• Print version

Integral cylinder pressure sensor cleans up diesel engines


The 2008 EUREKA Lillehammer Award went to a glow plug pressure sensor that can cut nitrogen oxide (NOx) and soot particle emissions from car diesel engines by up to 90%.

As a result of work in the EUREKA CYPRESS project, diesel cars can now meet new EU and US emissions standards with reduced need for excessively expensive NOx filters. The project received the Lillehammer Award for outstanding environmental benefits at the EUREKA Ministerial Conference in Ljubljana in June 2008.

Diesel cars are popular in Europe and around the world. But ever stricter emissions standards required more efficient control of fuel mixing and injection to optimise combustion. Development and integration of a piezo-resistive pressure sensor in the glow plug used to speed start up of the diesel engine has now made it possible to provide direct monitoring of combustion conditions in the cylinder. The resulting electrical output can be fed to the engine’s electronic control system to optimise operations, resulting in much lower emissions and better fuel consumption.

The new sensor had to be robust and reliable to withstand the harsh temperatures – up to 900°C – and vibration conditions found in the engine cylinder. “Combining the cylinder pressure sensor with the glow plug meant no significant change was necessary to the engine structure – and the glow function does not affect the measurement operation,” explains Dr Arjan Kölling of sensor manufacturer Sensata Technologies in the Netherlands and coordinator of the € 2.6 million, 27-month CYPRESS project. Moreover, the glow plug sensor unit is easy to design-in as a screw-in replacement for the existing glow plug.

This new cylinder pressure sensor is the first of its kind to be sufficiently reliable and economic for mass production. German project partner BERU has already started to manufacture and market pressure sensor glow plugs incorporating Sensata sensors at its Ludwigsburg headquarters. The first engines using these plugs are already being exported to the USA. And there is tremendous interest from European car manufacturers to incorporate these innovative products in their cars to meet forthcoming EURO 5 and EURO 6 emission standards.

More information:

The EUREKA Initiative: http://www.eureka.be

EUREKA E!3379 CYPRESS success story: http://www.eureka.be/files/:4841625

Sensata Technologies: http://www.sensata.com

Tougher exhaust regulations

Both the EU and the USA have been enforcing strict controls on diesel exhaust gas emissions since the 1970s, with ever tougher limits on carbon dioxide, hydrocarbons, NOx and particles. EURO 5 will limit NOx to 180 mg/km, while EURO 6 will cut levels to 80 mg/km. And in the USA, tightening of the Environmental Protection Agency regulations from BIN 8 to BIN 5 will cut NOx emissions from 125 mg/km to 44 mg/km. Therefore, alternative combustion strategies are required to improve fuel mixing and closed loop combustion control.

More information:

Euro 5 and Euro 6 standards: reduction of pollutant emissions from light vehicles:
Summary of legislation

US Tier 2 vehicle and gasoline sulphur programme: