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The aggressive reduction of future diesel engine NOx emission limits forces the heavy- and light-duty diesel engine manufacturers to develop means to comply with stringent legislation. As a result, different exhaust emission control technologies applicable to NOx have been the subject of many investigations. One of these systems is the NOx adsorber catalyst, which has shown high NOx conversion rates during previous investigations with acceptable fuel consumption penalties. In addition, the NOx adsorber catalyst does not require a secondary on-board reductant. However, the NOx adsorber catalyst also represents the most sulfur sensitive emissions control device currently under investigation for advanced NOx control. To remove the sulfur introduced into the system through the diesel fuel and stored on the catalyst sites during operation, specific regeneration strategies and boundary conditions were investigated and developed.

While standardized laboratory-scale wear tests are available to predict the lubricity of liquid fuels under ambient conditions, the reality is that many injection systems operate at elevated temperatures where fuel vaporization is too excessive to perform the measure satisfactorily. The present paper describes a High Pressure High Frequency Reciprocating Rig (HPHFRR) purposely designed to evaluate fuel lubricity in a pressurized environment at temperatures of up to 300°C. The remaining test parameters are identical to those of the widely standardized High Frequency Reciprocating Rig (HFRR). Results obtained using the HPHFRR indicate that wear rate with poor lubricity fuels is strongly sensitive to both temperature and oxygen partial pressure and may be orders of magnitude higher than at ambient conditions. Surprisingly however, wear rate was found to decrease dramatically at temperatures above 100°C, possibly due to evaporation of dissolved moisture.