Key Point: All heavy diesel vehicles sold in Australia since 2011 must meet ADR 80/03 emissions standards, which typically require AdBlue (also called Diesel Exhaust Fluid or DEF). This means the vast majority of modern commercial vehicles on Australian roads depend on AdBlue to operate legally and efficiently.
Understanding Australian Design Rules (ADR)
The Australian Government sets vehicle emissions standards through the Australian Design Rules (ADR). For heavy vehicles, ADR 80/03 is the primary regulation that governs nitrogen oxide (NOx) and particulate matter emissions.
ADR 80/03 Timeline
First significant NOx reductions, some vehicles began using SCR technology
AdBlue/SCR became standard for most heavy vehicles to meet NOx limits
Even stricter standards, higher AdBlue consumption (~5-7% of diesel)
What Are Euro Standards?
While Australia uses ADR regulations, these are closely aligned with European Union emissions standards (Euro standards). Understanding Euro standards helps because most heavy vehicles sold in Australia are marketed with Euro ratings:
| Standard | NOx Limit | AdBlue Required? |
|---|---|---|
| Euro 4 / ADR 80/02 | 3.5 g/kWh | Sometimes |
| Euro 5 / ADR 80/03 | 2.0 g/kWh | Yes |
| Euro 6 | 0.4 g/kWh | Yes (higher usage) |
How SCR Technology Works
To meet these strict emissions standards, modern diesel engines use Selective Catalytic Reduction (SCR) technology. Here's how the system works:
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1
Engine Combustion
Diesel combustion creates hot exhaust gases containing harmful nitrogen oxides (NOx)
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2
AdBlue Injection
AdBlue (urea solution) is injected into the exhaust stream before it reaches the SCR catalyst
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3
Chemical Reaction
Heat converts AdBlue to ammonia, which reacts with NOx in the catalyst chamber
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4
Clean Exhaust
NOx is converted to harmless nitrogen gas (N₂) and water vapor (H₂O)
Environmental Impact: SCR technology with AdBlue reduces NOx emissions by up to 90%, making modern diesel engines one of the cleanest combustion technologies available for heavy vehicles.