New High-Temperature Sensors for Innovative Engine Management

Requirements on future vehicles are reduction of energy consumption and emissions. To fulfil these, an optimization of the combustion process including all relevant parameters is necessary and therefore parameter field based control systems have to be replaced by closed loop regulating circuits. To realize the latter in series applications, new types of sensors designed for high temperatures and harsh environments have to be developed. The present paper describes the development of a combustion pressure sensor based on cubic Silicon Carbide (β-SiC) layers on Silicon. Results of in-cylinder measurements will be given in comparison to a Kistler reference sensor. SiC technology based on the hexagonal 4H and 6H polytypes we are developing for integrated signal electronics. The latter is needed for smart sensors and independently operating modules, applied in harsh environments. JFET transistors, which are the basis for monolithic circuit design, will be described and I-V-characteristics measured at elevated temperatures up to 400°C will be given.