With regulation becoming more strict and the emissions scandal still hanging over the industry many observers believe that the days of the diesel passenger car are strictly numbered.
However, leading emissions monitoring specialist Emissions Analytics says that many have been too fast to jump to the wrong conclusion and that governments are highly unlikely to give up the greenhouse gas advantage of diesel in the short- or medium-term.
Since the introduction of Euro 6 in September 2014, manufacturers have been forced to improve their after-treatment systems to meet the stricter legislated limits for NOx. Exhaust Gas Recirculation, Lean NOx Traps, and Selective Catalytic Reduction technologies have been employed as part of a complex strategy to reduce tailpipe emissions. There have been variable successes, with some achieving the regulated limits even in real-world driving and the worst more than 20 times the legal limit. Overall, average NOx emissions from Euro 6 diesels are down 55% compared to Euro 5s.
Nonetheless, there is still the fact that many new cars do not meet the legislated limits in real-world operation. Emissions Analytics data shows NOx emissions are on average 4.3 times over the limit for Euro 6 cars. However, Emissions Analytics’ data shows that modern diesels in their own right can be clean.
Emissions Analytics says since the launch of the EQUA Air Quality Index six months ago, twelve cars have how achieved an A-rating including the latest Volkswagen Tiguan, meaning it has met the 0.08g/km limit in real-world driving. The company believes this proves that diesels can be clean and the reason most are not is down to a failure of regulation and enforcement and not the technical impossibility.
Also in terms of CO2 emissions diesel still offers a 16% advantage, according to Emissions Analytics' testing, over petrol for the same distance driven in real-world operation. With hybrid and electric yet to make a serious mainstream breakthrough in volume terms Emissions Analytics’ says its data strongly suggests the policy focus should be on sorting the clean from the dirty diesels and incentivising manufacturers to bring forward clean technology.