Dual Fuel Engine Charge-Flow Control for Exhaust Temperature Balance
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Solution Overview
Problem
Dual fuel engines face challenges in maintaining optimal air-fuel ratios due to variable parameters like engine speed, load, natural gas quality, intake air temperature, and humidity, leading to inefficient combustion and increased emissions, as existing methods for controlling air-fuel ratios are complex and costly.
Innovation Solution
A system that uses a sensor to measure exhaust temperature, a processor to determine a target temperature, and adjusts diesel injection, rail pressure, intake throttle, wastegate, compressor bypass valve, exhaust throttle, and engine valve timing to control charge-flow, ensuring balanced operation of dual fuel engine banks and maintaining optimal exhaust temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If complex methods are used to directly control air-fuel ratio by measuring variable parameters, then engine performance can be optimized, but system complexity and cost increase
Solution Approach 1:
The patent implements closed-loop feedback control by measuring exhaust temperature and using it to adjust charge-flow parameters. The controller continuously monitors exhaust temperature and modifies intake throttle position, wastegate opening, or compressor bypass valve position to maintain optimal exhaust temperature, thereby optimizing air-fuel ratio and engine performance without requiring direct measurement of multiple variable parameters
Solution Approach 2:
The patent uses exhaust temperature as an intermediary parameter to indirectly control air-fuel ratio. Instead of directly measuring and controlling air-fuel ratio through multiple sensors and actuators, the system measures exhaust temperature (a downstream effect of air-fuel ratio) and uses this information to adjust charge-flow parameters, simplifying the control system while maintaining optimization capability
2Reliability
If air-fuel ratio is increased to prevent thermal limits and engine knock, then engine safety is improved, but combustion efficiency decreases and emissions increase
Solution Approach 1:
The patent dynamically adjusts charge-flow parameters based on real-time exhaust temperature measurements. The controller continuously modifies intake throttle position, wastegate opening, or compressor bypass valve position in response to exhaust temperature changes, allowing the air-fuel ratio to be optimized for each operating condition rather than being statically set, thereby maintaining both engine safety and combustion efficiency
Solution Approach 2:
The patent changes operating parameters (intake throttle position, wastegate opening, compressor bypass valve position) to control charge-flow and maintain optimal exhaust temperature. By dynamically adjusting these parameters based on exhaust temperature feedback, the system maintains appropriate air-fuel ratios that prevent thermal limits and engine knock while preserving combustion efficiency and minimizing emissions
3Productivity
If charge-flow is adjusted to maintain optimal exhaust temperature, then air-fuel ratio optimization is achieved, but control system complexity increases
Solution Approach 1:
The patent makes the exhaust temperature measurement serve multiple functions: it directly indicates combustion quality and air-fuel ratio adequacy, and it also reflects thermal management needs. This single measurement provides information that would otherwise require multiple sensors, simplifying the control system while enabling comprehensive air-fuel ratio optimization
Solution Approach 2:
The patent implements feedback control where exhaust temperature measurements are used to adjust charge-flow parameters. The controller monitors exhaust temperature and modifies intake throttle position, wastegate opening, or compressor bypass valve position to maintain optimal exhaust temperature, creating a closed-loop system that automatically optimizes air-fuel ratio without requiring complex direct measurement systems
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 approach improves engine performance by maintaining optimal air-fuel ratios, reducing emissions, and enhancing fuel efficiency by adjusting charge-flow based on real-time engine conditions, even under low load conditions.
Implementation Method 1
a sensor configured to measure an exhaust temperature
Implementation Method 2
When the diesel fuel compression ignites, it causes the natural gas to also burn. The combined combustion releases energy that powers the engine
Data Source
AI summary
Methods and systems of controlling a dual fuel engine with at least two banks of cylinders are provided. The method may include sensing at least one of temperatures of exhaust from the at least two banks and a pressure of an intake manifold of the at least two banks, and adjusting at least one of a gas flow, a charge flow, or an air flow to one of the at least two banks to balance one of exhaust temperatures of the at least two banks and intake manifold pressures of the at least two banks.