Ceramic Technologies for Automotive Applications
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Transcript of Ceramic Technologies for Automotive Applications
By Ummen Sabu13ETMMO8M.Tech Materials Engineering
School of Engineering Sciences and Technology UNIVERSITY OF HYDERABAD
CERAMIC TECHNOLOGIES
Current status and perspectives
FOR AUTOMOTIVE INDUSTRY
CONTENTS
Introduction
Engine accessory units
Ceramic matrix composites
Other ceramic technologies used
Conclusion
References
CERAMIC TECHNOLOGIES FOR AUTOMOTIVE INDUSTRY
Ceramics?
ceramics are compounds of metallic or non-metallic elements and other non-metals.
They are known for their high temperature withstanding ability and hardness
Ceramic materials are highly brittle in nature.
Automotive industry?
Automotive industries incorporates elements of mechanical, electrical, electronic,software and safety engineering as applied to the design, manufacture and operationof aircrafts, marine vessels, motorcycles,automobiles,buses and trucks and theirrespective engineering subsystems.
CERAMIC TECHNOLOGIES FOR AUTOMOTIVE INDUSTRY
Ceramics have a wide range of applications in the current automotive industry sector.
They range from small components used in automotives to construction of the engines
Traditional ceramics however cannot be used for these applications directly.
Automotive industries rely on Advanced ceramics and Engineered ceramics.
1. Engine accessory units
2. Ceramic Engines
3. Other ceramic technologies used in automotives
CERAMIC TECHNOLOGIES FOR AUTOMOTIVE INDUSTRY
Made of CERAMIC MATERIALS
Knock SensorValve SystemsSuper ChargerOther devices.........
KNOCK SENSOR
What are Knocks??
High frequency vibrations caused by impropercombustion of fuel in engine.
The fuel-air charge is meant to be ignited by the sparkplug only, and at a precise point in the piston's stroke.
Knock occurs when the peak of the combustionprocess no longer occurs at the optimum moment forthe four-stroke cycle.
The shock wave creates the characteristic metallic"pinging" sound.
Why do we care??
Knocks can rob power from the engine and worst,destroy the engine itself.
Nissan Research Center, Nissan Motor Co., Yokosuka 237-8523, Japan
KNOCK SENSOR
How can we prevent knocking??
lower compression ratio, higher octane fuel,change driving habits or……MECHATRONICS!
Knock Sensors generate a voltage whenvibration is applied to them utilizing thepiezoelectric effect
Generated voltage is sent to the enginecontrol unit which functions with amicroprocessor.
The ECU gives a proper signal to the igniterto adjust the spark timings to avoid knock
Nissan Research Center, Nissan Motor Co., Yokosuka 237-8523, Japan
KNOCK SENSOR
Nissan Research Center, Nissan Motor Co., Yokosuka 237-8523, Japan
VALVE SYSTEMS
Valve systems enabling smooth inflow and outflow of gases in combustionchambers are important for reciprocal engines operating at high revolution speeds.
The multi-valve system is beneficial for exchanging gases in the combustionchambers because of the large opening areas.
Valve weight reduction is also effective for smooth opening and closing, andlightweight materials, such as siliconNitride a ceramic, have been investigated aspossible replacements for the Ni-based super alloys currently used for exhaustvalves.
Moreover the valve materials have to withstand very high temperature
Recently silicon nitride valves have been used in formula racing cars.
Soon it will enter into the Commercial segment vehicles also
VALVE SYSTEMS
Nissan Research Center, Nissan Motor Co., Yokosuka 237-8523, Japan
Valves Valve Assembly
SUPERCHARGER DEVICES
Supercharger systems enable the generation of extraordinarily high engine powers
This is achieved by producing high pressure air in the engine cylinders.
Turbochargers, consists of a turbine-driven by exhaust gasesi.e. It use a turbine rotor driven by the gases from the engine exhaust manifolds.
An impeller linked by a shared axle with the turbine, compresses ambient air to deliver it to the engine’s air intake manifold.
SUPERCHARGER DEVICES
http://beamalarm.com/Documents/how_does_a_turbo_work.html
SUPERCHARGER DEVICES
Turbocharger systems are advantageous for yielding extraordinarily high power.
However, there is an inevitable delay between the intention to accelerate asexpressed by stepping on the accelerator pedal and the actual acceleration of theautomobile.
