P. A. Janakiraman

Bio: P. A. Janakiraman is an academic researcher from Indian Institute of Technology Madras. The author has contributed to research in topics: Internal combustion engine & Combustion chamber. The author has an hindex of 4, co-authored 6 publications receiving 42 citations.

Measurement of pulsating temperature and velocity in an internal combustion engine using an ultrasonic flowmeter

Abstract: A new ultrasonic meter is described which uses a linear spark as the source of the ultrasound pulse. Two quartz crystals downstream and upstream of the source act as receivers. The time taken by the pulse to reach the receivers is determined by the velocity and temperature of the gases. The flow properties at the intake and exhaust of an engine are measured using this meter.

An Ultrasonic Flowmeter for Measurement of Gas Velocity and Temperature in Intake and Exhaust of an Internal Combustion Engine

Abstract: A new ultrasonic velocity thermometer is presented for the simultaneous measurement of transient exhaust gas velocity and temperature under motoring and firing conditions in an internal combustion engine. Included in the instrumentation are a crank angle (CA) selection unit, a high voltage impulse generating unit, and other accessories. The instrument is described, and its operating principle and calibration are discussed. Its performance is compared with that of the spark discharge velocity meter and the wire resistance thermometer, under dynamic conditions. Exhaust temperature and velocity measurements are plotted against CA; these experimental results are discussed, including some comparisons with theoretical results obtained using a finite difference theory of gas exchange processes in internal combustion engines.

Effect of Fuel Injection Pressure on Performance of Single Cylinder Diesel Engine at Different Intake Manifold Inclinations

Abstract: In present days an automobile engine has to satisfy the strict environmental constraints and fuel economy standards in addition to meeting the competitiveness of the world market. Today the automobile engines have synthesized the basic knowledge of many disciplines like thermodynamics, fluid flow, combustion, chemical kinetics and heat transfer. Now-a-days internal combustion engines play an important role in automobile field. There are various factors that influence the performance of engine such as compression ratio, atomization of fuel, fuel injection pressure, and quality of fuel, combustion rate, air fuel ratio, intake temperature and pressure and also based on piston design, inlet manifold, and combustion chamber designs etc. Growing demand on reduction of internal combustion engine fuel consumption with increase of its performance new designs and optimization of existing ones are introduced. Air motion in CI engine influences the atomization and distribution of fuel injected in the combustion chamber. Fuel injection pressure plays an important role in better atomization of injected fuel allows for a more complete burn and helps to reduce pollution. In present work a single cylinder 5HP diesel engine is used to investigate the performance characteristics. The main objective of this work is to study the effect of the fuel injection pressure on performance and pollution of the single cylinder diesel engine at different intake manifold inclinations. From experiment it is found that engine at 60 0 manifold inclinations at 180 bars has given efficient performance and less pollution. I. INTRODUCTION Diesel engine plays a dominant role in the field of power, propulsion and energy. The diesel engine is a type of internal combustion engine ,more specifically it is a compression ignition engine ,in which the fuel ignited solely by the high temperature created by compression of the air-fuel mixture. The engine operates using the diesel cycle. The engine is more efficient than the petrol engine, since the spark -ignition engine consumes more fuel than the compression -ignition engine. The fuel injection system is the most vital component in the working of CI engine. The engine performance, power output, economy etc is greatly dependent on the effectiveness of the fuel injection system. The injection system has to perform the important duty of initiating and controlling the combustion process. When the fuel is injected in to the combustion chamber towards the end of compression stroke, it is atomized into very fine droplets. These droplets vaporize due to heat transfer from the compressed air and from an air-fuel mixture. Due to continued heat transfer from hot air to the fuel, the temperature reaches a value higher than its self- ignition temperature. This causes the fuel to ignite spontaneously initiating the combustion process. Quick and complete combustion is ensured by a well designed fuel injector. By atomizing the fuel into very fine droplets, it increases the surface area of the fuel droplets resulting in better mixing and subsequent combustion. Atomization is done by forcing the fuel through a small orifice under high pressure. The injector assembly consists of. 1. A needle valve

