Engine Control Device Ignition Timing Retard
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Solution Overview
Problem
In engines using gaseous fuel, when the internal pressure of the fuel tank decreases below a set pressure, the injection pressure of the injector also decreases, leading to potential inflow of combustion gas into the injector and difficulties in maintaining appropriate fuel injection, which can result in self-ignition and torque loss.
Innovation Solution
An engine control device that retards the ignition timing and increases the injection amount of gaseous fuel when the fuel pressure drops, extending the injection permission period to prevent combustion gas inflow and maintain stable fuel injection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the injection pressure decreases due to lower fuel tank pressure, then the fuel consumption is reduced, but the combustion gas may flow into the injector and cause self-ignition
Solution Approach 1:
The control device performs preliminary action by retarding the ignition timing before combustion gas inflow can occur. When the injection pressure is detected to be lower than the reference pressure, the ignition timing is automatically retarded to a value smaller than the reference ignition timing, preventing the combustion gas from flowing into the injector through the nozzle hole before the injection is complete.
Solution Approach 2:
The control device changes the ignition timing parameter in response to injection pressure changes. By dynamically adjusting the ignition timing based on the detected injection pressure (comparing it with reference pressure), the system adapts the combustion process to maintain reliability under varying fuel pressure conditions.
2Loss of energy
If the injection pressure decreases, then the fuel cost is reduced, but the torque output decreases due to insufficient fuel injection
Solution Approach 1:
The control device uses feedback by detecting the injection pressure and comparing it with a reference pressure to determine whether to retard the ignition timing. This closed-loop control ensures that the ignition timing is adjusted based on actual fuel pressure conditions, optimizing both fuel efficiency and torque output.
Solution Approach 2:
The system dynamically adjusts the ignition timing based on real-time injection pressure conditions. Rather than using a fixed ignition timing, the control device modifies the ignition timing parameter according to the detected fuel pressure, enabling the engine to adapt to varying operating conditions and maintain optimal performance.
3Duration of action of moving object
If the injection timing is advanced to maintain injection pressure, then the injection continues, but the diffusion combustion cannot be continued and must switch to premixed combustion
Solution Approach 1:
Instead of advancing the injection timing to maintain injection pressure (which would require switching combustion modes), the control device inverts the approach by retarding the ignition timing. This allows the injection to proceed at the original timing while preventing combustion gas inflow through ignition timing adjustment, avoiding the complexity of combustion mode switching.
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 solution suppresses combustion gas inflow into the injector, reduces torque loss, and minimizes self-ignition by adjusting ignition timing and injection quantity, ensuring consistent fuel delivery even at lower fuel pressures.
Implementation Method 1
The injector is configured to inject and stop the fuel by opening and closing a nozzle hole in response to driving of a needle by an electromagnetic solenoid.
Implementation Method 2
The needle is biased in a direction to close the nozzle hole by the spring load and the pressure of the gaseous fuel supplied to the injector.
Implementation Method 3
The needle is biased in a direction to close the nozzle hole by the spring load and the pressure of the gaseous fuel supplied to the injector.
Implementation Method 4
ignition timing of an air-fuel mixture in the cylinder after the gaseous fuel is injected
Data Source
AI summary
The electronic control unit performs a retarding process of retarding the ignition timing when the fuel pressure decreases, and lowers the peak of the combustion pressure in the cylinder, thereby suppressing the inflow of the combustion gas to the injector. Further, the electronic control unit performs an increasing process of increasing the injection amount of the hydrogen gas together with the retarding process, thereby suppressing the torque decrease of the engine due to the retard of the ignition timing.