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Various potential alternative fuels for internal combustion engines are studied nowadays to reduce dependency on fossil fuel. Hydrogen-rich reformate produced onboard as a result of fuel reforming in an internal combustion engine with a high-pressure thermochemical recuperation is a promising alternative gaseous fuel. This paper reports on the effects of the reformate fuel injection method on energy efficiency and combustion characteristics of a single-cylinder spark ignition (SI) engine with a high compression ratio (16:1) at steady-state conditions. A comparison between port (PFI) and direct (DI) reformate injection is performed. Engine performance and combustion parameters are evaluated and analyzed. For both injection strategies, a similar relatively high indicated efficiency (50%) is observed. This is a joint result of waste heat recovery and hydrogen combustion benefits.

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.

A computer model was built and a theoretical analysis was performed to predict the behavior of a system containing Homogenous charge compression ignition (HCCI) engine and a methanol reformer. The reformer utilizes the waste heat of the exhaust gases to sustain the two subsequent processes: dehydration of methanol to dimethyl ether (DME) and water, and methanol steam reforming (SRM) where methanol and water react to mainly hydrogen, CO and CO2. Eventually, a gaseous mixture of DME, H2, CO, CO2, water (reused) and some other species is created in these processes. This mixture is used for the engine feeding. By adding water to the methanol and fixing the vaporized fuel's temperature, it is possible to manage the kinetics of chemical processes, and thus to control the products’ composition. This allows controlling the HCCI combustion.