GM Volt Forum banner

Status
Not open for further replies.
1 - 20 of 241 Posts

·
Registered
Joined
·
430 Posts
Moderator Edit: This article shows an example of saving gasoline usage that is not guaranteed in every scenario. In other scenarios, the conversion losses associated with converting gasoline to electricity, then from electricity to kinetic motion, will result in more fuel usage than is saved by attempting to drive more miles without the engine running in the manner described here. Results will vary based on terrain, driving style, timing of this technique, weather, etc. Additionally, an added concern may be battery longevity due to the rapid cycling of the battery's state of charge.

For these reasons, we generally recommend to "let the Volt figure it out" rather than to try and outsmart the car's programming. Still, past forum posts have also chronicled potential fuel savings, while others have detailed worse gas mileage using these techniques. The results detailed here present a claim of fuel savings in at least some instances, and are worth discussing and debating. Please keep the debate civil.



A Technique of Traveling With Your Engine Off – by Mike Mas


Greetings GM Volt Forum Members – In this article, I’ll be sharing a technique I developed for traveling distances greater than the initial charge on the ELR or Volt. I call it “Volting”, a method I’ve been using for over a year which allows me to shorten my engine running time by over half on longer trips.

By using my Volting technique on a recent 230-mile round trip to Atlanta, it enabled me to keep my engine off for an additional “80 miles” over and above my initial 40 miles of electric range for a total of 120 miles. For over two hours (128 min) I glided along on electric power on this 230-mile trip. If all that seems unbelievable, I did so using less fuel then the conventional method we use when driving our Volt or ELR.

Like the sport of Vaulting - Where an athlete will vault from one location to another, “Volting” with our ELR or Volt, describes a similar technique of using your generator (ICE) to leap 20+ miles at a time in pure electric mode when traveling at distances greater then the initial charge. This method allows you to enjoy the silent flight of electric driving on longer trips. While I’m certain most Volt and ELR owners have used mountain mode to recharge and cruise home on electric power on occasion, this more refined technique can change the way we drive electric cars.





Before I get into the Volting details – for the benefit of new users, I would like to briefly go over the different “Engine Running” modes that enable our RX to run. While there are only two “selectable” engine-running modes titled; Hold & Mountain Mode, in reality there is a third mode which we’ll call “Auto Hold Mode” which is automatically activated when our battery is depleted.

Auto Hold Mode – As we’re cruising down the highway and our battery display winds down to less than a mile, the Voltec’s processor almost seamlessly fires up our engine to enable us to continue our journey using the generator.
This Auto mode function is similar to our selectable “Hold” mode except for the fact it’s not user selectable. When this mode is enabled, it blanks out the green battery display, and a fuel pump icon signifies our engine is now running. During this protocol, the once selectable “Hold” mode is now unavailable and ghosted on our display. When this Auto Hold Mode is activated, most all the power needed to drive the car is supplemented from the engine /generator.

Auto Hold Mode Protocol – Immediately after the Auto-Hold mode is activated, the generator will actually perform a short recharge mode to bring the high-voltage battery from 0 miles back up to 2 miles of range as a battery buffer. This buffer enables the generator to shut down when the vehicle is stopped in traffic and also allow the use of AC or heat, yet have ample charge to take off again on just battery power. Once the car starts traveling, the engine will re-start and run as needed. This 2 mile buffer insures the level of the battery will not go below the batteries rated shutdown level.

Hold Mode – In the selectable Hold mode, the Voltec’s processor starts the engine to preserve the batteries charge. The Hold modes purpose is not to provide any recharging function to the battery. The Hold mode’s task is to simply do exactly how it sounds; it will “hold” the batteries charge close to its current level or miles shown when you selected it. As an example, if you had 35 miles showing on your battery range, Hold mode will attempt to maintain this level of charge regardless of how close or far you have to drive. Without getting too technical, it’s possible for the battery voltage to vary when going up or down inclines where the high-voltage battery may lose or recover some charge.

