|
 Properties
and Advantages of Carbon Pistons compared to Pistons made out of
Aluminum Alloys used in different internal Combustion Engines
|
|
 Significant
reduction of exhaust emissions: HC > 40 %, CO > 50 %, NOX
> 12 %.
|
| Decrease
of fuel consumption of approximately 3 - 8 %. |
|
Reduction
of oil consumption of approximately 40 - 55 % |
|
Low
density: 1.70 - 2.20 g/cm3. Decrease of the piston weight by
10 - 20 %. Reduction of the acceleration of mass of 30 - 40 %. |
|
Low
coefficient of thermal expansion: 5 - 8 x 10-6/K;
a. t. to 450 °C. |
|
Very
small piston clearance, even at high thermal load |
|
Reduced
blow-by |
|
Increase
in compression by approximately 10 % |
|
Increased
mechanical strength at temperature rise: 2 - 5 % at 400 °C
90
- 110 MPa:
|
for low-loaded engines: small two-stroke and four-stroke
engines, e. g. lawn
mowers, chain saws, motorcycles, scooters, etc. |
|
110
- 130 MPa:
|
for medium loaded engines: four-stroke Otto and
Diesel engines, e. g. passenger
cars, motor cycles, boat engines, stationary engines. |
|
130
- 160 MPa:
|
for highly loaded engines: four-stroke Otto and
Diesel engines, e. g. with
turbo-supercharger and direct injection. |
|
|
Oxidation
resistance up to 600 °C: no burn-off, no coking at the surfaces
directed to the combustion. |
|
Constant
hardness of HRB = 90 - 125 within the entire temperature range. |
|
No
tribological changes at the piston surfaces, at the edges of the
grooves and at the area for the piston pin bores.
|
|
High
resistivity to wear at all tribologically active surfaces. |
|
Excellent
emergency-running properties: coefficient of friction lubricated
= 0.01 to 0.03, coefficient of friction, marginal lubrication =
0.04 to 0.07; no scoring, no seizing. |
|
Good
adhesion of lubrication oil to the surfaces.
|
|
High
dimensional stability: homogeneous distribution of compression
at the entire cylinder area; no slack in the area of the piston
rings. |
|
High
resistance to thermal shock and oscillating load. Remarkably low
Young's modulus, 8 to 15 Gpa,
prevents the generation of fatal thermal stresses. |
|
Thermal
conductivity: 35 - 120 W/mK: reduction of load on the piston rings and
lubrication oil. Ideal conditions for pistons with "insulating
effect", especially in Diesel engines. |
|
High
corrosion resistance: no deposits due to corrosive or
electrolytical processes at engine stop. |
|
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