Abstract: The invention presented herein makes it possible to construct and operate an engine monitoring apparatus that calculates the engine speed, the engine load and/or engine monitoring quantities basically only from the measurement of an angular velocity curve at the gear rim of an internal combustion engine (optionally, from a plurality of angular velocity curves). The basis is thus simultaneously created for monitoring all other measured quantities within narrow limits that are dependent on load and speed. The invention can also be utilized for control purposes or for measuring power.