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The electronic control unit (ECU) controls the EGR valve (4) to allow the exhaust gas to enter the intake manifold. On turbocharged engines, the control of the exhaust gas flow is also done by means of the throttle (5) which, when closed, lowers the pressure in the intake manifold and facilitates the flow of gases from the exhaust manifold.
Feb 13, 1998 · 2. The exhaust is added to the high-pressure air as it goes into the intake manifold, after the turbo compressor and after the intercooler, the last thing before the engine itself. The exhaust doesn't go through the intercooler. The exhaust is coming from the high-pressure side of the exhaust manifold, before it goes out through the turbo.
- High Pressure EGR
- Low Pressure EGR
- Hybrid (Combined), Dual Loop EGR
- Dedicated EGR
High pressure EGR, compared with a low pressure EGR system, is referred to as the “classic” EGR architecture. This architecture is the most widespread and has been used on diesel engines starting with Euro 2 pollutant emissionlimits. In a high pressure EGR system, the exhaust gas is taken before the turbine and reintroduced into the intake manifold...
Euro 6 standard reduced the NOxemissions limit to only 80 mg/km in the NEDC cycle, compared with 180 mg/km for Euro 5. This significant drop has imposed an increase of the EGR rates and the introduction of low pressure EGR systems. In a low pressure EGR system, the exhaust gas is taken after the turbine and reintroduced into the intake manifold bef...
Hybrid (combined) EGR system integrates both high pressure EGR and low pressure EGR on the same engine. This type of EGR architecture is also called dual loop EGR system. The advantage of this architecture is that combines the benefit of both low and high pressure EGR systems, switching between them depending on the operating point of the engine (s...
In spark ignitions engines, high levels of EGR rates (more than 15%) increase fuel efficiency and reduce pollutant emissions. The drawback is that high EGR rates can cause incomplete combustion and increased hydrocarbons (HC) emissions. To overcome this, the combustion stability can be improved by supplementing the air charge with either pure hydro...
The purpose of the throttle is to create a pressure difference between the exhaust and intake manifold (when closed) and to allow the exhaust gases to flow into the cylinders. Most of the EGR throttle valves are traditional ‘butterfly’ valves, similar to petrol engine throttles, and are controlled electronically the the engine control module (ECM).
Exhaust gas recirculation (EGR) has proven to be a successful method of emission control. In the case of conventional highpressure EGR, exhaust gas is removed immediately after the cylinder and mixed with the intake air. Additional low-pressure EGR is now commonly used to achieve the stricter limit values as of Euro 6 / Tier 2.
Mar 17, 2023 · High-pressure EGR – This system recirculates exhaust gases back into the engine at high pressure, typically just before the intake manifold. Exhaust gas cooling – This system cools the exhaust gases before they are recirculated back into the engine, which further reduces the formation of NOx.
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Nov 11, 2020 · Put simply, the exhaust gas recirculation system (EGR) reduces NOx emissions in internal combustion engines. The system is made up of an EGR valve, a temperature sensor, and a control unit and it is connected to both the ECU and the intake/exhaust manifolds in the engine. The main purpose is to reduce these NOx (nitrous oxide) emissions and it ...
