Dual Fuel Engine Evaporated Gas Dosing Control
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Solution Overview
Problem
Dual fuel compression ignition engines face challenges in managing evaporated natural gas, as existing systems fail to effectively utilize or vent it efficiently, leading to undesirable methane release into the atmosphere, which is a potent greenhouse gas.
Innovation Solution
A compression ignition dual fuel engine system with a gaseous fuel common rail and liquid fuel common rail, an evaporated gas system, and an electronically controlled supply valve that allows for the strategic dosing of evaporated gas into the intake manifold based on combustion conditions to prevent methane slip and optimize fuel combustion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If evaporated natural gas is vented from the storage tank to atmosphere, then tank pressure is relieved, but methane is released into the atmosphere causing greenhouse gas emissions
Solution Approach 1:
The system converts the harmful vented methane into a useful fuel source by routing evaporated natural gas through a heat exchanger to cool it, then injecting it into the engine's intake manifold where it is combusted. This transforms the greenhouse gas problem into a beneficial fuel contribution, simultaneously relieving tank pressure and reducing emissions.
Solution Approach 2:
The system changes the temperature parameter of the evaporated gas by passing it through a heat exchanger that cools the gas from evaporator temperature to near ambient temperature. This parameter change enables the gas to be properly mixed with air and combusted in the engine, converting it from a harmful vented substance into a usable fuel.
2Object-generated harmful factors
If evaporated natural gas is routed to the intake manifold for combustion, then methane emissions are reduced, but the air/gas mixture may become too rich causing combustion in the intake manifold
Solution Approach 1:
The system uses an electronic controller that receives signals from a manifold absolute pressure sensor and an engine position sensor to continuously monitor engine operating conditions. Based on this feedback, the controller dynamically adjusts the electronic control valve to regulate the flow of evaporated gas, ensuring the air/gas mixture remains within safe combustion parameters and preventing intake manifold ignition.
Solution Approach 2:
The system transitions from a static restriction orifice to a dynamic electronic control valve that can actively adjust its opening based on real-time engine conditions. This dynamic control allows the system to optimize the air/gas mixture ratio under varying load and speed conditions, maintaining safety while maximizing evaporated gas utilization.
3Reliability
If a restriction orifice is used to limit evaporated gas flow, then intake manifold combustion is prevented, but the amount of evaporated gas that can be utilized is limited
Solution Approach 1:
The system replaces the passive mechanical restriction orifice with an electronically controlled valve system. This substitution allows for active, dynamic control of gas flow based on engine conditions, replacing a fixed mechanical limitation with an adaptive electronic control system that can optimize both safety and utilization.
Solution Approach 2:
The electronic control valve serves multiple functions: it regulates gas flow to prevent intake manifold combustion, maximizes evaporated gas utilization under appropriate conditions, and provides flexible adaptation to varying engine operating conditions. This multi-functional component replaces the single-function restriction orifice.
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
The system effectively captures and utilizes evaporated natural gas, reducing methane venting to the atmosphere by integrating an evaporated gas dosing algorithm that controls the electronically controlled supply valve to ensure efficient combustion, thereby minimizing greenhouse gas emissions.
Implementation Method 1
As the liquefied natural gas in the storage tank absorbs heat, some of the gas evaporates off
Implementation Method 2
a relatively large charge of natural gas is ignited by a compression igniting a small pilot quantity of liquid diesel fuel
Implementation Method 3
The evaporated gas system may include a heat exchanger
Implementation Method 4
The electronically controlled supply valve is movable between an open position and a closed position
Implementation Method 5
a relatively large charge of natural gas is ignited by a compression igniting a small pilot quantity of liquid diesel fuel
Data Source
AI summary
A dual fuel compression ignition engine operates by injecting gaseous fuel and liquid diesel fuel from a common fuel injector directly into each engine cylinder. The gaseous fuel is ignited by compression igniting a small pilot injection quantity of the liquid diesel fuel. Evaporated natural gas from a cryogenic tank and/or a fuel conditioning module is dosed into an intake manifold of the engine with an electronically controlled supply valve. The electronically controlled supply valve may open to supply evaporated gas to the intake manifold contingent upon combustion conditions in the engine cylinder demonstrating a low risk of methane slip, and the dosing quantities are limited to reduce risk of ignition of an air/gas mixture in the intake manifold.