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Blocking EGR Warning


 
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PostPosted: Sat Oct 26, 2019 15:52    Post subject: Blocking EGR Warning Reply with quote

This is for information only, it is not designed to persuade anyone into making a decision either way, it is up to readers to read the information and make their own decisions.

EGR blanking is a common modification on many vehicles and Shoguns/Pajero's are no different, and often this is a result of a vehicle having a problem and the owner resolving the symptoms, but not the actual issue.

EGR systems are actually counterintuitive in that they recirculate exhaust gases back through the intake side of the induction system where they are reburned to reduce various emissions, the resulting gases are then sent to the exhaust where they go through either a catalytic convertor, a Diesel particulate filter (DPF) or both, and these lower the diesel soot particles before exiting the exhaust, and this combination reduced both the CO2 and soot particle emissions; and this raises the first issue of why CO2?

Money is the simple answer and many people are aware that most vehicles within the UK and European Union are subject to taxes based upon their CO2 emissions, and CO2 was chosen as it is the cheapest and easiest to tax, hence being cheap to initiate and it brings in the highest revenue returns, co the focus became mainly upon CO2 and other exhaust gases became less relevant as they were more expensive to initiate and yielded less current and future reenue streams for taxation authorities, usually Governments through their various treasuries.

In theory the hotter an engine runs, the more efficient it is within its mechanical limits, and there are currently many engines such as ceramic engines as prototypes which run at over 5,000 degrees C and are highly efficient, but the main focus was initially upon CO2 emissions, but run a ceramic engine at such temperatures then other items such as soot particles are virtually non existant due to these working temperatures, so no catalyst or DPF system is not needed and becomes redundant. However, raise the engines running tempertaure above certain temperatures and a combination of compression pressures and the reaction between Nitrogen and Oxygen with a carboniferous fuel creates a chemical reaction which causes and proportianally raises levels of both Oxides of Nitrogen AND Nitrous Oxides, which are not the same, but are often mistakenly assumed to be the same. We need only focus upon the Nitrous Oxides (NoX).

Engine manufacturers quickly realised that raising engine running, and particularly combustion temperatures meant their primary focus of reducing CO2 in all engines could be done by raising both the running temperatures, and particularly the combustion temperatures of all engines, and in diesel engines they reduced the emissions of soot particles, meaning they could simply introduce a catalytic convertor to reduce the main element of CO2 in all engines, and the soot particles sufficiently in diesel engines. This led to something called "lean burn" technologies which were nothing more than engines running with particularly high combustion temperatures, and much higher general running temperatures; while most people may be aware of lean burn technologies, they may also remember the GDI petrol engines which became similar to diesel engines in that they injected petrol directly into the combustion pre chamber or combustion chamber and both petrol and diesel engines and the rise of this technology also allowed for pulsed injection. Pulsed injection worked by giving two bursts of fuel and the first burst was simply a very rapid firing of a small amount of fuel, which, when ignited, heated the combustion chamber and once ignited the second main burst fired the majority of the fuel into the combustion chamber to produce the power stroke.

Such high combustion temperatures proved very successful in reducing the main pollutants and significantly improved fuel efficiency in petrol engines due to a longer burn time of the fuel and this meant induction efficiency needed improving and they used the turbocharger to do this as this improved volumetric efficiency by the forced induction of air and compressing it to levels unheard of except in very high powered engines of short duration or life such as Formula 1 engines, but the huge rising of NoX levels was not a concern at this time as emissions standards of the day, and future proposed emissions didn't put any real focus on NoX as CO2 was constantly being looked at to raise even more revenue without people revolting.

Emissions standards got particularly more stringent and this reached the point where NoX becaue a concern and this diveded the commonality of emissions standards between petrol and diesel engines, and they were diveded into petrol engine emissions and diesel engine emissions, so now they were being treated differently instead of commonly, or both as the same, which makes perfect sense as petrol and diesel engines produce dirrerent types of emissions and you cannot compare petrol engine emissions to diesel engines due to their fuels and the way they combust this fuel. Many engine volume manufacturers still relied partially upon the lean burn technologies and relied upon them to a lesser degree and combined them with other technologies to reduce emissions, many diesel engines had self regenerating DPF's fitted, as did some petrol engines, and many manufacturers began playing the game of figure manipulation in which they moved away from the traditional average measuring of emissions at peak engine power for petrols and at peak torque for diesel engines and in 2015 Volkswagen got caught out with their dieselgate scandal.

In very simple terms, VW stopped measuring their emissions at peak torque in their diesel engines and began measuring them at partial engine speeds, and this was at speeds lower than that required to bring in their turbochargers and this was a clearly fraudulent action and couldn't be a mistake, but why? because when a diesel engine is running on a test bench it has no load upon it, when the turbocharges isn't working the engine combustion temperatures are much lower, and at low engine speeds without the turbocharger running, much less fuel is injected into the engine and the control electronics inject much less fuel. Put these engines into a vehicle then you have load through weight and drag, add cargo and passengers and these rise, drive the vehicle and you create proportional drag and to overcome these you need the turbocharger running to produce the power to drive the car, and during most running conditions the turbocharger is running while the car is moving, and these factors create a huge rise in NoX compared to the conditions of a test bench testing emgine emissions, off load.

