control-systems-principles.co.uk.
Engine Speed Control
ENGINE SPEED CONTROL
Peter Wellstead and Mark Readman, control systems principles.co.uk
ABSTRACT: This is one of a series of white papers on systems modelling, analysis and
control, prepared by Control Systems Principles.co.uk to give insights into important
principles and processes in control. In control systems there are a number of generic
systems and methods which are encountered in all areas of industry and technology. These
white papers aim to explain these important systems and methods in straightforward terms.
The white papers describe what makes a particular type of system/method important, how
it works and then demonstrates how to control it. The control demonstrations are performed
using models of real systems that Control Systems Principles partners designed to teach
control ideas and that are now manufactured by TQ Education and Training Ltd in their CE
range of equipment. This white paper is about one of the most historically important control
problems - engine speed control and regulation.
1. Why is Engine Speed Control Important?
1.1. Some History
The speed control of engines is intimately associated with the origins of control theory. There are many
examples in the ancient times [1] of devices that could be said to incorporate feedback or regulation, and
most basic control textbooks [e.g.2] will have some discussion of the ancient origins of feedback
mechanisms. However, for the true beginnings of modern feedback control analysis we must look to the
practical problem of regulating the speed of engines and the centifugal governor (Figure 1).
Figure 1. A Simple Centrifugal Speed Governor.
In the beginning of mechanisation, the engine power was supplied by water wheels and wind mills – but
the really big change occurred when the steam engine arrived in the early 18th century. The development
of the steam engine in a useful form was crucial to the success of the Industrial Revolution. Equal