Emission standards are changing new 4x4s

THE Nissan Patrol that Australia has embraced over the past 50 years, even back to when it was called a Datsun Patrol, is a goner.

From November 1, 2016, Nissan won’t be able to legally sell you an old-school Patrol, as it’s powered by what is an unacceptably ‘dirty’ diesel engine – according to the latest exhaust emission standards, known as Euro 5 (see ‘Euro 5 Explained’ sidebar).

Back in 2007 the Patrol was also dealt a blow when the much-loved 4.2-litre six-cylinder diesel was the victim of Euro 4 exhaust emissions standards.

You can still buy a Patrol after November 1, but that Patrol, known as the Y62, is several worlds apart from the old Y61 Patrol. Among other things, the new Patrol has a 5.6-litre petrol V8 that produces up to 27 per cent more carbon dioxide (greenhouse gas) than the soon-to-be outlawed diesel.

You could argue that there’s a bias against diesel engines in these regulations, and in a way that’s true, but diesel emissions are more immediately dangerous to human health – especially in crowded cites – than petrol emissions, and Europe has plenty of big cities and generally high population densities. So where a petrol engine’s larger greenhouse-gas output might be killing the planet, diesel emissions, if not cleaned up, will kill you more quickly. What’s more, carbon dioxide output (like fuel consumption) isn’t regulated under Euro regulations.

The implementation of Euro 5 has caused a flurry of other activity across the market, and it’s not just restricted to the Patrol. The new 2.8-litre diesel engine in Toyota’s Prado comes courtesy of Euro 5, and likewise the timing of the release of new Hilux which shares the Prado’s new diesel engine. The 70 Series LandCruiser’s V8 diesel is also being updated with new technology to make it Euro 5 compliant.

Compared to Euro 4, Euro 5 (as applied to diesels) brings no change in carbon monoxide limits and little change in the legal levels of NOx. But emissions of particulate matter, or so-called soot, have been slashed tenfold to match that of petrol engines. So it’s no surprise that the introduction of Diesel Particulate Filters (DPFs) is the key technological change behind compliance with Euro 5. In fact, it’s as simple as this: no DPF means no hope of meeting Euro 5.

Diesel Particulate Filters are high-tech devices that clean themselves. They generally do this via a special engine program that detects when the filter is full, heats up the exhaust stream and then adds extra fuel, which triggers a catalytic reaction in the filter that burns off the collected soot in a relatively harmless manner.

The trouble is, all this needs high-tech electronic control of all the engine’s key systems, which isn’t cost effective to fit to an existing diesel engine given that an older diesel engine’s basic design (bore/stroke relationship, cylinder-head shape, etc.) would also be out of date.

Will DPFs be a problem? Well yes, they’ve already proven to be far from infallible, as any bit of technology always is. It’s just something else to go wrong. However, the problems with DPFs generally come from vehicles that are used for nothing but very short city commutes, where the exhaust gas can’t get hot enough to trigger the DPF
self-cleaning.

Euro 6 is slated (but still under some discussion) to arrive locally in July 2017 for new-design vehicles and by July 2018 across the board. It targets NOx emissions, which was largely left alone with Euro 5. And just as Euro 5 means DPFs, Euro 6 means Selective Catalytic Reduction (SCR) technology using Diesel Exhaust Fluid, commonly known as AdBlue, often based on urea and giving a distinctive ammonia smell.

Some vehicles, like the Ford Everest, already have SCR and are therefore ready for Euro 6. Like DPFs, SCR adds another level of complexity to the engine and also brings the need to replenish the AdBlue fluid – usually, but not exclusively, as a standard service procedure.