Gasoline Direct Injection Timing Control for Early Intake Valve Closure
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Solution Overview
Problem
Internal combustion engines with gasoline direct injection and variable intake valve actuation face challenges in achieving low exhaust smoke and stable combustion, particularly when intake valves close early, as they struggle to ensure complete fuel-air mixing and adequate fuel injection.
Innovation Solution
The engine employs electronic control means with memory storage to determine allowed crank angles for gasoline injection start and end, ensuring a minimum distance from intake valve closure and adjusting injection pressure based on operating conditions to guarantee a predefined fuel amount, thereby controlling the injection timing and pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If gasoline injection starts when the piston is sufficiently far from intake TDC to reduce smoke, then exhaust smoke is reduced, but the distance between end of injection and intake valve closure decreases, compromising complete fuel-air mixing
Solution Approach 1:
The system dynamically adjusts injection timing parameters based on intake valve closure timing. When early valve closure is detected, the control unit modifies the injection start time and duration to ensure adequate mixing time while maintaining smoke reduction. This parameter adaptation allows the system to resolve the contradiction between smoke reduction and complete mixing under varying operational conditions.
2Productivity
If the intake valve closes in advance to improve engine efficiency, then engine performance is improved, but the time available for fuel evaporation and mixing is reduced, leading to incomplete combustion
Solution Approach 1:
The system performs preliminary detection of intake valve closure timing and pre-calculates the required injection parameters before fuel injection begins. The control unit uses memory-stored reference values and real-time sensor data to determine optimal injection timing that ensures complete fuel evaporation and mixing even with early valve closure. This preliminary planning allows the system to maintain efficient combustion while ensuring complete fuel-air preparation.
3Adaptability or versatility
If variable actuation of intake valves is used to control closing instant, then engine adaptability is improved, but the complexity of the control system increases
Solution Approach 1:
The control system continuously monitors actual intake valve closure timing and uses this feedback to adjust injection parameters in real-time. The control unit compares detected valve closure events with reference values stored in memory and dynamically modifies injection timing and duration accordingly. This feedback mechanism enables the system to maintain optimal performance across a wide operating range while using a relatively simple control architecture that leverages existing sensor and actuator infrastructure.
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 approach maintains low exhaust smoke and stable combustion across all operating conditions, including early intake valve closure regimes, without compromising the injection of the required fuel amount.
Implementation Method 1
said pressurised fluid chamber is adapted to be connected by means of a solenoid valve with an exhaust channel with the aim of decoupling the variable actuation valve from the respective tappet and cause the quick closing of the valve due to the respective elastic return means
Implementation Method 2
each intake valve is provided with return spring means which push the valve towards a closed position
Implementation Method 3
said pressurised fluid chamber is adapted to be connected by means of a solenoid valve with an exhaust channel
Data Source
AI summary
An electronic control means of an engine controls a system for the variable actuation of intake valves and for controlling gasoline injection into the combustion chamber. To the electronic control means there are associated memory means. The electronic means are programmed for detecting a value of a crank angle at which the intake valve is closed, controlling the end of the injection with an anticipation with respect to the closing of the intake valve controlling the start of the injection substantially according to said crank angle limit value, and regulating the injection pressure to a value which is defined as a function of the injection time to guarantee the injection of a predefined amount of gasoline.