Engine Control Apparatus Air Volume Estimation Dynamics
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Solution Overview
Problem
Conventional engine control methods face challenges in accurately estimating intake air volume, especially during transient states with varying change rates, leading to inaccuracies in air-to-fuel ratio and torque control, which affects engine controllability.
Innovation Solution
An engine control apparatus that calculates a target air volume and actual air volume, using an estimator to predict subsequent air volumes based on a time lag, with a memory storing history to adjust for drive delay, and controllers for throttle and fuel injection to maintain accurate air-to-fuel ratios and ignition timing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the differential estimation correction method is used to extrapolate the slope of intake air volume, then the subsequent intake air volume can be estimated, but the accuracy of the estimated value decreases when the slope of the intake air volume varies
Solution Approach 1:
The patent applies dynamics by making the estimation gain variable rather than fixed. The estimation gain is dynamically adjusted based on the comparison between the latest actual intake air volume and the estimated value. When the actual value is larger than the estimated value, the gain is increased to accelerate convergence. This dynamic adjustment allows the system to adapt to varying slopes in intake air volume, resolving the contradiction between maintaining accuracy and adapting to changing conditions.
Solution Approach 2:
The patent implements feedback by continuously comparing the latest actual intake air volume with the estimated value and using this comparison to adjust the estimation gain. This feedback mechanism allows the system to learn from past estimation errors and correct future predictions. The feedback loop ensures that the estimation accuracy is maintained even when the slope of intake air volume varies, as the system automatically adjusts its estimation parameters based on actual performance.
2Ease of operation
If fuel injection rate is controlled on the basis of estimated intake air volume, then air-to-fuel ratio control is achieved, but variations in air-to-fuel ratio and torque occur when estimation accuracy decreases
Solution Approach 1:
The patent uses feedback to continuously monitor the relationship between actual and estimated intake air volumes and adjusts the estimation gain accordingly. This feedback mechanism ensures that the fuel injection rate control remains accurate even during transient states. By dynamically adjusting the estimation gain based on actual measurements, the system maintains consistent air-to-fuel ratio control, preventing variations that would otherwise occur when estimation accuracy decreases.
Solution Approach 2:
The patent applies dynamics by making the fuel injection control adaptive rather than static. The estimation gain used for fuel injection rate calculation is dynamically adjusted based on real-time comparisons between actual and estimated air volumes. This dynamic control approach allows the system to maintain proper air-to-fuel ratio even when operating conditions change, ensuring consistent torque output and preventing the variations that would occur with fixed-gain estimation.
3Device complexity
If the estimation gain is fixed at a predetermined value, then the calculation is simple, but the estimation accuracy depends heavily on the slope of the actual air volume
Solution Approach 1:
The patent applies dynamics by transforming the fixed estimation gain into a variable parameter that adapts to changing conditions. Instead of using a predetermined fixed gain, the system dynamically adjusts the estimation gain based on the comparison between actual and estimated intake air volumes. This dynamic approach increases calculation complexity slightly but dramatically improves estimation accuracy, especially during transient states when the slope of air volume changes.
Solution Approach 2:
The patent implements parameter changes by modifying the estimation gain parameter based on operating conditions. The gain is changed from a fixed predetermined value to a variable parameter that is adjusted according to the relationship between actual and estimated air volumes. This parameter change allows the estimation algorithm to adapt to different slopes and transient conditions, significantly improving accuracy while maintaining reasonable computational complexity.
Data Source
Figure 1
Figure 2A~2B
Figure 3A~3B
AI summary
An engine control apparatus includes a target air volume calculator (2b) which calculates a target air volume required by an engine (10), and an actual air volume calculator (2a) which calculates an actual air volume inhaled into a cylinder (19) of the engine (10) . The apparatus further includes an estimator (3) which calculates the estimated value of subsequent actual air volume on the basis of a time lag from a time when the target air volume is calculated to a time when the actual air volume reaches the target air volume. The apparatus can accurately estimate an intake air volume inhaled into the cylinder (19) to improve the controllability of the engine (10).