Dynamic Air Charge Control in Forced-Induction Engines

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Solution Overview

Problem

In internal combustion engines, especially those with forced induction, the air charge cannot be adjusted effectively in all operating states without increasing fuel consumption, due to the limitations of traditional throttle-valve control systems and boost-pressure control systems that do not account for the dynamic response of the induction pipe volume.

Innovation Solution

A method and device that control the mass flow rate of air in the charging mode by adjusting the pressure in the induction pipe using a charging device, allowing for a dynamic air-charge response that is independent of the throttle valve position, enabling faster and more reproducible air charge setting by selectively increasing or decreasing the mass flow rate of air based on a predefined dynamic response characteristic.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a throttle valve is used to control air charge in forced-induction engines, then air charge can be adjusted in throttle-valve mode, but fuel consumption increases due to the need to maintain higher pressure in front of the throttle valve

Engineering Contradiction:

Improveair charge adjustment capabilityVSAvoidfuel consumption

Core Design Contradiction:

Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The patent implements dynamic switching between two control modes (throttle-valve mode and charging mode) based on operating conditions. The control system dynamically adjusts the operating point of the charging device and throttle valve position to optimize performance. This dynamic approach allows the system to adapt to varying engine states and achieve optimal air charge control while minimizing fuel consumption by selecting the most efficient control strategy for each operating condition.

Inventive Principle:

Principle #15Dynamics

2Power

If a classical boost-pressure control system is used, then boost pressure can be controlled, but the induction pipe volume is not accounted for resulting in insufficient dynamic response

Engineering Contradiction:

Improveboost pressure controlVSAvoiddynamic response speed

Core Design Contradiction:

PowerVSSpeed

Solution Approach 1:

The patent applies preliminary action by pre-calculating and pre-adjusting the charging device operating point and throttle valve position based on predicted engine state changes. The control system anticipates the effect of induction pipe volume on dynamic response and prepares the system in advance, allowing for faster and more accurate air charge adjustment. This preliminary action compensates for the inertial effects of the induction pipe volume and enables the system to respond more rapidly to changing operating conditions.

Inventive Principle:

Principle #10Preliminary action

3Speed

If the mass flow rate of air is increased to build up induction pipe pressure rapidly, then dynamic response improves, but fuel consumption increases

Engineering Contradiction:

Improveinduction pipe pressure response speedVSAvoidfuel consumption

Core Design Contradiction:

SpeedVSLoss of energy

Solution Approach 1:

The patent utilizes parameter changes by dynamically adjusting the mass flow rate of air and the operating parameters of the charging device based on real-time engine state and desired dynamic response. The control system modifies flow rates, pressures, and temperatures as parameters to achieve optimal performance. By carefully managing parameter transitions and using the induction pipe volume as a buffer, the system can achieve rapid response when needed while maintaining fuel efficiency during steady-state operation.

Inventive Principle:

Principle #35Parameter changes

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 allows for more rapid and reproducible air charge setting in the induction pipe, reducing fuel consumption and ensuring consistent engine response across various engine states by directly controlling the mass flow rate via the charging device, rather than relying solely on throttle valve adjustments.

Implementation Method 1

the mass flow rate of air to be supplied is ascertained, which is to be provided to the charging device as a control variable

Methodology Applied

Scientific EffectMass flow rate control:

Implementation Method 2

the pressure in the induction pipe is adjusted by a control system in accordance with a specifiable dynamic charge response characteristic

Methodology Applied

Scientific EffectPressure control:

Implementation Method 3

The volume of the induction pipe causes a requested setpoint air charge to not immediately correspond to the actual air charge

Methodology Applied

Scientific EffectInduction pipe volume effect:

Implementation Method 4

with the aid of a throttle-valve control system, the mass flow rate of air into the engine being controlled

Methodology Applied

Scientific EffectThrottle valve control: Valve

Data Source

PatentUS7529615B2Method and device for controlling a charging device of an internal combustion engine during a charging mode

Publication Date: 2009.05.05 ROBERT BOSCH GMBH

AI summary

A method for setting a mass flow rate of air to be provided in a charging mode; in the charging mode (where a throttle valve is open), the pressure prevailing in an induction pipe only being set via an adjustable mass flow rate of supplied air; a requested torque corresponding to a mass flow rate of air into a cylinder, the mass flow rate of air into the cylinder being adjustable via the pressure in the induction pipe; to set the mass flow rate of air into the cylinder, the pressure in the induction pipe being adjusted by a control system in accordance with a specifiable dynamic charge response characteristic.