How does a low pressure EGR system work?
How does a low pressure EGR system work?
These keep the benefits of High Pressure EGR, as well as adding in a Low Pressure EGR (LP EGR) system, sometimes referred to as Long Route EGR. Low pressure EGR takes exhaust gas from further downstream of the turbine, often after a DPF, routing it into the intake stream, before the turbo compressor.
Where does exhaust gas go in a hp EGR?
HP EGR can have a valve mounted directly on the intake manifold, so when it opens, exhaust gas reaches the cylinders quickly. LP EGR requires exhaust gas to travel the entire length of intake plumbing before its result is achieved. This long path does however improve equal cylinder distribution in the LP EGR system.
Where is the EGR valve on the intake manifold?
In a high pressure EGR system, the exhaust gas is taken before the turbine and reintroduced into the intake manifold after the compressor, thus in the high pressure zone of both exhaust and intake manifolds. The EGR valve is placed on the exhaust manifold side for several reasons:
Which is better hp EGR or LP EGR?
In high speed, high load points, HP EGR gradually decreases the difference between exhaust and intake pressures, even lower than LP EGR, so HP EGR becomes the better option for the trade-off relationship between fuel economy, NOx and soot. Throughout the midrange and steady states, a combination of HP EGR and LP EGR can be used.
What are the symptoms of a bad EGR sensor?
One of the first symptoms commonly associated with a bad or failing EGR temperature sensor is engine ping or knock. If the EGR temperature sensor malfunctions it will cause issue with the EGR system flow.
What is the purpose of the EGR system?
The EGR is an exhaust gas recirculation device used for the purpose of lowering emissions. The purpose of the EGR is to allow a certain amount of exhaust to return and be mixed with the incoming fuel into the cylinders at cruising speed. This helps to cool the cylinders, allowing for a higher degree of ignition advance to burn more of the fuel.
What are the functions of the EGR valve?
The function of the EGR valve is to recirculate small amounts of exhaust back into the combustion chambers of the engine in order to decrease the combustion temperature, thereby reducing the formation of smog-producing nitrogen oxides. EGR valves can malfunction by becoming stuck open or closed due to carbon buildup.
What are the symptoms of a leaking EGR valve?
A faulty EGR valve or related component may leave the valve in either the stuck open or stuck closed position. The symptoms of a stuck open EGR valve are a rough idle with a lean air fuel mixture. The engine has a major vacuum leak. The symptoms of a stuck closed EGR valve are pre-ignition, ping, and knock.
