Variable Nozzle Vane Control for Diesel Ignition Delay
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Solution Overview
Problem
Existing control systems for compression self-igniting internal combustion engines face challenges in suitably adjusting the ignition delay period due to environmental changes and operational transients, leading to misfires, increased combustion noise, and poor exhaust emissions.
Innovation Solution
A control apparatus that adjusts the variable capacity mechanism of a supercharger to match the actual ignition delay period with a target period, using a variable nozzle vane mechanism to control the opening degree of nozzle vanes based on differences in ignition delay periods, considering factors like boost pressure, intake gas amount, and temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the boost pressure of intake air is made constant or the amount of gas supplied to the cylinder is made constant, then the ignition delay period can be adjusted, but the ignition delay period shifts from an appropriate value when outside air temperature or gas temperature varies
Solution Approach 1:
The control device calculates the actual ignition delay period based on detected values of intake air temperature, in-cylinder temperature, and fuel injection timing, then compares it with a target ignition delay period. The variable capacity mechanism is controlled based on the difference between actual and target values, creating a closed-loop feedback system that automatically compensates for temperature variations and maintains reliable ignition delay control.
Solution Approach 2:
The variable capacity mechanism of the supercharger is controlled to dynamically adjust the boost pressure based on the calculated difference between actual and target ignition delay periods. This dynamic adjustment allows the system to adapt to changing temperature conditions while maintaining appropriate ignition timing, resolving the contradiction between constant pressure control and temperature adaptability.
2Reliability
If the variable capacity mechanism is controlled to adjust ignition delay period, then combustion state can be optimized, but the system complexity increases
Solution Approach 1:
The control device performs multiple functions using the same computational platform: it calculates the actual ignition delay period from sensor data, determines the difference from target values, and controls the variable capacity mechanism. This multi-functional approach optimizes combustion stability without requiring separate dedicated systems for each function, thereby limiting the increase in overall system complexity.
3Productivity
If pilot injection and main injection are performed, then combustion efficiency is improved, but misfire and combustion noise increase when ignition delay period varies
Solution Approach 1:
The control device uses feedback control to calculate and adjust the ignition delay period based on actual combustion conditions and target values. By continuously monitoring and adjusting the timing parameters of pilot and main injection based on the difference between actual and target ignition delay periods, the system maintains consistent combustion behavior and prevents misfire and excessive combustion noise while preserving combustion efficiency.
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 allows for precise adjustment of the ignition delay period, ensuring ideal combustion states, reducing misfires, improving exhaust emissions, and maintaining sufficient engine torque while minimizing NOx and smoke generation.
Implementation Method 1
a supercharger (5) of a variable capacity type having a variable capacity mechanism (54)
Implementation Method 2
a combustible air-fuel mixture is generated due to evaporative diffusion of fuel (an ignition delay period)
Implementation Method 3
this combustible air-fuel mixture undergoes self-ignition nearly simultaneously at several locations in the combustion chamber, and combustion progresses rapidly (premixed combustion)
Data Source
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AI summary
In a diesel engine equipped with a turbocharger having a variable nozzle vane mechanism, an estimated ignition delay period Dest in pilot injection is calculated from a boost pressure PIM, an intake gas amount GCYL, an intake gas temperature TIM, a coolant temperature THW, a pilot injection time AINJP, and a pilot injection amount qpl, and a target ignition delay period Dtrg in the pilot injection is calculated from an engine speed NE and an engine load QFIN. A difference Ddif is obtained by subtracting the estimated ignition delay period Dest from the target ignition delay period Dtrg, a VN opening degree control value PVN is calculated from the difference Ddif, and the VN opening degree of the variable nozzle vane mechanism is controlled such that the estimated ignition delay period Dest matches the target ignition delay period Dtrg.