The invention discloses a low-pressure EGR
introduction device capable of realizing high EGR rate and a low-pressure EGR introduction method. Recycled
exhaust gas is led out through the upper side and lower side of a
turbine, passes through only one EGR valve and an EGR cooler, and then enters the upper side of an
air compressor. According to the scheme, two paths of EGR
exhaust gas are introduced into the upper side of the
air compressor through one
electric control valve, so that a low-pressure EGR scheme is obtained. Under the high-rotating speed condition,
exhaust gas can be introduced from the upper side of the
turbine. Under the low-rotating speed condition, exhaust gas can be introduced from the lower side of the
turbine. Compared with a high-and-low-pressure double-circuit EGR
system, the device and method have the advantages that high EGR rate can be realized, requirements for EGR under high-and-low rotating speed and load conditions can be met, and emission of
NOx of an engine can be effectively reduced; meanwhile, two paths of EGR exhaust gas share one EGR valve and one EGR cooler, structure is simple, weight is reduced, packaging complexity is reduced, and manufacturing cost is low.