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xbalanque

Why hybrid cars gas mileage is better in city ?

Q'Aminator

hybrid cars save energy in two ways: <br />1.by storing energy from the breaks<br />2.by engaging the gas motor only in it's most effective work RPM meaning that the system will engage the gas motor mostly at coursing speed (close to the most efficient motor RPM)<br />Having said the above, driving in the city almost never gets you to the efficient RPM.<br /><br />Also- it is true that the same energy that is being stored in the cars' battery needed to be generated by chemic energy. The cool thing about it is that the pollution can be outside of the city and not in the city. (Like in San Francisco, the electric buses generate the same pollution as a gas buses it is just not in the city.<br /><br />You can also add that electric engines are much quieter then gas engines.<br /><br />So- all in all- I the hybrid benefits are more visible in city driving

questioner

There are the two reasons mentioned already - using the energy from the breaks and using the gas engine only when it can work efficiently.<br />
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One more thing to note is that for several cars, the hybrid model of a car has a smaller gas engine than the regular models (e.g. for Honda Civic the gas engine for the hybrid model is 1.3L, which is not available in the regular models). So even without the other things, this engine will get better gas mileage than the larger engines.

tomchi

The gas mileage for some hybrids is better in the city because they spend more time using their electric motor instead of their gas engine. Most hybrids have battery packs which are charged by what is called "generative breaking". Instead of slowing down with traditional braking, these cars store some of the energy from braking into a battery pack. Then when the light changes and the car moves again, the energy stored in the battery can be used to move the car, or assist the engine in moving the car.<br />
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In the city this effect can be more pronounced because of more frequent stopping and starting.