| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for recalibrating an offset of an onboard NOX sensor without the danger of an early decrease of a power of an onboard battery and of igniting a fuel remaining unburnt in a gas exhaust system. SOLUTION: When supply of a fuel into a combustion chamber of a driving automobile engine 10 is stopped, an oxygen concentration in an exhaust gas discharged to a gas exhaust system 102 becomes not smaller than 20%. An output voltage of an onboard NOX sensor 10 when this state is maintained for 0.5 second or more, preferably one second or more, more preferably 2 seconds or more is made an output voltage of 'NOX concentration = 0'. |
