Hybrid misconceptions

[Its_not_easy_being_green]

In recent posts, I have come across some misconceptions about how to get the lowest carbon footprint from your hybrid vehicle. This is my best effort to address some of this confusion based on my own technical knowledge.

1)It is the electric motor which is primarily responsible for increased gas mileage of a hybrid vehicle.

This is not true. What is primarily responsible for increased gas mileage in a hybrid vehicle is the smaller gasoline engine. The 2008 Prius, for example, uses a 1497cc ICE. Compare this to the 1832cc engine which is standard in the Honda Goldwing motorcycle. While not surprising that the gas mileage of a Goldwing will easily beat that of a Prius, the Toyota maintains better gas mileage than any other coupe because of its ability to get full use of its small, efficient ICE. Having a high torque electric motor to kick-in when needed is what makes such a small engine usable in a normal sized compact car.

2) Driving on the electric motor alone is the best way to reduce carbon emissions.

For most hybrid owners, using only the electric motor will result in an INCREASE in net carbon emissions over the ICE, depending on how the battery is charged. If you bypass your battery from being charged by the on-board gasoline engine and use a zero emissions source of electricity, then without a doubt you will be driving at zero net CO2/mile.

If you are only charging the battery through the gasoline engine, or using a plug-in charging method from coal generated electricity, your CO2 emissions/mile from the electric motor will be higher than that of the ICE engine. This is because the energy that goes into charging the battery will always be more than what the battery can supply. So more gasoline will be burnt in charging the battery cell to power an electric motor then would be spent by just using the gasoline engine directly. Since coal burning generates even more carbon per unit of energy than gasoline (at present), an even greater increase in emissions will result by using a plug-in charging method. While conservative methods such as regenerative breaking do alleviate some of the losses, they can never compensate unless you only drive down hill.

Hopefully this is not going to be misconstrued as a knock against hybrid vehicles. There is no doubt that the impressive gas mileage achieved by these cars allows for the potential for decreased carbon emissions over the gasoline cars they replace. But this is only possible as long as their users understand how to make it happen.

All the best,

Frog

[jcoffman]

Why are you starting yet another post about the exact same topic? Why dont you instead tell us what makes you think you have any idea what you are talking about as you have no idea how a hybrid vehicle works?

[lh_newbie]

Why are you starting yet another post about the exact same topic? Why dont you instead tell us what makes you think you have any idea what you are talking about as you have no idea how a hybrid vehicle works?

ROFLMAO! Dude, some day we're going to go get a beer - bet your a riot!

[stevejust]

Please don't feed the troll.

[lh_newbie]

jcoffman isn't a troll. He's actually an independent thinker and has implemented many energy saving items in his house. He's even _eeks_ an intelligent person - so to have someone post the same things over and over and get called on the carpet for it by someone is very cool.

I love how this forum calls anyone that doesn't blindly agree with them a troll. Very open minded!

Brian

[Its_not_easy_being_green]

Thanks for the quick postings.

Why are you starting yet another post about the exact same topic?

This is a caveat related to my previous topic, but it is not the same.

Why don't you instead tell us what makes you think you have any idea what you are talking about as you have no idea how a hybrid vehicle works?

jcoffman,
I really am not emotionally attached to the principals of energy transfer which have lead me to the conclusions above. From the tone of your last few postings, it appears that I have offended your sensibilities in some way. If I have, then I apologize. I'm merely interested in beginning a rational and intelligent dialogue. If you have an additional insight which you would like to contribute then I am interested in reading it. Please share, starting from basic principles, your understanding of how a Hybrid-electric vehicle works and why the above reasoning is flawed.

Best,

Frog

[Its_not_easy_being_green]

Why are you starting yet another post about the exact same topic? Why don't you instead tell us what makes you think you have any idea what you are talking about as you have no idea how a hybrid vehicle works?

Looking at your comments from the previous thread, I think that I may not be communicating this clearly:

If you are only charging the battery through the gasoline engine, or using a plug-in charging method from coal generated electricity, your CO2 emissions/mile from the electric motor will be higher than that of the ICE engine

The internal combustion engine (ICE) I am referring to is specifically the engine in the hybrid. I am not claiming that the losses involved in driving on the fossil-fuel charged (EM) will be responsible for more emissions than ANY ICE, such as that in a large truck. I would be willing to bet that such charging scheme will bring the emissions of a Hybrid on par with other gasoline powered compact cars though. Of course if every SUV owner traded their vehicle in for a plug-in hybrid, and charged it on a coal powered-grid, vehicular generated carbon emissions would go down as a whole (by this charging method the same result would also probably occur with replacement by compact ICE cars). If these new hybrid owners were to get wise and also apply some of the principles above, then the real benefits of the hybrid-electric vehicle over standard compact gasoline powered cars would be fully realized.

Please let me know if I can further clarify this with another example.

