Biography

Dr Shaun Chan is an Associate Professor at UNSW (University of New South Wales) and a 2023 CSIRO International Hydrogen Research Program Mid-Career Fellow. His research focuses on combustion diagnostics in high-pressure, high-temperature environments. Dr Chan specializes in optical/laser-based imaging diagnostics in practical engine environments, advanced combustion strategies, and alternative fuels. Since joining UNSW, he has helped secure around $22 million in competitive external research funding, with $2.49 million as a grant or project leads.

Abstract

Hydrogen (H₂) fuel offers a compelling path towards decarbonizing transportation sectors, particularly on-road and off-road vehicles. However, implementing H₂-fueled internal combustion engines (ICEs) presents significant challenges due to the inherent H₂ properties. Its low volumetric density, low ignition energy, and high flame speed hinder power density and can lead to pre-ignition or backfiring.

Researchers at the UNSW Engine Research Group have made significant progress in addressing these challenges. Their approach, termed hydrogen-diesel dual direct injection (H2DDI), utilizes a high-pressure direct injection system for hydrogen fuel, coupled with a diesel pilot injection serving as an ignition source. This dual injection strategy directly introduces both fuels into the combustion chamber using separate injectors. The H2DDI technology has the potential to facilitate the adoption of hydrogen in highly efficient, heavy-duty compression-ignition engines currently used in applications like ships and stationary power generation. By enabling hydrogen use in these applications, H2DDI opens doors to new and decarbonized approaches for various industrial sectors.

The H2DDI technology effectively overcomes limitations associated with other H₂ introduction methods to enable operation with a high hydrogen energy share (up to 90%) in the medium load range. This translates to a significant reduction in CO₂ emissions (exceeding 80%) and increased engine thermal efficiency compared to a diesel-only operation in a small-bore engine. Notably, these achievements significantly outperform alternative approaches like H₂-Port Fuel Injection (H₂-PFI), where H₂ energy substitution is typically restricted to a range of 6-25% at high loads and 30-40% at low and medium loads due to the aforementioned implementation challenges. Importantly, H2DDI boasts significant operational flexibility. The system can adjust the energy share between hydrogen and diesel based on various factors, including fuel availability, economic considerations, or even evolving legislative requirements. This flexibility allows the engine to operate with an increased diesel energy share, or even solely on diesel fuel, if necessary.

This presentation will explore the unique experimental observations the researchers have made regarding the dual-fuel direct-injection combustion processes. A case study will be presented to demonstrate how this technology can be utilized to achieve decarbonization in stationary power applications.