This Turbo-lag is caused by the time required for the turbine to reach the speedRequired to supply boost pressure.
Reducing the rotor’s inertial mass is an effective way to shorten turbo-lag.
A ceramic turbocharger made of silicon nitride reduces turbolag because siliconnitride is lighter than the traditional Ni based super alloys
SUPERCHARGER DEVICES
Nissan Research Center, Nissan Motor Co., Yokosuka 237-8523, Japan
Comparison of revolution rates for ceramic and metal turbocharger rotors
Nissan Research Center, Nissan Motor Co., Yokosuka 237-8523, Japan
Oxygen sensors made of zirconia ceramics
cross-section of a honeycomb catalyst for installationin an automobile exhaust pipe
OTHER ENGINE ACESSORY UNITS
These devices are used for exhaust gas purification and to limit the amount of hydrocarbons released into the atmosphere.
Cams in engines are also produced from ceramics
Mainly for jet engines and space applications
AutomotiveMOTOR CORP
CERAMIC ENGINES
Ceramics have very high melting point, resistant to oxidation and corrosion andare very hard. In this respect they are superior to metals
However they are extremely brittle and prone to thermal shock failure
To overcome the inherent unfavourable properties of ceramics attempts weremade to combine ceramics and metals by making CERMETS
This met with little success
Silicon nitride developed in 1960’s had better toughness than conventionalceramics. Although the toughness was high compared to other ceramics ,it is stilltoo low for many structural applications
CERAMIC MATRIX COMPOSITES
Improvement in the toughness of these ceramics is possible by making composites with
ceramics
This became the future direction of research in this field.
Improvement in toughness of ceramics was achieved with the introduction of CMC
The central idea of CMC was to create barriers to crack propagation in the form of discrete particles or fibres have been incorporated into ceramic matrices.
CMCs are made from silicon carbide matrix toughened with coated fibers made from the same material
The processing techniques employed for the manufacture of CMC’s are Powder Metallurgy process Infiltration process Deposition process
AVANTAGES OF CMC
Increased fracture toughness
Elongation before rupture upto 1%
Higher dynamic load capability
These materials had better thermal shock resistance, largely due to a combination of low thermal expansion, high strength, and moderate thermal conductivity.
CMC’s IN CERAMIC ENGINES AND ITS COMPONENTS
The CMC’s developed were used in the manufacture of gas turbine engines and their components.CMC components offer benefits of higher temperature capability and less cooling requirements which correlates to improved efficiency and reduced emissions.Reduced Fuel Consumption
The manufacturing method of these components are trade secrets of the industries and detailed information is not available
Automotive
Automotive
CMC’s USED IN SPACE SHUTTLE COLOUMBIA of NASA
Columbia suffered a crack in its left wing by a during take-off.
During her return, superheated air entered the spacecraft through the wound and ripped the shuttle apart 15 minutes before touchdown.
The GE team, in collaboration with NASA and industry partners, helped design and fabricate unique patches to plug up in space similar damage on the shuttle’s wings and belly, and prevent disasters in the future
The team designed the patches from a special ceramic composite material that could survive wild temperature swings
Used in AUTOMOTIVES
Wide range of sensorsCeramic coatings for engine partsCeramic Brake discsSafety devices
WIDE RANGE OF SENSORS USED:
OTHER CERAMIC TECHNOLOGIES USED:
Ceramic coatings:
Ceramic coatings can augment vehicle performance.It is applied on cylinder heads,pistons,piston-skirts, intake manifolds
Ceramic brake discs:
Ceramics are used for the manufacture of brake discs due to their high wear strength and hot hardness
Used in safety devices in automobiles:
Piezoelectric ceramic materials are used in the safety air-bags construction in cars.
CONCLUSION
Starting from humble origins in earthenware and bricks, the ceramics have
come a long way where today they have revolutionized the modern
automotive sector.
More developments are expected in gas turbine engine construction using
ceramic matrix composites and additive manufacturing techniques.
REFERENCES
[1] K. Katayama, T.Watanabe, K. Matoba, N. Katoh, SAE Paper, No. 861128 (1986).[2] Y. Ogawa, M. Machida, N. Miyamura, K. Tashiro, M. Sugano, SAE Paper, No.860397 (1986).[3]. Ceramic technologies for automotive industry: Current status and perspectivesAkira Okada∗ Nissan Research Center, Nissan Motor Co., Yokosuka 237-8523, Japan