ETS Solenoid (Energize To Stop)
An ETS type fuel solenoid is de-energised in normal operation; to stop the engine it is energised briefly and fuel is cut. Because it does not draw current continuously its consumption is low, but the engine does not stop by itself on loss of supply or a broken wire. For this reason it requires an extra measure in the safety chain.
ETS solenoids are typically driven with a pulse of a few seconds; if left energised continuously the coil heats up and can burn out. For this reason a time relay, or a contact that senses that the engine has stopped and cuts the power, is usually added to the shutdown circuit.
- Advantage: it draws no current while running and creates no battery load in long-duration operation.
- Risk: since energy is needed for the stop command, the engine cannot be stopped when the battery is flat or a wire breaks. In that case a mechanical stop lever or an air shut-off valve is the only remedy.
In emergency stop design this distinction is decisive: in a system using ETS, the emergency stop button does not break the line, on the contrary it must apply power to the solenoid. The electronic throttle kit is not part of this chain; the GS740 and GS740-3P drive throttle position and do not intervene in the fuel shut-off circuit.
Context in which this term is used: Electronic speed and throttle control on a diesel engine