The Hold mode operates on a very intelligent protocol, unlike some RV generators which run at constant speed, with the Voltec system it constantly monitors the batteries status so as we negotiate an incline, the engine will increase speed to provide the needed power to replace or assist the current needed for the motors. As we go down a hill, it automatically reduces power, if the decline is long enough and sufficient regeneration power is provided, the system will actually shut the engine down until there is further need for power. As we stop the car, the engine will also shut down until there is enough power demand to start once again. In simple terms, the engine is producing all the power needed to propel the car and to save the battery for a future leg in the journey. Many Volt & ELR owners who commute to the city prefer to use hold mode to otherwise save their battery for stop and go city traffic.

Mountain Mode – This is by far my favorite mode since it gives us the ability to charge while we’re driving and also provide a means for “Volting” which is the topic of this article. As the name implies, GM incorporated the Mountain mode to allow the gas engine to start, recharge the batteries to around half charge if needed, and additionally use the engine to assist the battery when negotiating steep inclines.

Recharging on the Fly - The best feature of Mountain mode is it gives the owner the ability to actually recharge the high-voltage battery while in route. In the event the Volt’s battery is lower than 45% SOC (state of charge) or about 18-20 miles, Mountain mode will not only provide power to drive the car, but also the ability to re-charge the high-voltage batteries at around a rate of 12 KW. This is a fairly fast charging rate capable of replacing roughly one mile on the battery for each mile driven, that’s 2 miles of generated power each minute. This charging cycle will continue until the battery reaches 18-20 miles of range.


Mountain Mode Protocol – After Mountain mode recharges the battery to a level of 45% SOC, it then changes its operation to be similar to a “Hold” mode where its only function is to retain the battery at 45% SOC. Once it’s in this mode, it will change speed according to power demands and even shut the engine down when not needed.

Note: I would like to mention that regretfully on the Gen 2 models, for reasons unknown someone at GM made a terrible decision to reduce the charge level to only 9-10 miles. This is a very disappointing feature of the new cars as it reduces the MM re-charge distance to only half the range of the Gen 1 models. While Volting is still a possibility, it requires much more station keeping.


Battery Estimated Mileage - I would like touch base on the battery level indicator shown on your dash. Some owners are under the false impression this estimate is based on past driving habits, however there is no documentation I’ve found to back this up. The Voltec’s processor looks at the battery’s current state of charge, then compares this to the battery’s temperature and derives the approximate range.
Unlike other electrics such as the BMW I3 and others which stores driver profiles, the Voltec system does not know nor care who’s driving or their habits. I’ve found that regardless of how I or others drive my Volt or ELR, my estimate remains the same and is only affected by charging and temperature. When the temperature goes down, so does my estimated mileage.

I did want to mention, when using Mountain mode, at times the grayed out battery indicator at times will not show the correct level. Don’t be concerned, Mountain mode will continue to charge the battery regardless of this display. You can monitor the battery level by looking at the lighter gray levels on the lower portion of the battery display in relation to the centered red ring on the battery which signifies 45% SOC or around 18-20 miles. On occasion, you might be required to restart the car to see the correct “green” battery indicator.

Keep in mind your actual “Achieved Mileage” will depend on temperature, terrain and your driving habits. Also worth noting is; aside from temperature, the batteries range is greatly influenced by when the charge was completed. Immediately after a charge, there is a chemical change when the cells are balanced which may result in more actual mileage then shown.

Mechanical Drive Advantage – While I won’t get into the technical aspects, I would like to briefly mention there is also a mechanical advantage in the Voltec engine system that provides a mechanical path through the drive to couple the engine direct to the wheels for additional mileage at higher speeds. The reason I mentioned it is to express the fact that during Volting this fuel saving feature is inactive yet Volting remains more efficient than using the engine.





