A great deal of research has been directed towards understanding the dependence of emissions and fuel economy on the operating and design characteristics of spark-ignition homogeneous-charge engine. Several recent investigations have been concerned with modifying the conventional spark-ignition such that the part load BSFC (brake specific fuel consumption) is decreased. Many of the proposed modifications convert the engine from fixed to variable displacement, i.e., the engine size is varied to suit the vehicle needs. Another possible modification to the conventional engine is to control the load of the engine by controlling the timing of the intake-valve closure rather than by variable-density throttling. This investigation examines the delaying intake valve closing as a method of controlling the engine load without incurring the usual part-load throttling losses. The extended expansion engine (EEE) is an engine with the power output regulated by controlling the crank angle at which the intake valve closes (IVC). As in case of a conventional engine the intake valve opens just prior to and remains open through out the intake stroke of the engine. However, the intake valve also remains open over a portion of the compression stroke while the piston pushes part of the cylinder charge back into the intake manifold and stored in a plenum. A one-way valve is provided to prevent the charge from re-entering the carburetor. After the intake valve closes, the actual compression starts and the expansion and exhaust strokes are similar to those of the conventional engine. The effective cylinder volume determines the trapped cylinder charge and therefore the power output, at the time of the intake valve closing. This paper mainly deals with the numerical studies on single cylinder, four stroke, spark ignition, Extended Expansion Engine extended expansion engine with intake valve closure delayed to produce an expansion ratio that is larger than the compression ratio. The Engine processes are simulated on a computer using thermodynamic and global modeling techniques. Further the concept of lean burn technology is applied to the simulated processes and the engine performance and emission characteristics are studied from the simulated results. Two-zone combustion model is adopted for the analysis of combustion. The model is also associated with sub models for calculating the combustion duration and equilibrium composition of five product species. From this investigations and comparison of results, it is concluded that the simulation work developed predicts the performance and emission characteristics of this engine reasonably well. Therefore it is evident that the developed code can be used with confidence for further parametric studies.

The quest for increasing the efficiency of an internal combustion engine has been going on ever since the invention of this reliable work equipment. In recent times much attention has been focused on achieving higher thermal efficiency by reducing the heat loss to the surroundings by the application of “low heat rejection” concept using ceramic coating for engine components or ceramic components itself. In this direction, the present analysis focused on the formulation and development of a two zone combustion model for the prediction of combustion, heat release and performance of the conventionally Water cooled and low heat rejection engines. The low heat rejection concept is introduced in this model by developing and formulating a wall heat transfer model to consider the effect of instantaneous inside surface temperature on combustion and heat release of an LHR engine. The gas wall heat transfer by means of convection and radiation is calculated using various gas wall heat transfer models. The predictions by the computer model and experimental findings are demonstrated. The capability of this model and the comparison of the predicted results with experimental findings are highly satisfactory.

In the recent scenario of braking system for automobiles, disc brake takes up a wide range of applications, because of its simplicity in construction, operation and not self energizing as in the case of drum brakes. Since the disc brakes takes up a wide range of application, it is essential to ensure the reliable function of the braking system under varied operating conditions. The reliable function of the disc brake system is purely depends on the system based design. In this work, a linear regression technique is used for the optimal design of the disc brake rotor for varied operating conditions. Various forces involved during braking, energy generated during braking and the corresponding effective stopping distances were also calculated using appropriate governing relations and equations. In the varied operating conditions, the heat energy generated during braking should be driven away form the working surfaces of the components. To analyze this thermal loading and cooling phenomenon, a conventional convective heat transfer approach was also formulated and developed in this work. The analytical findings of the above approaches are demonstrated at the end and it is found to be quite satisfactory.

In the wide range of braking speed, the disc brakes are subjected to temperature variation and thermal loading. Different modelling approaches ranging from a simple lumped parameter model to complex three-dimensional models are available for the thermal analysis of the disc brakes. Based on the review of the above models, a model has been developed and formulated for the analysis of thermal loading of disc brake. The developed model is proposed to couple with a model for the thermal distortion of disc brake. It is also proposed to conduct the necessary experiments and thermal analysis to validate the results obtained from the synthesized analysis.

This paper deals with Numerical Study of 4-stoke, Single cylinder, Spark Ignition, Extended Expansion Lean Burn Engine. Engine processes are simulated using thermodynamic and global modeling techniques. In the simulation study following process are considered compression, combustion, and expansion. Sub-models are used to include effect due to gas exchange process, heat transfer and friction. Wiebe heat release formula was used to predict the cylinder pressure, which was used to find out the indicated work done. The heat transfer from the cylinder, friction and pumping losses also were taken into account to predict the brake mean effective pressure, brake thermal efficiency and brake specific fuel consumption. Extended Expansion Engine operates on Otto-Atkinson cycle. Late Intake Valve Closure (LIVC) technique is used to control the load. The Atkinson cycle has lager expansion ratio than compression ratio. This is achieved by increasing the geometric compression ratio and employing LIVC. Simulation result shows that there is an increase in thermal efficiency up to a certain limit of intake valve closure timing. Optimum performance is attained at 90 deg intake valve closure (IVC) timing further delaying the intake valve closure reduces the engine performance.

The quest for increasing the efficiency of internal combustion engines has been going on ever since the invention of this reliable workhorse. In recent times much attention has been focused on achieving higher thermal efficiency by reducing the heat loss to the surroundings by the application of “Low heat rejection” concept using ceramic coating for engine components or ceramic components itself. In this direction, the present analysis focused towards the formulation and development of a two-zone combustion model for the prediction of combustion, heat release and performance of the conventional and low heat rejection engines.