Vehicle Powertrain Systems

Chapter 1

Vehicle Powertrain Concepts

1.1 Powertrain Systems

Over the past 100 years, vehicles have changed our lives; they have provided mobility which we exploit in all our commercial activities around the globe and they have also provided millions of us with new opportunities afforded by personal transportation. At the very heart of vehicle design is the powertrain system; it is the engineering of the powertrain system which provides the driving force behind the mobility.

The output from the power source – to date, dominated by the internal combustion (IC) engine – is controlled by a transmission system and driveline to deliver tractive effort to the wheels. And all these components, collectively referred to as the powertrain system, are controlled by the driver. Drivers, who are also viewed as discerning customers by the vehicle manufacturers, have a range of performance criteria: acceleration, top speed, fuel economy, gradeability, and towing capacity are some of the more obvious quantitative features. But subjective judgements such as driveability, fun to drive, refinement and driving pleasure play a huge part in the commercial success of vehicles. On the other hand, society imposes different performance demands – with a huge recent emphasis on emissions and CO₂ usage of vehicles. And governments have gone as far as imposing overall emissions control targets on manufacturers' fleets of vehicles.

In order to meet all these conflicting demands, engineers must master the complete ...