Throttle Valve Control for Turbocharger Surge Prevention
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Solution Overview
Problem
Forced induction engines face damage and noise issues due to air pressure surges, which existing solutions often mitigate using bypass valves that add weight, cost, and complexity.
Innovation Solution
A method for controlling the throttle valve to maintain an air flow rate greater than or equal to the surge limit of the air compressor, determined by monitoring upstream and downstream air pressures, to prevent pressure surges without the need for a bypass valve.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a bypass valve is added to prevent pressure surge damage, then the air compressor is protected from damage, but the device complexity and weight increase
Solution Approach 1:
The patent replaces the mechanical bypass valve system with an electronic control system that uses sensors to monitor air pressure and flow rate, and an actuator to control the throttle valve position. This substitution eliminates the need for complex mechanical bypass components while achieving the same protective function through electronic sensing and actuation.
Solution Approach 2:
The patent changes the operating parameters of the throttle valve based on real-time monitoring of air pressure and flow rate. By dynamically adjusting the throttle valve position to maintain operation above the surge limit line, the system prevents pressure surge damage without requiring a bypass valve, thus reducing device complexity.
2Reliability
If a bypass valve is added to prevent pressure surge, then damage is avoided, but the cost and assembly complexity increase
Solution Approach 1:
The patent replaces the mechanical bypass valve system with an electronic control system that uses sensors to monitor air pressure and flow rate, and an actuator to control the throttle valve position. This substitution eliminates the need for complex mechanical bypass components while achieving the same protective function through electronic sensing and actuation.
Solution Approach 2:
The throttle valve, originally designed for controlling air flow to the engine, is given the additional function of preventing compressor surge through electronic control. By making the throttle valve multi-functional, the patent eliminates the need for a separate bypass valve component, thereby simplifying manufacturing and assembly.
3Speed
If the throttle valve closes quickly to reduce air flow, then engine speed control is improved, but pressure surge occurs damaging the compressor
Solution Approach 1:
The patent implements a feedback control system where sensors continuously monitor air pressure and flow rate, and this information is fed back to the control unit which adjusts the throttle valve position accordingly. This feedback mechanism allows the system to slow down the throttle valve closure rate when approaching surge conditions, preventing compressor damage while still achieving engine speed control.
Solution Approach 2:
The patent makes the throttle valve closure rate dynamic rather than fixed. The control unit adjusts the closure rate based on real-time operating conditions, slowing down the closure when pressure and flow rate indicate approaching surge conditions. This dynamic adjustment prevents compressor damage while maintaining effective engine speed 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 approach effectively prevents damage and noise from air pressure surges by ensuring the air flow rate exceeds the surge limit, thereby protecting the air compressor without the drawbacks of a bypass valve.
Implementation Method 1
an air compressor to deliver compressed air to the intake of the engine
Implementation Method 2
the exhaust gases from the engine turn a turbine which compresses the air
Data Source
AI summary
A method for controlling a forced induction engine includes: determining a first air pressure upstream of an air compressor, the air compressor supplying compressed air to the engine; determining a second air pressure downstream of the air compressor; determining a limit air flow rate to the engine corresponding to the surge limit of the air compressor based at least in part on the first and second air pressures; and controlling a throttle valve actuator to position the throttle valve at a position providing an air flow rate that is greater than or equal to the limit air flow rate. A vehicle power pack having a control unit implementing the method and a vehicle having the vehicle power pack are also disclosed.