The three-way catalytic converter
The three-way catalytic converter

This free course is available to start right now. Review the full course description and key learning outcomes and create an account and enrol if you want a free statement of participation.

Free course

The three-way catalytic converter

4.5 Catalyst deterioration

4.5.1 Introduction

In the UK, three-way catalysts must currently (1996) meet emission standards for a life of 50,000 miles; however, research efforts and legislation are set to double this requirement in the very near future to the current US standard of 100,000 miles. The catalysts do deactivate with use. Indeed the ability to withstand mild deactivation is built into the design of the catalyst, and into the entire emission control system in the vehicle. This is done by setting up vehicles at efficiencies well above the legal requirements at low mileage, so that as the catalyst slowly deactivates, it will still meet the emission standards.

However, the catalyst may be exposed to conditions that result in more severe deactivation above and beyond that which is ‘allowed for’ in its lifetime. The major causes of deterioration are thermal damage (due to exposure of the catalyst to high temperatures), and poisoning by contaminants in the exhaust (notably phosphorus, lead and sulfur). Research aimed at detecting deterioration, and trying to understand its nature, has included post-mortem examinations of used catalysts, and simulated ageing studies, in which the catalyst is exposed to high temperatures or catalyst poisons.


Take your learning further

Making the decision to study can be a big step, which is why you'll want a trusted University. The Open University has 50 years’ experience delivering flexible learning and 170,000 students are studying with us right now. Take a look at all Open University courses.

If you are new to university level study, find out more about the types of qualifications we offer, including our entry level Access courses and Certificates.

Not ready for University study then browse over 900 free courses on OpenLearn and sign up to our newsletter to hear about new free courses as they are released.

Every year, thousands of students decide to study with The Open University. With over 120 qualifications, we’ve got the right course for you.

Request an Open University prospectus