renewable energies

What makes hybrid cars so fuel efficient?

Why are hybrid cars so much more fuel efficient then “regular” cars?

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This entry was posted on Wednesday, March 28th, 2007 at 11:42 am and is filed under Hybrid Cars. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.

4 Responses to “What makes hybrid cars so fuel efficient?”

1. Pedro S on March 29th, 2007 at 10:01 pm

   the engine and brakeing system make power [electrict] and store it in batterys…when the engine is not not needed the car runs on batterys with the engine shut off,,,,saving fuel

2. chris_rob00112233 on March 31st, 2007 at 3:57 am

   They tend to be smaller cars or are stripped down compared to normal cars. As a result they are more aerodynamic or have less weight, making them more effecient and able to go farther on less gas and a smaller engine. Unfortunately they tend to be smaller, a problem if you need room for transporting people or things.

3. professorprius on April 1st, 2007 at 6:49 am

   Hi,

   actually, hybrid vehicles come in multiple levels and how efficient they are depends on how much of a hybrid they are.

   Stay with me and I’ll give you the full answer, starting with some basics.

   A full hybrid is able to move and power the A/C using electricity only, the internal combustion engine (ICE) does not have to start. Think of the Prius.

   This is done with a combination of a large nickel metal hydride (NiMH) storage battery and powerful electric motor/generators linked with a very efficient ICE.

   A partial hybrid must have the ICE running to move or power the A/C. The ICE is shutoff at stops, assuming the A/C is not running. Think of the Civic Hybrid.

   A partial has a small NiMH storage battery and less powerful electric motors whose main job is to boost the ICE and allow it to use less gas.

   A mild hybrid must have the ICE running to move or power the A/C and is only shut off at stops, assuming the A/C is not running. Think of the Malibu Hybrid.

   There is no additional boost to the ICE from the electric motor, the mpg gains are only from the ICE being shut off at idle or stops.

   So, essentially, a hybrid is trying to lessen how long and how hard the ICE is running. If the ICE can be bypassed or boosted by electricity generated and stored in the vehicle, than the ICE uses less fuel and produces less pollution because it’s not running.

   Using the Prius as an example, the ICE is a standard 1.5 liter 4 cylinder engine that Toyota uses in multiple vehicles.

   An electric motor/generator (the MG2) captures up to 26% of the braking energy lost to friction heat and converts that to electricity that is stored in the NiMH to be used to move the Prius. This is called regenerative braking.

   A different electric motor/generator (the MG1) uses that stored energy to turn the front wheels.

   The Prius NiMH can be recharged in three ways:

   1. the friction of the front wheels rolling on the ground
   2. the ICE running, with some of that power being diverted through the MG1 to the NiMH
   3. pressing the brake pedal and the MG2 recaptures some of that lost energy

   Plus, vehicles like the Prius are actually sculpted to slip through the wind as easily as possible. The Prius is actually more slippery than the new Corvette ( a .26 Cod vs. a .27 Cod- like golf, the lower the number the better). This means less fuel is used than a standard vehicle at the same speed, even without the hybrid system.

   One point I want to make about hybrids is they are not “stripped down”, lightweight versions of some other vehicle.

   You can get a Camry Hybrid, Altima Hybrid, maybe even still find an Accord Hybrid and these vehicles will have at least as many standard and optional features, mass, and sound deadening as their standard versions.

   It is a mistake to equate a vehicle like a Prius with a Yaris or Corolla, just as it is a mistake to equate a Civic Hybrid with a standard Civic or Fit.

   The Prius has more standard and optional features, more room and comfort, more power (torque especially), and more mass than the Corolla or the Yaris, speaking for Toyota.

   Hope that helps, if you need any other details let me know or check my other detailed posts here in Answers.

4. wOw on April 2nd, 2007 at 11:56 am

   I drive toyota prius and love it, but this article can educate you about hybrid cars

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