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.


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


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


KNOCK SENSOR


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


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.


http://beamalarm.com/Documents/how_does_a_turbo_work.html


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



Comparison of revolution rates for ceramic and metal turbocharger rotors


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

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

ceramic technologies for automotive applications

Engineering

hardness ceramic materials

automotive industryceramics

automotive industries

nissan motor

valve materials

lightweight materials

combustion chambers

knock sensorwhat