Variable Intake Valve Control for Turbocharged Gasoline Engines
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Solution Overview
Problem
Turbo-charged gasoline engines face inefficiencies due to the need for a 'waste-gate' valve to prevent high supercharger pressures at high engine speeds, leading to increased fuel consumption and suboptimal combustion conditions.
Innovation Solution
A variable driving system for the intake valve, controlled by a camshaft, tappet, and hydraulic system with solenoid valves, allows for precise adjustment of the intake valve's opening and closing moments and lift to match specific engine operating conditions, reducing the need for the 'waste-gate' valve and maintaining stoichiometric air/gasoline ratios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If a waste-gate valve is used to prevent high supercharger pressures at high engine speeds, then supercharger pressure is controlled, but fuel consumption increases and combustion efficiency decreases
Solution Approach 1:
The patent implements dynamic control of the intake valve timing and lift based on real-time engine operating conditions (speed, load, temperature). The control unit adjusts the intake valve closing timing relative to the piston position, creating variable compression ratios that adapt to changing engine demands, eliminating the need for static waste-gate pressure relief
Solution Approach 2:
The system changes the compression ratio parameter dynamically by varying the intake valve closing timing and lift. At high engine speeds, the compression ratio is reduced by closing the intake valve earlier, which lowers the peak combustion pressure and temperature, thereby controlling supercharger pressure without wasting energy through the waste-gate mechanism
2Reliability
If the compression ratio is reduced at high engine speeds to prevent detonation, then detonation is prevented, but the need for waste-gate valve intervention increases
Solution Approach 1:
The control unit proactively adjusts the intake valve closing timing before detonation can occur. By detecting engine operating conditions in advance and preemptively modifying the compression ratio through valve timing adjustment, the system prevents detonation rather than reacting to it, thereby eliminating the need for waste-gate intervention
3Device complexity
If the intake valve opening profile is fixed, then the system is simple, but it cannot adapt to varying engine speed and torque requirements
Solution Approach 1:
The patent transforms the static intake valve control into a dynamic system where the valve timing and lift are continuously adjusted based on engine speed, load, and temperature sensors. The control unit processes these inputs and generates real-time commands to the valve actuator, enabling the system to adapt to varying operating conditions while maintaining manageable complexity through electronic control
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 system optimizes air mass in the cylinder, reduces fuel consumption, and achieves efficient combustion by adapting the intake valve profile to engine speed and torque requirements, minimizing waste heat and maximizing supercharger pressure.
Implementation Method 1
a hydraulic system interposed between the tappet and the intake valve, comprising a pressure chamber that can be connected with an exhaust channel through a solenoid valve
Implementation Method 2
the intake valve closes due to the effect of spring means associated with it
Implementation Method 3
when the solenoid valve is open, the fluid is discharged from the chamber under pressure
Data Source
AI summary
In a turbo-charged gasoline engine the opening profile of each intake valve, defined by the opening and closing moments and by the lift, or by the opening stroke of the intake valve, is varied according to the engine operating conditions, so as to reduce or completely eliminate the intervention of a “waste-gate” valve and ensure that in each engine operating condition each cylinder processes only the quantity of air necessary for optimal combustion, with an air/gasoline dosage value close to the stoichiometric ratio.