Predicting Air Volume in Combustion Engine Load Changes

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Solution Overview

Problem

Conventional methods for determining air quantity in internal combustion engines, especially during load changes, suffer from delayed throttle valve adjustments, leading to reduced load change dynamics and inaccurate fuel metering, particularly in direct injection systems where air charge in the combustion chamber cannot be measured precisely before fuel injection.

Innovation Solution

A method that synchronizes the throttle valve setpoint signal with operating conditions, predicts air volume variables, and determines total air volume by combining actual and predicted values, allowing for accurate air quantity determination without delaying throttle valve actuation, thus enabling high load change dynamics without compromising fuel metering accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the throttle valve adjustment is delayed to determine filling influencing variables at the correct time, then the air quantity determination accuracy is improved, but the load change dynamics are reduced

Engineering Contradiction:
Improveair quantity determination accuracyVSAvoidload change dynamics
Core Design Contradiction:
Measurement precisionVSSpeed

Solution Approach 1:

The patent applies preliminary action by predicting the air charge in the combustion chamber before the actual injection timing. The prediction is based on synchronized throttle valve setpoint signals and operating condition criteria, allowing the air quantity to be determined in advance without delaying the throttle valve actuation. This enables accurate fuel metering while maintaining high load change dynamics.

Inventive Principle:
Principle #10Preliminary action

2Measurement precision

If the throttle valve setpoint signal is synchronized with operating conditions, then the air quantity determination is improved, but the system complexity increases

Engineering Contradiction:
Improveair quantity determinationVSAvoidcontrol system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies dynamics by synchronizing the throttle valve setpoint signal with operating condition criteria based on the actual engine operating state. The synchronization adapts dynamically to changing conditions, allowing the system to maintain accuracy without requiring overly complex static control structures. The controller adjusts the synchronization based on real-time operating parameters.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3376008B1Combustion engine and method for determining a volume of air in a combustion chamber of a combustion engine
Publication Date: 2021.05.12 VOLKSWAGEN AG
  • EP3376008B1 patent drawingFigure 1~2
  • EP3376008B1 patent drawingFigure 3~4
  • EP3376008B1 patent drawingFigure 5~6

AI summary

The present invention relates to a method for determining an air quantity in a combustion chamber (3) of an internal combustion engine (100) with fuel injection, in particular in a load-change operating condition, comprising synchronizing a throttle valve setpoint signal (25, 26) with an operating condition criterion (tn), determining a progression dynamic (28) of the throttle valve position taking into account the synchronized throttle valve setpoint signal (26), determining an actual air quantity (34) at an actual time (t0), determining a target time (t0+Δt), predicting a further air quantity (35) for the target time (t0+Δt) and determining a total air quantity (33) from the actual air quantity (34) and the further air quantity (35) for the target time (t0+Δt).