Unit 29

Hybrid Electric Vehicles

Hybrids

Hybrid Electric Vehicles• Hybrid Electric Vehicles are all the rage now.• Higher gas prices following the boom of sales

of gas-guzzling large SUV’s have caused Americans a lot of pain at the pump.

If you are interested in saving some money andreducing pollution and greenhouse gases…

Hybrid Electric Vehicles might just be for you!

Hybrids Might Be For You IF….

So, What is a Hybrid Anyways?• Hybrid Electric Vehicles combine a small

traditional gasoline powered engine with a battery-powered electric motor.

• Most of the driving uses the electric motor, especially while driving under normal conditions and at moderate speed.

• The energy comes from the battery.

So, Why a Gasoline Engine Too?

• The small 4-cylinder gasoline engine kicks in when the vehicle needs extra power.

• This includes accelerating rapidly (such as to pass someone), driving up steep hills, or driving at highway speeds above 55 mph.

How Does Battery Have Power?• When the gasoline engine kicks on, it also

turns a generator to generate electricity to recharge the battery.

• If your battery starts to get low, the gasoline engine will sometimes come on even under normal conditions to recharge the battery.

Getting Energy BackHybrids can also generate electricity through regenerative breaking. Basically, you recover some of the energy of motion when you break and send it back to the battery.

Plug-in Hybrids• Some newer hybrids can be plugged in at

home to recharge the battery so you do not need use gasoline to do it.

• This makes it even more fuel efficient!

The Problem With Gasoline Engines• Most cars have gasoline engines that are larger

and less efficient than they need to be under normal conditions.

• That is because even if you usually drive 35 mph in a flat area, your car needs to be able to drive 75 mph up a mountain road, just in case.

Why Hybrids Help• Hybrids on the other hand have small engines.

Thus, they are more efficient at using the energy under normal conditions.

• It also only kicks in when it is needed.• Thus, your fuel efficiency is significantly higher

than a comparable gasoline only vehicle.

How much better are hybrids?• A 2010 Toyota Prius gets 51 city/48 hwy mpg• A 2010 Honda Civic gets 26 city / 34 hwy mpgThat 25 mpg difference, if driven 15,000 mi/yr at

around $3.20/gallon will save you $905/year in gas and saves 287 gallons of gas from being burned and polluting our air.

What’s up with better City and Hwy?

• You may have noticed that the hybrids get better gas mileage in the city than the highway, which is opposite of how gasoline vehicles get.

• The reason is that in the city, the electric motor is doing most of the work and once you get on the highway, the gasoline engine has to kick in more.

• Traditional cars do better on the highway because their larger engines are now working their most efficient state.

• Still, Hybrids do get better highway mileage because even with the small gasoline engine on, much of the work is still done by the electric motor powered by the battery.