Reforming-Controlled Compression Ignition - A Method Combining Benefits of Reactivity-Controlled Compression Ignition and High-Pressure Thermochemical Recuperation

The paper describes the principles and benefits of a novel approach aimed at homogenous charge compression ignition (HCCI) engine control with simultaneous waste heat recovery (WHR) and onboard hydrogen production. This approach is called Reforming-Controlled Compression Ignition (RefCCI) and has unique advantages compared to known HCCI control methods.

The suggested RefCCI concept is analyzed using a dedicated computational model that simulates joint operation of the engine and the reformer in their mutual relationship. A kinetic model for predicting the chemical kinetics was applied in the reformer part of the computational routine and a reduced mechanism was applied for the HCCI combustion simulation. A first law analysis was performed to assess the existence of sufficient available energy for the reforming process.

The reforming-controlled fuel reactivity modification enhances combustion control at various operation regimes. The achieved efficiency improvement due to waste heat recovery is up to 6 percentage points. It is higher at regimes that normally have lower efficiency. The predicted system efficiency is approximately 50% for basic engine configuration and without any optimization of the engine and reformer design.