Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 20 of 40 for “"HCCI"”.
-
Understanding HCCI characteristics in mini-HCCI engines
… use of Homogeneous-Charge, Compression-Ignition (HCCI) combustion in a standard issue model-aero “diesel” engine. This two-stroke engine, unlike the more common glow-plug versions, operates without any form of combustion initiator. The fuel and air are premixed using a simple carburettor and …
-
Miniature HCCI Engine Compressor
Hydrocarbon fuels have a much higher specific energy than electric batteries, and are thus a desirable power supply for portable devices. A reliable lightweight long lasting power supply will be an enabler for human assist devices and miniature robotics. A prototype miniature free-piston engine …
-
The HCCI Fuel Number - Measuring and Describing Auto-ignition for HCCI Combustion Engines
HCCI is an advanced combustion concept, using premixed fuel and air with a diluted charge. This is thermodynamically favorable, leading to high efficiency and therefore lower CO2 emissions. The well-premixed and diluted fuel charge gives lower cylinder temperatures than conventional diesel …
-
Closed-Loop Control of HCCI Engine Dynamics
… of Homogeneous Charge Compression Ignition (HCCI) engine dynamics. HCCI offers a potential to combine high efficiency with very low emissions. In order to fulfill the potential benefits, closed-loop control is needed. The thesis discusses sensors, feedback signals and actuators for …
-
25cc HCCI engine fueled with Diethyl Ether
This research forms part of an ongoing HCCI study at the SASOL Advanced Fuels Laboratory to investigate and understand engine configuration and fuel chemistry effects on combustion in HCCI engines. This project continues from a previous project where a small Progress Aero Works (PAW) 6.5cc high …
-
Predictive Control of HCCI Engines Using Physical Models
Homogeneous Charge Compression Ignition (HCCI) is a promising internal combustion engine concept. It holds promise of combining low emission levels with high efficiency. However, as ignition timing in HCCI operation lacks direct actuation and is highly sensitive to operating conditions and …
-
Fuel effects in homogeneous charge compression ignition (HCCI) engines
Homogenous-charge, compression-ignition (HCCI) combustion is a new method of burning fuel in internal combustion (IC) engines. In an HCCI engine, the fuel and air are premixed prior to combustion, like in a spark-ignition (SI) engine. However, rather than using a spark to initiate combustion, the …
-
Two contrasting approaches to auto-ignition modelling for HCCI engines
… in Homogeneous Charge Compression Ignition (HCCI) engines. The first (empirical) auto-ignition model was adapted from its previously published form, for HCCI engine model implementation. This model was then combined with an explicit, single zone, thermodynamic engine model in order to …
-
Examination of the high load limit of an HCCI engine
… of homogenous charge compression ignition (HCCI) to gasoline engines is constrained by many factors. This work examines constrains imposed by nitric oxide (NOx) emission and by the need to maintain a minimum catalyst temperature on HCCI operation. Then the nature of the approach to high load …
-
Determination of the effectiveness of a Hot Tube igniter for initiating HCCI combustion
Homogeneous Charge Compression Ignition (HCCI) is a new internal combustion system that promises high efficiency and dramatically reduced nitrous oxide (NOJ and particulate matter (PM) emissions when compared to current spark ignition (SI) and compression ignition (CI) engine technologies. In its …
-
Vehicle fuel economy benefit and aftertreatment requirement of an HCCI-SI engine system
This body of work dimensions the HCCI fuel economy benefits and required aftertreatment performance for compliance with emissions regulations in North America and Europe. The following parameters were identified as key factors influencing the benefit of implementing HCCI over driving cycle: * …
-
A theoretical assessment of fuel combustion attributes to enhance the operational envelope of HCCI engines
Homogeneous Charge Compression Ignition (HCCI) is an alternative internal combustion (IC) engine that can provide high efficiencies while producing ultra-low nitrous oxides (NOx) and particulate matter (PM) emissions compared to existing compression ignition (CI) and spark ignition (SI) engines. …
-
Design of a viable homogeneous-charge compression-ignition (HCCI) engine : a computational study with detailed chemical kinetics
The homogeneous-charge compression-ignition (HCCI) engine is a novel engine technology with the potential to substantially lower emissions from automotive sources. HCCI engines use lean-premixed combustion to achieve good fuel economy and low emissions of nitrogen-oxides and particulate matter. …
-
Closed-Loop Combustion Control of a Multi Cylinder HCCI Engine using Variable Compression Ratio and Fast Thermal Management
… called Homogeneous Charge Compression Ignition (HCCI) engine. It utilizes a homogeneous premixed air fuel mixture like the SI engine, but the mixture is compressed to auto ignition like in the CI engine. Very dilute mixtures are used to slow down the combustion rate. This results in a low …
-
Characterization of Glow Plug and HCCI Combustion Processes in a Small Volume at High Engine Speed - Load Range, Emission Characteristics and Optical Diagnostics
… halfway to my PhD degree was to understand how HCCI combustion behaves in a small volume at high rotational speed. The investigation has been carried out using a modified model airplane engine. The whole study can be divided into two main parts; in the first, the nature of the glow plug …
-
Effect of ambient conditions and fuel properties on homogeneous charge compression ignition engine operation
… of Homogeneous Charge Compression Ignition (HCCI) combustion must demonstrate robust responses to variations in environmental conditions. This work examines the impact of ambient conditions and fuel changes on HCCI engine operation, and evaluates cam phasing as a mechanism to compensate for …
-
Extension of the high load limit in the Homogeneous Charge Compression Ignition engine
The Homogeneous Charge Compression Ignition (HCCI) engine offers diesel-like efficiency with very low soot and NOx emissions. In a HCCI engine, a premixed charge of air, fuel and burned gas is compressed to achieve autoigntion. Combustion occurs throughout the chamber volume resulting in short …
Page 1 of 2