Engine Control Device for Exhaust Pipe Freezing Prevention
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Solution Overview
Problem
In vehicles with engines, condensed water inside the exhaust pipe can freeze when external temperatures are below freezing, leading to increased engine noise and reduced engine output, especially in hybrid vehicles where engine operation is short, and existing solutions do not effectively synchronize the timing for draining and thawing with the stopping conditions of the EV mode.
Innovation Solution
An engine control device that regulates the flow rate of exhaust gas by increasing the number of engine revolutions when the external temperature is below freezing and the previous engine operation duration is short, using a controller to maintain the higher flow rate until a predetermined duration has elapsed, and includes features like intermittent control and exhaust heat recovery to prevent freezing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the number of engine revolutions is increased to discharge condensed water and melt ice inside the exhaust pipe, then the draining and thawing effect is improved, but fuel efficiency deteriorates
Solution Approach 1:
The controller performs preliminary warming of the exhaust pipe by increasing engine revolutions during cold start conditions (when coolant temperature is below freezing point). This preliminary action prevents ice formation before it occurs, eliminating the need for continuous high-revolution operation and improving fuel efficiency while maintaining reliability.
Solution Approach 2:
The system applies periodic intermittent control where engine revolutions are increased at specific intervals during cold operation. The controller monitors exhaust temperature and temporarily increases revolutions to maintain exhaust temperature above freezing point, then reduces revolutions when temperature is sufficient. This periodic action achieves reliable ice prevention while minimizing fuel consumption compared to continuous high-revolution operation.
2Productivity
If the number of engine revolutions is increased to promote draining of condensed water, then the drainage effect is improved, but engine noise increases
Solution Approach 1:
The system performs preliminary draining operations during cold start when the vehicle is first started. By increasing engine revolutions only during this initial period, the system achieves effective condensed water drainage before the vehicle enters normal operation, thereby minimizing noise exposure while maintaining drainage productivity.
Solution Approach 2:
The controller implements intermittent revolution increases at specific time intervals during cold operation. Engine revolutions are temporarily increased to promote drainage, then reduced to normal levels. This periodic approach maintains effective water drainage while limiting the duration of high-noise operation, thus reducing overall engine noise exposure.
3Reliability
If the number of engine revolutions is increased to melt ice inside the exhaust pipe, then the thawing effect is improved, but engine output is reduced
Solution Approach 1:
The system performs preliminary ice melting during cold start conditions by increasing engine revolutions when coolant temperature is below freezing point. This preliminary melting action clears the exhaust pipe before normal operation begins, ensuring reliable ice-free operation during subsequent driving while minimizing the period of reduced engine output.
Solution Approach 2:
The controller applies intermittent revolution increases to maintain exhaust temperature above freezing point during cold operation. By temporarily increasing revolutions only when exhaust temperature approaches freezing, the system achieves reliable ice prevention while minimizing the duration of reduced engine output, thereby improving overall power availability.
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
Effectively promotes the draining of condensed water and thawing of ice inside the exhaust pipe, preventing freezing and reducing engine noise and output degradation, while also improving fuel efficiency and preventing dirtying of parking spaces.
Implementation Method 1
raising the flow rate per unit of time of the exhaust gas enables the draining of condensed water and the thawing of ice inside the exhaust pipe to be promoted
Data Source
AI summary
There is provided an engine control device including (1) a regulator that regulates a flow rate per unit of time of exhaust gas discharged from an engine, and (2) a controller that, in cases in which an external temperature detection section detects an external temperature below freezing point, and a previous engine operation duration is shorter than a predetermined first duration, controls the regulator such that the flow rate rises to exceed a predetermined normal state, until a predetermined second duration has elapsed since the engine was started up.