TMC ( Techno Material Corp.)

• Valve Train Parts : Severe/Abnormal Wear at Cam/TappetCam/Tappet • Power Train Parts : Severe/Abnormal Wear at Piston Ring/liner

What Happened in Diesel Engines

TMC ( Techno Material Corp.)

Heavy Duty Diesel-Engine Exhaust Gas Regulation

It is a Chance of Technologies Advance.

0

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0 1 2 3 4 5 6 7 8 9NOx(g/kwh)

PM

(g/kw

h)

EURO1(1992)

EURO2(1996)EURO3(2000)

EURO4(2005)

Cam: Induction H Tappet: Hard Metal Ring: Cr-Ceramic Liner: High Alloy Cast

Cam: Induction H Tappet: ? Ceramic Ring : ? Cr-Diamond Liner: ? Laser Steel

Cam: Induction H Tappet : Chilled Cast Ring: Cr Plating Liner: High P-Cast

KOREA(2004)KOREA(2006)

KOREA(2000)

70Kg/mm^2

160Kg/mm^2

Stress: ?

TMC ( Techno Material Corp.)

Cam and Tappet Movement in Valve Train System

• Contact between Cam and Tappet Line contact, Rolling with sliding Crowned surface of tappet (for uniform wear)• Lubrication Cam Base Area : Hydrodynamic lubrication Cam Nose Area : Boundary lubrication # Nose ± 20° , Max. contact stress, Lubrication film failure Severe wear occurs

• Hertzian Contact Stress σmax [P/WR(1/E1+1/E2)]∝ ½

W = Cam width R = Cam radius

P = Max. load σmax =Max. Contact Stress

E1/E2 = Young’s modulus of Cam/Tappet

TMC ( Techno Material Corp.)

Valve Train System, OHV Type Diesel Engine

• Valve timing control • Profile of Cam nose will be maintained during engine life• Wear of Cam and Tappet Timing Changed Imperfect Burning PM and NOx increase in exhaust gasPM and NOx increase in exhaust gas If severe wear occurrs in cam and tappet Engine Fails

TMC ( Techno Material Corp.)

A case of failure - Tappet Pitting and Cam Scuffing

• High Hertzian Contact Stress• Adhesion of mating materials

TMC ( Techno Material Corp.)

Newly Designed Hard metal tappet - Characteristics I

• Simple Process– Low Sintering Temperature for WC Tip (1450 =>1050°C)– Direct Bonding of As-Received WC tip and Machined Body

• High Bonding Strength– Vacuum Atmosphere– High Wettability to Steel– Formation of Diffusion Layer

- Main composition : WC with Binder Alloy

– WC size : Average 1~5m Hardness : Above HRA 85 – Bending strength : Average 100

kgf/mm^2 (TRS)– Young’s modulus : 43,000 kg/mm^2– Thermal conductivity : 0.17 cal/cm

sec C (75W/mK)– Thermal expansion coefficient : 6 x

10-6/ C

TMC ( Techno Material Corp.)

Mass Production

Technical Alliance with the T.M.C, High Technology possession enterprise

There’s no Quality Problems in mass production of Hard Metal tappet for 5 years

38 @ 2000

240 @ 2300 90 @ 1200

H-Co 4 liter 4 140 @ 2900

8 LITER 6DAEWOO

CUSTOMER

8 LITER(Gas) 6 260 @ 2300 100 @ 1300

E/G Model Cylinder.no ISO PowerPS @ rpm

Torquekg.m @ rpm

12 LITER 6 340 @ 2100 145 @ 1260

▶CUSTOMER & SPECIFICATION OF ENGINE

▶ SUPPLY RECORD OF HARD METAL TAPPET(T.M.C)

TMC ( Techno Material Corp.)

Line contact, Reciprocal sliding with rolling.

Measure the rapid increase time of friction coefficient scuffing time

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0 1 2 3 4

Time (hr)

Friction c

oeffi

cie

nt

Scuffing occur

No Scuffing

Wear Test - Scuffing

TMC ( Techno Material Corp.)

Hard metal tappet have a longer scuffing time than Fe-alloy tappet

3 of 5 case of hard metal tappet have not scuffing during test

Hard metal tappet have a smaller friction coefficient than Fe-alloy tappet

Hard metal tappet have a better anti-scuffing characteristics than Fe-alloy tappet

Wear Test - Results

TMC ( Techno Material Corp.)

- Part test of engine, driven by electrical motor

- Performed 500 hours, at 2200 crankshaft RPM

- Contact stress of cam and tappet is higher than in a real engine

- 6 Fe-alloy tappets and 6 hard metal tappets are tested.

Rig Test(Motoring) - Pitting

- Fe alloy Tappets have pitting & all of them have not shown crowned shape

- Hard Metal tappets have no pitting & remain crowned shape

TMC ( Techno Material Corp.)

To test the Reliability of Engine parts

Engine Dynamo Test : 1,000 hour, 2200 RPM - Fe alloy tappets have pitting (2 of 6) & Not scuffing - Hard metal tappets have no pitting and no scuffing

Field Test : 100,000km- Bus and Truck mounting, Only hard metal tappet test.- No pitting and No scuffing- Crowned shape of tappet is remained.- The surface of Tappet and cam were fine-polished. - It means that it is possible to use the tappets again.

- There’s no wear problem after applying in the field for nearly 5 years

Dynamo Test & Field Test

TMC ( Techno Material Corp.)

Reliability of Tappet Bonding

Ultrasonic test of bonded parts

Last 3 years, mass production of Hard Metal tappet, There’s no apart of bonded part .

Quality assurance system of tappet produced, it has a reliabilities