HCCI and CAI Engines for the Automotive Industry


Book Description

Homogeneous charge compression ignition (HCCI)/controlled auto-ignition (CAI) has emerged as one of the most promising engine technologies with the potential to combine fuel efficiency and improved emissions performance, offering reduced nitrous oxides and particulate matter alongside efficiency comparable with modern diesel engines. Despite the considerable advantages, its operational range is rather limited and controlling the combustion (timing of ignition and rate of energy release) is still an area of on-going research. Commercial applications are, however, close to reality. HCCI a.




Reciprocating Engine Combustion Diagnostics


Book Description

This book deals with in-cylinder pressure measurement and its post-processing for combustion quality analysis of conventional and advanced reciprocating engines. It offers insight into knocking and combustion stability analysis techniques and algorithms in SI, CI, and LTC engines, and places special emphasis on the digital signal processing of in-cylinder pressure signal for online and offline applications. The text gives a detailed description on sensors for combustion measurement, data acquisition, and methods for estimation of performance and combustion parameters. The information provided in this book enhances readers’ basic knowledge of engine combustion diagnostics and serves as a comprehensive, ready reference for a broad audience including graduate students, course instructors, researchers, and practicing engineers in the automotive, oil and other industries concerned with internal combustion engines.




Water Injection and Its Impact on Knock Mitigation in Spark Ignited Engines


Book Description

Abstract : One of the limiting factors influencing the improvement of engine efficiency in gasoline engines is engine knock. Several techniques including reduced compression ratio, cooled exhaust gas recirculation, using high premium fuels, late intake valve closing have been used to mitigate knock at different operating regimes. Water due to its higher latent heat of vaporization compared to gasoline fuel has been used to reduce the charge temperature and mitigate knock. When water is injected into the intake manifold or into the cylinder, it evaporates by exchanging energy from the surrounding mixture resulting in charge cooling. This allows the engine to be run with advanced spark timing without engine knock resulting in better engine performance. With this motive, the impact of water injection on the combustion characteristics of gasoline direct injection engine was investigated. The research was conducted in three parts. First, an analytical model was developed using the principles of thermodynamics to determine the impact of direct water injection on the cycle efficiency. An ideal thermodynamic cycle with constant volume heat addition was considered for the analysis consisting of air, fuel and water mixture. State properties of the mixture were determined at different points in the thermodynamic cycle and efficiency was calculated. This established a baseline on the amount of water that can be injected into the cylinder and its impact on the overall cycle efficiency. This was followed by spray studies on a spray and combustion vessel that were conducted at engine conditions by varying the ambient conditions to determine the vaporization of water and water methanol sprays. This study gives a comparison of the amount of water that can be vaporized from the thermodynamic model. Experimental studies were conducted on a single cylinder engine with a compression ratio of 10.9:1. Baseline tests without water injection were run using gasoline fuel blended with 10% Ethanol (E10) (Anti-Knock Index = 87.0) injected directly into the cylinder. Impact of water injection was studied by injecting water and blends of water and methanol in the intake manifold at different water fuel ratios within controlled knock limit. Furthermore, injection mechanism was changed to direct water injection and tests were conducted at the same conditions to compare the effect of water injection mechanism on the combustion and knock performance.




Knocking in Gasoline Engines


Book Description

The book includes the papers presented at the conference discussing approaches to prevent or reliably control knocking and other irregular combustion events. The majority of today’s highly efficient gasoline engines utilize downsizing. High mean pressures produce increased knocking, which frequently results in a reduction in the compression ratio at high specific powers. Beyond this, the phenomenon of pre-ignition has been linked to the rise in specific power in gasoline engines for many years. Charge-diluted concepts with high compression cause extreme knocking, potentially leading to catastrophic failure. The introduction of RDE legislation this year will further grow the requirements for combustion process development, as residual gas scavenging and enrichment to improve the knock limit will be legally restricted despite no relaxation of the need to reach the main center of heat release as early as possible. New solutions in thermodynamics and control engineering are urgently needed to further increase the efficiency of gasoline engines.




End-zone Water Injection as a Means of Suppressing Knock in a Spark-ignition Engine


Book Description

Summary: An investigation has been made of the effectiveness of water injection into the combustion end zone of a spark-ignition engine cylinder for the suppression of knock. Pressure-time recoreds obtained show that injection of water at 60° B.T.C. on the compression stroke at a water-fuel ratio of 0.3 rendered M-3 fuel as good as S-3 fuel from an antiknock consideration. The optimum crank angle for injection of water into the end zone was found to be critical. As the injection angle was increased beyond the optimum, the quantity of water required to suppress knock increased to 3.6 water-fuel ratio at 132° B.T.C. The water quantity could not be increased beyond 3.6 water-fuel ration because of injection-pump limitations; however, a further increase in the injection angle up to the earliest angle obtainable, which was 20° A.T.C. on the intake stroke, continuously increased the knock intensity. The engine operating conditions of the tests did not simulate those encountered in flight, especially with regard to the operating speed of 570 rpm. For this reason the results should only be regarded as of theoretical importance until further investigation has been made.




Water Injection in the Modern Automotive Spark Ignition Engine


Book Description

"The injection of water in the spark ignition engine is not new. The effect of humidity in the air on the performance of the spark ignition engine probably initiated the early investigations. The water vapor in the inlet air decreases the speed of the flame front and necessitates spark advance to assure maximum power and maximum efficiency. Water particles in the air evaporate during the compression and combustion of the inducted charge and decrease the tendency of the engine to detonate. These effects are very evident when operating the spark ignition engine in a moist atmosphere. Water is not a foreign element to the internal combustion engine. It can be easily shown that when one pound of a hydrocarbon fuel burns more than one pound of water is formed in the combustion chamber ... The fundamental reason for injecting water is to suppress detonation. The exact nature as to how this is accomplished is not definitely known, but it is reasoned that the effect is due to the high heat of vaporization of the water"--Introduction, leaves 1-2.




Advances in Internal Combustion Engine Research


Book Description

This book discusses all aspects of advanced engine technologies, and describes the role of alternative fuels and solution-based modeling studies in meeting the increasingly higher standards of the automotive industry. By promoting research into more efficient and environment-friendly combustion technologies, it helps enable researchers to develop higher-power engines with lower fuel consumption, emissions, and noise levels. Over the course of 12 chapters, it covers research in areas such as homogeneous charge compression ignition (HCCI) combustion and control strategies, the use of alternative fuels and additives in combination with new combustion technology and novel approaches to recover the pumping loss in the spark ignition engine. The book will serve as a valuable resource for academic researchers and professional automotive engineers alike.







Engine Combustion Instrumentation and Diagnostics


Book Description

This book provides a complete description of instrumentation and in-cylinder measurement techniques for internal combustion engines. Written primarily for researchers and engineers involved in advanced research and development of internal combustion engines, the book provides an introduction to the instrumentation and experimental techniques, with particular emphasis on diagnostic techniques for in-cylinder measurements.