Dhananjay Kumar Srivastava

Development of surface functionalized activated carbon fiber for control of NO and particulate matter

This study investigates the development and potential application of activated carbon fibers (ACF) functionalized with ammonia for control of NO and particulate matter (PM) in diesel engine exhaust. A tubular reactor packed with ACF was used to experimentally study the oxidation of NO at room temperature. Tests were conducted at ACF functionalized with three aqueous ammonia concentrations (3, 5, 10 M), three basic reagents (ammonia, pyridine, amine) and three NO concentrations (100, 300, 500 ppm). After offline investigation, the ACF-packed tubular reactor was installed downstream of the engines exhaust to ascertain the PM capturing efficiency of ACF. The experimental conditions for PM removal included three weights of ACF (2, 3.5, 4.5 g), three engine loads (0, 25, 50 Nm) and three temperatures (150, 300, 450 degrees C). The maximum 70% conversion for NO was obtained at NO concentration of 300 ppm for ACF functionalized with 5M ammonia, whereas maximum 90% reduction in PM was observed at engine load of 25 Nm and 450 degrees C. The study shows significant potential for the ACF based filters in capturing both homogeneous and heterogeneous pollutants emitted from automobiles. Our previously developed transport model incorporating the mechanism for the oxidation of NO was also used to explain the experimental data.

Field Trials of Biodiesel (B100) and Diesel Fuelled Common Rail Direct Injection Euro-III Compliant Sports Utility Vehicles in Indian Conditions

Biodiesel is being explored as a sustainable renewable fuel for vehicles in India due to mounting foreign exchange expenditure to import crude petroleum. Significant amount of research and development work is being undertaken in India to investigate various aspects of biodiesel utilisation in different types of engines. This study is an effort to jointly investigate the use of biodiesel (B100) in an unmodified BS-III compliant sports utility vehicle (SUV) by a consortium of academia (IIT Kanpur) and Industry (M&M) to realistically assess whether biodiesel is compatible with modern engine technology vehicles. Two identical vehicles were operated in tandem using biodiesel (B100) and mineral diesel (B00) respectively for 30,000 kilometers in field conditions. The lubricating oil samples were collected and detailed analysis for assessing the comparative effect of new fuel (B100) vis-à-vis mineral diesel was carried out. After completion of the field trails, the vehicles and the engines were dismantled for assessment of carbon deposits and wear of various vital components/ parts. This paper reports some of the comparative emission results under vehicle running conditions, lubricating oil tribology results and carbon deposits on various vital engine components.

Experimental Investigation of the Effect of Exhaust Gas Recirculation on Lubricating Oil Degradation and Wear of a Compression Ignition Engine

This experimental investigation was aimed to investigate the effect of exhaust gas recirculation (EGR) on wear of in-cylinder engine parts. EGR setup was prepared for a two-cylinder, air-cooled, constant-speed direct-injection compression-ignition engine. Test setup was run for 96 hr under predetermined loading cycles in two phases; normally, operating condition (i.e., without EGR) and with a fixed EGR rate of 25%. Addition of metallic wear debris in the lubricating oil samples drawn after regular interval from both engine operating phases was investigated. Relatively higher concentrations of all wear metals were found in the lubricating oil of the EGR-operated engine, which indicates higher wear of various engine parts. Weight loss of piston rings used in both phases was compared to quantify the amount of wear of piston rings. To quantify the amount of cylinder wear surface roughness parameters of cylinder liners were measured at three positions (top dead center, mid-stroke, and bottom dead center) on thrust and anti-thrust side. A qualitative analysis was also carried out by taking surface profiles and Scanning Electron Micrographs at same locations.

Effect of laser pulse energy on the laser ignition of compressed natural gas fueled engine

Abstract. Laser pulses of few a nanoseconds’ duration are focused by an appropriate converging lens system, leading to breakdown of the medium (combustible gases), resulting in the formation of intense plasma. Plasma thus induced can be used to initiate the combustion of combustible air-fuel mixtures in a spark ignition engine provided the energy of the plasma spark is high enough. Laser ignition has several advantages over the conventional spark ignition system, especially in case of lean air-fuel mixture. In this study, laser ignition of compressed natural gas was investigated in a constant volume combustion chamber (CVCC) as well as in a single-cylinder engine. Flame kernel visualizations for different pulse energy of natural gas-air mixtures were carried out in the CVCC. The images of the development of early flame kernel stages and its growth with time were recorded by shadowgraphy technique. The effect of laser pulse energy on the engine combustion, performance, and emissions was investigated using different air-fuel mixtures. Increased peak cylinder pressure, higher rate of heat release, faster combustion, and increased combustion stability were observed for higher laser pulse energies. The effect of laser pulse energy on the engine-out emissions was also investigated in this study.

