Teaching my kids abouts cars
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Teaching my kids abouts cars

I think it's really important to know a bit about the internals of a car, so that when you are getting your car serviced you can talk intelligently with the auto technician. As well, there are many easy DIY jobs you can do on your car to save your some money which can make all the difference when you are young and starting out. This site is where I am recording everything I am teaching my kids about auto servicing, and because I think it will be useful to many other families as well. I hope you find it useful for your family.

Teaching my kids abouts cars

Is Your Diesel Car Active or Passive?

Kenzi Jacobs

If you've just bought a diesel-engined car, then you may not notice much of a difference as compared to your former, petrol-engined alternative. Certainly, it may "sound" a little different, and you obviously have to put different fuel into the tank, but there are other subtle and not-so-subtle differences to be aware of. In particular, you need to know about a crucial component known as the "diesel particulate filter." What is this, and why should you be aware?

Filter in Action

The DPS (for short) is a filter that is meant to trap soot particles that emanate from the engine during the exhaust process. Like any other filter, they can become clogged after time and must be cleaned regularly, especially if you want your vehicle to pass any emissions test in the future. Yet crucially, there are various different ways to clean such a filter, and the action that you take will vary depending on the particular model of vehicle.

Active Regeneration

For example, your car may be fitted with an active regeneration system, where special sensors determine how much soot is trapped within the filter based on exhaust back-pressure readings. The central computer will then adjust the timing of the fuel injection system to increase the temperature of the exhaust, which will burn off the soot and regenerate the filter. Sometimes this cleaning arrangement is pre-programmed to activate when the vehicle reaches a certain distance threshold.


Alternatively, the car may have a passive regeneration system fitted, which is designed to kick in when the vehicle reaches a certain speed on the motorway. At these speeds the exhaust temperatures are higher, and the gas is hot enough to regenerate the filter.

You will need to know if you have passive regeneration, especially if you don't tend to do a lot of motorway driving. If you are stuck on city streets as part of your commute, then your filter may eventually become blocked and lead to higher fuel consumption or an unwanted trip to your diesel service mechanic.


In this case, you will need to have a forced regeneration instead. Typically, a mechanic will hook up a special computer program to the car, which will force the regeneration process to begin. This may also involve additional costs, such as the replacement of engine oil and filter.

What You Can Do to Help

Finally, make sure that you use the right type of engine oil, as there are brands that are designed to create the lowest amount of soot residue. Try to modify your driving habits if your vehicle is fitted with a passive system. In other words, get out on the motorway once in a while to initiate the regeneration process.