Energy efficiency of high pressure pneumatic systems

Abstract: The energy efficiency assessment of high-pressure pneumatic circuits is the aim of this dissertation. From a historical perspective the past and cur- rent activities with regards to the energy saving conservation in pneumatic technology were examined, and it could be concluded that high pressure pneumatic circuits have been repeatedly used for years in several industrial applications but to date no studies on that specific field are known. After a systematic review of studies concerning energy saving in pneumatic applications, a complete dynamic model for a high-pressure air blowing machine, employed in the production of plastic bottles, was developed. A synthetic version of the real pneumatic system was considered and consisted of a valve manifold, two tanks, one that simulated the mould cavity where the plastic preform is commonly blown and the other, was intended to recycle air. The one-dimensional models were derived for the pneumatic valve, pipes and vessels. The dynamic modelling of the valve took into account the flow non-linearities through the various geometrical restrictions as well as the pressure and temperature evolution at the inner chambers. Because of the existence of flow discontinuities in the pipes, different solving methods were applied, taking as starting point the Method of Characteristics and continued delving into finite volume methods such as Riemann-solver-based schemes. On the experimental phase a single blowing station unit was designed and built up. The pressure and temperature characteristics at different positions of the pneumatic circuit were measured in detail. In addition, the fluid flow through the valve manifold could be characterised by the sonic conductance and critical pressure ratio, which were determined by the isothermal discharge method. Effort was also expended to study the behaviour of the pressure waves generated along the tubes. The pressure wave propagation was computationally charted, with the intention of assessing how this parameter affected the recycling process. The examination of the experimental results proved the efficiency of the re- cycling process and demonstrated to be in close agreement with the mathematical model. The parameters governing the maximum amount of air to be recycled at each working cycle were identified, and the influence of the pipe geometry was discussed. Finally the author provides recommendations for future research and makes suggestions regarding the valve design to enhance the efficiency of the system.

Manifold Gas Dynamics Modeling and Its Coupling With Single-Cylinder Engine Models Using Simulink

Abstract: A flexible model for computing one-dimensional, unsteady manifold gas dynamics in single-cylinder spark-ignition and diesel engines has been developed. The numerical method applies an explicit, finite volume formulation and a shock-capturing total variation diminishing scheme. The numerical model has been validated against the method of characteristics for valve flows without combustion prior to coupling with combustion engine simulations. The coupling of the gas-dynamics model with single-cylinder, spark-ignition and diesel engine modules is accomplished using the graphical MATLAB-SIMULINK environment. Comparisons between predictions of the coupled model and measurements shows good agreement for both spark ignition and diesel engines. Parametric studies demonstrating the effect of varying the intake runner length on the volumetric efficiency of a diesel engine illustrate the model use.

Invited review article: Unsteady and pulsating pressure and temperature: a review of experimental techniques.

Abstract: Unsteady flow of liquids and gasses are important in many scientific, engineering, and biological contexts. Measurement of the characteristics of unsteady and pulsating flows is more difficult than that of static flows. Time constants of the sensors must be understood, sampling rates must satisfy basic signal processing criteria and synchronization of the measurements with the flow may be necessary. Because of development of more advanced measurement devices, there has recently been a growing interest in unsteady and pulsating flow measurements and the number of papers in this field has increased in recent years. This paper reviews the current state of the art in sensors and measurement techniques for the characterization of pressure and temperature in unsteady and pulsating flows including an analysis of the advantages and limitations of each technique.

The Theory of Wave Action Approaches Applied to Reciprocating Engines

Abstract: It has long been realized that the design of the inlet and exhaust manifolds has a large effect on the performance of reciprocating engines. The unsteady nature of the induction and exhaust processes means that the effect of the manifold on charging and discharging is extremely dependent upon the engine speed. This is because the impedance (or admittance) of the manifold is a function of the frequency of the pulses entering it. The outcome of this is that it is possible to tune the manifolds to give a particular engine power output characteristic as a function of speed. In the case of a racing engine the manifolds will be designed to produce high power outputs at high speeds; this will produce the maximum specific power (power/weight) from the engine, but probably at the expense of flexibility. This is not an insurmountable problem in a racing car where the driver is skilled at obtaining the maximum performance from his vehicle by the use of the tachometer and the gearbox. However, the average driver does not want such a temperamental machine and road-going engines are often tuned to give a much more forgiving engine characteristic. Most modern car engines are designed to give a high torque at low engine speed; this means that as the engine slows down the torque rises, obviating the need to change gear.