Euro 2 (introduced in 1996):
* Less stringent limits: Allowed for higher emissions of carbon monoxide, hydrocarbons, and nitrogen oxides compared to later standards.
* No particulate matter (PM) limit: Did not regulate particulate matter emissions, which are fine particles that contribute to air pollution and health problems.
* Older technology: Engines using this standard often lacked sophisticated emission control systems like catalytic converters and exhaust gas recirculation (EGR).
Euro 4 (introduced in 2005):
* Significantly stricter limits: Imposed much lower limits on emissions of carbon monoxide, hydrocarbons, nitrogen oxides, and introduced limits on particulate matter.
* Advanced technologies: Engines meeting this standard typically employ more advanced technologies like improved catalytic converters, EGR systems, and diesel particulate filters (DPFs) to reduce emissions.
* Improved fuel efficiency: The stricter regulations and advanced technology often lead to improved fuel efficiency compared to Euro 2 engines.
Here's a table summarizing the key differences:
| Feature | Euro 2 | Euro 4 |
|---|---|---|
| Emission Limits | Less stringent | Significantly stricter |
| Particulate Matter (PM) | No limit | Regulated |
| Technology | Older, less advanced | More advanced, including catalytic converters, EGR, and DPFs |
| Fuel Efficiency | Generally lower | Often improved |
In short, Euro 4 engines are significantly cleaner and more efficient than Euro 2 engines. They contribute less to air pollution and have a reduced environmental impact. However, Euro 2 vehicles are generally older and may be less expensive, but their emissions will be significantly higher.
It's important to note that these are just general guidelines, and specific emissions levels can vary depending on the engine model and make.
