Understanding how engine speed is controlled in off-highway diesel engines is important. It’s the basis for our perception of an engine’s performance — whether it comes from objective assessment or subjective judgement. James Read, Perkins business development engineer, takes a close-up look at the separate elements that contribute to our view of an engine’s performance.
The engine is an integral part of the machine it powers. The operator depends on an engine’s ability to start and restart in all conditions, from very cold to very hot, to maintain speed under load, and to stop when it is turned off.
Starting and reaching its operating speed is the primary functional objective of an engine. The operator depends on the engine’s ability to start and restart in a reasonable time in all conditions.
In off-highway machines, the operator makes a speed demand and then loads up the engine through the operation of the machine. The engine has a ’speed governor’ that maintains engine speed under this varying load.
In highest regulated territories, electronic engine control is required to achieve the emissions standard. However, electronic engine speed control is available for lesser regulated engines and provides a number of benefits.
The ability of an engine to accept load and maintain engine speed is a function of both the engine and the machine. Maintaining speed under load affects productivity and leads to a perception of the capability of the machine and engine power.
When an engine runs at any speed under no applied load, we say the engine is at idle, or idling. While idling, an engine burns fuel, makes noise and wears. Automated speed control strategies are designed to reduce idling time.