The Subaru PZEV (Partial Zero Emission Vehicle) is the affordable, no-compromise, eco-friendly alternative. Although the Subaru PZEV runs on regular unleaded fuel, it offers significant smog-reducing environmental benefits and delivers equal performance compared to non-PZEV cars or SUVs, including hybrids, diesels and alternative fuel vehicles.
A PZEV is classified as the cleanest-running gasoline-powered car on the market and was developed to meet the air quality standards of California, the most stringent in North America. A PZEV must meet the Super Ultra Low Emissions Vehicle (SULEV) tailpipe standard and have zero evaporative emissions.
View Emissions Ratings
Emission standards are for the major pollutants in vehicle exhaust:
- NMOG, NMHC, or THC—types of carbon-containing compounds, including hydrocarbons
- NOx—Oxides of Nitrogen, which combine with hydrocarbons to create smog
- PM—Particulate Matter, tiny particles of solid matter that lodge in the lungs and deposit on buildings
- CO—Carbon Monoxide, a colorless, odorless, poisonous gas
- HCHO—Formaldehyde, a lung irritant and carcinogen
* Vehicle must also be certified to CA PZEV or SULEV20 standard
How does it work
With Subaru PZEV vehicles, the remarkable reduction of smog-forming emissions is achieved through modifications in four key areas:
A larger and finer mesh of catalyst-lined passageways within a Subaru PZEV catalytic converter greatly contributes to its ability to reduce emissions. Along the entire length of the mesh are precious metals (catalysts) whose role is to change the molecular structure of the offensive emissions that try to pass through. In fact, the contact area is almost twice that of a traditional catalytic converter, producing a much more effective conversion of pollutants.
The fuel injectors on Subaru PZEV vehicles close tighter than conventional injectors to prevent evaporative emissions from fuel leakage into the intake manifold.
Dual-filtration air-intake system
In a conventional vehicle, unburned gas fumes can escape through the engine’s air intake once the engine is shut off. To prevent this, Subaru PZEVs are equipped with a charcoal canister in the air intake that absorbs these evaporative hydrocarbon emissions.
Engine Control Module (ECM)
Vehicle emissions are worst in cold start conditions. Subaru addresses this problem by altering the programming in the Engine Control Module to delay ignition timing, making the exhaust gasses hotter, which helps the catalytic converter heat up sooner, reducing emissions.