**Friction**

146 Tribology in Engineering

[19] Rudnick LR. Automotives Gear Lubricants, Synthetics, mineral oils, and bio-based

lubricants: chemistry and technology. Taylor and Francis, Florida; 2006.

**Chapter 0**

**Chapter 9**

**Friction in Automotive Engines**

H. Allmaier, C. Priestner, D.E. Sander and F.M. Reich

Additional information is available at the end of the chapter

The current situation of the automotive industry is a challenging one. On one hand, the ongoing trend to more luxury cars brings more and more benefits to the customer and is certainly also an important selling point. The same applies to the increased safety levels modern cars have to provide. However, both of these benefits come with a severe inherent drawback and that is extra weight and, consequently, higher fuel consumption. On the other hand, increased fuel consumption is not only a disadvantage due to the ever rising fuel costs and the corresponding customer demand for more efficient cars. Due to the corresponding greenhouse gas emissions it is also in the focus of the legislation in many countries. Commonly road transport is estimated [13, 15] to cause about 75-89 % of the total CO2 emissions within the world's transportation sector and for about 20% of the global primary energy consumption [12]. These values do not stay constant; in the time from 1990 to 2005, the required energy for transportation increased by 37% [11] and further increases are expected due to the evolving markets in the developing countries. As industrial emissions decrease, the rising energy demand in the transport sector is expected to be the major problem to achieve a significant greenhouse gas reduction [26]. Consequently, about all major automotive markets introduce increasingly strict emission limits like the national fuel economy program implemented in the CAFE regulations in the US, the EURO regulation in

In particular, the European union introduced a limit for the average CO2 emissions for all cars to be available on the European market of 130 g CO2/km by 20151. Further, a long term target of 95 g CO2/km was specified for 2020 [6]. To put this into perspective, the average fleet consumption in 2007 was 158 g CO2/km and it had taken already about 10 years to get down to this value from the 180 g CO2/km that were achieved in 1998. Now a larger reduction is required in less time. The required reduction of emissions brings also a direct benefit for the customer as the fuel consumption is lowered. It is estimated [11] that the

<sup>1</sup> The limit applies to the average fleet consumption of every car manufacturer, calculated by averaging the fuel

©2013 Allmaier et al., licensee InTech. This is an open access chapter distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0),which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly

©2013 Allmaier et al., licensee InTech. This is a paper distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

consumption of all offered car models and weighted by the number of sold units of the specific models.

http://dx.doi.org/10.5772/51568

the European Union or the FES in China.

cited.

**1. Introduction**
