Neil Pattemore enters the DPF debate as he explains why workshops and car owners should treat key emissions components with the respect they deserve.
The British motorist has had a developing love affair with the diesel engine that has been driven (excuse the pun) by not only the power characteristics of this engine design, but also governmental incentives in the form of lower benefits-in-kind taxation for company car drivers.
However, although diesel cars have increased in popularity, the underlying problem has always been the exhaust emissions they create. The old diesel engines of yesteryear may have been noisy, lacked performance, were unrefined and emitted clouds of black smoke, but compared to today’s modern diesel emissions, they could almost be considered healthy!
The amount of particulate matter may have decreased as engines have improved, but the big issue today is the size of these particulates; the ultra-fine particulates emitted from today’s engines are small enough to not only enter the deepest parts of peoples’ lungs, but can pass into the bloodstream, carrying their cancer-creating toxins with them.
Emissions standards
As diesel engines have improved their performance and refinement, they’ve used increasing levels of technology, not only to control the combustion process, but also in the exhaust treatment systems, to ensure that the emissions were ‘cleaned up’ to meet ever-tighter European exhaust emission standards.
These standards have progressively made diesel engines more expensive to design and manufacture and have also created a challenge of delivering seductive power outputs and attractive fuel consumption, whilst still being able to meet the exhaust emission levels. An example of this was highlighted when the Volkswagen ‘dieselgate’ scandal hit the headlines last year – and it is highly likely that Volkswagen are not the only vehicle manufacturer to use similar ‘defeat device’ solutions.
“The old diesel engines of yesteryear may have been noisy, lacked performance, and emitted clouds of black smoke, but compared to today’s modern diesel emissions, they could almost be considered healthy!”
So, if the new technologies implemented by the engine designers work, why has air quality in many European countries, especially in the cities, declined after years of improvement? Quite simply, the diesel engine systems only work under certain operating conditions which are generally directly related to the load on the engine and the subsequent exhaust temperature required to keep the DPFs working correctly through the ‘regeneration’ process.
For many drivers who typically make short journeys, or are stuck in slow moving traffic, such as in many cities, the DPF never reaches the required temperature to regenerate and stay clean, creating real problems of driveability for the vehicle owners. Consequently, many garages have developed ways to remove these filters and re-program the engine management software to ‘fool’ the vehicle into thinking that the DPF is still fitted and working.
Original characteristics
Removing the car’s DPF might be tempting, because the damage caused by a clogged component can result in four-figure repair bills, however you’re essentially altering the original characteristics with which the car was built by doing so. These characteristics ultimately helped the car to achieve the requisite emissions targets that deemed it saleable to the public, so it is not good practice for a technician to remove such functionality.
It should also be noted that it is an offence under the Road Vehicles (Construction and Use) Regulations to use a vehicle that has been modified in such a way that it no longer complies with the air pollutant emissions standards it was designed to meet. That means you’re passing the legal compliance issue to your customer at the same time!
“You may feel that removing the DPF altogether is a better long term fix for the customer, but think more carefully about the consequences for them, as well as for your business.”
I believe that there are better ways, especially as you have a Duty of Care to your customers. Emissions component specialists are increasingly introducing replacement DPFs for post-2009 cars – these are Type Approved by their manufacturer and a cost-effective repair solution. Using your diagnostic equipment to conduct a ‘forced regeneration’ or using the new DPF cleaning services are also effective solutions.
One thing to ponder is that unless air quality in our cities improves, customers and the government will look ever-more seriously at electric vehicles as the solution to poor air quality – meaning far less to service or repair and with much fewer replacement parts. So be careful what you wish for – you may not like what you get!
