Subaru pzev how does it work

Once again, the result is a drastic reduction in emissions. October 23 , Tremblay Auto Groupe. September 11 , Tremblay Auto Groupe. Subaru Awarded for Residual Value. August 28 , Tremblay Auto Groupe. Sales: Service: Parts: Service Appointment. Print Share. How does a PZEV engine work? Fuel injectors Subaru PZEV fuel injectors are significantly more airtight than conventional injectors. The best advantage to the Subaru PZEV cars is that while they have revamped the cars to be more eco friendly, they have also not cut any corners in ensuring that the cars perform well.

The ability to reduce the smog-forming emissions from the car comes from changes made in four key areas in the car. The first was introducing a larger and finer mesh of catalyst-lined passageways in a Subaru PZEV catalytic converter. The entire length of the mesh is surrounded by precious metals, and the role of those medals is to change the molecular structure of emissions as they try and pass through the metal.

The dual-filtration air-intake system has been updated in the PZEV to remove the gap in the dual-filtration air-intake system that can allow for emissions to escape when the engine is off.

These cars have the same engines and transmissions and are built on the same platforms. There are three unique components in the fuel systems, and one in their exhaust, that makes a PZEV:.

Anti-Permeation Fuel System Liners. When fuel system components get saturated with gasoline, they leak gas vapor through the outer surfaces, letting it evaporate into the air. So, engineers building PZEVs line the insides of fuel caps, fuel hoses, seals, gaskets, and plastic fuel tanks with layers of low-permeability polymers such as ethylene vinyl alcohol to keep fuel from soaking through. This stops off-gassing as the vehicle sits unused. Carbon Canister Scrubbers. Temperature swings from day to night can cause gasoline to evaporate past the fuel cap and into the atmosphere.

Refueling also forces gasoline vapor out the system and past the gas pump nozzle. To capture gas before it reaches the air, a car fixes a canister of activated carbon carbon that's processed to be more porous in the fuel-filling line from cap to gas tank. The canister traps most of these hydrocarbons, which the engine destroys by pulling them into the combustion chamber.

Even so, the canisters still leak small amounts of vapor. PZEVs add an auxiliary scrubber canister of honeycomb-shaped carbon that captures 95 percent or more of the vapor leaking out the primary canister. Carbon Air Intake Trap.

After you shut off an engine, fuel vapor remains in the combustion chamber and intake manifold. That vapor evaporates, and like with the carbon canister, a filter of activated carbon grabs outgoing hydrocarbons before they can make it into the surrounding air.

Newer designs are using a metal honeycomb filter spread with zeolite, another porous filter mineral.