Project sponsored by Caterpillar

Suitable for students with Engineering or Chemical Sciences backgrounds

Gas Phase Control for Selective Catalytic Reaction Based Aftertreatment

Modern Diesel engines use Selective Catalytic Reduction (SCR) as the dominant technology to reduce NOx emissions. A lot of effort has been spent on optimising the catalyst material, but the conversion depends just as much on the parameters of the exhaust gas itself. There is a huge opportunity for improving NOx conversion and reducing size and weight of the aftertreatment system if gas phase parameters can be controlled dynamically. This project will investigate ways to identify, model, measure and control the relevant gas phase parameters.

Background

Modern Diesel engines run at high thermodynamic efficiency, which means high combustion temperatures. A side effect is that high levels of NOx are generated, which are not compatible with the strict emission limits. Therefore DeNOx aftertreatment systems are employed to reduce the NOx emissions, and the dominant technology in the medium and heavy duty segment is Selective Catalytic Reduction (SCR) using ammonia as a reducing agent.

While a lot of effort has been spent on optimising the catalyst material, the conversion depends just as much on the parameters of the exhaust gas itself. These are subject to change and hard to measure and control, and existing attempts to optimise the gas phase are typically limited to simple static models.

Aims and Objectives

There is a huge opportunity for improving NOx conversion and reducing size and weight of the aftertreatment system if gas phase parameters can be controlled dynamically. This requires dedicated sensors and actuators to measure and influence gas phase parameters in order to create optimal conditions with the given physical limits.

The key research questions are:

• How sensitive is the DeNOx process to different gas phase parameters?
• What in the penalty of controlling these parameters?
• What are the key aspects of an effective control strategy?
• Which actuators and sensors can be used to implement it?

Work Programme

The suggested work programme for a four year period study is:

1. Starting from existing models, estimate the sensitivity of the SCR process to gas phase parameters. Survey the literature for similar work, especially in stationary applications where SCR systems have been used for decades.
2. Design a total information control system to demonstrate control authority and estimate the potential benefits in simulation. Design an experimental test rig for an engine test cell to verify the simulation results. Plan verification tests.
3. Implement the experimental test rig, and run initial identification and verification tests. Explore options for monitoring gas phase parameters using production sensors.
4. Analyse the commercial impact of the required changes to the system. Assess the potential impact on reliability and packaging. Communicate the results to relevant partners. Write up.

The Engineering Doctorate (EngD) is of four years duration, and carries an enhanced annual stipend of £18,363.

To apply send your CV and covering letter to the EPSRC Centre for Doctoral Training in Carbon Capture and Storage and Cleaner Fossil Energy: ccscfe<στο>nottingham.ac.uk

Please quote ref: ENG829               Closing date: 8 April 2015