Unattended Charging While Stopped - I love driving my Volt or ELR in town in electric mode so when I’m sitting in traffic, I can have the AC or heater running with my engine completely off. While most of the time I plan my trip to have a sufficient charge on hand, there are occasions that I don’t, so here’s an option you won’t find in your GM manual that will allow you to recharge your battery unattended, while you’re in a restaurant or shopping without even being in the car.

If the Volt or ELR battery is below 15-18 miles, unattended charging can be achieved by selecting Mountain Mode which starts the engine. I then leave the ignition on, lock the doors and go about my business. The ICE will remain running at a high-Idle speed for what ever time needed (up to 20-30 min.) to charge the high-voltage battery back up to 18-20 miles of range. As the batteries reach 45% state of charge, Voltec automatically shuts the generator down. When I climb back in the car, I’m ready to drive in all electric mode again.





Taking Precautions When Traveling – This is a different world we live in today and you don’t want to find yourself stranded on the road, therefore I avoid having zero miles on my battery in any situation.
The fact is, any gas engine could experience a mechanical break down. Remember, there are a lot of parts, with the most venerable our seldom-used fuel system; i.e. injectors, filters, pumps as well as the possibility of getting some bad fuel. While the chances of losing an engine are very low, there still is a possibility. I have a rule to keep no less than 5 miles on my battery so in the unlikely event I lose my engine, I can drive my Volt or ELR to a safe location rather than be stuck on the side of a dark dangerous highway with my family in the car. Other advantages are; you can retain your lights and heat if needed. Its better to be safe than sorry!

Volting - Getting back to the topic of Volting, possibly the best way for me to describe this method is to provide a trip example. My little town of Blairsville is a little over 100 miles from Atlanta. Using a round trip of 230 miles, I provided two examples below showing the comparison of driving the conventional way and my Volting method.
As you’ll see, the Volting method allowed me the opportunity to travel 120 miles of this trip in all electric mode. So instead of running my engine for 180 miles during this 230 mile trip, it only ran for 100 miles using the Volting method. This relates to an unbelievable 80 less miles of running time on my engine and beautiful silent electric flight for over two hours during my trip.


CONVENTIONAL VERSES VOLTING COMPARISON


Conventional Method -Electric Driving: 40 miles / Gas Powered Driving: 190 miles.


Volting Method - Electric Driving: 120 miles / Gas Powered Driving: 110 miles.





These figures are staggering – but they are 100% correct and the real clincher is; I’m using less fuel to do the same trip. With the “Volting Method” it allows your engine to be completely off for over 50% of the trip when compared to the conventional method, thus saving wear and tear on your mechanical components and some emissions.

Here’s a quick rundown of a typical trip to Atlanta:

Depart - My trip begins with 40 miles of electric range and my first stop is IHop in Canton, GA, 75 miles from home. As soon ass my initial charge runs down or about 35 miles from the I-Hop, I select Mountain Mode to recharge the battery. As I reach the Canton I Hop, my battery is back up to 20 miles.

Canton to Atlanta - After breakfast, I depart Canton in electric mode with my recovered 20 miles of battery and I continue my 37-mile trip to Atlanta. When I get 20 miles from Atlanta, I restart the generator for the 2nd time and charge until I get to my destination. As I get off Interstate 75 in Atlanta, I use electric power to complete my few city errands.

Depart Atlanta – I head back home with the remaining 15-20 miles of electric, which I achieved on my trip up. As my charge depletes, I restart for the third time and charge on my way back to Canton for dinner at Olive Garden.

Canton To Home - After dinner, I leave Canton with 20 miles of battery. When the charge is depleted, I select Mountain mode for 4th and last time. When I get around 18 miles from home, I go back to Normal and glide home on electric power.





Nothing Complicated – The whole trip only involved me selecting; Mountain Mode just 4 times. Instead of running the generator almost the entire trip, I gain 80 miles of shear silence, as well as 80 miles less wear and tear on my engine.

