were inaccurate.

I simply went to the EPA listing to see what they claimed. In those cases where he had identified the car, I tried to use the exact make and model matching the hybrid. You've updated his copied list of non-gas cars and that is good but that was not what he'd posted.

Now when it comes to automatic vs. manual, we'll have to agree to disagree. My wife has knee problems and has already been advised to have knee replacement surgury. I've also had occasion to teach manual transmission to a young man who had always driven an automatic (famous quote, "So that is why the manuals leave me behind at a light!") For many folks, a manual transmission car is not in the cards.

Although individuals may prefer a manual transmission, the reality is there is one extra pedal in those cars and not everyone can drive one. However, automatics are universally drivable and that is what every current hybrid has.

BTW, I believe there were two manual transmission hybrids, the Insight and I thought some of the first generation Honda Hybrid Civics (not sure about this.) I would have no problem with comparing those manual transmission hybrids to a manual transmission gas-only car. It would at least be as close as possible to comparing similar cars.

Bob Wilson

Re: Non-hybrid fuel efficiency
 

We seem to be having a communication problem. Maybe something was changed in this tread before I got involved? You say: "You've updated his copied list of non-gas cars and that is good but that was not what he'd posted." I've not done any such thing?? In fact I don't even see a local copy of any list, only an outside link to high mileage non-hybrid cars in 2006??

You got it right on the manual model cars. The Insight and gen 1 HCH were both available in manuals.

Re: Non-hybrid fuel efficiency
 

The tricky part about comparing the manual transmission Insight and Civic to gas-only cars is that the transmission isn't the only thing about the drivetrain that's different. For reasons known only to Honda, the MT vehicles got lean-burn capability while the CVT versions did not. In my mind it is the inherent thermodynamic advantage within the ICE that is the real reason that the MT versions have so much higher FE capability. Unfortunately I can't prove it without data from a fleet of mule cars with lean burn ICEs and automatic transmissions. Or stoichiometric ICEs and manual transmissions. Both would be better. ;)

Re: Non-hybrid fuel efficiency
 

He'd cited a specific web site:
http://www.whybuyhybrid.com/top-fuel...d-cars-in-2006

It lists these cars having any 40 MPG or better ratings:Noticing the article was from 2006, I went to the current, 2007, fuel economy ratings site for US cars:
http://www.fueleconomy.gov/feg/sbs.htm

I selected the gas cars as functionally close to our current hybrids and that means automatics. Anything else is an apples-to-oranges comparison because we have a large number of USA drivers who do not know how to drive a manual and others with physical problems that prevent them driving a manual.

Finally, the original article did not specify a hybrid so I picked one that is close to the Compact/Sub-Compact rating. In the case of the Honda Civic, I used the Honda Civic hybrid. I didn't choose a green Saturn SUV or Silverado hybrid because none of the cars claiming to have a 40 MPG rating are either SUVs or pickup trucks.

Bob Wilson

Re: Non-hybrid fuel efficiency
 

Hi,

I've run out of gas several times as part of my fuel studies and the furtherest distance traveled on the battery was less than half a mile. I slow down and drive to the first safe place to refuel from the 1 gallon, spare can.

Running the tank dry is important to getting accurate gasoline performance data. The gas sample testing, each starting with running the tank dry, includes:

• Shell 87 #1 - best, spring
• Texaco 87 - spring
• Citgo 87 - spring
• BP 87 #1 - spring
• Conoco 87 - spring
• Shell 87 #2 - best, spring
• Shell 93 #1 - spring
• Texaco 93 - spring
• Exxon 87 - best, summer
• Chevron 87 - best, summer
• Shell 87 #3 - best, summer
• BP 87 #2 - summer
• Shell 93 #2 - summer

Around December and January, I will repeat the testing the best gasolines from the above list.

I retested Shell 93 because of interest in highway performance on hilly roads. Preliminary data suggests higher octane gas works well at ICE speeds from 3,800-4,500 rpm. However, at these rpm ranges, there are very high fuel burn rates for both 87 and 93 octane fuel. Easier on the engine with less 'pre-knock,' 93 octane fuel has a marginal impact on high power performance, which is a fairly rare event at speeds under 70 miles per hour.

The best approach is to reduce speed as soon as practical and drive directly to a safe place to refuel. The maximum range speed in normal hybrid mode is 18-20 miles per hour and in EV mode, slower will go much, much further.

The most frequent threat to the 2001-03, NHW11 Prius battery is to climb a 6% grade hill at speeds above 70 miles per hour or faster. Actually, a Prius can sustain 55-60 miles per hour until the hill runs out. A speed of 65 miles per hour is marginal and faster speeds drain the battery.

The 2004, NHW20 model should be able to handle hills faster but I don't have hill climb data to document the critical speeds.

I have no experience with HCH and Saab. However, I fixed your link. <GRINS>

Bob Wilson

Re: Non-hybrid fuel efficiency
 

That is certainly true for most of the Honda hybrids prior to the 2006 Civic Hybrid (HCH-II).

There have been reports of owners who have run out of gas and managed to power their way to the gas station on electric only (search the HCH-II forum). I am sure that in those instances, it was likely to have been an EV powered glide only since the electric motor only provides 20 hp. An EV powered glide can be sustained for a couple of miles at most.

MSantos

Re: Non-hybrid fuel efficiency
 

I previously owned a 2005 smart fortwo cdi (common-rail diesel injection) which netted a lifetime average of 4.7L/100km (50 MPG US). This was in mostly city driving with about 20% freeway. Although it was a little more efficient than my current Honda Civic Hybrid (petrol, 5.2L/100km, or 45 MPG US), it used a dirtier fuel and produced more noxious emissions in quantity. Certainly my CO2/km rating is on par between then and now.

Any car can produce reasonably good numbers on the freeway, but few can make a real difference in city driving, and the above two are examples of the latter.

Re: Non-hybrid fuel efficiency
 

Do you have a block heater for the Civic? Does this include last winter's driving?

Bob Wilson

Re: Non-hybrid fuel efficiency
 

No, it doesn't have a block heater and it hasn't gone through a Winter or full year cycle yet. In my situation, the car is garaged at home and at work in semi-heated group parking conditions. In Winter, Toronto roads will be cold but bare most of the time.

Another qualification: I use the auto climate control, and on one occasion of favourable, steady driving in the Summer heat I still got 4.3L/100km (55 MPG US). I'm assuming that that should be the worst of the fuel-impacting load that it will see. The Canadian import of the HCH-II has heated side-mirrors but no navigation option.

When I had the smart fortwo, my fuel economy in Winter was affected by using snow tires and the winterized diesel. I really don't anticipate much difference on the hybrid during Winter except for cool batteries.

Re: Non-hybrid fuel efficiency
 

I think you will find that the opposite is true. The HCH has much better numbers in warm weather than it does in winter, and that's absent any effect for snow tires. Instead of contrasting the relative amounts of energy used by auto climate control to cool or to heat, or analyzing the exact differences between summer and winter fuel additives, which I'm sure others can do, let me just say that I can tell you anecdotally and from my own experience and that of the other posters here and the data in our database, the HCH likes warm weather. Ambient temperature is the top indicator, in my experience, of overall fuel efficiency for the HCH, on the same order as (and sometimes even more so than) the driving techniques that many people use to be efficient drivers. Hot is good, cold is bad.