Particulate Filter Cleaning via Reverse Turbo Rotation
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Solution Overview
Problem
Existing methods for cleaning exhaust particulate filters during vehicle-off conditions are inefficient, leading to increased engine emissions and decreased performance due to the need for additional components and potential soot re-entry into combustion chambers, and may not be feasible during prolonged periods without regeneration conditions.
Innovation Solution
A method involving the reverse rotation of a turbocharger or engine using an electric motor to flow ambient air through the particulate filter, depositing soot on an intake air filter, and subsequently routing it to the engine cylinders for combustion, thereby reducing the need for additional components and avoiding increased exhaust temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If additional components are used to remove and burn soot from the PF, then soot removal effectiveness is improved, but device complexity and cost increase
Solution Approach 1:
The system uses the engine's own intake air system and combustion process to handle the soot removal. Ambient air is routed through the PF to collect soot, then the soot-laden air is directed to the intake manifold and combustion chambers where the soot is burned during normal engine operation. This eliminates the need for separate soot burning components.
Solution Approach 2:
The intake air system serves dual purposes: providing air for combustion and transporting soot from the PF to the combustion chambers. The existing intake manifold, air filter, and combustion chambers are utilized for both their primary function and for soot processing, reducing the need for additional dedicated components.
2Reliability
If a separate heater is used to burn soot, then soot combustion is improved, but parasitic loss of engine power increases
Solution Approach 1:
The engine's own combustion process is used to burn the soot. The soot-laden air introduced into the combustion chambers is combusted using the engine's normal combustion cycle, eliminating the need for separate heating systems and associated energy losses.
Solution Approach 2:
The soot, which is a harmful byproduct requiring energy-intensive removal, is converted into a fuel source. The soot accumulates on the air filter and is then introduced into the combustion chambers where it burns during normal engine operation, actually contributing to the combustion process and reducing the need for external energy input.
3Reliability
If backwashing PF during engine operation, then soot removal is improved, but combustion stability deteriorates due to soot entering combustion chambers
Solution Approach 1:
The soot is collected on the air filter before being introduced into the combustion chambers. This preliminary collection step ensures that soot is concentrated and controlled, and only then is it introduced into the combustion process in a managed manner, preventing direct disruption to combustion stability.
Solution Approach 2:
The air filter serves as an intermediary component. It first collects soot from the ambient air that has passed through the PF, then gradually introduces the soot-laden air into the combustion chambers. This intermediary step prevents direct injection of large amounts of soot that would disrupt combustion, instead allowing controlled introduction that maintains stability.
4Reliability
If engine operates with increased exhaust temperature to burn soot, then soot removal is improved, but emissions quality deteriorates
Solution Approach 1:
The engine uses its own combustion process to burn soot, eliminating the need for external heating systems that would increase exhaust temperatures. The soot burns during normal combustion cycles, maintaining exhaust temperatures within normal operating ranges and preserving emissions quality.
Solution Approach 2:
The soot, normally a harmful emission requiring energy-intensive treatment, is converted into an internal fuel source. By introducing soot into the combustion chambers where it burns during normal operation, the system eliminates the need for separate high-temperature soot burning processes, thereby avoiding increased exhaust temperatures and maintaining emissions compliance.
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 reduces costs associated with supplemental components, allows for opportunistic cleaning during prolonged vehicle operation, and improves emissions quality and engine performance by avoiding increased exhaust temperatures during engine operation.
Implementation Method 1
A turbocharger including an exhaust turbine and an intake compressor may be rotated in a reverse direction via an electric motor coupled to the turbine
Implementation Method 2
flowing ambient air through the PF and then routing the ambient air with soot collected from the PF to an intake manifold to deposit the soot on an air filter
Implementation Method 3
During an immediately subsequent engine start, the soot deposited on the intake air filter may be routed to the engine cylinders (for combustion) along with the intake air flow
Data Source
AI summary
Methods and systems are provided for cleaning an exhaust particulate filter by routing air via the exhaust particulate filter during a vehicle-off condition. In one example, during vehicle-off conditions, a turbocharger may be reverse rotated via an electric motor or an engine may be reverse rotated via an electric machine to route air via the exhaust particulate filter and the soot collected from the particulate filter may then be deposited on an air filter coupled to the intake manifold. During a subsequent engine start, the soot from the intake air filter may be routed to the engine cylinders for combustion.