Engine Crank Sensor Simulator

The above image shows the Daqarta Generator running the included CrankFM.GEN setup to simulate the output from an engine crank position sensor, for testing an Electronic Control Unit (ECU) or Module (ECM) without an engine present.

This setup smoothly cycles the simulated engine speed back and forth between 600 and 6000 RPM. The image shows the output waveform near the high end of that range; the speed is shown via the RPM mode readout on the Frequency Counter at the bottom of the image.

The CrankFM.GEN setup uses the included Crank25-1.DQA file as an Arb wave to simulate a crank sensor gear having 25 tooth positions, with one of them empty as a reference. Creating Pulse-Train Arbs has complete instructions for creating this and other tooth patterns.

This simulation uses a trick to allow the trace to synchronize to the crank reference: The first pulse after the gap is made slightly taller than the rest, and the Trigger Level (horizontal blue line near the top of the trace) is set to catch this pulse but miss the rest.

Without this trick, each trace update would sync to whatever pulse from the stream happened to arrive next, and the reference gap would roll arbitrarily across the trace. (The ECU wouldn't care, but it would be hard on the eyes. The Frequency Counter could still read the correct RPM, by setting the Cylinders control to twice the number of actual teeth present on the gear, not counting any missing teeth.)

The Engine Crank/Cam Sensor Simulator topic discusses how the CrankFM.GEN setup was created, and how to use it. It also discusses how to create defined test schedules, such as the included CrankRamp.GEN that accelerates linearly to a selected speed, holds for a selected time, and then proceeds to accelerate or decelerate to the next speed in the test sequence.