Internal combustion engine combustion chamber pressure sensing apparatus

• Main Authors: SELLMAIER; FRANZ, BOENING; BERNWARD, BONE; RAINER, NAGEL; RUDOLF
• Format: Patent
• Language: English
• Published: 01.01.1985
• Edition: 3
• Subjects: BLASTING; COMBUSTION ENGINES; CONTROLLING COMBUSTION ENGINES; HEATING; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS; IGNITION, OTHER THAN COMPRESSION IGNITION, FORINTERNAL-COMBUSTION ENGINES; INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIRCHEMICAL OR PHYSICAL PROPERTIES; LIGHTING; MEASURING; MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER,MECHANICAL EFFICIENCY, OR FLUID PRESSURE; MECHANICAL ENGINEERING; PHYSICS; TESTING; TESTING OF IGNITION TIMING IN COMPRESSION-IGNITION ENGINES; WEAPONS

To obtain higher current yield from ion current measurable across the electrodes of a spark plug upon application of a biasing potential thereto, occurring immediately after an ignition event due to ionization of burning hydrocarbons within the combustion chamber of an internal combustion engine (ICE), the polarity of the circuit including a spark plug is so selected that the smaller one of the electrodes, typically the center electrode of the spark plug, has a positive measuring voltage and positive ignition voltage applied thereto so that the positively charged ions, which have a substantially greater mass than the electrons, will be caused to flow to the negatively charged substantially greater electrode, thus resulting in an enhanced ion current. A standard automotive ignition circuit can be used, with the battery connected, as customary, with negative-ground (FIG. 3) by reversely connecting the secondary of the ignition coils-with respect to customary connection-to the center electrode of the spark plug. An auxiliary biasing battery can be avoided by charging a capacitor, for example from the ignition system, to provide measuring energy.