Soot Particle Filter Regeneration via Cylinder Deactivation
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Solution Overview
Problem
Gasoline engines with soot particle filters face challenges in regeneration due to limited oxygen availability during stoichiometric combustion, leading to increased NOx emissions and inefficient regeneration processes, especially in scenarios where prolonged overrun operation is not feasible.
Innovation Solution
The method involves supplying fresh air to the soot particle filter via switched-off cylinders to introduce excess oxygen for regeneration while maintaining driver torque, controlling the air supply through valve adjustments to manage thermal load and achieve optimal regeneration temperatures, and optionally using additives to lower the burn-off temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If lean-burn operation (λ > 1) is used to provide excess oxygen for regeneration, then oxygen availability for soot combustion is improved, but NOx emissions increase due to exceeding the conversion range of the three-way catalytic converter
Solution Approach 1:
The invention segments the engine cylinders into active combustion cylinders and deactivated oxygen supply cylinders. The deactivated cylinders function solely as air pumps to deliver fresh oxygen to the DPF, while active cylinders perform combustion. This separation allows independent optimization of oxygen supply and combustion functions, resolving the contradiction between oxygen availability and NOx control.
Solution Approach 2:
The deactivated cylinders act as an intermediary mechanism between the atmosphere and the DPF, transporting fresh air and oxygen without direct combustion involvement. This intermediary function enables oxygen delivery to the filter while preventing the formation of NOx that would occur in lean-burn combustion, as the oxygen is supplied through mechanical displacement rather than chemical reaction.
2Quantity of substance
If overrun mode is used for regeneration, then oxygen is supplied through idle cylinders acting as air pumps, but regeneration cannot be activated unless the driver simultaneously requests it and is only feasible during extended downhill driving
Solution Approach 1:
The engine control unit automatically manages the regeneration process by deactivating specific cylinders to supply oxygen, without requiring driver intervention or specific driving conditions. The system self-regulates the oxygen supply mechanism through valve control, enabling regeneration to occur under various driving conditions including normal operation, thereby increasing adaptability to different driving cycles.
3Quantity of substance
If fresh air supply is increased for regeneration, then oxygen concentration in the DPF is improved, but thermal load on the filter increases requiring temperature management
Solution Approach 1:
The invention dynamically controls the fresh air supply to the DPF by adjusting cylinder valve timing and lift characteristics. The valve control system modulates the amount of fresh air entering the deactivated cylinders based on real-time regeneration needs and temperature conditions, enabling adaptive management of both oxygen concentration and thermal load throughout the regeneration process.
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 efficient soot particle filter regeneration during driving, reducing NOx emissions and maintaining engine performance without the limitations of lean combustion, while ensuring safe mixture preparation and ignitability, thus meeting stringent emissions requirements.
Implementation Method 1
The filter regenerates during separate regeneration phases via an oxidative combustion of the particles to non-toxic CO2, which occurs as an exothermic reaction
Implementation Method 2
The filter regenerates during separate regeneration phases via an oxidative combustion of the particles to non-toxic CO2, which occurs as an exothermic reaction
Implementation Method 3
The rotating pistons act as an air pump, drawing fresh air and the oxygen it contains through the engine for regeneration in the diesel particulate filter
Implementation Method 4
Because of their diesel-like combustion process, these engines emit higher levels of particulate mass and number. To comply with these limits, it is necessary to equip these gasoline engines with an exhaust aftertreatment system that includes a particulate filter in addition to the standard three-way catalytic converter
Data Source
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AI summary
The invention relates to a method for the regeneration of a soot particle filter (9), which is arranged on the outlet side of an internal combustion engine (1), said method comprising the following steps: detecting a loading value of the soot particle filter (9); detecting an operating temperature of the soot particle filter (9); switching off a cylinder (2) of the internal combustion engine (1); starting a supply of fresh air to the soot particle filter (9) via the switched-off cylinder (2a); setting a cylinder valve (3; 4) to control the supply of fresh air; regenerating the soot particle filter (9). The invention further relates to a controller, an internal combustion engine (1) and a motor vehicle (100) for carrying out a method of this kind.