A Surefire Monitor For Misfiring Engines

In 1989, the California Air Resources Board created a headache for the auto industry. It set a mid-1994 deadline for carmakers to install detection devices for cylinder misfires, which eventually can destroy a catalytic converter and thus cause more pollution. At the time, there wasn't a built-in monitor that could do the job.

Now, a Purdue University team has developed a way to use sensors along with a digital signal-processing chip from Texas Instruments Inc. to detect even the slightest misfiring. The system measures the speed at which a piston completes one stroke and compares that to the adjacent piston's speed. In a smooth-running engine, the two speeds are the same. The system can distinguish between actual misfires and vibrations caused by rough roads or the drivetrain. Look for a red warning light on dashboards across the country to start flashing "misfire" sometime near the end of the decade.