Particulate Characterization of Biodiesel Fuelled Compression Ignition Engine

Environmental concerns have increased significantly world over in the past decade. Regulatory agencies are becoming increasingly concerned with particulate emissions as the health and environmental effects are getting understood better due to rapid development in instrumentation. Biodiesel is one of the most promising alternative diesel fuels, which is getting global acceptability among the automotive/ engine manufactures as well as users due to numerous benefits it offers over the conventional diesel. While much of literature is available on particulate emitted by diesel fuelled engine, little is known by particulate emissions from biodiesel fuelled compression ignition (CI) engine. This study concentrates on the characterization of particulate emissions from mineral diesel vis-à-vis biodiesel (B100) and its optimum blend (20%, B20) with mineral diesel. The engine exhaust particle sizer (EEPS) was used for size, surface area and mass distributions of particulate emitted by these fuels under varying engine operating conditions. EEPS measures particulate size range from 5.6 nm to 560 nm with a size resolution of 16 channels per decade (a total of 32 channels). A naturally-aspirated, single-cylinder, direct-injection, water-cooled, compression ignition engine was operated at a constant speed of 1500 rpm at different engine loads for the experiment. It was found that number and size distribution of particulate depend on the engine load. The width of the size distribution increased with increasing engine load. The number distribution was found to obey log-normal assumption. Compared with mineral diesel fuel, biodiesel and its blend showed lower particle size, number and mass distribution, indicating towards lower environmental and health impact compared to mineral diesel.

Laser plasma ignition: status, perspectives, solutions

Laser ignition can yield certain advantages compared to conventional sparkplug ignition. Among other already frequently discussed reasons due to: i) option for sequential or multipoint ignition which can contribute to more reliable ignition in direct injection engines; ii) ignition of leaner mixtures at higher compression being most relevant for gas engines. A satisfying solution to the above mentioned requirements is the longitudinally diode-pumped passively Q-switched Cr4+:YAG/Nd 3+:YAG laser capable of emitting ∼1-ns-pulses of at least 20 mJ . This type of solid-state laser (SSL) confectioned in an engine-compatible form can be called a laser sparkplug. Early versions of this concept comprised a high-power diode pump laser (quasi-cw power <500 W @ ∼500 μs duration) which were placed remote from the engine to avoid detrimental influences of temperature, vibrations, pollution etc. In this case only the SSL is exposed to the elevated temperature in the vicinity of the cylinder walls (<100°C). Recently, technical and cost-oriented considerations allow a change of concept from fiber-based remote pumping via edge emitter arrays to the use of newly developed so-called power VCSELs with two-dimensional stacking. Collimation to form a round pump beam thereby becomes much easier. Their temperature resistance allows lower-cost direct mounting although thereby a wavelength shift is induced. The Q-switched SSL in the sparkplug also faces temperature dependent phenomena like reduction of pulse energy and efficiency, a change of pulse timing and beam profile which will be discussed in the paper.

Horizons in Internal Combustion Research

With the major concern to increase the efficiency of internal combustion (IC) engines, various technologies and innovations have been implemented to improve efficiency and reduction of emissions. This monograph gives a detailed description of advanced IC engine concepts. The monograph is divided into advanced technology for IC engines, exhaust after-treatment and its heat recovery, simulations in the field of IC engine such as HCCI and GCI. Toward the end of this monograph, an overview has been presented related to future mobility solutions of Indian automotive industry. The latest research topics are included in this monograph which will be very useful to students, research scholars as well as industries working in IC engine.

Variable Valve Actuation Systems

Internal combustion (IC) engines today represent a class of heat engines marked by their high power-to-weight ratio, making them the suitable choice for portable power solutions. Being reliable and robust, their widespread use in commercial vehicles is, therefore, implicitly justified. Being a heat engine, the efficiency and performance of an internal combustion engine are limited by the temperature of heat addition and rejection. Moreover, with the inherent irreversible and non-ideal nature of the various processes of the power cycle, a fraction of the ideal thermodynamic efficiency is realised accounting for the low overall thermal efficiency. The text that follows is centred around the gas exchange process in an IC engine. The working of conventional camshaft-driven valve train systems, which have been in use for quite a long time, has been discussed followed by its limitations and their repercussions on the performance and efficiency of an IC engine. The origins of the unavoidable pumping losses accompanying load control using a throttle valve have been explained. An overview of the various strategies and methods used in commercial vehicles to mitigate such losses (variable valve timing and variable valve lift) has been given while providing some insight into the working of some experimental variable valve actuation systems. The discussion then shifts to fully flexible camless valve actuation systems explaining the working of some popular actuation systems, highlighting their advantages and limitations. The basic control logic of such systems is then discussed followed by a list of some unique attributes and advantages of the same. Few experimental results from the literature have also been cited to substantiate the utility of variable valve actuation systems.