Emission Control Systems

This chart serves to remind us what really happens to the exhaust emissions when a single cylinder misfire or partial misfire occurs.

Example 1: one fouled spark plug on a four-cylinder engine. Three “normal” cylinders + one “no spark” cylinder

CO2 = {3(15.0%) + 1(0.0%)} divided by 4 = 11.25% CO2

CO = {3(0.5%) + 1(0.0%)} divided by 4 = 0.375% CO

HC = {3(20 ppm) = 1(6000 ppm)} divided by 4 = 1515 ppm HC

O2 = {3(0.5%) + (1(20%)} divided by 4 = 5.375% O2