Nicky and I have just bought a new diesel Audi A6 Quattro to tow our BRe. There were a few factors which drove us down the new diesel route which may be interesting to others.
Firstly I ought to come clean and mention that I work for a company which makes exhaust gas emissions equipment used in automotive research and have spent the last 20 years working to detect NOx and particulates.
Here's a bit of background information. Diesel is currently out of fashion, as it is deemed to be dirty. This is not entirely fair with particulates as the implementation of Diesel Particulate Filters has effectively removed particles from diesel exhausts; this was mandated in Euro 5b from September 2011. DPFs are very effective, they remove more than 99% of particulate matter from the exhaust and render diesels less sooty than direct injection petrol cars (without a GPF). DPFs cannot be turned on and off so cheating is not really possible. NOx is a different story, until Euro 6, diesels could produce much more than petrol vehicles. Removing NOx from diesel exhaust is hard and requires heat in the exhaust, which means load on the engine; it's easier to clean up a truck than a car. You can turn a NOx reduction system on and off, and this is where the VW US scandal came from.
Because of the legislative threats being made about older diesels we decided to look at Euro 5 & 6 petrol cars and only Euro 6 diesels. It's quite hard to tell what emissions legislation a vehicle complies to just by looking at how old it is; Euro 6 was applied to new models from September 2014, to all vehicles manufactured after September 2015 and all vehicles sold after September 2016. So any diesel sold after September 2016 is definitely Euro 6, but this does seriously limit the choice in secondhand vehicles!
The diesel A6 is more fuel efficient than the petrol version, 50mpg vs 40mpg, according to Audi; I doubt we'll achieve this but the ratio between them is probably right. We do about 15000 miles a year and enough long trips to keep the DPF happy. There are some very good deals to be had on new diesels because of the bad press they have been getting, we got more than 25% off the list price by shopping around on the Internet, which made the difference between new and secondhand (post September 2016) negligible.
In summary, if you don't do all your driving in a big city, a new, big, cheap, diesel may be a good solution. That's what we thought and I guess time will tell.
Mark
