The GPPS offers Siemens VDO's customers a simple in-cylinder solution to help significantly reduce oxides of nitrogen (NOx) and particulate emissions by integrating key functions into the same compact space. The sensor, integrated into the glow plug due to lack of room in the cylinder chamber, measures combustion inside the engine. The pressure-sensing glow plug provides feedback to the engine-management system, which controls the timing and quantity of fuel injected into the cylinder to stabilize combustion temperatures, allowing the engine to adjust injection characteristics to avoid combustion conditions producing high NOx levels.
The GPPS also eliminates the need for the customer to redesign the engine because the sensor is integrated into the glow plug. As global emissions standards become stricter, the GPPS engine technology also provides a solution to significantly reduce the cost, weight, and packaging of diesel after-treatment solutions.
"The use of diesel is increasingly being viewed as a conservation technology to reduce the nation's oil consumption as clean diesel vehicles are 20 to 40 percent more fuel-efficient and emit 10 to 20 percent less greenhouse gas than their gasoline counterparts," said Siemens VDO Sensors Division General Manager Bret Sauerwein. "However, new legislation norms in both the U.S. and Europe set extremely low emission targets for the future diesel engine."
Achieving low combustion temperatures in the cylinder is key to lowering NOx emissions because raw NOx is primarily emitted at the engine's peak combustion temperature and pressure. Siemens VDO has been working on a solution to this challenge with Federal-Mogul Corp. since 2003 and has brought the GPPS to maturity, which is scheduled for production in 2008.
At the center of the GPPS sensing element is a disk made of polycrystalline piezo ceramic mounted in the glow plug structure between two isolating washers. During the combustion process, the pressure increase applies a force onto the glow plug, and its degree of structural change is passed on along an optimized stress transfer path and onto the piezoelectric element. The degree of force applied to the glow plug is captured by the piezo element and processed to deliver an accurate electronic measurement of cylinder pressure in the engine's combustion stroke.
Siemens VDO also offers a Stand Alone Pressure Sensor (SAPS) based on the same principles of the GPPS and will be available without the glowing feature for heavy duty or stationary engine applications.
Siemens VDO is a tier-one supplier of automotive electronic/electrical systems and components with applications covering gasoline and diesel powertrain technologies, safety and chassis systems, body electronics, and interior products, including infotainment systems. Worldwide sales reflecting fiscal year 2005 totaled $11.3 billion (euro 9.6 billion).
Siemens AG is one of the largest global electronics and engineering companies with reported worldwide sales of $96 billion in fiscal 2005. Founded nearly 160 years ago, the company is a leader in the areas of medical, power, automation and control, transportation, information and communications, lighting, building technologies, water technologies and services, and home appliances.
In the U.S., Siemens has sales of $18.8 billion and employs approximately 70,000 people throughout all 50 states and Puerto Rico. Eleven of Siemens' worldwide businesses are based in the U.S. With its global headquarters in Munich, Siemens AG and its subsidiaries employ 460,000 people in 190 countries. For more information on Siemens in the United States: http://www.usa.siemens.com.