The risks of removing the diesel particulate filter from a car

Automobile manufacturers love to talk about how they build a certain margin of safety into their designs, showcasing tests in various conditions, graphs, and calculations. However, in practice, unfortunately, things often turn out the opposite. A prime example is the problems with the diesel particulate filter (DPF), which, on many cars, fails to function properly and causes a lot of headaches for owners and mechanics.

Stand MS900

The risks of removing the diesel particulate filter from a car

Automobile manufacturers love to talk about how they build a certain margin of safety into their designs, showcasing tests in various conditions, graphs, and calculations. However, in practice, unfortunately, things often turn out the opposite. A prime example is the problems with the diesel particulate filter (DPF), which, on many cars, fails to function properly and causes a lot of headaches for owners and mechanics.

The purpose of the Diesel Particulate Filter

It's known that diesel fuel burns differently from gasoline. Inside the cylinders of a diesel engine, the pressure is higher but the temperature is lower, as there are no spark plugs. In hydrocarbon fuel, hydrogen is more active; it burns first, leaving carbon atoms to "cluster together." Fortunately, as we know from chemistry classes, they can do this. Sadly, in this case, instead of forming diamonds, they form tiny graphite particles, that is, soot.
This soot is a dangerous carcinogen, heavily polluting the atmosphere and causing respiratory diseases up to cancer. To eliminate soot from exhaust gases, the DPF (diesel particulate filter) was invented. Since the introduction of Euro 4 standards in 2006, this device has been mandatory on any car equipped with a diesel engine.

The DPF is installed roughly where catalytic converters are found in gasoline cars – in the exhaust system. The soot filter is often combined with a catalyst but has several differences. The most important is the built-in regeneration process. The DPF does not constantly fight soot; it accumulates it and then, under suitable conditions, burns it off.

While the standard DPF cleaning system is well-designed, in reality, situations where it can fully function can be long-awaited. To burn off the soot, a temperature higher than what the diesel exhaust system usually has is needed. This means increasing RPMs and injecting more fuel, and this needs to last at least 20-30 minutes. Generally, if a car is used only within the city, such conditions might be awaited for years. During this time, the DPF gets clogged.

It's worth noting that diesels are rarely fitted in leisure convertibles, where once a week, you might take a high-speed highway drive. Diesel cars are mostly workhorses, with every kilometer and every minute accounted for. And sometimes, every cent for maintenance. When factory cleaning of the DPF ceases to be effective, the filter stops allowing gases through, the car breaks down, and commercial vehicle owners are ready to solve the problem by any means.

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Ways to solve problems with the Diesel Particulate Filter

When the filter is clogged and standard regeneration doesn't help, there are three options:
1. Replace the DPF with a new one.
2. Clean the DPF.
3. Remove it.

The first option is suitable only for collectible cars, as the cost of a new original DPF is often comparable to the residual value of the car, and a cheap aftermarket one lacks the necessary properties and quickly clogs up. We will return to cleaning later; first, let's talk about removal.
This "barbaric" method is quite popular due to its radical nature. The logic of diesel owners is easy to understand: no filter – no problems. No errors, no clogs, no increased fuel consumption for regeneration, no increased consumption when it fails... in short, savings all around. Few think about the downsides of this solution, and companies that remove DPFs also don't like to talk about it to clients.

Disadvantages of removing the Diesel Particulate Filter

The advantages of removing the filter are obvious: no more problems with it, possibly reduced fuel consumption, and even improved car dynamics. However, for this, the operation needs to be performed correctly, including properly flashing the car's ECU. If the DPF is simply removed, consumption will increase, and the ECU will constantly show errors.
The disadvantages are less known, but there are more of them:

1. Incompatibility. Not all engine components can work properly when the ECU is reprogrammed. It may be necessary to remove the EGR valve or even the catalyst.
2. Lowering the environmental class. The car's parameters will have to be downgraded to Euro 2, and it will no longer meet modern emission standards. Moreover, removing the DPF can be classified as a legal violation. There will be problems passing inspections, entering EU countries, and fines during checks.
3. Color and smell of exhaust gases. They will become classic diesel-like, "like a tractor's," with black smoke during sharp accelerations and hill climbs.
4. Turbocharger. Engineers usually design this component based on the engine's parameters. Reducing exhaust tract resistance will lead to changes in the turbocharger's operation. It might start to whistle, or it could fail prematurely.

In general, removal is a rather ambiguous solution. Moreover, reversing it will be much more difficult than cutting it out.

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Cleaning the DPF

Meanwhile, solving the problem of a clogged DPF can be quite simple and costs about the same as removing it. Our MS 900 stand will help with this. It was initially designed as equipment for cleaning DPFs, FAPs, and any other types of DPFs. The complex, consisting of three modules, can not only wash but also dry filters, and most importantly, measure resistance parameters before and after the operation.
The DPF cleaning stand uses only clean water and compressed air, making it safe for personnel and the environment. The washing process takes no more than 2-3 hours, after which the filter, and the car with it, will be in the same condition as when it left the factory. Including environmental parameters. 


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