Volting Fuel Cost – Even if this technique used more fuel it would be acceptable to me. However, after checking it numerous times and traveling the same 60-65 mph speed for over a year now, the Volting method continues to burn less fuel than using the conventional manner of driving.

Below, I have provided two dash displays from one of my typical trips to Atlanta; the first showing as I leave Atlanta and the second my arrival home. I would like to mention that I only use mid-grade gasoline in both my cars, and my average mileage is 32-37 mpg.

As we look at the first image, it shows I traveled 125 miles. When we subtract the 36 miles for the initial battery charge since I have 3 miles remaining, it leaves 89 miles. As we calculate 2.1 gallons used, it shows that my mileage is 42.38 mpg.





As we look at the second image, it shows I traveled 229 miles. When we subtract the 29 miles for the initial battery charge since I have 10 miles remaining, it leaves 200 miles. As we calculate 4.8 gallons of fuel, it shows that my mileage is 41.67 mpg.





As these results confirm, Volting not only allows you to travel with your engine off for over half the trip, it also allows you to do so at slightly less cost with an extra 5 mpg. Its hard to imagine but this method saves me almost two gallons when compared to conventional electric driving.

How Does it Do It – Even before I tried this Volting method, this is why I knew it would work - When I used to travel with company in my RV with a Cummins 8.3 liter diesel, I would run the generator to power the A/C unit. The generator would burn ¾ to 1 gal per hour, so I would typically burn around 8 gallons a day. A year later, I installed what I call a “No Gen” package, which included a high output alternator and an 12 volt to 110 volt inverter. This mod now allowed me to run my AC unit with the generator off since it was now powered by the main engines alternator. Before I installed the inverter package I got 9-10 m.p.g., after we installed the inverter package, I still got the same mileage 9-10 mpg. While I’m sure there was some extra consumption, it was so small it was not even measurable, I just acquainted it to the fact my 1000 ft lbs. of torque diesel, just didn’t feel the small amount of power required from the alternator.

Using this same logic on a smaller scale, when our engine is powering the Volt or ELR in Mountain Mode at 60-65 mph, the primary work load is to move the vehicle, the small extra amount of power or work needed to recharge the battery is minimal when compared to the work load needed to push the car at that speed, the result is we’re getting the charge almost free. The best way for me to evaluate the added efficiency is the fact the energy used to charge the battery is put to a more efficient use when used to power the car. My mileage has proved that!

In conclusion - I would like to mention on this same trip there are two engine running periods where I could have recharged for an additional 30 miles of electric driving. This event would have increased my electric driving from 120 miles, to 150 miles or more on this same 230 mile trip.

My only regret is that Mountain Mode only allows me to charge to 45% SOC. I’m working with some programmers in hopes to change the coding to enable charging to 75-80% as this would double my in-route electric range to 40 miles per charge. I’ll keep the GM Volt forum posted as to my success.

In summary, Volting is a sophisticated yet easy method of traveling distances greater than our initial 35-40 miles of electric range. Volting allows owners to squeeze additional “Electric” miles that even the designers at GM did not anticipate. Hopefully, in some time in the future, GM and other electric car manufactures will incorporate a “recharge mode” that will incorporate this very same “Volting” feature!

Best Regards – Mike Mas

Addendum: While I didn’t want to get over-technical with this article, there is reader concerns how Volting can occur using less fuel so I provided a chart below to help explain just how Volting would work on a 120 mile trip.













 

·
Registered
Joined
·
260 Posts
Awsome post. I have experimented with going back and for between standard Touring mode and Hold. Using Touring mode for going down large long hills that one would normally have to use the brake to slow to keep with in the speed limit and then using Hold for going up the other side of the hill. On large hills I have picked up a substantial amout of range on the battery depending on the size and lenth of the hill. So I could use Mountain mode for going up the other side instead of Hold. Never thought about that. I have a question about Mountain mode. Just wondering. Do you know if mountain mode uses more gas than hold mode? If so any idea how much more? Thanks, Rick
 

·
Registered
Joined
·
3,439 Posts
Interesting. I am surprised there is not a gas penalty for that as is the conventional wisdom. I don't quite follow your calculations for gas use. Have you run identical trips using both methods?
 

