Dual-Fuel Engine Cold Start via Diesel Pilot Injection
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Solution Overview
Problem
Dual-fuel engines, particularly diesel-natural gas engines, face challenges in achieving improved cold start capabilities and efficient operation with high compression ratios, leading to issues with ignition and emissions control.
Innovation Solution
A dual-fuel engine system that operates in both start and run modes using a combination of diesel fuel and natural gas or propane, with a controller managing fuel injection and combustion, allowing for dynamic control of the fuel mixture and injection, and optimized compression ratios to enhance ignition and reduce emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If high compression ratios are used for efficient operation, then fuel efficiency is improved, but cold start capability deteriorates
Solution Approach 1:
The system performs preliminary action by injecting a small amount of diesel fuel before the main natural gas injection to prepare for ignition. This preliminary diesel injection creates a combustible environment that enables reliable cold starts while allowing the engine to operate at high compression ratios for fuel efficiency during normal operation.
Solution Approach 2:
The system changes operating parameters dynamically by switching between different fuel injection modes. During cold starts, it uses a higher proportion of diesel fuel to ensure ignition, then transitions to primarily natural gas injection once the engine is running, thereby resolving the contradiction between cold start reliability and fuel efficiency.
2Reliability
If diesel fuel is used for reliable ignition, then ignition reliability is improved, but emissions control deteriorates
Solution Approach 1:
The system applies partial action by using only a small amount of diesel fuel (e.g., 5-20% of total fuel energy) during cold starts and idle conditions, just enough to ensure reliable ignition. Once the engine is running, it switches to primarily natural gas, thereby maintaining ignition reliability when needed while minimizing emissions during most operation.
Solution Approach 2:
The system dynamically adjusts the fuel mixture composition based on operating conditions. The controller modifies the proportion of diesel to natural gas in real-time, using more diesel during cold starts and idle, then transitioning to predominantly natural gas during steady-state operation to balance ignition reliability with emissions control.
3Object-generated harmful factors
If dual-fuel mode is used for emissions reduction, then emissions are improved, but cold start capability deteriorates
Solution Approach 1:
The system employs periodic action by alternating between different fuel modes based on operating conditions. During cold starts, it uses a diesel-rich mixture for reliable ignition, then periodically transitions to a natural gas-rich dual-fuel mode during normal operation to reduce emissions, thereby resolving the contradiction between cold start capability and emissions reduction.
Solution Approach 2:
The system performs preliminary diesel injection to prepare for ignition in cold conditions, then transitions to dual-fuel mode once the engine is running. This preliminary action ensures cold start reliability while enabling emissions reduction through subsequent dual-fuel operation.
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 enables efficient cold starts and reduced emissions by dynamically controlling the fuel mixture and injection, optimizing combustion efficiency and minimizing the need for additional ignition sources, while maintaining compliance with regulatory standards.
Implementation Method 1
combust a mixture of the first and second fuels
Data Source
AI summary
A method for operating a dual-fuel engine. Embodiments include receiving sensor input information, including information representative of a temperature of the engine. A first fuel, optionally diesel fuel, and a second fuel that is different than the first fuel, optionally natural gas, are supplied to the engine during a start mode when the engine temperature is below a normal operating temperature range. The first and second fuels can be supplied to the engine during a run mode when the engine temperature is within the normal operating temperature range.