Session: 03-03 Advanced Compression Ignition Combustion Strategies

Paper Number: 197487

197487 - Experimental Investigation of Hydrogen Combustion Using High-Pressure Direct Injection (Hpdi) in a Heavy-Duty Compression Ignition Engine 

Abstract: 

Hydrogen high-pressure direct injection (HPDI) combustion has emerged as one of the promising pathways for achieving high thermal efficiency and near-zero carbon emissions in the heavy-duty transportation sector, powered predominantly by compression ignition engines.  This study experimentally investigated the hydrogen HPDI combustion on a single-cylinder 2.1 L heavy-duty compression ignition research engine. The engine is equipped with a high-pressure direct injection system integrated into a modified cylinder head with dual fuel injection capability.

Steady-state engine testing was conducted at a compression ratio of 16:1. A high-pressure direct injector capable of delivering both diesel and hydrogen at injection pressures up to 350 bar was used for dual-fuel operation. A dual-injection strategy consisting of a diesel pilot injection followed by a main hydrogen injection was implemented at an engine speed of 1200 RPM and a target load of 20 bar nIMEP, representative of the engine’s peak torque condition. The effects of hydrogen injection pressure (260, 280, and 300 bar), injection dwell duration (1–24 CAD), and hydrogen substitution ratio (96–99%) on combustion behavior, efficiency, and emissions characteristics, including NOx, HC, and H2 slip, were investigated.

The results showed that mixing-controlled hydrogen combustion assisted by diesel pilot injection enabled stable engine operation at the peak torque condition across all injection pressures evaluated. Higher hydrogen injection pressures promoted improved mixing and combustion stability, while shorter injection dwell durations resulted in increased maximum pressure rise rates (MPRR). The study highlights the optimization strategies that balance the tradeoff between achieving thermal efficiency and controlling NO_X emissions.

Presenting Author: Niranjan Miganakallu Southwest Research Institute

Presenting Author Biography: Niranjan Miganakallu has been employed as a Research Engineer in the Powertrain Engineering Division at the Southwest Research Institute. He completed his PhD from Michigan Technological University and his post doc at the University of Wisconsin Madison. His research interests are advanced powertrains, low carbon fuels, hydrogen combustion.

Authors:

Niranjan Miganakallu Southwest Research Institute