·
Registered
Joined
·
1,997 Posts
Nice write up. I have done the same thing with long trips of 300-400 miles. However, I think the key to your 42 MPG is really your speed of 60-65 MPH. When I go on a long trip my goal is to get there ASAP. So speeds of 70-80 MPH are normal. So my mileage goes down even using combinations of MM and HM. Usually about 36 MPG.

However, on shorter trips I have compared HM and MM. With HM it is not unusual for me to 45-47 MPG going speeds of 60 MPH. However, when using MM MPG goes down below 40 every time. MM runs the engine at higher RPMs which tends to be less efficient. Many discussions on that.

As for running at highway speeds on electric only vs. say HM I never really notice the ICE anyway. More noise from wind and road than the engine.
 

·
Moderator
Joined
·
8,680 Posts
As we've told you before, posting the same thing in two places on this forum is inappropriate.

It looks to me like your "Volting" is basically the same as the mountain mode games folks have been trying for several years. Some times you can come out ahead by a little with them, but mostly it comes out the same as letting the car drive itself for fuel consumption, and it can be worse in some scenarios, especially if you end up doing the mountain mode based charging at high freeway speeds or while climbing hills.

A Mountain Mode cycle means incurring the conversion losses to electricity on more of the energy, and paying for the battery charging losses as well - it can only come out ahead if it allows you to operate the engine at a more efficient point (which is possible, if you choose your timing carefully, but won't happen by chance anywhere you might use it.)

Different things may be important to different people, but "engine on miles" isn't a consideration for me. I care about fuel efficiency and about engine noise - but if running the engine most of the time at low rpm is more efficient on a trip I can't avoid using gas for, I'd do that.
 

·
Registered
Joined
·
43 Posts
Good stuff Mike, thanks for sharing!
I have been experimenting with this too but purely as a means to try to get better MPG. Actually I'm more interested in EV cruising and I never framed it quite like you did, great article.
In an unrelated tid bit that I'm sure others have used, if I want to warm the car up (when it's parked and not plugged in) and not waste my battery (when it's more than half full), I simply turn the car on and pop the hood, then I can heat on the coolant when I start driving.
 

·
Registered
Joined
·
241 Posts
While I applaud your achievement, it might be a good idea to point out (especially to new Volt owners) that you have not gained any additional electric miles, in the conventional sense of the term (miles traveled without burning gasoline). What you have done is judiciously used Mountain Mode and rest stops, where you power off and power back on in Normal mode, to burn as little gas as possible. Any "extra" EV miles that the car records is the result of a glitch in the Volt's mileage counting process, in which, after you turn off the car and turn it back on, it "forgets" that the available electric charge was gas-generated. Feel free to correct me if I'm wrong, but there have been lots of threads that document this process, with people thinking that they're getting "free" electric miles when, in fact, they are just gaming the system.
 

·
Registered
Joined
·
724 Posts
The only rational explanation I can see that would explain why using mountain mode is more efficient in your scenario, is that when recharging the battery in Mountain mode, the ICE is running all the time at high speed.

In regular ICE mode, the engine starts and stops a lot depending on the driving speed and condition, so the electricity production efficiency in that mode would be less than when it is created with the ICE running regularly at high speed.
 

·
Registered
Joined
·
175 Posts
I appreciate all the work that went into that post but I don't get it.

I can barely hear the engine running under normal use. While it is catching up in mountain mode the engine is very noticeable. I really like just driving the volt and not worrying about all of that. I plug in when I am at home. I run the heat at full blast. I floor it often. At the end of the month my onstar notice shows 95% electric.

