The new regulations for diesel engine emissions have many changes and terminology that can be quite confusing. DPF, DEF, Regeneration - what does it all mean? Fire departments need to know. When a new apparatus is purchased, this type of information is in the chassis manual for your particular truck.
These changes have been put in place to reduce the amount of “black soot” we commonly see out of diesel exhausts. The US has taken the initiative to lower emissions below those in Europe and Japan. I remember the old days when the diesels were two-stroke. There was plenty of acceleration and power, but also lots of black-colored exhaust. Then four-stroke diesels started appearing. We lost some performance, but this was enhanced with turbocharging.
DPF means Diesel Particulate Filter. This is a special filter that has been placed in the exhaust system. With these filters, “regeneration” needs to occur periodically, based on alerts shown on the dashboard of the truck. When this occurs, the driver has to place the truck out of service for approximately 45 minutes (let’s not worry about the human lives we have to save!), park the truck, and place it in regeneration mode. This makes the truck ramp-up in RPMs to get the exhaust temperature hot enough to burn off some of the soot/particulate in the DPF. If this is not done regularly, the filter and engine begin to “degrade” to the point where the filter will need to be replaced to the tune of roughly $40,000.00, plus the costs of having front-line apparatus out of service.
Subsequently, DEF (Diesel Emission Fluid) was introduced. This is a Urea additive placed in a small tank/reservoir on the apparatus and injected in measured amounts into the DPF—making regeneration unnecessary, saving diesel fuel and out-of-service time in the process. However, DEF has a shelf life, must be stored at a certain temperature, and can lead to other problems if not handled properly.
In my department, for instance, we started experiencing many truck breakdowns while on alarms or on routine movements. We noticed that the fuel filters were getting clogged and the trucks’ fuel systems weren’t functioning correctly. To find out what was going on, we purchased a very expensive fuel testing kit that measured the ingredients of the diesel fuel. The results showed that many of the trucks had very high percentages of DEF additive (bio-diesel additive, in our case).
After some investigation, we found that the maintenance facility where our vehicles would fill up on diesel was pouring the correct amount of bio-diesel additive into the tanks. But instead of stirring the additive in on a regular basis to mix it with the fuel, they poured it into the top of the tanks and let it settle on the bottom. This threw the ratio out of whack, and because the disbursement pipes were located at the bottom of the tank, the trucks that filled up had a much higher amount of additive than they should have.
It is important that fire districts familiarize themselves with the new emission laws and learn from the experiences of other departments. While there is legislation in the works to exempt fire departments from having to meet the new emission regulations (the construction industry and military are already exempt), it is never a bad idea to be over-prepared.