Internal combustion engine knocking sensing and recognition system

US4467634A · kind A · utility

Assignee

• Robert Bosch GmbH · DE

Inventors

• Siegfried Rohde · Schwieberdingen, DE
• Jorg Bonitz · Mühlacker, DE
• Robert Entenmann · Memmingen, DE
• Rochus Knab · Kornwestheim, DE
• Herbert Schramm · Leonberg, DE

Key dates

• Filing date: Jul 12, 1982
• Grant date: Aug 28, 1984
• Expiry date: Jul 12, 2002

Classification

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

Abstract

A knocking sensor (10) which provides output signals representative of combustion condition under knocking to thereby generate knocking signals which have mixed therewith noise or stray interference signals, and which also furnishes noise or stray interference signals under other than knocking combustion conditions, has its output connected to a plurality of parallel connected selective filters (2, 3). The filters have different pass band frequencies. One of the filters (3) is tuned to sense knocking frequencies, one or more other filters (2) being tuned to preferentially select noise or interference signals. A selection and discriminating circuit (10) having comparators (11) is provided connected to the filters to eliminate noise signals by comparing the signal level of the output received from the filters with a reference, which may be a dynamic reference, the outputs from the discriminators being processed in a logic circuit (15) to provide output signals (18) if (1) the filtered signal having the frequencies expected upon knocking exceeds a threshold level and (2) the filtered signal having the frequency band of the stray, or noise signals is below a threshold level and, prefer…