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Ramadandi, Padmavathi
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EGR flow control strategy for a smaller capacity diesel engine using a phase shifting chamber

Mahindra & Mahindra, Ltd.-Karthikeyan N. Krishnan, Padmavathi Ramadandi, Vinodini Bhargava, Karthik Chandana
  • Technical Paper
  • 2020-01-1358
To be published on 2020-04-14 by SAE International in United States
Exhaust gas recirculation (EGR) is an effective strategy to control NOx emissions in diesel engines. EGR reduces NOx through lowering the oxygen concentration in the combustion chamber, as well as through heat absorption. The stringent emission norms have forced diesel engines to further improve thermal efficiency and reduce nitrogen oxides (NOx). Throttle control is adopted in diesel intake system to control the EGR & fresh charge flow and to meet the emissions norms. In three or lesser cylinder. diesel engines, predominantly single and two-cylinder diesel engines, there is a higher possibility of the exhaust gas reaching the intake throttle and Particulate matter getting deposited on the throttle body. This can significantly affect the idling stability and intake restriction in prolonged usage. In idling condition, the clogged throttle body stagnates the fresh charge from entering the cylinder. The work aims at the study of flow pattern for EGR reaching the throttle body. A numerical study is conducted on a two-cylinder smaller displacement diesel engine. In a two-cylinder engine with an EGR circuit the intake valve of…
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Effect of Gasoline-Ethanol Blends on GDI Engine to Reduce Cost of Vehicle Ownership

Mahindra & Mahindra, Ltd.-Kartick Ramakrishnan, Padmavathi Ramadandi, Karthikeyan N Krishnan
  • Technical Paper
  • 2019-28-2379
Published 2019-11-21 by SAE International in United States
A major challenge for combustion engine development is to optimize the engine for improved fuel economy, reduce greenhouse gases. Stringent CAFÉ and emission norms require the customer to pay higher capital on vehicles. To offset the cost of ownership- cheaper and alternative energy sources are being explored. Ethanol blend with regular Gasoline, and CNG are such alternative fuels. Reducing the consumption of Gasoline also helps India’s dependence on import of crude oil.The study was carried on turbo-charged gasoline direct injection engine. The effect of ethanol on engine and vehicle performance is estimated and simulated numerically. The work is split into three stages: first the base 1D engine performance model was calibrated to match the experimental data. In parallel, vehicle level Simulink model was built and calibrated to match the NEDC cycle performance. Second, the thermal efficiency of the ethanol blend is calculated as a linear function of theoretical Otto cycle efficiency. The engine performance for varying compression ratio & ethanol gasoline blend is studied for vehicle level using a MATLAB code. Third, 1D code was…
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Practical Considerations in the Airflow Optimization of a Single Cylinder Diesel Engine

Mahindra & Mahindra Ltd.-Siva Krishna Reddy Dwarshala, Padmavathi Ramadandi, Rehan Shaik, Radhakrishnan Shankar
Published 2014-04-01 by SAE International in United States
The present work is concerned with the design of an optimum air intake system for a single cylinder reciprocating diesel engine. It is a well known fact that air flow rates of a naturally aspirated engine are sensitive to the geometrical dimensions of the pipes that connect the engine to the atmosphere. Hence, tuning intake system dimensions for optimum airflow rates is of great importance. In this scenario simulation tools can be useful for the optimization of intake system. The one dimensional simulation tool AVL BOOST is used to predict air flow rates with different combinations of connecting hose diameters and lengths. Subsequently air flow rates are measured with selected clean hoses on an engine steady state test bench. It is found in the initial tests that the lengths and diameters of optimum hoses deviate from the AVL BOOST predicted optimum geometric dimensions. Analysis of test data and measurement systems is done to find out the possible reasons for mis-match between the predictions and measurements in order to improve the airflow rates on actual engine.…
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