Guys, the engine will not operate as a standard engine does, it will operate as a generator. Generator maintenance intervals are at set number of operating hours.
Can't say what the interval would be, but it may be something like every 1000 hours. It will have nothing to do with miles driven.
"The balance of power is the scale of peace. The same balance would be preserved were all the world destitute of arms, for all would be alike; but since some will not, others dare not lay them aside. Horrid mischief would ensue were one half the world deprived of the use of them; the weak would become a prey to the strong." -Thomas Paine