Blocking Cylinder Fuel Injection to Increase Tank Venting Purge Flow
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Solution Overview
Problem
Existing methods for increasing the purging air mass flow in internal combustion engine tank venting systems are limited, often requiring additional components and complex system configurations, which increase costs and complexity, and do not adequately address the need for maximizing purging air mass flow, especially during idling modes.
Innovation Solution
The method involves blocking the direct fuel feed to cylinders, utilizing the tank venting system's purging air mass flow as part of the fresh air mass flow to maintain the prescribed air-fuel ratio, and activating secondary lambda control circuits to regulate fuel and air mass flows, thereby maximizing purging air mass flow without additional components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If additional components are integrated into the tank venting system to increase purging air mass flow, then the purging air mass flow is improved, but the device complexity and cost increase
Solution Approach 1:
The invention utilizes the existing intake system and negative pressure conditions to drive purging air flow through the tank venting system without requiring additional pumps or active components. The system serves itself by leveraging the engine's operating conditions to create the necessary pressure differential for purging.
Solution Approach 2:
The tank venting valve is integrated into the existing fresh air system infrastructure, allowing the same system components to serve multiple functions: fresh air intake and fuel vapor purging. This eliminates the need for separate dedicated purging components.
2Quantity of substance
If the tank venting valve is opened to increase purging air mass flow, then the purging air mass flow is improved, but the air-fuel ratio control precision deteriorates
Solution Approach 1:
The lambda value control continuously monitors the air-fuel ratio and provides feedback to the control unit. Based on this feedback, the control unit dynamically adjusts the tank venting valve opening to maintain the prescribed air-fuel ratio while maximizing purging air mass flow within the constraints of proper combustion mixture control.
3Productivity
If the purging air mass flow is increased during idling modes, then the purging efficiency is improved, but the risk of disrupting combustion mixture control increases
Solution Approach 1:
The control unit dynamically adjusts the tank venting valve opening based on real-time operating conditions, including engine load, speed, and lambda values. During idling modes, the system optimizes the balance between purging efficiency and combustion stability by continuously adapting the venting valve position to maintain reliable combustion mixture control while maximizing purging within safe limits.
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 increases the purging air mass flow, ensuring efficient operation and maintaining the air-fuel ratio, even during idling modes, by leveraging existing system components and improving regulation quality.
Implementation Method 1
Owing to a pressure which prevails at the at least one feed point and which is negative relative to the tank venting line and dependent on the load point, the fuel tank of the tank venting system is vented via the at least one venting path
Data Source
AI summary
A method for operating an internal combustion engine which has a number of cylinders and which comprises a fuel system and a fresh air system, whereby fuel is fed in a fuel mass flow via a fuel supply line of the fuel system to the cylinders at a prescribable air-fuel ratio directly by means of the injectors, and fresh air is fed in a fresh air mass flow via a fresh air system, whereby the fuel system comprises a tank venting system with a tank venting line that has a tank venting valve and that, via the interconnected tank venting valve, is connected to at least one line section of the fresh air system via at least one feed point, thereby forming at least one venting path, whereby, owing to a pressure which prevails at the at least one feed point and which is negative relative to the tank venting line and dependent on the load point, the fuel tank of the tank venting system is vented via the at least one venting path, a venting process in which a purging air mass flow containing fuel is removed from the tank venting system and fed to the cylinders as a portion of the fresh air mass flow, so that a total fuel mass flow is fed into the cylinders directly by means of the injectors of the fuel system as well as indirectly via the fresh air mass flow. It is provided that the direct feed of fuel by means of the injector of at least one of the cylinders is blocked, as a result of which a purging air mass flow comprising the fuel volume equivalent that is now absent due to the blocking of the at least one cylinder can advantageously be removed from the tank venting line, while maintaining the prescribed air-fuel ratio via the at least one venting path at the at least one feed point, and this purging air mass flow can be fed as a portion of the fresh air mass flow to the cylinder(s) that is/are still being supplied with fuel.