Chemical oxidation of CO and HC, as well as the organic portion (OF) of diesel particles, is aided by diesel oxidation catalysts. They also oxidize sulfur dioxide, which is produced by the combustion of sulfur-containing fuels and is found in diesel exhaust.
What does a diesel oxidation catalyst reduce?
Catalytic converters developed specifically for diesel engines and equipment to minimize carbon monoxide (CO), hydrocarbons (HC), and particulate matter (PM) emissions are known as Diesel Oxidation Catalysts (DOC). DOCs are simple, economical, and maintenance-free, and they are ideal for all diesel engine types and applications.
A monolith honeycomb substrate coated with platinum group metal catalyst is placed in a stainless steel container in modern catalytic converters. The honeycomb structure, which has a lot of narrow parallel channels, has a lot of catalytic contact area with the exhaust fumes. Several exhaust contaminants are transformed into innocuous chemicals as the heated gases reach the catalyst: carbon dioxide and water.
Carbon monoxide, gas phase hydrocarbons, and the SOF component of diesel particulate matter are oxidized to CO2 and H2O by the diesel oxidation catalyst:
The oxygen in diesel exhaust is sufficient for the reactions described above. Depending on the engine load, the concentration of O2 in diesel engine exhaust gases ranges from 3 to 17 percent. Figure 2 shows typical conversion efficiencies for CO and HC in the Nett diesel oxidation catalyst. The activity of the catalyst increases as the temperature rises. For the catalyst to “light off,” a minimum exhaust temperature of around 200°C is required. Conversions can be higher than 90% at high temperatures, depending on the catalyst size and design.
Can you clean a diesel oxidation catalyst?
Cleaning often entails removing the DOC from the car, heating it, and blowing out the ash from pressurized air and a vacuum system before capturing it in a sealed container. Cleaning services are provided from professionals.
How does a doc work?
Before we get into why you should clean your DPF and DOC, it’s important to understand how these engine components function together. The DPF is safeguarded by the DOC. Because vapor can obstruct the DPF’s capacity to catch and remove particulates, manufacturers route the exhaust first through the DOC, then into the DPF. The DOC directs exhaust through a honeycomb ceramic structure coated with a catalyst, which converts carbon monoxide and hydrocarbons to carbon dioxide and water chemically. After that, the exhaust gases are driven through porous channel walls in the DPF, capturing and retaining the leftover ash and soot.
When Is It Time To Have Your DPF or DOC Cleaned?
Depending on your duty style, a reasonable rule of thumb is to get your vehicle cleaned every 200,000 miles or less. You can either use passive or active regeneration to burn off the surplus ash and soot on your own. Active regeneration requires far higher temperatures than passive generation, which uses typical exhaust temperatures and nitrogen dioxide to oxidize the build-up. Despite these several cleaning cycles, it is still necessary to get your truck serviced.
Why Should You Have Your DPF/DOC Cleaned?
If you don’t clean your filter, soot and ash will build up and harm or ruin it. When travelling with a load, soot and ash burn off as rapidly as they gather, but when idling or driving in sluggish traffic, they tend to accumulate and linger.
A decrease in engine performance or an increase in the number of regeneration cycles are two significant symptoms that it’s time for a professional cleaning. Cleaning the DPF on a regular basis could reveal:
If left ignored, a dirty filter may not appear to be a major source of damage, but you’d be shocked how pricey it can be. As a result, cleaning is an important aspect of maintenance. When you consider the cost of replacing parts, which can be approximately $3,000 (if not more), as well as the cost of unexpected downtime, skipping this relatively straightforward step can have a significant impact on your bottom line.
Visit our service department right away if you believe your diesel needs DPF servicing. Throughout the Upper Midwest, our mobile truck service technicians are available to assist you.
How does catalytic oxidation work?
The epoxidation of propylene is one of the most difficult selective oxidations that has been accomplished with supported gold catalysts.
The conversion of methanol to the more valuable molecule formaldehyde using oxygen in the air is an example of catalytic oxidation:
In the absence of catalysts, this conversion is extremely sluggish.
Metal oxides and metal carboxylates are common oxidation catalysts.
Do diesel engines have catalytic convertors?
If you’re asking whether or not diesels have catalytic converters, the answer is that they do. These, on the other hand, function differently than they would in a car with a gasoline engine.
What happens in an oxidation type catalytic converter?
Catalytic converters come in a variety of shapes and sizes. A simple ‘two-way’ oxidation cat converts carbon monoxide (CO) to carbon dioxide (CO2) and hydrocarbons, which are basically unburned fuel particles, to carbon dioxide and water.More advanced ‘three-way’ catalytic converters are fitted to modern cars and do the above while also reducing emissions of nitric oxide (NO) and nitrogen dioxide (NO2), collectively known as NOx, a major cause of localised air pollution.
How does a DPF regenerate?
When the filter reaches about 45 percent capacity, extra fuel is automatically injected. This is known as active regeneration. The additional fuel raises the temperature of the exhaust, allowing the accumulated soot to be burned off.
The travel, however, must be lengthy enough to complete the cycle. The DPF warning light is likely to appear on the dashboard of drivers whose journeys rarely last the required period of time.
What does Doc stand for in diesel engines?
The diesel oxidation catalyst (DOC) is used to control diesel particulate emissions in most stand-alone applications by controlling their organic component (OF).
How often should a DEF filter be cleaned?
Trucks’ diesel engines can create dangerous emissions. Fortunately, a diesel particulate filter is in place to prevent those fumes from causing significant damage (DPF). The hazardous soot from the engine is captured by a DPF. Cleaning the DPF on a regular basis is required to keep it operational. Furthermore, the frequency with which you should clean your diesel particulate filter varies by model.
The soot in the DPF should be cleaned out every six months, according to some manufacturers. Some versions, on the other hand, can go longer between cleanings. Some suppliers may give you a mileage recommendation, saying that you should clean your car every 200,000 kilometers.
The quality of your engine even influences how often you should clean the DPF. If the DPF is not cleaned regularly, it will deteriorate with time. That damage can spread to the engine over a prolonged period of neglect, exacerbating the problem.
Cleaning is required on a regular basis not only to preserve the truck and its components in good working order, but also to ensure that you are following all applicable requirements. Failure to clear the DPF at least once a year may result in significant fines.
Consult your manufacturer for suggestions on how frequently you should clean your diesel particulate filter. Understanding the symptoms that it’s time to clean the filter is also beneficial. DPF problems are often indicated by excessive exhaust smoke coming from the truck, a pungent fuel odour building, and a drop in fuel efficiency.
Additionally, a light on your dashboard informs when the DPF needs to be cleaned. When it’s time for maintenance, this light will normally flash orange, so pay attention to where it is located.
Understanding your individual DPF and engine maintenance requirements will assist you in keeping each system operating during each journey. If you need a new DPF, there are a variety of semi-truck components and accessories available, including filters for Volvo, Mack, and other brands.