Fuel Injector Driver Mode Switching for Cold Start
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Solution Overview
Problem
High resistance fuel injectors, such as those used in CNG applications, face difficulties in cold weather due to sticky seals, which are harder to open with low current saturated switch drivers, potentially leading to overheating and performance issues.
Innovation Solution
A controller-driven fuel injector system that switches between peak and hold mode to unstick the seal and saturated mode to prevent overheating, using a driver with both modes and a temperature sensor to determine the operational mode based on weather conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If saturated switch mode is used for high resistance fuel injectors, then the actuation coil operates cooler, but the injector opens slowly and may fail to open in cold weather due to sticky seals
Solution Approach 1:
The fuel injector driver dynamically switches between saturated switch mode and peak and hold mode based on operating conditions. During cold start conditions, the driver uses peak and hold mode to quickly open the injector, then transitions to saturated switch mode for normal operation, allowing the system to adapt its characteristics to different operational requirements.
2Speed
If peak and hold mode is used to quickly open the injector, then the injector opens rapidly, but the actuation coil overheats due to high current exposure
Solution Approach 1:
The driver uses periodic pulsed current application in peak and hold mode, where current is applied in pulses rather than continuously. This allows the actuation coil to be energized quickly to open the injector, then the current is reduced or interrupted, preventing sustained overheating while still achieving rapid opening when needed.
Solution Approach 2:
The system dynamically transitions from peak and hold mode with high current to saturated switch mode with lower current after the injector is opened, allowing rapid opening when needed while preventing sustained overheating during normal operation.
3Reliability
If saturated switch mode is used for high resistance injectors, then the system is simpler and cooler operating, but reliability decreases in cold weather when seals are sticky
Solution Approach 1:
The fuel injector driver incorporates dynamic mode selection capability, transitioning between saturated switch mode and peak and hold mode based on temperature sensors and operating conditions. This adds control complexity but ensures reliable operation across different temperature ranges by using the appropriate mode for each condition.
Solution Approach 2:
The system detects cold start conditions using temperature sensors and proactively switches to peak and hold mode before the injector needs to open, ensuring the seal is not sticky and the injector can open reliably. This preliminary adaptation to cold conditions prevents potential failure.
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
Effectively opens high resistance fuel injectors in cold weather without overheating the actuation coil, ensuring reliable fuel delivery and preventing damage from high current exposure.
Implementation Method 1
This injector is driven by a peak and hold fuel injector driver that applies a relatively high current to quickly open the injector using an actuation coil that generates a magnetic field used to open a valve assembly
Data Source
AI summary
An engine control system includes a fuel injector and a sensor that is configured to provide a signal indicative of a temperature. A controller is in communication with the sensor. The controller includes a fuel injector driver in communication with the fuel injector. The fuel injector driver includes a saturated mode and a peak and hold mode. The controller is configured to command the fuel injector driver to control the fuel injector with one of the saturated mode or the peak and hold mode based upon the signal. For a high resistance injector, the peak and hold mode is used in cold weather conditions to break free an injector seal, and then the fuel injector driver reverts to the saturated mode.