Hybrid Cars

With the cost of gasoline hovering around the $3.00 per gallon mark, many of us are spending $40 or more each time we fill up our cars at the gasoline station.  And just as fuel economy starts to become more worrisome for many consumers we've got some new technologies hitting the highways of America with a promise to lower those monthly gasoline bills - hybrid cars.

What is a Hybrid Vehicle?

On the one hand our highways are full of cars that run on gasoline.  On the other hand we've got fuel cell cars and other electric vehicles that are slowly moving from the research labs to the automobile manufacturer's production lines.  In between we've got a hybrid car - a vehicle that offers us a compromise between these two ends of the spectrum.

One of the important features of a hybrid vehicle is that it does not require any shift in infrastructure or normal operating procedure.  That is, hybrids meet the basic requirements that we've come to expect when buying a new car:

• You can drive the car 300 miles or more before refueling is required.
• You can refuel the car quickly and conveniently - that is, a widespread refueling infrastructure exists.
• The car performs like other cars on the road today in terms of safety, handling, and acceleration.

Right now, fuel cell cars do not meet any of these three criteria completely.  However, hybrid cars do - and to understand why, you need to know a little bit more the theory behind hybrid cars and the technologies used in these cars, SUVs, and trucks.

Hybrid Vehicle Theory

The theory behind a hybrid car is quite simple - overcome the limitations of today's electric cars by leveraging the power of gasoline driven engines.  In fact, hybrid technology has actually been around for years and those that are familiar with the workings of today's diesel powered locomotives understand this point - hybrids use a traditional fuel, such as gasoline, to produce electricity that drives an electric motor.

Putting together a hybrid car is a somewhat complex engineering feat that utilizes the following closely integrated vehicle components:

Gasoline Engines

The power plant of a hybrid remains the internal combustion gasoline engine.  To achieve some of the engineering goals of these vehicles, the engines utilize advanced fuel efficient technologies to both lower emissions and increase the car's fuel economy.

Fuel Tank

The batteries found in today's electric vehicles are just not able to match the density of gasoline in terms of energy stored per pound.  That is, you can store a lot more energy in gasoline compared to batteries on a pound for pound basis.  That's just one of the reasons that hybrid cars still depend on gasoline and traditional fuel tanks.

Electric Motor / Generator

The electric motor on a hybrid car is sophisticated and can work in one of two ways - parallel or series - which we will describe in detail later on.  Essentially, the electric motor(s) drive the wheels of the car and / or the motor can act as a generator that captures energy when slowing a car.

Batteries

Right now, batteries in a hybrid car are used to store supplemental energy that can be used to drive the electric motor.  For example, the supplemental energy stored in batteries could be used to move the vehicle up a steep hill or incline.  Energy can be stored to the batteries as well as drawn from them as the car moves along the roadway.

Electric Motor Vehicles Technologies

As mentioned, hybrid electric vehicles, or HEVs, produced today depend on both electric motors and internal combustion engines.  Hybrid cars use energy stored in a battery to move an electric motor, which then moves a car in one of two ways:

• Parallel Hybrid Motor Design - with the parallel design, the internal combustion engine and the electric motor are connected directly to the vehicle's wheels.  The internal combustion engine is used for highway driving while the electric motors add power during periods of high demand such as acceleration.
• Series Hybrid Motor Design - with the series design, the engine is connected to a generator that produces electricity that is used to drive the electric motor powering the wheels of the car.  With all wheel drive, or AWD, vehicles such as the Toyota Highlander SUV, two electric motors drive the vehicle. 

Of course car manufacturers can also use combinations of the above two designs to try and achieve even greater savings.

New Hybrid Cars, Trucks and SUVs

New hybrids on the road today fall into the three major categories of non-commercial vehicles - cars, trucks, and SUVs.  Listed below are hybrids you'll find on the road today, grouped by these categories:

Light Duty Hybrid Cars

• Honda Accord - 30 MPG City / 38 MPG Highway.  Honda's Integrated Motor Assist (IMA) hybrid system utilizes a high-output electric motor/generator, which uses a 3.0-liter i-VTEC engine for primary power.  This engine also provides for more efficient engine operation by capturing electrical energy during braking or deceleration and using that energy to help power the car.
• Honda Civic - 40 MPG City / 45 MPG Highway.   The Honda Civic Hybrid four-door sedan uses both a 1.3-liter, 8 valve, VTEC gasoline engine and the added power of an ultra-thin electric motor to achieve a fuel economy of 40/45 mpg (manual transmission).  Civic Hybrids are emissions certified nationwide as SULEV-II, except those sold in California and some Northeastern states where there are certified as Advanced Technology Partial Zero-Emissions Vehicles (AT-PZEV).
• Honda Insight - 60 MPG City / 66 MPG Highway.  This gasoline-electric hybrid vehicle is not EPACT compliant, but does meet California ULEV (Manual Transmission) and California SULEV (CVT Transmission) emission standards. Combining an efficient 1.0 liter, 12-valve, 3-cylinder gasoline engine with an electric motor powered by advanced nickel-metal hydride batteries, the Insight can travel up to 700 miles between refueling.
• Toyota Prius - 48 MPG City / 45 MPG Highway.  The Prius satisfies Super Ultra Low Emission Vehicle (SULEV-II) and California Advanced Technology Partial Zero Emission Vehicle (AT-PZEV) standards.  Available with an electronically controlled continuously variable transmission (ECVT), the Prius seats up to 5 passengers.
• Toyota Camry - 35 MPG City / 34 MGP Highway.  The Camry achieves Super Ultra Low Emission Vehicle (SULEV-II) as well as BIN 3 emission status with its 4 cylinder, 2.4L engine.  The Camry uses a user-selectable continuously variable transmission technology.
• Nissan Altima - 35 MPG City / 33 MGP Highway.  The Altima achieves Super Ultra Low Emission Vehicle (SULEV-II) status with its 2.5 liter engine.  The Altima is a front wheel drive, continuously variable transmission (CTV) that seats four adults comfortably.
• Chevy Malibu - 24 MPG City / 32 MPG Highway.  The Malibu is powered by a 4 cylinder, 2.4L engine that allows it to achieve Super Ultra Low Emission Vehicle (SULEV-II) as well as BIN 3 emission status.  The Malibu utilizes a computer-controlled continuously variable lockup transmission.
• Saturn Aura - 24 MPG City / 32 MPG Highway.  The Aurua is powered by a 4 cylinder, 2.4L engine that allows it to achieve Super Ultra Low Emission Vehicle (SULEV-II) as well as BIN 3 emission status.  Like the Malibu, the Aurua also utilizes a computer-controlled continuously variable lockup transmission.
• Lexus GS450h - 22 MPG City / 25 MPG Highway.  This hybrid from Lexus is powered by a 6 cylinder, 3.5L engine.  Emission status is not yet available for this vehicle.  The GS450h uses a user-selectable continuously variable transmission technology.
• Lexus LS600h - 20 MPG City / 22 MPG Highway.  Another hybrid from Lexis, this time powered by an 8 cylinder, 5.0L engine.  Emission status is not yet available for this vehicle.  The GS450h uses a user-selectable continuously variable transmission technology.

Hybrid SUVs

• Ford Escape - 34 MPG City / 30 MGP Highway.  The Ford Escape Hybrid has a full hybrid system that enables it to run on its gasoline engine, electric battery power or both together.  The Escape meets SULEV-II, BIN 3, and AT-PZEV emissions standards. The Escape also comes with a four-wheel drive option and runs on a Duratec I-4 Atkinson Cycle 2.3L engine.
• Mercury Mariner - 34 MPG City / 30 MPG Highway.  The Mercury Mariner has a full hybrid system that enables it to run on its gasoline engine, electric battery power or both together.  The Mariner meets SULEV-II, BIN 3, and AT-PZEV emissions standards. The Mariner also comes with a four-wheel drive option and runs on a Duratec I-4 Atkinson Cycle 2.3L engine.
• Toyota Highlander - 27 MPG City / 25 MPG Highway.  The Highlander is a gasoline-electric hybrid vehicle with a 3.3 L (DOHC) 24 valve with (VVT-i) gasoline engine.
• Lexus RX 400h - 26 MPG City / 24 MPG Highway.  The Lexus RX 400h is a gasoline-electric hybrid vehicle with a 3.3 L (DOHC) 24 valve with (VVT-i) gasoline engine.  The RX 400h is powered a continuously variable, user-selectable lockup transmission.
• Mazda Tribute - 34 MPG City / 30 MPG Highway.  The Mazda Tribute is hybrid 2WD SUV that achieves BIN 3 and SULEV-II emissions status.  The Tribute is powered by a 2.3L engine and a continuously variable, user-selectable lockup transmission.

Hybrid Trucks

• Chevy Silverado / GMC Sierra Hybrid - 18 MPG City / 21 MPG Highway.  The Silverado and Sierra use a four speed automatic transmission and a 5.3 liter engine in this first appearance of hybrid trucks.

Driving Hybrid Vehicles

Since hybrid cars utilized advanced systems to generate and recapture energy, there are certain driving habits that can maximize the fuel economy of these vehicles.  Some of these methods also apply to gasoline powered cars:

• Slow Down - As speed increases so does the wind drag on the car.  The drag force at 70 miles per hour is roughly double that of a car traveling at 50 miles per hour.  So by keeping your speed down, you can increase your gas mileage.
• Maintaining Speed - Engines run most efficiently when they are operated at a constant speed.  Speeding up or slowing down decreases efficiency and fuel economy.
• Stopping the Car - Hybrid cars are able to recapture energy either through magnetic braking systems and / or via the engine acting as a generator.  The more time you give an electric hybrid time to slow down, the greater the amount of energy that can be recaptured by these systems.

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