New electronic system will control car exhaust emissions

It is hoped that the research will result in the creation of a system that not only warns the driver about impending engine failures, but also identifies the likely sources of the problem.

Currently, cars are equipped with modern electronic control systems, which ensure that cars meet pollution standards by automatically adjusting the amount of fuel being delivered to the engine. Electronic chips have been carefully programmed to deliver the right amount of fuel, depending on how much air it is using, allowing the engine to adapt fuelling to different situations, such as climbing steep hills and sudden acceleration. Car owners are thus ensured that their vehicles do not break the law.

With conventional technology, these chips are calibrated for each line of new engine to precisely meter the amount of fuel for a wide range of driving conditions. However, this “engine mapping” process is long and expensive, says Matthew Franchek, Associate Professor of Mechanical Engineering at Purdue University.

Current technology is neither able to keep up with engine ageing, nor with changes in the environment, or with the type of fuel used, Franchek told edie. The performance of older engines ceases to match the carefully calibrated data programmed into the electronic control system, through factors such as clogged fuel injectors, the changing performance of engine sensors, and a variety of other age-related factors. As a result, exhaust emissions increase. Often the original calibration will require adaptation within the first 10,000 miles, depending on the altitude at which the car is driven. In general, auto manufacturers make their engines to last 150,000 miles before ageing is detected.

Conventional systems do attempt to correct excessive emissions, but assessments are often inaccurate, and so any corrective action altering the amount of fuel being injected into the cylinders is subsequently wrong.

The new control technology being developed at Purdue should eliminate the expensive engine-mapping process, by using newly developed mathematical models. It will more accurately assess the root causes behind changing engine performance, and thus make the system better able to adapt to changes in ageing engines, whilst also reducing maintenance costs by automatically keeping the engine running smoothly, says Franchek.

A paper about the fuelling control research will be presented on 23 August during the 5th International Symposium on Advanced Vehicle Control at the University of Michigan in Ann Arbor, and the technology is expected to be commercially available in about two years time.