Boost Reservoir Discharge Control for Turbo Lag Reduction
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Solution Overview
Problem
Turbocharged engines experience power lag and reduced performance during transient conditions due to insufficient turbocharger turbine spin-up, as the boost air is consumed faster downstream of the compressor than upstream, leading to inadequate torque delivery and inefficient use of stored compressed air.
Innovation Solution
A method where pressurized charge from a boost reservoir is discharged into either the intake or exhaust manifold based on engine operating conditions and the composition of the charge, to rapidly increase exhaust temperature or pressure and expedite turbine spin-up, using a controller to decide the discharge location based on factors like boost reservoir composition, pressure, and engine conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If pressurized charge is discharged into the intake manifold to provide increased torque, then torque output is improved during transient conditions, but the boost air is depleted faster and torque drops when the supply is depleted
Solution Approach 1:
The patent segments the discharge of pressurized charge into two distinct pathways: discharge into the intake manifold to provide torque, and discharge into the exhaust manifold to expel exhaust gases. This segmentation allows the system to manage boost air consumption more effectively by directing charge to the exhaust manifold during certain conditions, preventing premature depletion and maintaining torque supply duration.
Solution Approach 2:
The patent introduces the exhaust manifold as an intermediary pathway for discharge. By discharging pressurized charge into the exhaust manifold, the system creates an intermediate step that helps manage the depletion of boost air and prevents direct, rapid consumption from the intake manifold, thereby extending the duration of effective torque supply.
2Device complexity
If the boost reservoir has a small volume, then device complexity is reduced, but the boost air is consumed faster and torque compensation is insufficient
Solution Approach 1:
The patent implements dynamic control of the discharge process by adjusting the timing and duration of discharge events based on real-time engine conditions. The controller dynamically determines when to discharge pressurized charge into the intake manifold versus the exhaust manifold, optimizing torque compensation without requiring a large reservoir volume. This dynamic approach allows effective torque management with a compact reservoir.
3Stability of the object's composition
If the boost reservoir is charged with a large percentage of exhaust gas, then the charge composition is optimized for certain conditions, but the lack of sufficient excess oxygen reduces the ability to compensate turbo lag
Solution Approach 1:
The patent employs dynamic adjustment of charge composition based on real-time engine conditions. The controller determines the optimal discharge strategy by considering factors such as current boost levels, exhaust gas temperature, and torque demand. This dynamic approach allows the system to optimize both charge composition and turbo lag compensation by selecting appropriate discharge timing and destination based on prevailing operating conditions.
Solution Approach 2:
The patent utilizes parameter changes in the discharge process, specifically varying the timing and duration of discharge events. By adjusting these parameters dynamically, the system can optimize the interaction between charge composition and turbo lag compensation, allowing effective performance even with varying exhaust gas content in the reservoir charge.
4Speed
If pressurized charge is discharged to rapidly increase exhaust temperature and expedite turbine spin-up, then turbine response time is improved, but the selection of discharge location requires complex control logic
Solution Approach 1:
The patent implements preliminary action by pre-charging the reservoir with a mixture of exhaust gas and fresh air during steady-state operation. This preliminary charging prepares the reservoir with optimized charge composition that can be rapidly discharged into the exhaust manifold during transient conditions to expedite turbine spin-up. The preliminary action reduces the need for complex real-time control decisions during critical transient events.
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 reduces turbo lag and improves engine performance by effectively utilizing the stored charge to enhance turbine spin-up and maintain torque output, even when boost air is depleted, by strategically directing the pressurized air to either the intake or exhaust manifold.
Implementation Method 1
discharging pressurized charge from a boost reservoir to an exhaust manifold... rapidly increase exhaust temperature or pressure and expedite turbine spin-up
Implementation Method 2
discharging pressurized charge from a boost reservoir to an intake manifold... provide increased torque to address turbo lag while the turbine spools up
Data Source
AI summary
Methods and systems are provided for reducing turbo lag in a boosted engine. A boost reservoir coupled to the engine may be charged with compressed intake air and/or combusted exhaust gas. The pressurized charge may then be discharged during a tip-in to either the intake or the exhaust manifold.