Active Air Control Reference Number: 08-06 Inventors: Dr. Kirby
Chapman, Diana K. Grauer In an attempt to decrease pollutant
emissions, the natural gas compression industry has refined the
turbocharged engine to allow for increased air flow into the
system. However, the physics of such systems, and the
environments in which they operate, constrain further
advancement in emission reduction. Within a specific engine
frame, the fuel flow rate, air flow rate, and scavenging
efficiency of the system must be the same for each cylinder to
achieve identical corrected trapped equivalence ratios. If this
is not accomplished, some cylinders will operate leaner than
average and some richer than average. Since NOx production is a
highly nonlinear function of the corrected trapped equivalence
ratio, the rich cylinders can produce disproportionately more
NOx than the lean cylinders. The only way to lower the overall
engine NOx production, and therefore engine emissions, is to
ensure that each cylinder operates at the same t