Opposed-Piston Engine Mass Airflow Sensor Placement
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In uniflow-scavenged, opposed-piston engines, precise control of mass airflow is crucial for maintaining unidirectional gas flow and efficient combustion, but existing methods lack accuracy and precision, especially in turbocharged configurations with multiple air handling devices.
Innovation Solution
An electronic mass airflow sensor is positioned between the outlet of the charge air cooler and the air intake component in the charge air channel, measuring the rate of mass airflow and generating electronic signals to control air handling, fuel provisioning, and exhaust gas recirculation devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a mass airflow sensor is positioned upstream of the compressor inlet in the charge air channel, then the sensor can measure mass airflow early in the air handling process, but the measurement accuracy is insufficient for precise control of fuel injection and air handling devices
Solution Approach 1:
The patent positions the mass airflow sensor downstream of the charge air cooler, allowing the air handling system to first cool the compressed air before measurement. This preliminary cooling action enables more accurate density-based mass airflow calculations, as the temperature is stabilized and known, improving measurement precision without adding complex sensor systems
Solution Approach 2:
The charge air cooler acts as an intermediary component between the compressor and the mass airflow sensor. By placing the cooler in the charge air channel, the system mediates the temperature of the air before it reaches the sensor, creating more favorable measurement conditions and enabling precise mass airflow determination through density calculations
2Productivity
If multiple air handling devices are used in turbocharged opposed-piston engines to maintain unidirectional gas flow, then engine performance and thermal efficiency are improved, but the precision of mass airflow measurement and control deteriorates
Solution Approach 1:
The patent segments the air handling system into distinct functional zones: compression, cooling, measurement, and distribution. By positioning the mass airflow sensor in the charge air channel downstream of the cooler but upstream of the intake ports, the system creates a dedicated measurement zone where air conditions are stable and known, enabling precise measurement even in multi-device turbocharged configurations
Solution Approach 2:
The patent implements a feedback control system where the mass airflow sensor provides real-time measurements to the control mechanism, which then adjusts air handling devices and fuel injection accordingly. This closed-loop feedback enables precise control of mass airflow to the intake ports, maintaining measurement precision and control accuracy despite the presence of multiple air handling devices
3Ease of operation
If the mass airflow sensor is positioned to measure air flow early in the charge air channel, then the measurement can be used for control purposes, but the density and temperature conditions vary too much for accurate measurement
Solution Approach 1:
The patent applies preliminary cooling action through the charge air cooler before the air reaches the mass airflow sensor. This ensures that the air temperature is reduced and stabilized, creating consistent density conditions that improve measurement accuracy. The cooling action is performed in advance, so when measurement occurs, the air properties are favorable and stable
Solution Approach 2:
The patent changes the temperature parameter of the charge air by cooling it in the charge air cooler before measurement. This parameter change transforms the air from hot, dense post-compression state to a cooler, more stable state that is more suitable for accurate mass airflow measurement, while still allowing the measurement to be used for real-time control purposes
Data Source
AI summary
An opposed-piston engine includes an electronic sensor located in a charge air channel, at position between an outlet of a charge air cooler and an air intake component that distributes charge air to cylinder intake ports of the engine. The electronic sensor is disposed to measure a rate of mass airflow between the outlet of the charge air cooler and the intake component and generate electronic signals indicative of the rate of mass airflow from the charge air cooler. A control mechanization of the opposed-piston engine is electrically connected to the electronic sensor for controlling air handling devices, fuel provisioning devices, and/or EGR devices in response to the electronic signals.