Intake-Air Temperature Correction with Dynamic Time Constant
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional intake-air physical quantity measurement apparatuses face issues with excessive correction of intake-air temperature detection signals due to heat transfer from integrated heaters and ambient EMC noise, leading to inaccurate temperature measurements and complex control structures.
Innovation Solution
An internal-combustion-engine control apparatus with an intake-air-temperature correction control system that includes a first-order advance compensation mechanism, time constant determination, and delay compensation to correct intake-air temperature signals, using a time constant selection process based on intake-air flow rate signals to suppress excessive corrections and maintain signal accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If first-order advance compensation is applied to improve responsiveness of intake-air temperature detection, then measurement accuracy is improved, but excessive correction occurs due to ambient environment and EMC noise
Solution Approach 1:
The patent applies dynamic gain adjustment to the first-order advance compensation filter, where the gain is varied based on the detected intake-air flow rate. When intake-air flow rate is high, a larger gain is applied to improve responsiveness; when intake-air flow rate is low, a smaller gain is applied to suppress excessive correction from noise and ambient effects. This dynamic adaptation resolves the contradiction between measurement precision and reliability.
2Volume of moving object
If integrated substrate is used to downsize measurement apparatus, then device size is reduced, but heat capacity increases causing detection delay
Solution Approach 1:
The patent applies first-order advance compensation (predictive filtering) to the intake-air temperature detection signal. This preliminary action anticipates future temperature values based on past and present measurements, effectively compensating for the detection delay caused by the heat capacity of the integrated substrate. The compensation filter calculates predicted temperature values that account for the thermal inertia of the integrated measurement apparatus.
3Speed
If gain of first-order advance compensation is increased to improve responsiveness, then detection accuracy is improved, but excessive correction occurs when temperature signal suddenly changes
Solution Approach 1:
The patent dynamically adjusts the gain of the first-order advance compensation filter based on the intake-air flow rate. During sudden temperature changes (such as cold start conditions), the intake-air flow rate provides a reference signal that allows the system to select an appropriate gain level. This prevents excessive correction while maintaining responsiveness, resolving the contradiction between speed and measurement precision.
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
The solution effectively suppresses excessive corrections in intake-air temperature detection signals, improving measurement accuracy and simplifying the control structure by dynamically adjusting time constants to account for heater temperature changes and ambient noise.
Implementation Method 1
an intake-air flow rate detection device is heated up by a heater incorporated in the intake-air physical quantity measurement apparatus so as to be kept at a constant temperature
Implementation Method 2
an intake-air temperature detection device measures not only an intake-air temperature but also heat transfer caused through heating by the heater
Data Source
AI summary
The internal-combustion-engine control apparatus has an intake-air-temperature correction control apparatus including a first-order advance compensation means that calculates an advance-compensation amount for an intake-air temperature detection signal, a time constant determination means that calculates a time constant of the first-order advance compensation means, and a first-order delay compensation means that receives a calculation value of the first-order advance compensation means; the time constant determination means includes a time constant setting means that sets a time constant, based on an intake-air flow rate detection signal, an upper-limit-value setting means that sets an upper limit value of the time constant calculated by the time constant determination means, and a minimum value selection means that selects and outputs a minimum value of a time constant set by the time constant setting means and the upper limit value set by the upper-limit-value setting means.