NewsTech News

The systems approach Electrical systems and circuits

What is a system?

System is a word used to describe a collection of related components, which interact as a whole. A motorway system, the education system or computer systems, are three varied examples. A

One further definition of a system: ‘A group of devices serving a common purpose’. Using the systems approach helps to split extremely complex technical entities into more manageable parts. It is important to note however, that the links between the smaller parts and the boundaries around them are also very important. System boundaries will also overlap in many cases.

Splitting the vehicle into systems is not an easy task because it can be done in many different ways. From the viewpoint of this book a split between mechanical systems and electrical systems would seem a good start. This division though, can cause as many problems as it solves.

For example, in which half do we put anti-lock brakes, mechanical or electrical? The answer is of course both! However, even with this problem it still makes it easier to be able to consider just one area of the vehicle and not have to try to comprehend the whole. Most of the chapters in this book are major sub-systems of the vehicle and, indeed, the sub-headings are further divisions.

Vehicle systems

Splitting the vehicle into systems is not an easy task because it can be done in many different ways. From the viewpoint of this book a split between mechanical systems and electrical systems would seem a good start. This division though, can cause as many problems as it solves. For example, in which half do we put anti-lock brakes, mechanical or electrical?

The answer is of course both! However, even with this problem it still makes it easier to be able to consider just one area of the vehicle and not have to try to comprehend the whole. Most of the chapters in this book are major sub-systems of the vehicle and, indeed, the sub-headings are further divisions.

Open loop systems

An open loop system is designed to give the required output whenever a given input is applied. A good example of an open loop vehicle system would be the headlights. With the given input of the switch being operated, the output required is that the headlights will be illuminated.

This can be taken further by saying that an input is also required from the battery and a further input of, say, the dip switch. The feature that determines that a system is open loop, is that no feedback is required for the system to operate.

Closed loop systems

A closed loop system is identified by a feedback loop. It can be described as a system where there is a possibility of applying corrective measures if the output is not quite what is desired. A good example of this in a vehicle is an automatic temperature control system.

The interior temperature of the vehicle is determined by the output from the heater, which is switched on or off in response to a signal from a temperature sensor inside the cabin. The feedback loop is due to the fact that the output from the system, temperature, is also an input to the system.

Summary

Many complex vehicle systems are represented in this book as block diagrams. In this way several nputs can be shown supplying information to an ECU which, in turn, controls the system outputs.

Related Articles

Leave a Reply

Your email address will not be published.

Back to top button