Engine Fuel Injection Control for Cold Start Emissions
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Solution Overview
Problem
Conventional fuel injection control apparatuses fail to appropriately control fuel injection timing during cold starts, leading to increased residual unburned hydrocarbons due to interference between injected fuel and blow-back exhaust gas, which affects engine performance and emissions.
Innovation Solution
An engine fuel injection control apparatus comprising a fuel injection valve, a variable valve device, and a controller that adjusts the fuel injection timing based on the overlap amount between the intake and exhaust valves, with the controller setting the fuel injection end timing relative to the intake valve open timing to optimize vaporization and reduce unburned hydrocarbons by utilizing blow-back exhaust gas during cold starts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the intake valve open timing is corrected to a more retarded timing to suppress interference between injected fuel and blow-back exhaust gas, then fuel adherence to intake port surfaces is reduced, but the fuel injection timing becomes inappropriate with respect to the gas flow surrounding the intake valve, leading to increased residual unburned hydrocarbons
Solution Approach 1:
The patent implements dynamic adjustment of fuel injection timing based on real-time detection of intake valve timing and overlap amount. The ECU continuously monitors valve operation and adapts the fuel injection end timing accordingly, transitioning from static to dynamic control to optimize fuel vaporization while preventing adherence to intake port surfaces under varying cold start conditions.
Solution Approach 2:
The system employs feedback control by detecting the actual intake valve open timing and overlap amount, then using this information to adjust the fuel injection end timing. The ECU receives feedback from valve position sensors and modifies injection parameters in response, creating a closed-loop control system that resolves the contradiction between preventing fuel adherence and ensuring complete combustion.
2Use of energy by moving object
If the fuel injection end timing is set to occur after the intake valve opens to utilize gas flow, then fuel vaporization improves, but fuel collides with blow-back exhaust gas causing increased residual unburned hydrocarbons during cold starts
Solution Approach 1:
The patent applies preliminary action by detecting the anticipated overlap amount between intake and exhaust valves before fuel injection occurs, and pre-adjusting the fuel injection end timing accordingly. The ECU calculates the optimal injection timing in advance based on predicted valve timing conditions, ensuring fuel is injected at the most appropriate moment to vaporize efficiently without colliding with blow-back exhaust gas.
Solution Approach 2:
The system dynamically changes the fuel injection timing parameter based on detected valve operation conditions. The ECU adjusts the injection end timing parameter in response to varying overlap amounts and intake valve timings, optimizing the balance between fuel vaporization efficiency and prevention of harmful emissions under different cold start scenarios.
3Productivity
If the overlap amount between intake and exhaust valves is increased to improve charging efficiency, then engine performance improves, but fuel injection timing becomes inappropriate due to increased interference with blow-back exhaust gas
Solution Approach 1:
The patent implements dynamic fuel injection timing control that adapts to varying overlap amounts. As the overlap amount changes to optimize charging efficiency, the ECU continuously adjusts the fuel injection end timing to maintain appropriateness. This dynamic coordination allows the system to benefit from increased overlap for charging efficiency while automatically compensating for timing interference through real-time parameter adjustment.
Solution Approach 2:
The system uses feedback from valve timing detection to automatically adjust fuel injection parameters in response to changing overlap amounts. When overlap increases to improve charging efficiency, the ECU receives feedback and modifies injection timing accordingly, simplifying the control operation by making the system self-adjusting rather than requiring manual intervention to coordinate multiple parameters.
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
The solution effectively reduces residual unburned hydrocarbons by advancing or retarding the fuel injection end timing relative to the intake valve open timing, leveraging blow-back exhaust gas to enhance fuel vaporization and minimize fuel adherence to intake port surfaces, thereby improving engine efficiency and emission control.
Implementation Method 1
leveraging blow-back exhaust gas to enhance fuel vaporization
Data Source
Figure 1
Figure 2(A)~2(B-3)
Figure 3
AI summary
An engine fuel injection control apparatus includes a variable valve device (100) that at least varies an intake valve open timing of an intake valve (23). A controller (70) adjusts the variable valve device (100) and a fuel injection timing of a fuel injection valve (53). The controller (70) controls a fuel injection end timing in accordance with an overlap amount of the intake valve (23) and an exhaust valve (33). The controller (70) adjusts the fuel injection timing such that the fuel injection end timing is more advanced than the intake valve open timing and such that as an amount by which the overlap amount exceeds a prescribed overlap amount becomes larger, a time interval between the fuel injection end timing until and the intake valve open timing is set to become increasingly larger, upon determining that the engine (1) is being cold started and the overlap amount is larger than the prescribed overlap amount.