Internal Combustion Engine Intake Air Control via Pressure and Temperature
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for accurately detecting and estimating the intake air amount in internal combustion engines, especially those with superchargers, face challenges due to reverse air flow and inaccuracies in air flow sensor measurements.
Innovation Solution
A control device that calculates the intake air amount by using pressure and temperature sensors to determine the change in air amount between the upstream and downstream sections of the throttle valve, and adjusts calculations based on previous intake air values, allowing for accurate estimation even during reverse flow conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If air flow sensor is used to detect intake air amount, then detection method is simple, but measurement accuracy deteriorates during reverse flow and supercharging
Solution Approach 1:
The patent introduces pressure sensors and temperature sensors as intermediary devices to detect air state parameters in the upstream section. These sensors serve as mediators to indirectly calculate the intake air amount through thermodynamic relationships, avoiding the direct measurement limitations of air flow sensors during reverse flow and supercharging conditions.
Solution Approach 2:
The patent replaces the mechanical air flow sensor measurement method with a thermodynamic calculation approach. By substituting direct mechanical flow detection with pressure and temperature-based calculations using ideal gas law relationships, the system achieves accurate intake air amount estimation without the limitations of mechanical flow sensors in complex operating conditions.
2Measurement precision
If air flow sensor is installed upstream of supercharger, then introduced air amount can be detected, but reverse flow causes excessive detection and lowers accuracy
Solution Approach 1:
The patent performs preliminary detection of air state parameters (pressure and temperature) in the upstream section before the throttle valve. By measuring these parameters upstream of the supercharger where reverse flow occurs, the system can calculate the change in air amount and compensate for reverse flow effects before they affect the final intake air amount calculation.
Solution Approach 2:
The patent uses feedback from pressure and temperature sensor measurements to continuously update the calculation of intake air amount. The system monitors the state of air in the upstream section and uses this feedback information to adjust the calculation, thereby compensating for reverse flow interference and maintaining measurement accuracy under varying operating conditions.
3Measurement precision
If only introduced air amount is used for calculation, then calculation is simple, but accuracy deteriorates due to volume changes in upstream section
Solution Approach 1:
The patent changes the parameters used for calculation from simple volumetric flow measurement to thermodynamic parameter measurement (pressure and temperature). By measuring pressure and temperature changes in the upstream section and applying thermodynamic relationships, the system accurately calculates intake air amount while accounting for volume changes in the upstream section during supercharging and reverse flow.
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 solution provides a more accurate calculation of intake air amount, enabling efficient engine operation by adjusting the air-fuel ratio and adapting to various intake system configurations, including those with superchargers.
Implementation Method 1
a first pressure sensor for detecting the pressure of the upstream section
Implementation Method 2
a temperature sensor for detecting the temperature of air flowing through the upstream section
Data Source
Figure 1
Figure 2A~2D
AI summary
A control device for an internal combustion engine, which can accurately estimate an intake air amount introduced from an intake system into an internal combustion engine, is provided. The control device calculates the change amount of an air amount in an upstream section upstream of a throttle valve of the intake system based on the pressure and temperature of air in the upstream section; calculates a throttle passage air amount flowing out to an intake manifold, which is a section downstream of the throttle valve, based on the change amount and an introduced air amount flowing into a supercharger; and calculates the intake air amount based on the throttle passage air amount.