Hydrogen-Fueled Rotary Engine

Prediction and analysis of nitric oxide emissions

Context

For the completion of my Master's degree at the Catholic University of Louvain, I've selected a thesis subject related to my future career interests in the automotive industry. The university had discontinued a previous project attempted by earlier students consisting on the restoration and conversion into hydrogen of a 1989 Mazda 13B rotary engine. 

The thesis was divided into two parts: the experimental work focused hands-on skills on restoring engines to run on gasoline and starting the conversion to hydrogen fuel, while the theoretical work involved the prediction and analysis of nitric oxide in the exhaust gases.

Challenges Encountered

Throughout this project, I faced numerous challenges that were successfully overcome through creative problem-solving, innovation, and effective team communication during regular meetings. Since the project had previously been undertaken by other students, my first task was to thoroughly review and understand the work that had already been done on the engine. This deep investigation not only helped me get up to speed but also led to the discovery of several errors in the earlier work, which I was able to correct.

M84 ECU

The initial plan was to manage the engine using the MoTeC M84 ECU, which is capable of running rotary engines. However, the Mazda 13B engine includes specific features—such as the oil metering pump (OMP)—that are not supported by the M84. This presented a key decision point: either develop a custom OMP control system using an Arduino, or invest in the more advanced MoTeC M130 ECU with the dedicated rotary engine package.

We conducted preliminary tests using an Arduino-based system, which demonstrated some potential but ultimately proved inefficient for our needs. As a result, we opted to upgrade to the M130, ensuring full compatibility and more reliable control of the engine’s complex features.

Part Replacement

One of the major challenges in restoring a vintage engine is the scarcity of spare parts. A notable example was the oil metering pump (OMP), which lubricates the rotor inside the housing. We identified a malfunction in the spring that actuates the ECU-controlled valve. To resolve the issue, we disassembled the component for a detailed inspection, successfully diagnosing and repairing the fault—ultimately saving costs and preserving the project budget.

Restoration defaults

Some issues were identified in the previous work done on the engine, both in assembly and in component selection.

One example was an improperly torqued joint bolt, which caused oil leaks in the distribution system just before the turbocharger inlet. Another issue involved the starter motor, which was underpowered and unable to reliably start the engine—a common problem in certain Mazda models. To address this, we replaced it with a higher-performance starter capable of delivering nearly twice the power, ensuring consistent and efficient engine starts.

Learning outcomes

Practical

This project provided me with invaluable mechanical experience in component testing, engine assembly, and the design and initialization of electronic systems. The electronics and control systems had to be completely rebuilt using a MoTeC M130 ECU with the GPR Rotary package.

Technical

This thesis also offered a valuable opportunity to enhance my programming skills, particularly in Python. I used the language to simulate engine operation and model chemical reactions within the combustion chamber, focusing on predicting and converting nitric oxide (NO) emissions.

The foundation of this work was based on Ferguson’s research on piston engines, which I adapted for rotary engine applications. This required modifying the equations to account for the varying temperature distribution within the housing. Unlike piston engines—where intake, combustion, and exhaust occur in the same region and a constant temperature can be assumed—rotary engines separate these phases spatially, leading to non-uniform thermal conditions.

This adaptation led to an important insight: rotary engines may offer a significant advantage over piston engines in hydrogen combustion applications, particularly regarding NOx emissions. Because the combustion gases in rotary engines pass through cooler areas of the housing before being expelled, the formation of additional nitrogen oxides is reduced.

Leadership and team work

Throughout this project, I had the opportunity to lead and coordinate a team of seven members, including mechanics, electro-mechanics, and electricians. As this project served as my final year thesis, I was responsible for managing the team and assigning tasks following our weekly meetings. This process allowed me to appreciate the complexities of leadership, ensuring that deadlines were met and everyone contributed effectively. The experience can be considered a success, as strong relationships were maintained among all team members throughout the project.

Work organisation

Originally intended for a group of two or three students, this project was ultimately assigned to me alone, requiring significant organizational effort to stay on track with both the experimental and theoretical work. To manage this, I used an organizational tool like TRELLO, which was essential for meeting my deadlines and allowed me to quickly adapt to any last-minute challenges.

Budget management

This project came with an allocated budget that I was expected to adhere to as closely as possible. The budget was initially determined through an early evaluation of the engine's condition, which helped estimate the remaining work and identify the parts that needed to be ordered. However, mistakes made in previous years by other students revealed that some parts were unsuitable for the engine, requiring additional funding. Initially, these overages weren’t a concern due to the safety margin built into the budget. However, as more hidden issues with the engine were uncovered, further financial support from the university's research department became necessary. This situation gave me the opportunity to present and justify the additional expenses to the committee.