ENGINEERING TRIPOS PART IIB - 2012/2013

Module 4A13 - Combustion and IC Engines

AIMS

The aim of this course is to introduce students to fundamental combustion concepts, and their influence on internal combustion engine preformance and emissions.

LECTURE SYLLABUS

1. Chemical thermodynamics and equilibrium (1L)

• Mass, energy and atomic species conservation
• Multispecies equilibrium and calculation method

2. Chemical kinetics (1L)

• Principles of chemical kinetics: law of mass action and activation energy
• Hydrocarbon reaction chains
• Pollutant formation
• Multistep reactions and explosions
• Steady state and partial equilibrium approximations
• Characteristic time and space scales

3. Applications of chemical kinetics: limit reators (1L)

• Common approximations in combustion analysis:
• Static reactor
• Perfectly stirred reactor
• Plug flow reactor
• Thermal explosions
• Autoignition

4. Laminar premixed flames (1L)

• Laminar premixed flames: concepts and measurements
• Conservation equations for combustion in one and multiple dimensions
• Characteristic time and space scales, Zeldovich number
• One-dimensional conservation equation and simplified solutions
• Effects of mixture compostion, stretch and curvature

5. Laminar non-premixed flames (1L)

• Laminar diffusion flames: concept and measurement methods
• Characteristic time and space scales
• Conserved scalars and mixture fraction
• One-dimensional conservation equations: co-flow and opposed flow

6. Kinetics of pollution formation (NOx,CO, particles) (1L)

• Zel'dovich and extended NOx formation chemistry
• Time scales for CO and HC chemistry
• Particle formation and oxidation mechanisms

7. Flames and Turbulence (1L)

• Characteristic time and space scales
• Regimes of turbulent combustion
• Measurement methods and results
• Approaches to modeling turbulent combustion

8. Gas turbine combustion - performance and emissions (1L)

• Gas turbine combustion principles
• Emissions and stability in industrial gas turbines and aeroengines

9. SI engines - performance and limits to performance (1L)

• Basic engine cycles, mean effective pressure and efficiency
• Limits to efficiency and pressure: autoignition, rate of combustion, heat losses.

10. SI engines - enhancing performance and emissions (1L)

• Improving performance:scavenging efficiency,flow exchange processes,direct injection
• Emission control;catalysts and cycle control.

11. CI engines - performance and limits to performance (1L)

• Basic engine cycle, mean effective pressure and efficiency
• Limits to efficiency and power: autoignition, rate of combustion, heat losses.

12. CI engines - enhancing performance and emissions (1L)

• Multiple injection in CI engines
• Principles and perormance of particle trapping and oxidation systems

13. Turbocharging (1L)

• Principles of turbocharging and relevant physics
• Turbocharger matching

14. Future development in combustion engines (1L)

OBJECTIVES

On completion of the course, students should:

• Understand fundamental concepts in combustion, including:
• Adiabatic flame temperatures and equilibrium compostion
• Time scales for physical transport rates and kinetics
• Origin of explosive behaviour
• Conserved scalars
• Premixed laminar flame burning rates
• Non-premixed laminar flame burning behaviour
• Role of turbulence in combustion
• Origins of pollutant formation in combustion
• NOx
• CO
• uHC
• Particles
• Understand combustion issues particularly relvant to gas turbines
• NOx, CO, Particles tradoffs
• Flame stability
• Relight
• Understand the preformance/efficiency characteristics of IC engines
• Gasoline/Diesel combustion (HCCI)
• Interpertation of cylinder pressure data
• Fuel economy
• Limits
• Fuel effects (bio etc)
• NA and Turbo/Boosted
• Hybird/downsizing concepts
• Understand how "engine out" and "tailpipe" emissions may be contolled in IC engines
• Catalysts, DPFs, SCRs

Please see the Booklist for Group A Courses for references for this module.

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Last updated: May 2012

teaching-office@eng.cam.ac.uk