Top Ten Hybrid Myths

[gadget_lover]

Yes, they are going to change it. It will make it difficult to compare cars from previous eras to future models.

Unless they work some real magic, I don't see it as an improvement. Why? Because cars behave differently under different conditions and the EPA can only emulate one set of conditions. No matter whcich set of conditions they choose, it will only match "real life" for a very small part of the population.

I'd like to see the numbers that matter to me; that calls for a handful of standards.

1) Vaction hightway mileage; The milage you get when traveling at 70 mph for 6 hours with an ectra 800 pounds of cargo.

2) Commuter milage; The milage you get when you start cold, stop for gas, then stop for coffee, then drive 20 miles at 75 MPH and 5 miles in stop and go, followed by 5 minutes of wandering aimlessly through a full parking lot.

3) Shopping milage; The milage you get when you drive 1 mile to the store, shop for 1/2 hour and drive home again.

4) Shopping spree milage; The milage you get when you drive to the store, buy groceries, then to the pet store, then to the hardware store, then the school and finally back home.

5) Garage sale milage; The milage you get when driving from random point to random point, starting and stoppng frequently for several hours.

6 Last but not least; bragging rights milage; The milage you get when you overfill the tank so you can include the extra half gallon in the filler neck, then drive at 55 on a slight downhill drafting a truck with a 30 MPH tail wind.

Sadly, the garage sale milage is closest to the current city EPA milage.

Daniel

 

[cobb]

I had an old 79 vw diesel dasher its epa was 49, it did pretty close to that. My dad has a golf that gets around 43. Uncle had a geo metro, he got nearly 50 mpg with it and it was gas. Just seems as technology has gotten more advanced, fuel economy has gone down for the most part. I think a diesel hybrid should be the next focus.

I dont know any hybrid owners personally, but we had a new story a few months ago last year, an investigated on your side report that hybrid cars got best 30mpg at least to some owners in the local area. After the investigation it was blamed on driving habits.

 

[gadget_lover]

I had an old 79 vw diesel dasher its epa was 49, it did pretty close to that. My dad has a golf that gets around 43. Uncle had a geo metro, he got nearly 50 mpg with it and it was gas. Just seems as technology has gotten more advanced, fuel economy has gone down for the most part. I think a diesel hybrid should be the next focus.

I dont know any hybrid owners personally, but we had a new story a few months ago last year, an investigated on your side report that hybrid cars got best 30mpg at least to some owners in the local area. After the investigation it was blamed on driving habits.

I'm interpreting cobb's sentence as :
"we had a news story a few months ago last year, an Investigated on your side report that hybrid cars got no better than 30mpg, at least to some owners in the local area. After the investigation it was blamed on driving habits."


Yes, it's well known that there are certain driving conditions that are all wrong for the hybrid design. People who drive less than a mile and then park for over 1/2 hour, for instance, will always be driving the car when it's cold and lest efficient. People who go thorugh a drive through within 5 minutes of starting their trip will also see a hit. What's not reported is the milage these same folks were getting with their normal car before they got the hybrid. If a person drives short trips with a cold engine, the car runs richer and they burn more gas. It's that simple.

It's my guess that the person reporting 30 MPG in a hybrid rated at 50 mpg will also get only 20 in a car rated for 30.

I understand that people want diesels, but they are not really a good match for a parallel hybrid. A major reason a parallel hybrid is so clean is that it stops and starts the engine frequently. The ICE is used only when necessary. A diesel is at it's MOST dirty when starting up and shutting down.

The other value to a hybrid is the use of two power sources that each have deficiencies. The electric motor torque supplements the hybrid's (typically anemic) gas engine, and the gas engine supplements the electric motor's (typically too small) battery pack. Between the two, it delivers the power of a larger engine with the polution and milage of a much smaller engine.

The diesel already has range, and it already has lots of torque. The electric motor does not add a lot to the package. So what it really needs is a way to start and stop cleanly. A proper 48V satrter system may take care of that in a mild hybrid configuration.

Daniel

 

[cheapo]

regarding #6...........I am not sure if the charger is a family sedan, but it seats five, and it'll smoke all the hybrids off the road.

-David

 

[gadget_lover]

Since the 2006 charger is 6.4 seconds (0-60) per http://www.allpar.com/cars/lx/dodge-charger.html and the Accura is 7.5 Per Honda) , the Charger does indeed take the title.

Since I get up to freeway speed quite well with 0-60 in the mid teens, I don't think 6.5 VS 7.5 matters much.

Does anyone notice that the freeway onramps are either real long and straight, where you have 1/2 a mile or more to hit 65 or they are curved with a 25 MPH limit until it straightens out? Doesn't that make 25-65 more important than 0-60?

Daniel

 

[ikendu]

I understand that people want diesels, but they are not really a good match for a parallel hybrid. A major reason a parallel hybrid is so clean is that it stops and starts the engine frequently. The ICE is used only when necessary. A diesel is at it's MOST dirty when starting up and shutting down.

Daniel

That sounds right. But I notice that when GM, Ford and Chrysler went to design their 70+ mpg family size cars, all three of them turned to diesel/electric hybrids. Also, for a series hybrid, the diesel may be the perfect liquid fueled engine. The series hybrid seems like the best design for a plug-in hybrid electric vehicle (PHEV).

Does the Toyota design actually represent a kind of parallel & series design with that planetary gear transfer system? The Honda design seems like a pure parallel system to me.

 

[gadget_lover]

Actually, the Toyota is considered a full parallel hybrid and the Honda a mild parallel hybrid.

The Honda has the electric motor tied to the motor's output, so it runs the ICE whenever the electric is used.

The Totota can use either power source independently. It can use both at once. It can also run the ICE at an optimum RPM to generate electricity without using it to turn the wheels. It can even provide power to turn the wheels while also generating power for the battery pack. That last trick is why Toyota dubbed it the "power split unit" in some of their documentation.

I know that a lot of people like the series hybrid concept, but (other than trains) the examples so far have not been any more efficient than a conventionaly connected diesel. The achilles heel is the need for an ICE that is big enough for the maximum forseeable sustained power demand PLUS the conversion losses. Your serial hybrid loses efficiency if you have to stop and let the engine run every few hours to charge up the battery.

For an ideal PHEV I'd want the lightest possible power plant. I believe that will be something like the Toyota system with some sort of mechanical disconnect to divorce the mass of the ICE drivetrain from the CVT when on pure electric mode. A PHEV, after all, is supposed to almost never use the ICE.

When the family sedan diesel/electric hybrids of the big three are mentioned, I have to point out that none of them are in production. It's easy to make a car that get's 70 MPG. It's more complex if you have to make it run cleanly, operate without special procedures, run just like a normal car and provide acceptable performance without being overly expensive.


Daniel