Intake Pulsation Compensation for Variable Valve Systems
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Solution Overview
Problem
Existing methods for compensating intake pulsation in engine intake systems are inaccurate due to factors like valve operation and valve-overlap, leading to incorrect fuel injection and reduced engine performance and increased noxious gas emissions.
Innovation Solution
A method and apparatus that calculate a basic air charge amount and pulsation compensation coefficient based on sensor measurements, adjusting for changes in valve operation, valve-overlap, and valve lift to accurately correct intake pulsation and ensure precise air supply to the engine.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional pulsation compensation methods are used based on intake valve timing, then pulsation can be partially compensated, but the compensation becomes inaccurate when valve operation or valve-overlap changes occur
Solution Approach 1:
The patent applies dynamics by making the pulsation compensation coefficient variable rather than fixed. The system dynamically adjusts the compensation coefficient based on detected pulsation amplitude, which changes with valve operation modes (standard, VIS, VCM) and valve-overlap conditions. This allows the compensation mechanism to adapt to different operating conditions, resolving the contradiction between measurement precision and adaptability.
Solution Approach 2:
The patent implements feedback by continuously monitoring intake manifold pressure to detect pulsation amplitude and using this information to adjust the pulsation compensation coefficient. The MAP sensor provides real-time pressure feedback, which is processed to determine the appropriate compensation level, creating a closed-loop system that maintains accurate intake amount detection despite changing valve operation conditions.
2Productivity
If variable intake systems (VIS) or variable charge motion (VCM) are applied to improve engine performance, then engine efficiency is improved, but the pulsation waveform changes making compensation more difficult
Solution Approach 1:
The patent applies parameter changes by adjusting the pulsation compensation coefficient based on the detected pulsation amplitude, which varies with different intake system configurations. When VIS or VCM is activated, the pulsation characteristics change, and the system responds by modifying the compensation parameter to maintain accurate intake amount calculation, thus resolving the contradiction between engine performance improvement and measurement accuracy.
3Productivity
If valve-overlap is increased to improve exhaust gas flow, then exhaust efficiency is improved, but exhaust gas flows back to intake valve changing pulsation waveform
Solution Approach 1:
The patent uses feedback from MAP sensor pressure measurements to detect changes in pulsation waveform caused by valve-overlap and exhaust gas recirculation to the intake. The system adjusts the pulsation compensation coefficient based on this feedback, maintaining accurate intake amount detection despite the altered pulsation characteristics, thus resolving the contradiction between exhaust efficiency and measurement accuracy.
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 allows for more accurate fuel injection, improving fuel efficiency, preventing excessive fuel supply, and reducing noxious gas emissions by accurately compensating for intake pulsation influences.
Implementation Method 1
The flow rate of the intake air is calculated using internal pressure of the cylinder that is calculated from the pressure of the surge tank measured by a manifold absolute pressure (MAP) sensor
Implementation Method 2
The air flowing in the cylinder 40 is compressed, ignited, and burned in the cylinder 40 by downward movement of a piston 50
Implementation Method 3
Since air has a property (inertia) in which flow is maintained at the same speed, every time the intake valve 20 opens/closes, portions with high air density and low air density are formed at the intake valve
Data Source
AI summary
A method for correction of intake pulsation is provided. The method includes calculating a basic air charge amount of a cylinder or a charge amount conversion coefficient based on a measurement value of a sensor disposed in an intake system of an engine. A basic pulsation compensation coefficient for correcting an intake amount from a basic waveform of pulsation is calculated based on opening/closing of an intake valve and engine RPM. The basic pulsation compensation coefficient is then corrected when the basic waveform of the pulsation is changed.