The effective braking cycle on most internal engine compression brakes fitted to hydromechanical engines is actuated by using which of the following?

The effective braking cycle on most internal engine compression brakes fitted to hydromechanical engines is typically actuated using an electric over hydraulic system. This system utilizes an electric signal to control hydraulic pressure, which in turn activates the engine compression brake.

In these setups, when the driver activates the compression brake, the electric signal engages the hydraulic system to amplify the force applied by the engine's compression. This effectively increases the braking power by allowing the engine's compression to be used as an additional braking source.

Electric over hydraulic systems are advantageous because they provide quick and reliable response times, which are crucial for effective braking. The hydraulic fluid handles the high pressures involved in braking applications, while the electric control offers precision and ease of integration with other vehicle systems.