This may be achieved by pre drying means, such as a pump to provide a stream of {TAIL ~ air} after switch off of the engine, which air may be heated by residual heat from {HEAD ~ the catalyst} or engine 
This may be achieved by pre drying means , such as a pump to provide a stream of { TAIL ~ air } after switch off of the engine , which air may be heated by residual heat from { HEAD ~ the catalyst } or engine
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH