Governmental organisations in Europe, USA and Japan have, for many years, imposed regulations reflecting increasingly strict exhaust-gas emission limits for new vehicles. These regulations currently define the limits, at least in outline form, for vehicles produced as far ahead as 2012.
In response, engine manufacturers are rapidly developing new technologies. In passenger car diesel (PCD) applications this has primarily meant improvements in combustion through turbo-charging, intercooling and higher fuel injection pressures. In passenger car gasoline (PCG) applications, this has seen the introduction of direct injection gasoline (DiG) technology, variable valve actuation (VVA) and increasing use of exhaust gas recirculation (EGR). In addition to such fundamental improvements in engine technology, both gasoline and diesel engine manufacturers are likely to rely on increasing use of exhaust after-treatment devices.
Historically, engine oils have been shown to poison after-treatment devices, reducing their efficiency. This necessitates reformulation of the lubricant whilst seeking to maintain or improve performance levels.
This paper outlines the major changes in passenger car emission limits, some of the key developments in engine technology to meet those limits and their effects on lubricant technology.