Engine Reformer Startup Control for Stable Air-Fuel Ratio
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Solution Overview
Problem
Conventional engines with reformers face performance deterioration due to unstable reformed gas composition immediately after startup, leading to unstable engine speed and exhaust issues, as the reformer may not be sufficiently heated, resulting in inadequate air-fuel ratios.
Innovation Solution
The engine incorporates a control unit that adjusts the flow rate of reforming air and fuel to a reformable state, with the reformed-gas adjuster set to a degree of opening smaller than normal during engine startup, gradually increasing as the reformer stabilizes, to maintain a stable air-fuel ratio and reduce performance degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the reformed-gas adjuster is set to normal degree of opening immediately after engine starts, then the flow rate of reformed gas is sufficient for engine operation, but the composition of reformed gas is unstable causing performance deterioration
Solution Approach 1:
The control unit performs preliminary action by detecting engine startup state and automatically adjusting the reformed-gas adjuster to a degree of opening smaller than normal before the reformer produces stable reformed gas. This preliminary adjustment prevents unstable reformed gas from entering the intake flow passage during the critical startup period when the reformer is still heating up, thereby resolving the contradiction between sufficient gas flow and composition stability.
2Stability of the object's composition
If the reformed-gas adjuster is controlled to smaller degree of opening during startup, then the air-fuel ratio stability is improved, but the engine power output is reduced
Solution Approach 1:
The control unit implements dynamic adjustment of the reformed-gas adjuster based on engine operating conditions. During startup when stability is critical, the adjuster is set to a smaller degree of opening. Once the engine reaches normal operation and the reformer produces stable reformed gas, the control unit increases the degree of opening to normal levels, thereby restoring full power output. This dynamic adaptation resolves the contradiction between stability and power.
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 configuration reduces performance deterioration caused by unstable reformed gas composition during engine startup, ensuring a stable air-fuel ratio and improved engine operation by controlling the flow rates of reforming air and fuel, particularly in ammonia engines where instability is more pronounced.
Implementation Method 1
a reformer (36) configured to reform fuel into reformed gas
Implementation Method 2
a reformed-gas adjuster (38) disposed in the reforming flow passage and configured to adjust a flow rate of the reformed gas
Implementation Method 3
a reforming-air adjuster disposed in the reforming flow passage and configured to adjust a flow rate of the reforming air
Data Source
AI summary
An engine includes a reformer, a reforming-air adjuster, a reforming-fuel supply unit, a reformed-gas adjuster, and a control unit. The reformer is configured to reform fuel into a reformed gas. When a start signal is input, the control unit controls the reforming-air adjuster and the reforming-fuel supply unit to a reformable state in which the fuel is reformable in the reformer, and the control unit controls the reformed-gas adjuster so that the reformed gas flows through the reformed-gas adjuster with a degree of opening smaller than a normal degree of opening that is a degree of opening of the reformed-gas adjuster when composition of the reformed gas is in a stable state before the composition of the reformed gas becomes in the stable state, for a given period of time including at least a period immediately after the engine starts.