Frog

[stevejust]

jcoffman isn't a troll. He's actually an independent thinker and has implemented many energy saving items in his house. He's even _eeks_ an intelligent person - so to have someone post the same things over and over and get called on the carpet for it by someone is very cool.

I love how this forum calls anyone that doesn't blindly agree with them a troll. Very open minded!

Brian

Brian: I'm not sure how you could possibly have misinterpeted my comment. The troll I was referring to is the person who started this thread: Frog/It's not easy being green. In the prior thread he started containing all of his hybrid misconceptions, it was uncovered he didn't know that OEM hybrids don't plug in. I think it's incredibly funny that someone who doesn't know the first thing about what they're talking about would come to a forum like this and start pontificating with zero basis in fact, but I also don't necessarily think it should be encouraged.

p.s., I see that you're both from the DFW area. I have an office in Dallas that I'll be at next week, or at least Mon-Weds. I wonder if it'd be worth trying to get some of the DFW people on this message board together?

[lh_newbie]

JCoffman lives in Denton - I live in Dallas. We're talking an hour or more depending on traffic. I simply don't have time for such a meeting. Thanks for the thought though.

[Its_not_easy_being_green]

I think it's incredibly funny that someone who doesn't know the first thing about what they're talking about would come to a forum like this and start pontificating with zero basis in fact, but I also don't necessarily think it should be encouraged.

Please, set me straight. I'm eager to learn!!

Frog

[Hydrotopia]

Let the man talk. Maybe the topic is worth a separate thread without the personal comments.


The hybrid should produce better CO2 ratings because it involves charging the battery with a generator in the engine - which is efficient because it takes nominal engine use and turns it into power. Since the Prius gets over 40mpg it can't be considered as being underaverage in CO2 pollution. Don't forget the gain gotten from replacing the worst efficiency use, that is powering from a stop, with electric propulsion.

The best case this thread makes is for powering plug-in cars with solar or another non-CO2 source.

.

[Its_not_easy_being_green]

The hybrid should produce better CO2 ratings because it involves charging the battery with a generator in the engine - which is efficient because it takes nominal engine use and turns it into power.

Let me pose some questions. Say I removed the ICE from my hybrid, and drive around only on the electric motor. Then when I'm ready to charge the battery, I drive home, put the gasoline engine back in and let the car sit in my driveway with the engine running to recharge the battery. Once back to full charge, I pull the engine out again and drive around on electric power.

What has this accomplished in terms of reduced carbon emissions?

What if I removed the electric motor from the hybrid and drove around purely on the gasoline engine? How would the gas mileage change?

[Hydrotopia]

Because the ICE is doing work when it's in the car moving. There's probably an efficiency gain you don't see in your way of looking at it because it overlaps with nominal use while moving the Prius. This gain is furthered by the fact that the electric motor is more efficient than an ICE and runs in the most efficient range while operating.

Them Toyota engineers ain't no dummies.

.

[SoCalSolar]

I was on the previous thread as well ... I am trying to be open minded and patient... sigh.

Ok - I think what Frog is trying to say is that future plug-in hybrids would be most optimized by being charged by a renewable source - something like your home solar, microhydro, or wind system. This would be great and perhaps "one day", like 2075, it might be possible. Various styles of hybrids are likely to become the dominant vehicles as the years go on. There may end up being 300 million types of hybrids or full electric cars on the road in 20 years. For the next decade or two it is unlikely that the general population will have that widespread an infrastructure of home based renewable energy. ...or maybe 150 million homes will get solar modules in the next 20 years. It could happen... ...a man can dream...

As far as today's hybrids - there seems to be a misconception with the thread's main point regarding how hybrids charge their batteries. My Prius not only charges with regenerative braking, but - as mentioned with the previous post - coasting. Not just down hill, but - for example - at freeway speed as the ICE is just maintaining the car's motion, excess energy from both the ICE and the front wheels motion is charging the battery. I do not know the exact percentage, but I would guess that around 50% of the battery charge does not come from the gas engine. It does, however, depend on the driver's habits.

I admit that being a Prius owner, that is what I generally talk about. The first few years of the Civic hybrid were a different system - which may have done a larger percentage of charging with the ICE - would love it if someone has that specific info... also on the diffences with Honda's new model Civic's system.

The all-electric mode of the Prius'start-up is of great benefit; but also when driving in a parking lot, stop-and-go traffic, etc. the car hardly uses the ICE at all, and the braking and coasting keep the battery charged with no or very little gas.

The system is not 100% efficient, but it's CO2 footprint is not likely the same as a car of similar size - ie: Corolla or civic (4 door), non-hybrid.

Mike

[SoCalSolar]

Frog - you kinda sound like HAL from "2001: A Space Odyssey"... are you milking us humans for information?

Sorry... couldn't help myself. (I think it is a worthy discussion - we are all learning more about hybrids - probably a good thing).