Camshaft Adjustment for Internal Combustion Engine Cylinder Torque
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Solution Overview
Problem
Internal combustion engines face undesired deviations in combustion processes due to pressure changes in the rail and delivery volume changes of the high-pressure pump, affecting air and fuel quantity control in cylinders.
Innovation Solution
A method and device that measure actual camshaft and rail pressures, determine phase correction values, and adjust camshaft positions using a camshaft adjuster to balance cylinder-specific torque components, with additional adjustments based on intake pipe and cylinder pressures to maintain consistent combustion processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the high-pressure pump delivery volume or rail pressure increases, then the fuel delivery capability is improved, but the camshaft torsion increases causing deviation in inlet valve control times
Solution Approach 1:
The control unit continuously monitors the actual camshaft position via a camshaft sensor and compares it with the expected position. When deviations are detected due to camshaft torsion from high-pressure pump operation, the control unit calculates cylinder-specific phase correction values and adjusts the camshaft position using a camshaft adjuster, creating a closed-loop feedback system that compensates for the harmful effects of increased fuel delivery capability on valve control precision
Solution Approach 2:
The system dynamically changes the camshaft position parameter by determining phase correction values for individual cylinders based on actual camshaft position deviations. The camshaft adjuster modifies the camshaft angular position to compensate for torsion-induced timing errors, allowing the system to maintain precise valve control times even when operating at high rail pressures or with increased pump delivery volume
2Reliability
If the camshaft position is adjusted for each cylinder to compensate for torsion, then the combustion process consistency is improved, but the control system complexity increases
Solution Approach 1:
The control unit performs multiple functions using a unified approach: it monitors camshaft position, calculates phase correction values for all cylinders, and controls the camshaft adjuster. This multi-functional control strategy allows the system to maintain combustion consistency across all cylinders through a single integrated control mechanism rather than requiring separate control systems for each cylinder, thereby managing complexity while achieving reliability
Data Source
AI summary
The present disclosure relates to internal combustion engines and the teachings thereof may be embodied in methods for controlling an internal combustion engine. The method may include: measuring the actual camshaft position using a camshaft sensor, measuring the actual rail pressure using a rail pressure sensor, calculating, for each of the plurality of cylinders, a phase correction value depending at least in part on the measured actual rail pressure and a mass of fuel to be injected, calculating, for each cylinder, a corrected actual camshaft position based at least in part on the measured actual camshaft position and the respective phase correction value, and adjusting the camshaft position using a camshaft adjuster based on one or more of the corrected actual camshaft positions.