This Rotary Valve allows the simple selection of exhaust gas from two separate location
- pre and post catalytic converter exhaust gas for example, so that either pre-treated
(engine-out) or post-treated (cat-out) gas can by analyzed. It makes use of 6MM
direct ports installed before and after the catalytic converter (See Bridge P/N
001212 6MM Hardseal Exhaust Port Maker Kit), and includes two 6MM adapters that
are installed in the ports, and connect by 90 degree swivel adapters to the braided
sample lines shown above. Ports 1 and 2 are active in the valve, leaving ports 3
and 4 for future expansion if multiple gas selection is desired. Generally Port
1 is used for Pre-Cat converter gas (engine-out exhaust gas) and Port 2 is connected
to the Post Cat-Converter port. By simply turning the valve handle, either gas sample
can be easily directed to the analyzer.
When Port 1 is selected, the analyzer will show engine-out gas readings, Lambda,
AFR, and Combustion Efficiency using a Model 9004 or 9005 EGA. When Port 2 is selected,
the effect of the cat converter on the engine-out gases can easily be seen, along
with the greatly increased Combustion Efficiency value. In addition, it is readily
seen that the Lambda and AFR values calculated by the gas analyzer are not effected
by the cat converter – a valuable instructional aid.
Using the gas reading changes between Port 1 and Port 2, the cat converter CO and
HC (Model 9004/9005) oxidation efficiency and NOx (Model 9005) reduction efficiency
can easily be determined. The oxidation efficiency of the cat converter can also
be easily seen in the improvement of the Combustion Efficiency (Model 9004/9005)
value. Further, off-stoichiometric operation (either rich or lean) can be shown,
as well as the effects this has on cat converter operation.
The combination of direct gas sampling from the pre and post cat converter locations
and the analysis capabilities of the Bridge Model 900403 and 900503 EGAs make a
powerful instructional tool to better understand the effects on the internal combustion
engine combustion process itself as well as its effects on post gas treatment in
the cat converter.
The Sampling Valve comes ready for use, with two 22 inch long braided flexible lines
going to 90 degree swivel fittings which attach to 6MM exhaust port thread adapters,
that screw into the exhaust gas ports installed in the exhaust system.
The Bridge exhaust analyzer probe attaches to the 90 Degree fitting above the valve
– a ½ turn quick release that matches the fitting on the end of the Probe S-Bend.
(The flexible tip is removed from the quick release fitting on the Bridge probe
S-bend.. See the picture below.)
This product uses a Teflon-sealed rotary valve that samples the port desired, and
closes the unused port automatically. Simply turning the valve handle to the port
desired allows only the exhaust from the selected port to enter the exhaust gas
analyzer.
The 2-port Manifold/Valve showing the standard Bridge probe attached. In the foreground
are 8 inch long gas cooling extensions (optional accessory P/N 000889) mounted to
the 90 degree swivel fittings/6MM exhaust header adapters that are inserted into
the threaded ports in the exhaust system.
P/N 000889 8 inch Stainless Steel Gas Cooling Extensions
These stainless steel extensions go between the high temperature flexible line and
the 90 Degree swivel fitting and provide an additional 8 inches of cooling before
the exhaust gas reaches the flexible lines. These extensions are intended to be
applied to systems which extend beyond the 44 inch capability of the standard system
or operate with the engine under load where exhaust gas temperatures may exceed
the 450 Degree F limit of the flexible lines.