diesel truck enthusiasts, long-haul truckers and in particular fleet managers had a Chicken Little moment way back in 2010 when the Environmental Protection Agency (EPA) mandated the use of selective catalytic reduction in diesel engines.
How come? Because the thing that SCR does work its magic is a consumable fluid called diesel exhaust fluid and owners of diesel vehicles they should have add to them vehicles. Nobody likes to pay more money for something uncomfortable.
The reality of DEF and SCR shot out don’t be that bad – once the engine manufacturers are on their way in head using and make the engines still reliable – e in the end, despite the added cost of the fluid itself, the increased fuel efficiency e reduced emissions made the hassle of gasket off a tank in more of liquid once in a little kind of worth it.
Like this, how does exactly SCR work, and what role ago DEF play in make it happen? We will explain to you.
First of all, the selective reduction of the catalyst is not new technology, despite being mandated only by the EPA in the last decade or so. Was in tour for almost half a century and it was first Used in the power generation industry a reduce oxides of carbon nitrogen power installations.
It’s those oxides of nitrogen thing that you need to hold in mind because it is those compounds – nitrogen monoxide and nitrogen dioxide – that are i big problems with diesel combustion, and are what it gave.
Like this, in an SCR-equipped vehicle, the engine exhaust gas is directed first through a particulate filter for catch all the soot and ash generated by the combustion of a relatively impure fuel. Who cares of the appearance of “rolling coal” of old diesel engines that made they relatively unpopular in the United States in sixties, seventies and eighties.
From the particulate filter, the exhaust gas travels past a nozzle that sprays diesel exhaust fluid into the stream of gas. DEF is made from deionized water and a very pure form of urea. Yup, urea is found in urine – stop giggling, please – but this is a refined form of the compound and is mostly used in the agricultural industry as a component of fertilizer.
The hot exhaust gas and DEF then enter the catalytic converter where the DEF urea and exhaust gas react with a variety of metal compounds to convert nitrogen dioxide and monoxide in nitrogen and water. Nitrogen is the main component of the air we breathe and it is harmless to the environment. Water is, well, water.
This is obviously a super-simplified version of how SCR works, but it is no different from the way your petrol engine with the catalyst works, apart from the extra step of inject urea into the waste stream. The most modern diesel engines use SCR in combination with exhaust gas recirculation and a diesel particulate filter (DPF) for reduce emissions.
Exhaust gas recirculation or EGR is a common process that is used in almost all modern ICE engines for reduce the amount of unburned fuel in an exhaust gas vehicle. The disadvantage of EGR is that it can negatively affect vehicle performance and fuel economy, in more adds another complex system to already complex machine.
In response to weaknesses of EGR, some companies are removing it system from their engines and using slightly more DEF a treat their exhaust gases, thus getting similar results without the sacrifices in performance And economy.
All of this sounds good, Right? Well, not everyone is convinced that SCR and DEF are good the things. I mean, you probably have to fill it up up all the time, right? And its expensive, Right? No. A typical tank of DEF will do it need to be refilled approximately every time the oil is changed. It’s mostly water too, so it won’t break the bank. One 2.5 gallon pack of BlueDEF (as opposed to your stuff dealer could sell) set you back.
Understanding this increasingly visible emissions control system is becoming more And more critical like USA truck producers begin offer more diesel models in traditionally dominating gasoline segments.
Everything is fine of the Big Three are both already offering or plans offer a lighter of small displacement-duty diesel engine in their high volume half-ton truck range. Ford had his(now sadly discontinued), GM has its own and Ram has the fantastic . All of these will have DEF tanks and SCR systems.
Where DEF really gets critical is in big diesel engines. we don’t mean like your Cummins 6BT, we are talking about Class 8 semi-truck. These vehicles do millions of miles over their lifespan and their huge diesel engines go through a lot of fuel in that time. These vehicles spend a lot of DEF as you can imagine, then a truck stops, the DEF is sold to the pump.
SCR technology is also coming to the world of marine diesel. The International Maritime Organization (IMO) first it has introduced limiting mandates amount of NOx emissions in 2000 and has been ever since tighten those rules. With some marine diesel engines easily of the size of a house, their capacity for pollution is immense, therefore again, SCR and DEF go long way towards cleaning these vehicles up.
“SCR is a technology that exists in this moment and everything is spent over the world to increase fuel efficiency e reduce NOx emissions, “said Charles Culverhouse, CEO of Old World industries, producers of BlueDEF and Peak Automotive Chemicals, in an interview with Roadshow. “The DEF works and its made by commonly available ingredients that are already be produced in large quantities for the agricultural sector. The infrastructure is already in place. “
This is an important thing to remember. The world it will never abandon diesel soon. we depend on with diesel engine vehicles – are trucks, trains or boats – a move our assets and ourselves around the world. While traditional diesel fuel may not be a great long-term solution for the planet, the SCR technology and the advent of more costEffective biofuels mean that until we are ready to completely abandon internal combustion, we will keep things relatively clean.
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