It is hard for me to believe there isn't a mileage penalty. There are losses in the generator, charger, battery... vs just driving the wheels. The only way to know for sure is drive a full tank each way and do the math by hand.
 

·
Registered
Joined
·
430 Posts
Discussion Starter · #11 ·
Awsome post. I have experimented with going back and for between standard Touring mode and Hold. Using Touring mode for going down large long hills that one would normally have to use the brake to slow to keep with in the speed limit and then using Hold for going up the other side of the hill. On large hills I have picked up a substantial amout of range on the battery depending on the size and lenth of the hill. So I could use Mountain mode for going up the other side instead of Hold. Never thought about that. I have a question about Mountain mode. Just wondering. Do you know if mountain mode uses more gas than hold mode? If so any idea how much more? Thanks, Rick
Actually both modes mountain and hold will use the same fuel once the battery is up to 18-20 miles of range. Once mountain mode recharges the battery, it changes its protocol to about the same function as hold mode to just supply current as needed to drive the car and run accessories ans maintain the 18-20 miles of range on the Gen 1

Thanks
 

·
Registered
Joined
·
430 Posts
Discussion Starter · #12 ·
I appreciate all the work that went into that post but I don't get it.

I can barely hear the engine running under normal use. While it is catching up in mountain mode the engine is very noticeable. I really like just driving the volt and not worrying about all of that. I plug in when I am at home. I run the heat at full blast. I floor it often. At the end of the month my onstar notice shows 95% electric.

It is hard for me to believe there isn't a mileage penalty. There are losses in the generator, charger, battery... vs just driving the wheels. The only way to know for sure is drive a full tank each way and do the math by hand.
Thanks for the reply - regarding the fuel, its more economical with Volting - I explained why in the article.

For myself, I really don't mind running my engine - but it is an electric car so therefore why not use it as such. The question is; would you rather travel running the engine and the electric drive or just the electric drive?
 

·
Registered
Joined
·
1,997 Posts
The question is; would you rather travel running the engine and the electric drive or just the electric drive?
40 miles and under, electric drive. Over 40 miles, in HM at speeds above 50 MPH, except for my last 40 miles. HM is where I get the best efficiency. I am not sure how you came out with your MPG using MM but good for you. I do not think that is what happens for most people.

I do agree with you on long trips using MM when needed to charge the battery charged as much as possible. But I tend to keep as much a charge as possible all the time. My luck I would have engine trouble just before I selected MM to charge it back up. :)

BTW, i think my lifetime MPG for just the ICE is about 37 on both Volts. I wish that could have been better. Maybe folks with the Gen 2 will post much better lifetime ICE only MPG.
 

·
Registered
Joined
·
430 Posts
Discussion Starter · #15 ·
Hello guys - I added this addendum to help explain the fuel savings;


Addendum: While I didn’t want to get over-technical with this article, there is reader concerns how Volting can occur using less fuel so I’m going to offer a scenario which will help clear up the matter.

Lets take a situation where we’re driving down the road at 60 mph in mountain mode. We’ll say the battery is below 45%, so our little I4 engine is both charging the battery and pushing the car at 60 mph. While this does not sound so amazing, lets look at it a bit closer; the engine is generating (charging) at a rate of “one mile of charge per minute” therefore this is enough energy to propel another car (or ours) at 60 mph going in the battery each minute.

Therefore, at any given moment our little engine in Mountain mode is producing enough power to propel two (2) cars at 60 mph or 120 mph of energy, since its moving the car at 60 mph and storing energy to propel the car at some time in the future at 60 mph. The real important fact here is its doing so using about the same amount of fuel it takes to move one car.
 

·
Registered
2013 Volt
Joined
·
1,596 Posts
Idleup, there is one more aspect to volting that you are not considering. It is a well accepted fact that lithium ion batteries have a finite number of full charge cycles in them, and you are burning through them at an accelerated rate. If I could hear the engine at all while traveling at 60 mph, I'd say that accelerated usage might well be worth it. Or, if there was a definite and sizeable reduction in gas used, that would offset the increased usage of battery cycles. As it is, this would not be worth it for me. I'm more concerned about the longevity of the battery pack than putting miles on the engine.
 

