Lambda Sensor Humidity Compensation for Diesel Hybrid Engines
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Solution Overview
Problem
Existing methods for determining the lambda value in internal combustion engines fail to accurately account for rapid changes in humidity, leading to measurement errors and the need for frequent thrust comparisons, which is impractical in vehicles like diesel hybrids with infrequent thrust operations.
Innovation Solution
The method involves using a humidity sensor to adjust the lambda value calculation, eliminating the need for humidity-dependent correction factors and enabling effective compensation for humidity changes, allowing for precise lambda value determination even during rapid humidity fluctuations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If thrust comparison is used to correct lambda sensor measurements, then measurement precision is improved, but the method becomes impractical for vehicles with infrequent thrust operations
Solution Approach 1:
The patent introduces an air humidity sensor as an intermediary device to measure humidity independently. This mediator provides the necessary environmental data without requiring thrust comparison operations, thus resolving the contradiction by enabling precise lambda measurements through a different measurement pathway that is always available in diesel hybrid vehicles.
Solution Approach 2:
The patent replaces the mechanical thrust comparison method (which requires specific engine operating conditions) with an electronic sensing approach using a humidity sensor. This substitution allows continuous humidity measurement regardless of engine load or thrust operation status, making the system practical for diesel hybrid vehicles while maintaining measurement precision.
2Measurement precision
If humidity-dependent correction factors are applied to lambda calculations, then measurement precision improves, but device complexity increases
Solution Approach 1:
The patent extracts the humidity measurement function from the complex thrust comparison correction system. By separating humidity sensing into its own independent measurement channel using a dedicated humidity sensor, the system simplifies the overall architecture while maintaining the ability to apply humidity-dependent corrections to lambda calculations.
3Measurement precision
If frequent thrust comparisons are performed to maintain accuracy, then lambda value precision is improved, but loss of time and operational efficiency worsen
Solution Approach 1:
The patent enables continuous humidity measurement through the humidity sensor, which operates independently of engine thrust cycles. This continuous measurement capability eliminates the need for periodic thrust comparisons, maintaining lambda value precision without the time losses associated with frequent comparison operations.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach ensures precise lambda value calculation, reducing the influence of humidity variations and eliminating the requirement for frequent thrust comparisons, thus improving engine control accuracy and efficiency, especially in diesel hybrid vehicles during coasting modes.
Implementation Method 1
a humidity sensor (200) is provided that supplies a measurement value (wmessakt) for a current water vapor volume concentration wmessakt in the intake air
Implementation Method 2
The sensor is used to determine the oxygen concentration in the exhaust gases of internal combustion engines... The Nernst cell is connected to the control device via clamps that belong to the measurement electrode and to the reference electrode. Between these clamps, a Nernst voltage can be picked off that is a function of the ratio of the oxygen concentrations
Implementation Method 3
the sensor has a measurement, or Nernst, cell, having a measurement electrode and a reference electrode that are situated on a solid electrolyte, and has a pump cell having an outer electrode and an inner electrode
Data Source
AI summary
In a method for determining the lambda value with a broadband lambda sensor of an internal combustion engine, a measurement current is supplied by the lambda sensor, which measurement current is proportional to the oxygen content or rich gas content in the exhaust gas of the internal combustion engine, and the corresponding proportionality factor is determined by a thrust comparison. The thrust comparison uses the O2 concentration of dry air as reference, independent of an actually present air humidity, and the lambda value is calculated on the basis of a modified Pischinger conversion equation in which a signal supplied by a humidity sensor is taken into account.