In-Cylinder Direct Injection Engine Fuel Control for Spark Plug Wetting
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Solution Overview
Problem
In-cylinder direct-injection internal combustion engines face challenges with spark plug wetting and poor starting capability at extremely low temperatures due to insufficient fuel atomization and ignition issues, which existing methods fail to adequately address.
Innovation Solution
A control device that calculates the required fuel injection amount and timing to avoid spark plug wetting by determining optimal injection start and end timings and number of ignition cut-offs, ensuring successful first-cycle ignition and improved starting capability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If ignition cut-off is performed at extremely low temperature to accumulate fuel for combustion, then fuel accumulation for ignition is improved, but spark plug wetting occurs and starting capability deteriorates
Solution Approach 1:
The patent changes the parameter of injection timing by defining specific start and end timings for fuel injection during ignition cut-off. By controlling the injection duration and timing window, the system accumulates sufficient fuel in the cylinder while preventing excessive fuel from wetting the spark plug, thus resolving the contradiction between fuel accumulation and starting reliability
Solution Approach 2:
The patent dynamically adjusts the injection timing parameters based on engine operating conditions. The injection start timing and end timing are set as dynamic parameters that define a specific time window, allowing the system to adaptively control fuel delivery during the ignition cut-off period to optimize both fuel accumulation and prevent plug wetting
2Quantity of substance
If fuel injection timing is extended to ensure sufficient fuel supply, then fuel accumulation is improved, but spark plug wetting increases
Solution Approach 1:
The patent applies partial action by providing just enough fuel injection during the ignition cut-off period without excessive injection. By setting specific start and end timings for injection, the system delivers the precise amount of fuel needed for accumulation while stopping before excess fuel can wet the spark plug, achieving the optimal balance between fuel supply and preventing harmful wetting
3Reliability
If ignition cut-off period is extended to accumulate more fuel, then combustion quality is improved, but starting time increases
Solution Approach 1:
The patent performs preliminary action by pre-setting the injection timing parameters (start timing and end timing) before the ignition cut-off begins. This preliminary configuration ensures that fuel injection occurs at the optimal moments during cranking, allowing sufficient fuel accumulation and combustion preparation without unnecessarily extending the overall starting time
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 control device effectively prevents spark plug wetting and enhances starting capability at low temperatures by calculating and adjusting fuel injection parameters, ensuring successful engine start and improved performance in engines with unsatisfactory combustion or high friction.
Implementation Method 1
a time period from fuel injection until the fuel reaches an ignition position is shorter than in a port injection engine injecting fuel into the intake port. Accordingly, atomization of the fuel injected into the cylinder is insufficient at the time of start at an extremely low temperature
Implementation Method 2
the air-fuel mixture is ignited by a spark plug
Implementation Method 3
the air-fuel mixture is ignited by a spark plug and burnt
Data Source
AI summary
A requested injection amount of fuel necessary during ignition cut-off at the time of start at an extremely low temperature is calculated (step ST2), injection start timing and injection end timing between which wetting of a spark plug by fuel is less likely are set (step ST3), and the number of times of ignition cut-off is calculated based on the injection start timing and the injection end timing and the requested injection amount (step ST4). The injection start timing and the injection end timing are thus restricted to timings between which plug wetting is less likely, and the number of times of ignition cut-off is calculated based on the injection start timing and the injection end timing and the requested injection amount, so that wetting of the spark plug by fuel at the extremely low temperature can be avoided even in an in-cylinder direct-injection engine.