·
Registered
Joined
·
3,766 Posts
It seems like I've done better on fuel consumption just driving in hold mode with 3/4 battery charge and driving more or less at posted speed limit even when that's 70mph. Maybe you can game the system in just the right manner a gain a little sometimes. At more local driving the posted limit is 55 with a state max of 65mph I get better than 40 mpg.

The display data is not 100% accurate under all conditions either. If I leave home fully charged and go down the hill, the display will indicate 0.4 miles on gas but 0.00 fuel consumption by the time I get to the bottom and I'm certain the engine didn't run.
 

·
Registered
Joined
·
1,623 Posts
Hello guys - I added this addendum to help explain the fuel savings;


Addendum: While I didn’t want to get over-technical with this article, there is reader concerns how Volting can occur using less fuel so I’m going to offer a scenario which will help clear up the matter.

Lets take a situation where we’re driving down the road at 60 mph in mountain mode. We’ll say the battery is below 45%, so our little I4 engine is both charging the battery and pushing the car at 60 mph. While this does not sound so amazing, lets look at it a bit closer; the engine is generating (charging) at a rate of “one mile of charge per minute” therefore this is enough energy to propel another car (or ours) at 60 mph going in the battery each minute.

Therefore, at any given moment our little engine in Mountain mode is producing enough power to propel two (2) cars at 60 mph or 120 mph of energy, since its moving the car at 60 mph and storing energy to propel the car at some time in the future at 60 mph. The real important fact here is its doing so using about the same amount of fuel it takes to move one car.
If what you are suggesting is correct then the GM engineers missed an opportunity to double the MPG of the ICE. I doubt that they -- and their counterparts throughout industry and the folks who write the CARB and CAFE rules -- would have missed such an opportunity.

KNS
 

·
Registered
Joined
·
38 Posts
Hopefully, in some time in the future, GM and other electric car manufactures will incorporate a “recharge mode” that will incorporate this very same “Volting” feature!
The Audi A3 E-tron has that kind of feature. It can fully recharge the battery when running on the highway (or anywhere else for that matter) in order to use it later. They often advertise it for long distances on the highway when you have already used all the charge of the battery and want to charge it again to use it later in the city where it matters the most in term of fuel economy. Would be great to have that feature in the Volt
 

·
Registered
Joined
·
3,766 Posts
Hello guys - I added this addendum to help explain the fuel savings;


Addendum: While I didn’t want to get over-technical with this article, there is reader concerns how Volting can occur using less fuel so I’m going to offer a scenario which will help clear up the matter.

Lets take a situation where we’re driving down the road at 60 mph in mountain mode. We’ll say the battery is below 45%, so our little I4 engine is both charging the battery and pushing the car at 60 mph. While this does not sound so amazing, lets look at it a bit closer; the engine is generating (charging) at a rate of “one mile of charge per minute” therefore this is enough energy to propel another car (or ours) at 60 mph going in the battery each minute.

Therefore, at any given moment our little engine in Mountain mode is producing enough power to propel two (2) cars at 60 mph or 120 mph of energy, since its moving the car at 60 mph and storing energy to propel the car at some time in the future at 60 mph. The real important fact here is its doing so using about the same amount of fuel it takes to move one car.
You might be consuming 2x the fuel to charge and cruise at 60mph but going 120mph would require 4x the power and about that much more fuel.

The specific fuel consumption needs to be so much more efficient in this mode as to overcome all the losses of conversion to electricity. It doesn't seem like there could be that much improvement available. I think the range estimate being reset after a rest stop might be confusing the data.
 
1 - 20 of 241 Posts
Status
Not open for further replies.
Top