Exhaust Gas Counter Pressure Model Smoothing
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Solution Overview
Problem
Existing methods for controlling internal combustion engines struggle to accurately determine exhaust gas counter pressure during valve lift adjustments, leading to potential jumps in pressure curves that are not representative of the actual exhaust gas counter pressure.
Innovation Solution
A method and device that determine first and second model values of exhaust gas counter pressure based on operating variables, using a lowpass filter to create a filtered model value that approximates the current exhaust gas counter pressure during valve lift adjustments, thereby smoothing out jumps and ensuring accurate operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If valve lift is adjusted in the internal combustion engine, then the engine operation can be optimized for different conditions, but jumps in the exhaust gas counter pressure curve occur that are not representative of the actual pressure
Solution Approach 1:
The patent determines model values for the exhaust gas counter pressure in advance for different valve lift positions. Before actually adjusting the valve lift, the control device already has pre-calculated model values ready, which are then used to smooth the transition and avoid jumps in the pressure curve during the adjustment process.
Solution Approach 2:
The patent introduces model values as an intermediary between the actual valve lift adjustment and the exhaust gas counter pressure determination. These model values act as a mediator that smooths out the transition, allowing the system to transition between different valve lift positions without creating unrealistic jumps in the pressure curve.
2Measurement precision
If the exhaust gas counter pressure is determined during valve overlap phase, then the pressure can be measured, but the determination is inaccurate during valve lift adjustments
Solution Approach 1:
The patent creates model copies of the exhaust gas counter pressure for different valve lift positions. Instead of directly measuring the pressure during complex valve lift adjustments, the system uses pre-determined model values that copy the expected pressure behavior, providing accurate determination without the measurement difficulties associated with dynamic valve adjustments.
3Reliability
If model values are determined for different valve lift positions, then accurate pressure approximation is achieved, but the device complexity increases
Solution Approach 1:
The patent changes the parameter being controlled from direct pressure measurement to using pre-determined model values. By shifting from measuring actual pressure during dynamic conditions to using pre-calculated model values for different valve lift positions, the system achieves higher reliability while the complexity is managed through parameter transformation rather than additional hardware.
Data Source
AI summary
The invention relates to the operation of an internal combustion engine, a first model value or a second model value of the exhaust gas counter pressure is determined upstream of the exhaust gas catalytic converter of the internal combustion engine as a function of at least one operating variable of the internal combustion engine, which is representative of the exhaust gas counter pressure in a current operating mode of the internal combustion engine, assuming a low valve lift or a high valve lift.