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Technical Paper

Valve Opening and Closing Event Finalization for Cost Effective Valve Train of Gasoline Engine

2019-04-02
2019-01-1191
With more stringent emission norm coming in future, add more pressure on IC engine to improve fuel efficiency for survival in next few decades. In gasoline SI (spark ignition) engine, valve events have major influence on fuel economy, performance and exhaust emissions. Optimization of valve event demands for extensive simulation and testing to achieve balance between conflicting requirement of low end torque, maximum power output, part load fuel consumption and emission performance. Balance between these requirements will become more critical when designing low cost valve train without VVT (Variable valve timing) to reduce overall cost of engine. Higher CR (Compression ratio) is an important low cost measure to achieve higher thermal efficiency but creates issue of knocking thereby limiting low speed high load performance. The effective CR reduction by means of late intake valve closing (LIVC) is one way to achieve higher expansion ratio while keeping high geometric CR.
Technical Paper

Dynamic Strength Co-Simulation of Valve Train Mechanism Design Virtual Validation

2020-04-14
2020-01-0949
As the automotive market is very dynamic and vehicle manufactures tries to reduce the vehicle development cycle time, more focus is being given to CAE simulation technologies to reduce the design cycle time and number of physical tests. CAE engineers are continuously working on improving the accuracy of CAE simulation, such as using flexible body dynamic simulation in place of linear static analysis. Strength calculation under dynamic condition is more accurate as compared to static condition as it gives more clear understanding of stress variation with motion, contacts and mass inertia. Failure has been observed in new development of valve train pivot screw under test conditions. As per linear static analysis, design was judged OK. Normal linear static analysis is a two stage process. In 1st stage loads are calculated by hand or peak loads are taken from Multi body dynamic (MBD) rigid body analysis.
Technical Paper

Integrated Exhaust Manifold Cylinder Head Design Methodology for RDE in Gasoline Engine application

2020-04-14
2020-01-0169
In recent years, world-wide automotive manufacturers have been continuously working in the research of suitable technical solutions to meet upcoming stringent Real Driving Emission (RDE) and Corporate Average Fuel Economy (CAFÉ) targets, as set by international regulatory authorities. Many technologies have been already developed, or are currently under study by automotive manufacturer for gasoline engines, to meet legislated targets. In-line with above objective, , Integrated Exhaust Manifold (IEM) is the key technology of the Internal Combustion (IC) engine to expand lambda 1 region expansion by reducing fuel enrichment at high load-high RPM by reducing exhaust gas temperature for RDE regulation. This technology also helps to increase fuel economy during cold start stage of World-wide harmonized Light vehicles Test Cycles (WLTC) by faster warm-up and High Speed fuel consumption by fuel enrichment reduction.
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