Engine Intake Pressure Calculation With Humidity-Corrected Gas Constant
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Solution Overview
Problem
Conventional methods for calculating intake pipe pressure in engines do not account for changes in the gas constant due to humidity, leading to inaccuracies in pressure calculations.
Innovation Solution
A control device that measures air amount and humidity, using these measurements to calculate the air amount flowing into the engine's cylinder and subsequently corrects the gas constant for more accurate intake pipe pressure calculations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the ideal gas state equation is used to calculate intake pipe pressure without considering humidity, then the calculation is simple, but the accuracy of the intake pipe pressure calculation deteriorates due to changes in the gas constant
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the gas constant R based on measured humidity levels. The control device changes the parameter R from a fixed value to a variable that adapts to atmospheric humidity conditions, thereby improving calculation accuracy without requiring a completely new calculation model
Solution Approach 2:
The patent implements feedback by using the humidity measurement unit to continuously monitor atmospheric humidity and feed this information back to the pressure calculation unit. This feedback loop allows the system to automatically adjust the gas constant and maintain accurate pressure calculations under varying humidity conditions
2Measurement precision
If humidity measurement and gas constant correction are added to improve pressure calculation accuracy, then the measurement precision improves, but the device complexity increases
Solution Approach 1:
The patent introduces an intermediary approach by using a humidity measurement unit that provides correction data without requiring complete redesign of the pressure calculation system. The humidity data acts as an intermediary parameter that adjusts the gas constant, bridging the gap between simple ideal gas calculation and accurate real-world conditions
Solution Approach 2:
The patent changes the parameter R (gas constant) from a fixed physical constant to a variable parameter that depends on humidity. This parameter change allows the system to maintain the simplicity of the ideal gas equation form while incorporating the complexity of real atmospheric conditions through parameter adaptation
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
The solution increases the accuracy of intake pipe pressure calculations by considering humidity-induced changes in the gas constant, improving calculation precision even under varying atmospheric conditions.
Implementation Method 1
The conventional technique of the present invention is calculated by using an ideal gas state equation P·V=M·R·T to calculate an intake pipe pressure
Data Source
AI summary
An object is to provide a control device that calculates an intake pipe pressure of an engine, in which the humidity of air is measured, and a change in a gas constant due to a change in the total number of moles of air is corrected, to improve the accuracy of the calculation value of the intake pipe pressure.A control device that controls an engine provided with an air amount measurement unit that measures an air amount passing through a throttle throttle valve provided in an intake passage of the engine, and a humidity measurement unit that measures a humidity of air passing through the throttle throttle valve, includes: an air amount calculation unit that calculates an air amount flowing into a cylinder of the engine based on a measurement result of the air amount measurement unit; and a pressure calculation unit that calculates a pressure of the intake manifold on a downstream side of the throttle throttle valve based on the air amount measured by the air amount measurement unit, the air amount calculated by the air amount calculation unit, and the humidity measured by the humidity measurement unit.