What Is PZEV and How Is It Fueling the Need For Alternative Fuel?

March 13, 2017

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In 1989, the California Air Resources Board created the Partial Zero-emissions Vehicle (PZEV) category. Vehicles that meet SULEV (Super Ultra Low Emission Vehicle)standards, have a 15-year / 150,000 mile warranty, and have zero evaporative emissions may fall into this category.

PZEV vehicles have 4 primary technological differences from other vehicles

Anti-Permeation Fuel System Liners

You cannot smell the odor of gasoline vapors as you walk past a Partial Zero-emissions Vehicle because of anti-permeation fuel system liners. This is because the vehicle's fuel system is lined with polymers, preventing fuel to "permeate" the fuel system parts such as fuel hoses, gaskets, fuel capes, etc..

Carbon Canister Scrubbers

Vehicles have canisters of activated carbon in the fuel-filling line. Even though this is effective in capturing most of the vapor, there is still residual fuel vapor released into the air. A PZEV is equipped with auxiliary "scrubber" canisters of honeycomb-shaped carbon that can capture the residual fumes.

Closed Coupled Catalytic Converters

Lined with precious metals such as platinum, palladium, and rhodium, normal catalytic converters convert the harmful gases produced by gasoline into less environmentally-harmful gases. PZEV's differ in that they have two closed, coupled catalytic converters near the engine. This is because vehicles produce dirtier emissions on first ignition. To add further cleanliness, a third catalytic converter is placed where the two exhaust pipes converge in order to clean the nitric oxide and nitrogen dioxide before exiting.

Carbon Air Intake Trap

Residual fuel vapor stays in the intake manifold and combustion chamber after you shut off your vehicle's engine. Therefore, a filter of activated carbon traps prevents them from entering the atmosphere. Newer PZEV's use a metal honeycomb-shaped filter with zeolite.

Other types of low-to-zero emission vehicles on the market

Hydrogen-fueled vehicles

Hydrogen vehicles are being tested by numerous car companies today, but they have not yet become popular due to the scarcity of hydrogen fueling stations. Nevertheless, there are a few car makers out there that are testing the technology. Currently, the Honda FCX Clarity is being leased to drivers in California, and the famous BMW Hydrogen 7 is being leased to big names, such as film director Florian Henckel von Donnersmark.

There are two types of hydrogen cars: The first uses hydrogen combined with oxygen to produce electricity that powers an electric engine. The second works in the same fashion as your typical gasoline combustion engine. Both of these models produce water vapor as its byproduct.

Electric vehicles

Electric cars have been around for quite a while actually! A Scottish inventor by the name of Robert Anderson built the first electric-powered carriage in 1832. In 1897, electric taxis were showcased on the streets of New York.

The primary hurdle that car makers are facing with the electric vehicle is developing a long-lasting battery. As of now, there are a number of electric vehicles on the market, such as the famed Tesla Roadster. The average range of most electric cars is about 100 miles, with many exceeding that mile count, with a 4-hour average charging time. You can expect to dish out about $23,000 to $100,000 for an electric car.


Biodiesel is essentially produced from cooking oil and grease. With the many fast-food joints on every block, biodiesel enthusiasts are opening up shop in their own homes and saving a lot of cash.

But don't run to your kitchen and pour your leftover french fry grease into your diesel truck's fuel tank! There is a process you must go through to turn regular cooking oil into biodiesel. On top of that, you must also do some altering of the normal diesel engine due to biodiesel viscosity. Not to mention, if done wrong, you can seriously harm your engine, making it dangerous for unskilled people attempting to produce results without training and knowledge.

About the Author

Kimberlea Buczeke is an automotive expert at RepairPal, the leading online source of auto repair resources and estimates. With many ASE Master certified mechanics on staff who have decades of experience, RepairPal knows all the fine points of car repair.

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