Engine Control Device Volumetric Efficiency Calculation
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Solution Overview
Problem
Conventional techniques inaccurately calculate volumetric efficiency when the intake valve does not close at the bottom dead center, leading to reduced accuracy in intake gas amount calculation, which affects the controllability of the exhaust gas recirculation device and exhaust-gas conditions.
Innovation Solution
A control apparatus for internal combustion engines that calculates volumetric efficiency based on the actual cylinder-volume when the intake valve closes, using a crank mechanism to determine the cylinder-volume and subsequently calculates the intake gas amount, allowing for precise engine control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If volumetric efficiency is calculated based on stroke volume assuming intake valve closes at bottom dead center, then calculation is simple, but accuracy of intake gas amount calculation deteriorates when intake valve does not close at bottom dead center
Solution Approach 1:
The patent changes the parameter used for volumetric efficiency calculation from fixed stroke volume to variable cylinder volume at actual intake valve closing timing. By dynamically adjusting the volume parameter based on actual valve closing position, the calculation maintains both simplicity and accuracy without requiring complex additional measurements.
2Measurement precision
If intake gas amount calculation accuracy is improved by using actual cylinder volume, then exhaust gas recirculation controllability improves, but calculation complexity increases
Solution Approach 1:
The patent performs preliminary determination of the relationship between crank angle and cylinder volume, storing this data for direct lookup during operation. This preliminary action allows the system to use accurate variable volume calculations without adding real-time computational complexity, as the complex volume calculations are pre-computed and stored.
Data Source
AI summary
Provided are a control device for an internal combustion engine, wherein the internal combustion engine is provided with a crank mechanism for converting a reciprocating motion of a piston into a rotating motion of a crankshaft, a cylinder accommodating the piston, and an intake valve capable of opening and closing an inlet for sucking gas into the cylinder, and the control device is provided with: a volumetric efficiency calculating unit for calculating a volumetric efficiency representing a suction efficiency when gas is sucked into the cylinder, on the basis of a cylinder capacity when the intake valve is closed; a gas suction amount calculating unit for calculating a gas suction amount sucked into the cylinder, by means of a predetermined formula, on the basis of the calculated volumetric efficiency; and a control unit for controlling the internal combustion engine on the basis of the calculated gas suction amount.