Engine Injector Fail-Safe Control for Torque Maintenance
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Solution Overview
Problem
Conventional dual port injector engines experience a significant reduction in torque when an electrical failure occurs in one of the injectors, making it difficult for drivers to safely operate the vehicle to a repair shop.
Innovation Solution
A control method that determines the occurrence of electrical failures in injectors and enters a fail-safe mode, where fuel supply to the affected injector is cut off, and the normally operating injector increases its fuel injection to maintain required fuel levels, with options to cut off all injectors if necessary, and operates in a limp home mode to limit torque and RPM.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If fuel supply is cut off to the affected injector when electrical failure occurs, then fuel injection control is simplified, but torque reduction occurs
Solution Approach 1:
The system changes the injection quantity parameter of the normally operating injector to compensate for the failed injector. By increasing the injection amount of the working injector, the system maintains the total fuel supply to the cylinder, thereby preventing torque reduction while keeping the control logic relatively simple.
Solution Approach 2:
The system dynamically adjusts the injection quantity of the normally operating injector based on the failure detection. The ECU modifies the injection control strategy in real-time, transitioning from normal dual-injector operation to single-injector compensation mode, maintaining torque while adapting to the failure condition.
2Power
If injection quantity of normally operating injector is increased to compensate, then torque is maintained, but fuel air ratio stability becomes difficult to control
Solution Approach 1:
The system uses feedback from the lambda sensor to monitor the actual air-fuel ratio and adjusts the injection quantity of the normally operating injector accordingly. This closed-loop control ensures that even with single-injector operation, the fuel air ratio remains within the optimal range, maintaining both torque and mixture stability.
Solution Approach 2:
The system temporarily allows for slight deviations in fuel air ratio during the transition to fail-safe mode, prioritizing torque maintenance. The ECU compensates by adjusting other parameters such as ignition timing and throttle position to maintain overall engine performance and protect the catalytic converter.
3Ease of operation
If fail-safe mode is activated to prevent torque reduction, then drivability is improved, but catalytic converter damage risk increases due to unstable fuel air ratio
Solution Approach 1:
The system activates fail-safe mode with pre-programmed protection strategies before actual damage can occur. The ECU monitors fuel air ratio deviations and implements corrective actions in advance, such as enriching the mixture or adjusting ignition timing, to prevent catalytic converter damage while maintaining drivability in fail-safe mode.
Solution Approach 2:
The system converts the potentially harmful condition of unstable fuel air ratio into a protective mechanism. By detecting the failure and activating fail-safe mode, the system uses the abnormal operating condition as an opportunity to implement protective measures, such as limiting engine load or adjusting combustion parameters, that ultimately protect the catalytic converter while maintaining vehicle drivability.
Data Source
AI summary
A method for controlling a plurality of injectors installed in the same cylinder of an engine may include determining whether an electrical failure occurred in any of the injectors, and entering a fail-safe mode when an electrical failure has occurred only in one of the plurality of injectors in the same cylinder. In the fail-safe mode, fuel supply to an injector that has experienced an electrical failure is cut off, and the amount of fuel injected into the cylinder by a normally operating injector is increased.