Secondary Air Flow Control Using Lambda Feedback in IC Engines
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for controlling secondary air mass flow in internal combustion engines lead to deviations in exhaust gas lambda, affecting catalyst conversion capability and potentially increasing raw emissions, necessitating improved control strategies.
Innovation Solution
A method and device that determine the secondary air mass flow using a throttle equation based on pressure conditions and exhaust gas lambda values, deriving an effective throttle area through recursive algorithms like LMS or NLMS, allowing precise control of the secondary air mass flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the combustion chamber lambda target value is adjusted to regulate exhaust gas lambda, then the exhaust gas lambda is regulated, but raw emissions from the internal combustion engine increase
Solution Approach 1:
The patent implements a feedback control system where the actual secondary air mass flow is continuously measured and compared with the target value. The controller adjusts the secondary air mass flow based on this feedback to maintain the desired exhaust gas lambda, eliminating the need to adjust combustion chamber lambda and thus preventing increased raw emissions.
Solution Approach 2:
The patent replaces the mechanical/chemical adjustment of combustion chamber lambda with an electronic control system that directly regulates the secondary air mass flow using actuators such as valves or pumps. This substitution allows precise control of exhaust gas lambda without affecting combustion parameters and raw emissions.
2Ease of operation
If secondary air mass flow is not accurately controlled, then the system is simpler to operate, but exhaust gas lambda deviations occur affecting catalyst capability
Solution Approach 1:
The patent employs a feedback control mechanism where the actual secondary air mass flow is measured and continuously compared with the target value. The controller automatically adjusts the air flow based on this feedback, maintaining accurate exhaust gas lambda control while automating the process to preserve operational simplicity.
Solution Approach 2:
The control system performs self-regulation by automatically adjusting the secondary air mass flow based on measured deviations from the target value. This self-service capability maintains accurate exhaust gas lambda without requiring manual intervention, thus preserving ease of operation while ensuring reliability.
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
Accurately controls the secondary air mass flow, enhancing catalyst efficiency and reducing raw emissions by aligning the actual flow with target values, thus optimizing the exhaust aftertreatment system.
Implementation Method 1
a) determining a first secondary air mass flow ({dot over (m)}secAirNoAeff) related to the effective throttle area (Aeff) using a throttle equation and depending on a pressure (pS) in the secondary air supply
Implementation Method 2
an exhaust gas lambda sensor for determining a current exhaust gas lambda value (λsens)
Implementation Method 3
An external mass air flow is introduced into the exhaust manifold at the exhaust valves of the engine, which reacts exothermically with a rich combustion chamber lambda on the hot surfaces of the manifold and turbocharger
Data Source
AI summary
A method for controlling a secondary air mass flow in a secondary air supply of an internal combustion engine. The internal combustion engine comprises the secondary air supply, a device for determining a pressure in the secondary air supply, and an exhaust gas lambda sensor for determining a current exhaust gas lambda value. The method includes a) determining a first secondary air mass flow) related to the effective throttle area using a throttle equation and depending on a pressure in the secondary air supply, b) determining a second secondary air mass flow based on the measured exhaust gas lambda value and taking into account a primary air mass flow of the internal combustion engine and a supplied fuel mass flow, c) deriving an effective throttle area from the first secondary air mass flow determined in step a) and the second secondary air mass flow determined in step b), and d) controlling the secondary air mass flow in the secondary air supply using the effective throttle area determined in step c) or a quantity derived therefrom.