A system for measuring in-cylinder parameters utilizing an image charge measured in an engine cylinder by an in-cylinder pressure sensor due to chemi and or thermal ionization in Engine. The in-cylinder pressure sensor includes a sensing element, which is a metal sensor probe with a selective coating (e.g., metal, oxides of metal, native oxides, semiconductor, oxides of semiconductors, ceramics, glass, dielectric, etc., in the form of a coating on the metallic probe, tube, etc) in order to function in harsh, corrosive and/or elevated temperature environments. The output of the sensor can be connected to a signal-conditioning unit, which includes a low noise differential charge amplifier with an auto offset correction circuit to measure fast varying signals. The signal out from the conditioning unit can be acquired utilizing a high-speed microcontroller-based data acquisition system with suitable software to analyze and estimate parameters such as, for example, in cylinder pressure and knocking.