In the rush to boost engine power while reducing NoX emissions manufacturers ran for the cheapest fix with the most profit and this was exhaust gas recirculation and testing was already showing that production engines with low bypass rates were controlling combustion tempertures with their lowly bypass ratios of as little as 10% of the exhaust gases and this was rapidly increased to the 50-60% of exhaust gases being bypasses and run through the engine for a second combustion and this is currently where we are, so how does this work.
If you use an air flow meter meter to monitor the air flow into an engine, they currently measure air volume, density and temperature and this data is fed to the engine control unit (ECU) and this determines the exact quantity of fuel to be injected into the engine, by introducing a proportion of exhaust gas you reduce this quantity of good quality air and add heated, less dense air you also reduce the fuel requirement and less fuel means less power and lower combustion heat and this significantly reduces the amount of NoX being produced and improves fuel efficiency, hence instant improved MPG for the same vehicle with the same engine. Block your EGR and your fuel efficienct decreases and lower MPG and your NoX rises rapidly and this has other knock on effects. Your turbocharger works harder and with variable vane turbochargers this means accelerated wear and internally this means your exhaust valves become worn much more rapidly as they are at their upper margins constantly, for thermal material loading; there are other problems, your engine was designed for specific oils working at specific temperatures and these are always working at their upper end, or eceed their upper end working temperatures and the oil significantly and rapidly degrades, and your cooling system is working much harder to remove this addditional heat along with the anti freeze in your cooling system.
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PostPosted: Sat Oct 26, 2019 15:52    Post subject: Google Ads keep the POCUK free to join!


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PostPosted: Mon Jan 13, 2020 22:13    Post subject: Re: Blocking EGR Warning Reply with quote

assassin wrote:
Block your EGR and your fuel efficienct decreases and lower MPG and your NoX rises rapidly and this has other knock on effects. Your turbocharger works harder and with variable vane turbochargers this means accelerated wear and internally this means your exhaust valves become worn much more rapidly as they are at their upper margins constantly, for thermal material loading; there are other problems, your engine was designed for specific oils working at specific temperatures and these are always working at their upper end, or eceed their upper end working temperatures and the oil significantly and rapidly degrades, and your cooling system is working much harder to remove this addditional heat along with the anti freeze in your cooling system.


If you assume that this engine is running at high power most of the time, then I can agree with the logic. And then there would be noe issues with EGR and intake blockage.
But that is almost never the reality for the waste majority of drivers, as those engines mostly run at low power in normal traffic situations.
That's when clogging, fuel in the oil and so on happens. The exhause seldom reach high enough temp for long enough time to burn off the exhause particles (cleaning out DPF).
As a wise man once said: EGR is like thake a *beep* in your smoothie blender together with your fruits, it's not good for anything Cool
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PostPosted: Sun Feb 02, 2020 8:13    Post subject: Re: Blocking EGR Warning Reply with quote

assassin wrote:
This is for information only, it is not designed to persuade anyone into making a decision either way, it is up to readers to read the information and make their own decisions.

If you use an air flow meter meter to monitor the air flow into an engine, they currently measure air volume, density and temperature and this data is fed to the engine control unit (ECU) and this determines the exact quantity of fuel to be injected into the engine, by introducing a proportion of exhaust gas you reduce this quantity of good quality air and add heated, less dense air you also reduce the fuel requirement and less fuel means less power and lower combustion heat and this significantly reduces the amount of NoX being produced and improves fuel efficiency, hence instant improved MPG for the same vehicle with the same engine. Block your EGR and your fuel efficienct decreases and lower MPG and your NoX rises rapidly and this has other knock on effects. Your turbocharger works harder and with variable vane turbochargers this means accelerated wear and internally this means your exhaust valves become worn much more rapidly as they are at their upper margins constantly, for thermal material loading; there are other problems, your engine was designed for specific oils working at specific temperatures and these are always working at their upper end, or eceed their upper end working temperatures and the oil significantly and rapidly degrades, and your cooling system is working much harder to remove this addditional heat along with the anti freeze in your cooling system.


Couple of points I disagree on. Given the EGR valve is closed when any throttle is applied the turbocharger does not have to work any harder. And the oil is cleaner with an egr block as no soot is going back through the engine. Cooling systems do not have to work harder as the egr valve is closed when the engine is working. It does not affect fuel consumption in the real world (although maybe on a long downhill stretch it may - in the process its just strangling your engine some more)

Some real world results from a Pajero 3.2 common rail.
cold ambient temperatures - egr closed
2400rpm and above - egr is always closed
half throttle and above - egr is aways closed
idle - 60%open and throttle butterfly half closed (to suck more egr through)
light throttle motorway cruising - 20-60% open and is some cases the butterfly will close a little as well.

trick the ecu into thinking its cold outside and it stays shut, exactly where you want it, to save your engine and make it last longer. If you don't want to disable the egr, then fit a decent catch can to remove the oil vapour (that the soot sticks to) and clogs the intake.
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