Particulates in the trap are ignited and burnt off by exhaust gas {TAIL ~ whose temperature} has been raised by {HEAD ~ the electric heater} 
Particulates in the trap are ignited and burnt off by exhaust gas { TAIL ~ whose temperature } has been raised by { HEAD ~ the electric heater }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD