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Next generation Inventions for Automotive Prime Movers based on Diesel’s Model. P M V Subbarao Professor Mechanical Engineering Department. Methods of Building a Rational & Powerful Artificial Horse…. Soot Formation in CI Combustion.
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Next generation Inventions for Automotive Prime Movers based on Diesel’s Model P M V Subbarao Professor Mechanical Engineering Department Methods of Building a Rational & Powerful Artificial Horse….
20th century Development of Injection Pressure & Injection System in CI Engines
Current CI Religion in I.C. Engines Diesel Engines High CR No throttling , quality governed, High fuel economy at part load Low specific power heterogeneous combustionHigh NOx and Smoke
Diesel Engine Menace Why Menace? • Stratified charge and φ-T in-cylinder distribution. • Stoichiometric zones: High AFT-NOx in post flame. • Rich zone: High PAH- Soot. • Lean zone: Poor combustion- High CO and UBHC NOx • Respiratory problems. • Ground ozone and PM formation. • Acid rain. • Visibility and haze. • Nutrient pollution.
A Model for Secular I.C. Engines The Right Diesel like (CI) Engines Homogeneous charge, high CR, high vol. High Fuel economy
Homogeneous Charged Combustion • To achieve the kind of combustion depicted in previous paragraphs, three • major aspects should be addressed: • 1. How to create a homogeneous mixture? • 2. How to achieve self ignition of this mixture? • 3. How to control combustion so that engine is safe and performance is better?
Various Options for advanced CAI combustion • HCCI (Homogeneous Charge Compression Ignition) • RCCI ( Radical Controlled Compression Ignition) • PCCI (Premixed Charge Compression Ignition) • MK combustion (Modulated Kinetics Combustion) • TS combustion (Toyota Soken Combustion) • ATAC (Active Thermo-Atmosphere Combustion) • AR Combustion( Active Radical Combustion) • CAI (Controlled Auto-Ignition) • All of the above concepts are a kind of auto ignition of the fuel.
Combustion phasing control strategies • There is no direct control over the combustion timing in concept HCCI engine, unlike CI and SI engines. • State of the art strategies available as of now are • Spark assisted HCCI • Injection assisted HCCI • Retarded main inj.(MULTIDIC) • EGR • Controlling intake air temperature • Variable CR and VVT • Modifying Fuel composition • Water Injection
Advanced CI Engine for Next Decade HCCI-DI Engine. Divide the fuel into Primary (main) and Pilot (Early) Fuel. Pilot fuel is responsible for homogenization. Primary fuel is responsible for Compression Ignition. Identify the conditions for avoidance of Self Ignition due to Pilot fuel Injection. How to develop a dual injection system????
Developed HCCI-DI fuel injection system Developed System Multi injection using single Injector without any geometry modification • External pump (Pilot) • 2 pumps • Belt drive from extended cam shaft • Fuel injector • HP pipe 1, 2 and 3 • T-junction • Split ratio control lever • Inj. timing control cam
Schematic Diagram of HCCI-DI Engine test setup Engine specifications
Reduction of Particulates thru HCCI Smoke Opacity is the fraction (or %) of incident light which is adsorbed or scattered by the particulate matter in exhaust gas.
Combustion Analysis thru Pressure-Crank Angle Diagram Identification of Different Combustion Parameters
In-cylinder Processes in a Moderate HCCI-DI Engine SAE paper 2014-01-2661
Schematic Diagram of HCCI-DI Engine test setup with EGR & Fuel Heating
HCCI-DI Engine is a Consciously Knocking Engine The slope of RI for pure HCCI (100% premixed) combustion will be much steeper than 80% and 95% split ratio.
HCCI-DI is a Consciously Knocking Engine • Corresponding RI was 2.94 W/m2 and 13.5 W/m2. • Only 0.7 bar IMEP increase leads to 4 times increase in RI !!! • This RI (13.5 W/m2) is about 8 times higher to the baseline combustion at similar load condition. • The slope of RI for pure HCCI combustion will be much steeper than 80% and 95% split ratio.
Final Recommendations COV of IMEP beyond 4 bar IMEP condition is found within 5%. COV for baseline combustion remains around 3% irrespective of load.
Conclusions • HCCI Engine Technology is an obvious future choice. • Extensive CAD is essential for the development of HCCI Engines. • CAD combined with experimental study will develop a better engine with faster development cycle. • More avenues for future research and development.