Engine Exhaust Temperature Control to Prevent Filter Condensation
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Solution Overview
Problem
Condensed water generated in the exhaust passage of an internal combustion engine can adhere to the filter, inhibiting the particulate matter collection effect by trapping PM, even after the engine is restarted.
Innovation Solution
A control device that raises the upstream exhaust temperature in the exhaust passage to vaporize condensed water before it adheres to the filter, using methods such as ignition retardation or applying voltage to an electrically heated catalyst.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the engine is stopped and the filter temperature is raised to evaporate condensed water, then the filter is protected from freezing damage, but condensed water may still adhere to the filter when the engine is restarted before the exhaust passage is sufficiently warmed
Solution Approach 1:
The control device performs preliminary warming of the exhaust passage and filter before the engine is stopped. By raising the temperature in advance, the system ensures that condensed water does not adhere to the filter when the engine restarts, thus preventing both freezing damage and PM collection inhibition without requiring extended warming time after restart.
2Stability of the object's composition
If condensed water adheres to the filter pores, then the filter structure is maintained, but the PM collection effect is inhibited
Solution Approach 1:
The control device monitors filter temperature and exhaust passage temperature to determine the appropriate timing for engine shutdown. By maintaining the filter temperature above the dew point through controlled warming, the system prevents condensed water formation that would block pores, thereby preserving both structural integrity and PM collection efficiency.
3Speed
If the engine operates without sufficient exhaust passage warming, then the engine can be restarted quickly, but condensed water generates and adheres to the filter
Solution Approach 1:
The system performs preliminary temperature management by monitoring exhaust passage temperature and filter temperature before engine shutdown. When temperatures are sufficient, the engine is stopped; when temperatures are insufficient, the system continues warming. This ensures rapid restart capability while preventing condensed water adhesion to the filter.
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
Rapid vaporization of condensed water prevents the inhibition of PM collection, reducing the amount of PM discharged during vehicle operation.
Implementation Method 1
executes temperature raising processing of raising an upstream-side exhaust temperature that is a temperature of exhaust on a side further upstream than the filter in the exhaust passage until a state where condensed water at the filter has been vaporized is achieved
Implementation Method 2
applying voltage to an electrically heated catalyst
Data Source
AI summary
A control device for an internal combustion engine is applied to an internal combustion engine mounted on vehicles in which filters for collecting PM are arranged in an exhaust passage. After the internal combustion engine is started, the control device of the internal combustion engine executes a temperature raising process of raising the upstream side exhaust temperature, which is the temperature of the exhaust gas on the upstream side of the filter in the exhaust passage, until the condensed water of the filter reaches a vaporized state.