74-5 DWP
Evaluation of the Stone Industrial
Corporation Copper-Plated
Combustion Chamber Concept
July 1973
Emission Control Technology Division
Office of Air and Water Programs
Environmental Protection Agency
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Background
Stone Industrial Corporation of College Park, Maryland, has
had a long-term development project related to a copper-plated
combustion chamber concept for reciprocating internal combustion
engines. A majority of their experience with this concept has
been with Diesel engines. Their work has shown reduction in
Diesel smoke levels and some improvement in fuel economy. As
an extension of this effort and to investigate the effect of
their copper-plated combustion chamber concept in a light duty
automotive application, Stone prepared two gasoline-powered
vehicles. The Emission Control Technology Division was contacted
by Stone in regard to conducting confirmatory testing on these
vehicles. Emissions data from these vehicles presented by
Stone demonstrated the potential of achieving low levels of
all three emissions. Thus, test work was undertaken by the
Test and Evaluation Branch.
Device Description
Stone's concept involves plating of the piston crowns, valve
faces, and cylinder head area exposed to the combustion chamber
with a layer of copper on the order of one and one-half
thousandths of an inch in thickness. Stone claims that the
cuprous oxide film that develops on these surfaces helps to
conserve and uniformly distribute heat within the combustion
volume. This claim can be supported by the high reflectivity
level of cuprous oxide in the infrared range (i.e., greater than
75% for wave lengths between 0.7 and 10.0 microns). In
addition, cuprous oxide has a low level of thermal conductivity.
Two cars with the copper-plated combustion chambers were tested.
One vehicle was a 1971 Ford Torino with a high compression
ratio 351 CID engine. 50,000 miles had been accumulated on
this vehicle with the modified combustion chamber. The other
was a 1972 Ford Torino with a low compression ratio 351 CID
engine. 18,000 miles had been accumulated on this vehicle with
the modified combustion chamber. In addition to the plated
combustion chamber, both vehicles were modified as follows:
a) modified spark timing
b) provisions for lean carburetion
c) restricted choke action
d) deceleration air bleed
Attached is a more detailed description, prepared by Stone,
of these modifications.
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Test Program
Three tests were conducted on each car in accordance with the
1975 Federal Test Procedure (FTP) as described in the November 15,
1972, Federal Register. All test work was conducted at 4000 Ibs.
inertia weight.
Results
The results from the tests are reported in the attached table.
These results demonstrate that emission levels below 1975 interim
standards can be achieved with this system. Good fuel economy
was demonstrated during this testing. General impression of
vehicle driveability was acceptable.
Conclusions
Stone Industrial Corporation's copper-plated combustion chamber
concept with lean carburetion and spark timing modifications
demonstrated the potential for achieving emission levels below
1975 interim standards. These vehicles, as equipped, also
demonstrated good fuel economy with acceptable driveability.
These vehicles did not, however, meet either the statutory 1975
or 1976 emission standards.
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STCbiK TU.'.'ING MODIFICATION'S
The 1972 low compression 351 Cleveland Engine is equipped with a 12127
Motoi'craft Distributor with a 73F134 vacuum retard especially made for Stone
:', I, 1> by Ford Motor Co.-npany. The centrifugal weights have been changed to give
:m .idv.-mce of 28° B'i'DC on acceleration, to caintain a 14° of advance at 2000 KPM
cruising, and then to have a full retard on deceleration. The distributor is set
up with a dwell of 29° + 2° at any range. The basic timing is 10° BTDC, in gear
with vacuum disconnected and plugged, engine running at 640 RPM.
The carburetor is a 1971 Hotorcraft, four barrel, D10FAAA. The main jets
have been switched from No. 62's to 58's. The power valve is modified to open
only when manifold vacuum is 7" Jig. or below. The accelerator pump is re-
adjusted to give 1/3 of the punp stroke. An anti-stall dash pot is used to
catch the .throttle on deceleration so that the throttle plates do not close
completely for approximately 8 seconds.
The choke is set very lean to hold the action time down on a cold start.
Added to the carburetor are two tubes at the vent holes and connected to
a carbon canister to prevent fuel vapor boil over when the engine is shut off
hot.
Under the carburetor we are using cylindrical, two ply screens, closed at
the bottom, made of copper, for better vaporization of the fuel. This lets us
run lean at idle and without misfire, and then a hot idle compensator is added
to the carburetor.
The PVC valve is modified so that it doesn't close completely at any
vacuum, but allows the naxinum air in on deceleration.
The 1971 hish compression 351 Cleveland Engine is equipped with a 12127
Hotorcraft Distributor with a 73F134 vacuum retard especially made for Stone
R & D by Ford Motor Company. The distributor is set to give an 18° B'i'DC
advance on acceleration and 12° BTDC at Steady State 50 MPH 2200 RPM. The
basic timing is 6° BTDC, all vacuum lines disconnected and an idle speed
of 680 RPM.
With the retard line connected we have a timing of 10° ATDC, and 640 RPM.
The carburetor is a 1971 Hotorcraft, four barrel, D10FAAA. The main jets
have been switched from 62's to 55's. The power valve is modified to open
only when manifold vacuum is 7" Hg. or below. The accelerator pump is re-
adjusted to give 1/3 of the pump stroke. An anti-stall dash pot is used to
catch the throttle on deceleration so that the throttle plates do not close
completely for approximately 8 seconds.
The choke is set very lean to hold the action time down on a cold start.
Added to the carburetor are two tubes at the vent holes and connected to
a carbon canister to prevent fuel vapor boil over when the engine is shut off
hot.
Under the carburetor we are using cylindrical, two ply screen, closed at
the bottom, made of copper for better vaporization of the fuel. This lets us
run lean at idle without misfire, and then a hot idle compensator is added to
the carburetor.
The PVC valve is modified so that it doesn't close completely at any
vacuum, but allows the maximum air in on deceleration.
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1975 FTP Results and Fuel Economy
Low Compression Ratio
Standard
Standard
Test
Test
Test
Avg.
Test
Test
Test
Avg.
:rim
:utor)
HC
gm/mi
1 1.53
2 1.37
3 1.18
1.36
HC
gm/mi
1 1.04
2 1.03
3 1.04
1.04
1.5
T
0.4
CO
gm/mi
12.79
13.13
11.77
12.56
High
CO
gm/mi
9.31
9.72
9.63
9.55
15.0
3.4
NOx
gm/mi
2.19
2.12
2.30
2.20
C02
gm/mi
847.07
799.97
779.78
808.94
Fuel Consumption
mpg (carb. bal.)
10.35
10.88
11.14
10.79
Compression Ratio
NOx
gm/mi
2.30
2.31
2.49
2.37
3.1
0.40
C02
gm/mi
772.06
771.96
768.01
770.68
...
Fuel Consumption
mpg (carb. bal.)
11.38
11.37
11.39
11.38
...
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