George Delagrammatikas

Associate Professor of Mechanical Engineering

Homogeneous Charge Compression Ignition Engines


A thesis submitted in partial ful llment
of the requirements for the degree of
Master of Engineering


George Delagrammatikas, Ph. D.


A homogeneous charge compression ignition (HCCI) engine test stand was developed for
research and instructional purposes. A commercially available 6 hp diesel engine was modi-
ed to run as an HCCI engine using 91 RON gasoline and intake heaters for ignition control.
The design philosophy behind the necessary engine modi cations and the methodology im-
plemented to design the necessary laboratory infrastructure are detailed in this work.

A custom ac motor dynamometer was designed to accommodate the system constraints
according to proper mechanical design axioms. It was fabricated using the available facilities
and was fully integrated into the laboratory control and data acquisition systems. The system
was first proven with the baseline diesel engine, where data compared favorably with the
manufacturer's published data sheets.

The diesel engine was then modi ed with a new intake, complete with a fuel injection
system which included a custom fuel injector driver. A modi ed piston was also prepared with
a compression ratio of 17.7:1 (lowered from 19.3:1), and is ready to use for future projects if
the lower compression ratio is desired. The engine was instrumented with a variety of sensors
to measure in-cylinder pressure, engine rotational position, fuel flow rate, and exhaust gas













Figure 1: HCCI Test Stand at The Cooper Union

Stable HCCI combustion was vari ed via both in-cylinder pressure curves and positive
engine power output. An average 1.4 hp was recorded with a bmep of 2.3 bar and an average
BSFC of 410 g/(kWh). The engine in HCCI mode produced less power less efficiently than
the engine in diesel mode. While a lower power output was expected, a lower efficiency was
likely due to poor ignition control and the use of the stock diesel bowl-in-piston type piston.
A list of future recommendations is offered to the reader who may be interested in continuing
the project.











Figure 2: LabView Control Panel for HCCI Test Stand














Figure 3: Pressure vs. crank angle plots for 500 consecutive combustion cycles operating in HCCI mode.  Note the transient progression from misfire to stable HCCI combustion.















Figure 4: Pressure vs. crank angle data for 150 consecutive engine cycles operating under stable HCCI mode.