The invention discloses an online detection and evaluation method of fuel impingement. The online detection and evaluation method comprises the following steps of calculating the current position of a
piston and the volume in a cylinder of an engine according to cylinder
diameter,
stroke, connecting rod length, rotating speed,
cam shaft phase and
compression ratio collected; calculating the density and the temperature of gas in the current cylinder according to the current position of the
piston and the volume in the cylinder of the engine, the gas quality and flow, the pressure after intercooling, the temperature after intercooling, EGR (
Exhaust Gas Recirculation) rate and calibration parameter; calculating the real-time spraying pressure of the whole spraying process according to the
diameter of spraying holes, the conical angle of the spraying holes, the number of the spraying holes, the flow coefficient of a spraying
nozzle, the
rail pressure, the electrifying time and the calibration parameter; judging whether the phenomenon of fuel impingement occurs according to the density and the temperature of gas in the cylinder, the real-time spraying pressure of the whole spraying process, the
diameter of spraying holes, the number of the spraying holes and the flow coefficient of the spraying
nozzle. The online detection and evaluation method disclosed by the invention has the advantages that by the arrangement, the fuel impingement can be accurately evaluated in real time.