Two-Stroke Opposed-Piston Air Boost Control for Altitude Efficiency
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Solution Overview
Problem
Two-stroke engines face challenges in transient control and fuel economy optimization under varying altitudes and ambient conditions due to fixed ratio operation of blower devices, leading to reduced engine power and thermal inefficiencies.
Innovation Solution
A method and system for controlling an air boosting apparatus in a two-stroke, opposed piston engine that adjusts operation based on engine speed, torque demand, altitude, and ambient conditions to optimize pressure ratios and air-to-fuel ratios, using a controller with maps for optimal fuel economy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the blower device operates at a fixed ratio to engine speed, then the device complexity is reduced, but the fuel economy deteriorates under varying altitude and ambient conditions
Solution Approach 1:
The blower device control transitions from a fixed ratio system to a dynamic control system that adjusts the blower speed based on real-time engine operating conditions including altitude, ambient temperature, and engine load. This dynamic adjustment allows the system to optimize air boosting across varying conditions while managing the additional control complexity through electronic control mechanisms.
Solution Approach 2:
The system changes operational parameters (blower speed, air boosting ratio) based on detected altitude and ambient conditions. By monitoring environmental parameters and adjusting blower operation accordingly, the system maintains optimal fuel economy across different operating scenarios rather than relying on a single fixed ratio setting.
2Reliability
If the blower device size is selected for worst-case scenario, then the reliability is improved, but the power consumption increases under normal operating conditions
Solution Approach 1:
The system employs dynamic control of the blower device based on real-time detection of engine operating conditions and environmental factors. Rather than operating at constant high power, the blower adjusts its output dynamically to match actual needs, reducing power consumption during normal conditions while maintaining reliability through appropriate boosting when required.
Solution Approach 2:
The system applies partial action by providing just enough air boosting for current operating conditions rather than continuously operating at maximum capacity. This approach reduces unnecessary power consumption while maintaining reliability by providing adequate boosting when needed, avoiding the excessive action of oversizing the blower for all conditions.
3Adaptability or versatility
If engine power level is reduced at high altitude, then the adaptability to altitude conditions is improved, but the thermal efficiency deteriorates due to temperature rises in cylinder line and exhaust system
Solution Approach 1:
The system changes operational parameters including air boosting level, fuel injection timing, and air-to-fuel ratio in response to detected altitude changes. By adjusting these parameters dynamically, the system maintains appropriate power output and thermal efficiency at high altitude while adapting to the thinner air conditions, preventing excessive temperature rises through controlled combustion parameters.
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
Enhances fuel economy by dynamically adjusting the air boosting apparatus to maintain optimal pressure and air-to-fuel ratios, improving engine performance and efficiency under varying conditions.
Implementation Method 1
an air boosting apparatus arranged to boost air pressure in a charge air stream upstream of a cylinder of the engine
Data Source
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AI summary
A method includes operating an air boosting apparatus of a nvo-stroke, opposed piston engine as a function of one or more factors including a first engine speed, a first torque, demand, a first altitude, a first transient rate, and one or more first ambient conditions to provide a first pressure S ratio (PR} of pre-turbine pressure (PTP) versus turbocharger compressor discharge pressure (CDP} and a first air-to-fuel ratio (AFR).