About Hybrid Cars

Hybrid cars are selling better than expected, to the dismay of American car makers.  A hybrid is similar to a conventional car except that its drive train has been modified to have both an internal combustion engine (ICE) which drives the front wheels and one or two electric motors, powered by batteries, that drive the rear wheels. 

Plug-in hybrids are hybrids that can be plugged into an electrical outlet while the batteries charged, would be even more economical and not use nearly as much liquid fuels as the hybrids that are now available.  Plug-in conversion kits are starting to become available, but at a fairly hefty cost. 

Battery technology is always of concern when powering a car that is partially powered with batteries, especially when they are constantly being charged and discharged.  Batteries on hybrid cars are usually guaranteed for 100,000 miles, although the expected life is said to be greater than 150,000 miles. Toyota, the largest producer of hybrids, has stated that they have not had a single claim on their batteries. 

The biggest disadvantage of a hybrid car is its initial cost, which is about $3000-$5000 (US) more than the conventional version of the car.

All hybrid cars are not created equal.  There are "true hybrids" that can, if necessary, run on either the internal combustion engine (ICE) or battery power and "pseudo hybrids" that cannot run on battery power alone. Some of features that differentiate a hybrid from a conventional vehicle are:

Electric Motor Drive - Usually the motor(s) are used to drive the vehicle at low speeds where they are more efficient than a ICE.  The motor also provides assist to the ICE for acceleration, passing or hill climbing.  This allows a smaller ICE to be used.  The motor is typically sized only to get the vehicle up to about 25 miles per hour and to cruise at that speed.  Only 10-15 miles may be driven at that speed in the all electric mode.

Regenerative Braking - The electric motor shuts down during braking and coasting.  Then the wheels drive the motor and the motor acts like a generator, charging the batteries. 

Automatic Start/Shutoff - The engine automatically shuts off when the vehicle comes to a stop.  The motor starts when the accelerator is pressed to start up again.  The division of power between the engine and motor is controlled by a computer to balances the power as needed.

Internal Combustion Engine - The ICE is usually smaller than the engine in a conventional car because it is not used as much for acceleration.  Only the ICE is used to power the vehicle at cruising speeds.  The motor comes on to assist it during passing or hill climbing, if there is a demand for it.  A portion of the engines power is also used to charge the batteries if needed.

There may be some variations in this scheme, but is generally as described.  The key to getting the most mileage is the relative size of the engine and motor and how the computer is programed to divide the power between the two drives.

There are several things to consider before you buy a hybrid:

• They are good for the environment.  While driving at low speeds only the motor is used which has no pollutants.  Hybrids consume less gas and therefore has less pollution per mile driven.
• Hybrid cars currently cost from $3,500 to $6,000 more than a comparable cars.  The gas cost savings during the ownership of a car are not likely to pay for the additional initial cost.
• The U.S. federal government currently gives tax breaks through 2006.  The amount depends on what tax bracket you are in.  Some states also give tax breaks.
• The battery pack is expensive.  If you are planning on driving the car more than 150,000 miles you may have to spend $1,000 and $2,000 for a new battery pack.

For the most part performance is not an issue, with most hybrids getting at least as good of performance as the equivalent conventional model.  Some get even better performance than the gas powered model.  The Honda Accord has added a new feature, it's the first hybrid that shuts down half the engine's cylinders under light load to save even more gas. 

Hybrids are so popular that sales of some models, especially the Prius, are greater than anticipated and unable to keek up with demand.  The popularity is driven by 1) the price of gasoline 2) concerns about environmental damage by gas guzzling cars and 3) people enamored by the cars and want to be enablers of the technology.  These factors have lead to acceleration of production plans for the introduction of new models.  There are a limited number of models available at the present time.   By 2007 there will be a full slate of models to chose from.  The table below lists the six currently available models and the future models that have been announced to date.

                                                Engine/Motor   EPA MPG
Model                    Type             Disp, hp/hp    City/Hiway    MSRP

Honda Insight         Small car        1.0 L, 65/13        61/66       $21,050
Honda Civic            Compact        1.3 L, 85/13        47/48       $21,530
Kia Rio                   Compact        2006 limited production
Hyundai Accent      Compact        2006 limited production 

Nissan Altima          Mid size         2.5 liter/67 hp     2007
Toyota Prius           Mid size        1.5 liter/44 hp      60/51       $19,993
Honda Accord        Full size         3.0, 240/16          30/37       $32,140
Toyota Camry         Full size         2007
Chevrolet Malibu     Full size         2007 

Lexus GS 450h         Sports sedan    2006

Ford Escape 2WD     Sm SUV         2.3 L,133/94         31/36     $26,810
Saturn Vue             Sm SUV         2006
Mercury Mariner     Sm SUV         2.3 L,133/22         33/29     2006
Mazda Tribute         Sm SUV        2007
Lexus RX400h           Mid SUV      3.3 liter/38 hp       29/31    $48,535
Toyota Highlander    Mid SUV       3.3 L, 208/267       33/28    $33,030  6/200
Chevrolet Tahoe       Lg SUV        2007

Dodge Ram              Pickup         4.7L, 325/47    limited production
GM Sierra               Pickup          295/0                   18/21     2005
Chevrolet Silverado  Pickup          295/0                   18/21     $30,345

The Union of Concerned Scientists operates both a web site and a blog about hybrids.  The web site, Hybridcenter.org, gives very detailed information about the five cars that it currently covers.  It also has an article titled "Watchdog Hollow Hybrids" that takes task with the GM Sierra and the Chevrolet Silvarado as not being true hybrids stating that "GM's claim to have hybridized their large pickups rings hollow; it turns out to be a low-tech solution with only about a 10 percent (1-2 mpg) increase in fuel economy compared to GM's similar models.  This runs the risk of poisoning the hybrid truck market."  Their blog, hybridblog.org, is intended to help stimulate an informed debate and exchange of useful information about technological, policy, and consumer developments in the hybrid vehicle market.  Green Car Congress has a large category on hybrids which is updated frequently.  Further information on hybrids may be found at these web sites: eartheasy Hybrid cars, hybridcars.com, Hybrid Mileage Comes Up Short and www.fueleconomy.com. 

Comments

[Stelle Courney]

Consumers should think of hybrid vehicles as a way to expand fuel choices. The way I see it, owning a hybrid vehicle affords me the option to continue using my car even in the face of a shortage in gasoline supply. Now, isn't that convenient?