Process for determining and evaluating the combustion pressure of an internal combustion engine

US5020360A · kind A · utility

Assignee

• Robert Bosch GmbH · DE

Inventors

• Thomas Brosi · Murrhardt, DE
• Werner Hess · Stuttgart, DE
• Winfried Moser · Ludwigsburg, DE
• Hermann Schneider · Schweich, DE

Key dates

• Filing date: Apr 27, 1990
• Grant date: Jun 4, 1991
• Expiry date: Apr 27, 2010

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y02T10/40
• WIPO field: Engines, pumps, turbines
• WIPO sector: Mechanical engineering

Abstract

A process for determining the combustion pressure of an internal combustion engine is proposed. Conventional processes of this type have the disadvantage that the determination methods are very costly. Furthermore, stringent requirements are made of the sensors to be used. By comparison, the process proposed here is distinguished in that the combustion pressure is calculated from the combustion chamber pressure (p(.alpha.)) determined with simple sensors, by determining the compression pressure (p.sub.k (.alpha.)). These values for the compression pressure are subtracted from the combustion chamber pressure in order to calculate the combustion pressure p*(.alpha.)). Preferably, the course of the compression pressure is obtained by measuring the combustion chamber pressure values during the compression until top dead center in the working phase and storing them in a memory. The compression values occurring after top dead center are obtained by reflection at an axis extending through top dead center, resulting in a symmetrical curve course for the compression pressure. In this way, the combustion pressure can be calculated particularly simply.