GasEngineanalysis燃气发动机分析.pptVIP

Gas Engine Analysis The Ignition System Setup Connection (secondary) Setup Connection (Primary) Collecting Ignition The voltage from ignition signal is very high and can damage the recip trap intrument. It is therefore essential to reduce the voltage using attenuator. Set attenuator to maximum (500). Connect the lead. Look at the reading on the display, if it is too small (under 1000 mV), reduce the attenuation one level (to 100 x). This will increase the reading on the display by factor of five. If reading still below 1000 mV, reduce the attenuation again. Press trapdef button to restart the sampling. Wait until asterisk “ * “ appear on the display. Press trap to save the data. Do not adjust the attenuation level. Ignition Calculation Example 100 x attenuation. 4000 mV in the display Primary ignition Voltage = 4000 mV x 100 / 1000 mV/V = 400 V The Ignition System Primary Ignition Parade: The Ignition System The Ignition System Ignition Signature Analysis Evaluation : Signal level (Volt, delay time, etc) Consistent pattern Misfiring Bridge voltage : Gap, richer mixture, higher compression. Misfire mean that the plug no longer bridges the gap Pressure Time Traces Pressure-Time Trace Pressure-Time Traces Pressure Volume-Curve Pressure-Time Trace Vibration Vs Crank Angle Pressure-Time Traces Engine Health Report Engine Healt Report Ignition secondery Report * The ultimate purpose of the ignition system is to ignite the air/fuel mixture in the pre combustion chamber at the proper degree of crankshaft rotation and insure that the flame propagates through the combustion chamber at design rates. In reality, the ignition system provides the electrical arc across the spark plug electrode in the pre-combustion chamber to ignited that portion of the air/fuel mixture passing through the electrode corridor during the arc duration. The ignition system has performed its designed task when it delivers an electrical arc across the properly spaced electrodes of only the designed