Internal combustion engine knock sensing method and system

US4478068A · kind A · utility

Assignee

• Robert Bosch GmbH · DE

Inventors

• Jorg Bonitz · Mühlacker, DE
• Robert Entenmann · Memmingen, DE
• Rochus Knab · Kornwestheim, DE
• Bernhard Miller · Weil der Stadt, DE
• Siegfried Rohde · Schwieberdingen, DE
• Herbert Schramm · Leonberg, DE
• Walter Viess · Schwieberdingen, DE

Key dates

• Filing date: Aug 23, 1982
• Grant date: Oct 23, 1984
• Expiry date: Aug 23, 2002

Classification

• Technology area (CPC G): Physics
• CPC primary: G01L23/225
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

To recognize knocking conditions in signals derived from a knock sensor, which signals representative of knocking may be masked by background or noise signals, and to clearly distinguish the knocking signal from background or noise signals, the knocking signals are integrated with respect to measuring or strobing intervals during a predetermined angle of crankshaft rotation, digitized in an A/D converter (7) and then compared in a comparator (9) with the same signals which have been passed through a low-pass digital filter (8) to compare the integrated, digitized signal of a then occurring combustion process or event with similar signals of prior combustion processes or events to thereby recognize and distinguish knocking signal conditions from noise signal conditions; digital filtering and comparison as well as sequence timing can be carried out in a single microprocessor (FIGS. 2:14), earlier combustion events being weighted in accordance with the remoteness of their occurrence and/or engine speed and engine loading, the reference signal, for example, being generated in accordance with the formula: EQU y(t.sub.i)=(1-k).y(t.sub.i-1)+kx(t.sub.i) wherein PA1 y(t.sub.i) is the refere…