Support the channel by shopping through this link: https://amzn.to/3RIqU0u
Patreon:   / d4a  
Become a member:    / @d4a  

Today we're doing an in-depth video about the EGR or the exhaust gas recirculation system. We are going to talk about the history and evolution of these devices, their operating principle, their difference in petrol/ gasoline and diesel engines, their benefits, drawbacks, real-world problems, and more. By the end of this video, you will have a firm grasp of this important and often very misunderstood engine component and you will be able to make an educated decision on whether you should delete it or not. So instead of me feeding you over-generalized subjective opinions and telling you what to do today I’d like to empower you with knowledge so that you can decide yourself and I’d appreciate it if, after watching the video, you tell me what kind of conclusion you have reached.

So let’s start with the history. Why were EGR systems invented? As you probably know they were invented to reduce emissions but what’s important is to understand which emissions specifically EGR devices are concerned with and they’re concerned with Nox or nitrogen oxides.

Now nitrogen oxides form whenever we create a sufficiently high temperature. To create nitrogen oxides all you need is heat and nitrogen and oxygen. As we know the air we breathe in or the atmosphere of the earth in which we live in mostly consists of nitrogen and oxygen. And whenever we have heat in the presence of these two we create Nox or nitrogen oxides.

So what do you think is one of the greatest sources of nitrogen oxide emissions? Believe it or not, it’s lightning storms. Yes. A very natural thing. The temperature of a lighting bolt is 28.000 Celsius or 50.000 Fahrenheit and lightning storms of course occur in the atmosphere where we have nitrogen and oxygen.

But here’s the catch. Lightning storms are something temporary, they don’t occur continuously in the same location and most lighting bolts are between clouds or within a cloud which means that most nox emissions from lightning storms occur 4-5 kilometers above the earth’s surface.
On the other hand vehicle transportation is continuous and concentrated mostly in urban areas. Engines create hot combustion whenever they are operational and vehicles travel on the surface which means that they can dramatically increase continuous local concentration of Nox emissions.

Nitrogen oxides react with other elements and form smog and acid rain. But their impact isn’t limited to the environment. Nitrogen oxides are primarily composed of NO which is nitric oxide and No2 which is nitrogen dioxide. Of these two nitrogen dioxide is the one that creates serious health concerns for humans as it negatively impacts respiratory health and causes an increased number of asthma cases as well as other lung and respiratory-related diseases.

The problem we have is that the more heat and pressure we create the greater the amount of nitrogen dioxide we create. Interestingly enough, one of the first major contributors to increased nitrogen dioxide emissions from engines were early catalytic converters, a device designed to reduce emissions. Early catalytic converters were mostly concerned with converting carbon monoxide to less harmful carbon monoxide and burning unburned fuel or unburned hydrocarbons. The problem was that back in the late 70s when these early catalytic converters became relatively widespread manufacturers prioritized performance over emissions. Hence, engines ran much richer or with more excess fuel than today. The high amount of unburned fuel riching the catalytic converter led to a very high reaction rate inside the converter which resulted in very high temperatures of the converter. These high temperatures than made the catalytic converter itself a source of nitrogen oxide emissions. However, manufacturers soon improved the design of catalytic converters and resolved these issues.

The actual major source of nitrogen oxides is the technological advancement of the engines themselves. Increased compression ratios as well as the advent of widespread forced induction have increased the amount of heat and pressure inside the combustion chamber.

A special thank you to my patrons:
Daniel
Pepe
Brian Alvarez
Peter Della Flora
Dave Westwood
Joe C
Zwoa Meda Beda
Toma Marini
Cole Philips

#d4a #egr #diesel

00:00 Video contents
00:48 History and Purpose of EGR
06:48 How EGR Works
11:34 Pumping Losses
12:16 Diesel Problems
15:51 EGR and PCV
20:42 I Blame the Government
22:00 I Blame the Manufacturers
23:38 I Blame the Users
26:37 I Blame "Tuning" Shops
29:27 EGR Reduces Engine Life?