WEICHAI & PSI SERVICE MANUALS AVAILABLE ONLINE AT FLYPARTSGUY.COM The sensor must not be exposed to strong mechanical shocks (e.g. while the sensor is installed). Otherwise the sensor element may crack without visible damage at the sensor housing. For physical reasons the sensor needs ambient air at its reference gas side. Replacement of the air volume inside the sensor must be guaranteed by a sufficient air permeability of the wires and the connectors between sensor and ECU. The breathability should be higher than 1 ml/minute at a test pressure of 100mbar. Underfloor installation of the sensor remote from the engine requires an additional check of the following points:
- Positioning of the sensor with respect to stone impact hazard. - Positioning and fixing of cable and connector with respect to mechanical damage, cable bending stress and thermal stress. The sensor cable must be routed so that it is free of bends, mechanical tension, and chafing points considering the movement of the exhaust system in relation to the vehicle body. The cable and connector should not be subjected to excessive temperatures that could cause damage. Additional instructions for the installation downstream the catalytic converter - Between catalyst and sensor location absolute gas tightness of the exhaust system must be ensured.
- When the sensor is installed in the exhaust pipe there should be no detachable connections between catalytic converter and sensor (e.g. flange, clamp-screw joint). - In order to protect the active sensor ceramic against condensation water from the exhaust gas side the sensor heater voltage must be power controlled after cold start of the engine. During the condensation water phase, the ceramic temperature should be kept at approx. 302degF ~572degF (150°C-300°C). The corresponding control parameter must be determined according to application. - The sensor should be mounted as close to the outlet of the catalytic converter as possible without exceeding sensor maximum temperatures.
- The sensor should be mounted as far from the exhaust pipe outlet as possible to avoid dilution from ambient air. Minimum distance between sensor and exhaust outlet should be 15.7 inches (400 mm). CATALYTIC CONVERTER A very important component in a low emission engine is the catalytic converter. Weichai Engines use a TWC converter. For this type of catalytic converter to work properly, the following two criteria must be met: - The air-to-fuel ratio must oscillate between rich and lean. - The catalyst substrate (also known as a “brick,” located inside the converter shell) must be kept hot.
Strict compliance with these provisions, conditions, and operating limits for catalytic converters must be maintained. If these parameters cannot be met or are not known, additional engineering and validation are required. WEICHAI EMISSION-RELATED INSTALLATION INSTRUCTIONS GET YOUR WEICHAI & AFTERMARKET SERVICE PARTS AT FLYPARTSGUY.COM