Boost Reservoir Pressure Control for Turbo Lag Reduction
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Solution Overview
Problem
Turbo lag in engines with turbochargers occurs due to the delay in providing boosted air pressure, as the density of compressed air in boost reservoirs decreases, especially when warmed air is purged and not immediately replenished, leading to reduced engine throttle response and inability to meet torque demands.
Innovation Solution
A pressurized air induction system (PAI) that uses an external source of compressed air to maintain boost pressure in the reservoir by replenishing it when pressure drops below a nominal threshold and increasing pressure before purging warmed air, ensuring consistent air density and rapid boost delivery during torque demands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If boosted air is stored in a reservoir to reduce turbo lag, then throttle response is improved, but air density decreases when warmed air is purged and not immediately replenished
Solution Approach 1:
The system performs preliminary action by pre-filling the reservoir with cold compressed air before the purge event. The controller detects the purge condition and activates the external compressed air source to replenish the reservoir with cold air, ensuring that when the warmed air is purged, the reservoir is already replenished with high-density cold air, preventing a drop in air density and maintaining throttle response.
2Quantity of substance
If the reservoir is purged of warmed air to maintain density, then air density is improved, but boost pressure decreases temporarily
Solution Approach 1:
The system uses feedback control by continuously monitoring reservoir pressure and temperature. When the controller detects that the reservoir pressure drops below a threshold during or after a purge event, it automatically activates the external compressed air source to replenish the reservoir, maintaining boost pressure within the desired range while ensuring adequate air density.
3Stress or pressure
If external compressed air source is used to maintain reservoir pressure, then boost pressure is improved, but system complexity increases
Solution Approach 1:
The system applies multi-functionality by utilizing an existing external compressed air source (such as an air suspension system) for a secondary function - replenishing the reservoir during purge events. This existing component serves dual purposes: its primary function for suspension and its secondary function for reservoir replenishment, thereby maintaining boost pressure without adding a completely new dedicated system, thus limiting the increase in overall system complexity.
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 enhances engine performance by maintaining elevated boost pressure and responsive throttle response, reducing turbo lag by ensuring the reservoir can rapidly provide boost pressure when needed, even during increased torque demands.
Implementation Method 1
an external source of compressed air may increase the pressure of the boost reservoir by supplying additional compressed air to the PAI system
Implementation Method 2
the boosted air is typically cooled by flowing the air through a charge air cooler (CAC) before entering the engine intake manifold, a process that also increases the density of the air
Data Source
AI summary
Methods and systems are provided for boosted engines. In one example, a method for a boosted engine method may include storing compressed air in a reservoir for supply to the engine during increased engine load operating conditions and replenishing the air in response to pressure dropping below a nominal threshold; and increasing the pressure beyond the nominal threshold in response to increased temperature of the stored air in the reservoir even when operating conditions include decreased engine load, and purging the increased temperature stored air to bring pressure back down toward the nominal threshold. In one example, increasing pressure to the reservoir may include supplying compressed air from an air suspension system. In one example, increasing pressure to the reservoir may include supplying compressed air from an air compressor separate from an engine turbocharger compressor. In one example, the method may include, in response to a vehicle operator tip-in during the increasing of the pressure beyond the nominal threshold, simultaneously supplying stored compressed air to the engine while replenishing the air.