Dual Ignition Coil Control via Single Wire Pulse Encoding
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Solution Overview
Problem
Operating dual ignition coils in spark ignited engines with lean or dilute mixtures poses challenges due to the risk of misfire and undesirable combustion timing, particularly when control signals are degraded, leading to increased complexity and potential misfires.
Innovation Solution
A method that commands two different ignition coil charging current times via a single conductor and ignores specific voltage pulses in the ignition coil commands to mitigate the risk of misfire, ensuring proper processing and timing of spark delivery by selectively charging and discharging the coils based on the presence or absence of voltage pulses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If two control signals are delivered via two conductors to control each ignition coil, then the control precision and reliability of each coil is improved, but the device complexity and number of control wires is doubled
Solution Approach 1:
The patent combines control signals for two ignition coils into a single control wire by using different pulse widths to encode different coil charging durations. The controller generates a first control signal with a first pulse width for the first ignition coil and a second control signal with a second pulse width for the second ignition coil, both transmitted through the same control wire. This merging reduces the number of control wires while maintaining the ability to independently control each coil's charging time.
2Productivity
If two ignition coils are controlled individually to increase spark energy and duration, then the engine can operate with lean air-fuel mixture or diluted mixtures to improve fuel economy and emissions, but the possibility of misfire or undesirable combustion timing increases if control signal degradation occurs
Solution Approach 1:
The patent implements a feedback mechanism where the controller monitors the actual charging times of both ignition coils and compares them against the commanded charging times. If the actual charging time differs from the commanded charging time for either coil, the controller adjusts subsequent control signals to compensate for the discrepancy. This feedback ensures that even if one coil experiences signal degradation or timing variations, the system can detect and correct for it, maintaining reliable combustion timing.
Solution Approach 2:
The controller commands different charging current times for the two ignition coils in advance of the combustion event, with the first ignition coil being charged for a first amount of time and the second ignition coil being charged for a second amount of time that is different from the first. This preliminary action allows the system to optimize spark energy and duration for lean or diluted mixtures before combustion occurs, improving fuel economy and emissions while maintaining combustion reliability through the pulse width encoding scheme.
3Adaptability or versatility
If the number of ignition coil control conductors is doubled to provide independent control, then the control flexibility and precision is improved, but the ease of manufacture and system simplicity is reduced
Solution Approach 1:
The single control wire serves multiple functions by transmitting encoded control signals for both ignition coils simultaneously. The pulse width modulation scheme allows the same physical medium (control wire) to carry distinct control information for two different coils, making the system more universal and reducing the number of dedicated control lines needed. This multi-functionality simplifies manufacturing and assembly while maintaining control flexibility.
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 reduces the likelihood of improper spark timing, maintains desirable ignition timing, and simplifies the control system by reducing the number of control wires, thereby enhancing reliability and efficiency in spark delivery.
Implementation Method 1
An ignition coil assembly includes a first ignition coil and a second ignition coil that are different from one another... The first ignition coil and the second ignition coil may be charged for different amounts of time
Implementation Method 2
Each of the two ignition coils may be charged and discharged individually so that charging of one coil overlaps with charging of the other coil
Data Source
AI summary
A system and method for mitigating the possibility of missing ignition coil commands is presented. In one example, one or more ignition coils may not be charged and/or discharged during a cylinder cycle in response to the absence of a voltage pulse forming at least a portion of an ignition coil command.