Engine Pre-Turbine Pressure Estimation Without Harsh Exhaust Sensors
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Solution Overview
Problem
Existing systems lack an efficient method to accurately monitor pre-turbine pressure in combustion engines, particularly in high-temperature and high-pressure environments, which is crucial for engine control and sensor failure backup.
Innovation Solution
A pressure monitor that calculates pre-turbine pressure by deriving normalized turbine speed, heat capacity ratio, and turbine power, using a linear relation between turbine expansion ratio and normalized turbine power, with optional inputs from VGT position for variable geometry turbines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a pressure sensor is installed directly in the exhaust manifold to measure pre-turbine pressure, then measurement accuracy is improved, but the sensor is exposed to high temperature and high pressure environments exceeding 500 degrees Celsius and 2 bar, which reduces reliability and increases the risk of sensor failure
Solution Approach 1:
The patent uses an estimation model as an intermediary to indirectly determine pre-turbine pressure without placing a sensor directly in the harsh exhaust manifold environment. The model uses inputs from other sensors (post-turbine pressure, turbine speed, temperature) and calculations to derive the pre-turbine pressure, thereby protecting against direct sensor exposure while maintaining measurement capability
Solution Approach 2:
Instead of directly measuring pre-turbine pressure with a sensor in the harsh environment, the system creates a computational copy or estimate of the pressure value using a model that processes data from other less harsh measurement points, effectively replicating the measurement function without the physical exposure
2Reliability
If conventional estimation methods are used for pre-turbine pressure, then sensor failure risk is reduced, but measurement accuracy deteriorates due to sensitivity to exhaust mass flow deviations and environmental conditions
Solution Approach 1:
The patent improves estimation accuracy by using normalized parameters (normalized turbine speed, normalized turbine power) that are less sensitive to environmental variations. The model transforms raw sensor inputs into normalized form and uses calibrated relationships to compensate for mass flow deviations and environmental conditions, thereby maintaining accuracy without direct sensor exposure
Solution Approach 2:
The system uses feedback from multiple sensor inputs (post-turbine pressure, turbine speed, temperature measurements) to continuously refine the pre-turbine pressure estimation. The model processes these feedback signals through calibrated relationships to maintain accurate pressure estimation despite variations in operating conditions
3Speed
If a direct pressure sensor is used in the exhaust manifold, then real-time pre-turbine pressure data is obtained, but the system complexity and cost increase due to additional sensor equipment and protection mechanisms
Solution Approach 1:
The patent makes existing sensors and the estimation model serve multiple functions: the same computational model provides both real-time pre-turbine pressure estimation for control purposes and serves as a backup monitoring system for sensor failure detection, eliminating the need for separate protection mechanisms and reducing overall system complexity
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
Provides high-accuracy pre-turbine pressure estimation, less sensitive to exhaust mass flow deviations, and can serve as a reliable backup or primary input for engine controllers.
Implementation Method 1
a turbine provided in an exhaust channel coupled to the exhaust manifold
Implementation Method 2
derive a normalized turbine speed, normalized for a pre turbine temperature, and a heat capacity ratio of exhaust gas before the turbine
Implementation Method 3
derive, for said first inputs, a linear relation between a turbine expansion ratio and a turbine power value normalized by the second input
Implementation Method 4
equate the turbine power value to the actual turbocompressor power; thereby deriving the pre turbine pressure
Data Source
AI summary
A pressure monitor is arranged to calculate a pre-turbine pressure. The monitor is programmed to derive a normalized turbine speed, normalized for a pre turbine temperature, and a heat capacity ratio of exhaust gas before the turbine as first inputs; determine a turbine power normalizing factor as a second input; determine an actual turbocompressor power value as a third input; derive, for said first inputs, a linear relation between a turbine expansion ratio and a turbine power value normalized by the second input; and equate the turbine power value to the actual turbocompressor power; thereby deriving the pre turbine pressure from said linear relation, as an output.