Coolant Pump Control for Engine Stop Cooling
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Solution Overview
Problem
The automatic stop function in internal combustion engines can lead to negative effects such as increased nitrogen oxide emissions and potential coolant boiling due to inadequate cooling during engine shutdown, as the coolant flow is interrupted, causing overheating in components like the intercooler and EGR cooler.
Innovation Solution
A method where coolant is continuously pumped through the cooling circuit during the stop function, maintaining specific temperature ranges (70° C to 80° C for the charge air cooler and 95° C to 105° C for the EGR cooler, and using an ambient heat exchanger for re-cooling, even when the engine is not operating, to prevent overheating and ensure effective cooling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the automatic stop function is activated to reduce fuel consumption and emissions during idle periods, then fuel efficiency improves, but coolant flow is interrupted causing overheating in cooling system components
Solution Approach 1:
The control device activates the coolant pump before the automatic stop function is engaged, ensuring coolant circulation is already established when the engine shuts down. This preliminary action prevents temperature rise in cooling system components by maintaining coolant flow during the transition to idle state.
Solution Approach 2:
The coolant pump continues to operate during the automatic stop function to maintain continuous coolant circulation. This ensures that heat is continuously removed from the intercooler, EGR cooler, and engine components even when the engine is not running, preventing overheating and maintaining system readiness for rapid restart.
2Use of energy by moving object
If coolant circulation is interrupted during engine shutdown to save energy, then power consumption decreases, but nitrogen oxide emissions increase due to inadequate cooling
Solution Approach 1:
The control device activates the coolant pump in advance before the automatic stop function engages, ensuring that coolant circulation is already established. This preliminary cooling action prevents excessive temperatures that would lead to high nitrogen oxide emissions during subsequent engine operation.
Solution Approach 2:
The coolant pump operates continuously during the automatic stop function to maintain uninterrupted coolant flow. This continuous cooling prevents thermal conditions that would cause nitrogen oxide formation, ensuring low emissions when the engine restarts, while the pump is controlled to consume minimal power.
3Temperature
If the coolant pump operates continuously during stop function to maintain cooling, then component temperature is controlled, but additional power is consumed
Solution Approach 1:
The control device automatically manages the coolant pump operation based on engine state and temperature conditions. The pump is activated only when needed (before and during automatic stop function) and deactivated when cooling demands are met, allowing the system to self-regulate power consumption while maintaining adequate component temperatures.
Solution Approach 2:
The control device adjusts the coolant pump's operational parameters (activation timing, duration, and intensity) based on real-time temperature conditions and engine state. This optimized control ensures sufficient cooling of components during minimal pump operation periods, reducing power consumption while maintaining temperature control.
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 prevents the intercooler from overheating, maintains efficient exhaust gas recirculation, reduces nitrogen oxide emissions, and avoids coolant boiling, while minimizing power consumption and maintaining effective cooling, thus enhancing the durability of engine components.
Implementation Method 1
absorbing heat energy from components integrated into the cooling circuit, including the combustion engine
Implementation Method 2
this heat energy is then transferred to the ambient air via a heat exchanger, particularly the main radiator
Implementation Method 3
an EGR cooler can be integrated into the EGR system. This cooler acts as a heat exchanger, allowing the transfer of thermal energy from the recirculated exhaust gas to a coolant
Implementation Method 4
charge air coolers are typically integrated into the fresh gas stream downstream of the compressor. These coolers provide at least partial cooling of the fresh gas (charge air) heated by compression
Data Source
Figure 1
Figure 2
AI summary
A method for operating an internal combustion engine 10 is provided, wherein the internal combustion engine 10 comprises at least one combustion engine 12, for which an automatic stop function is provided, a fresh gas stream 74, an exhaust gas stream 76, and a cooling system. Furthermore, a compressor 98 is integrated into the fresh gas stream, and an intercooler 78 is integrated between the compressor 98 and the combustion engine 12. The intercooler 78 is also integrated into a cooling circuit of the cooling system. Additionally, at least one cooling circuit of the cooling system is provided, comprising a cooling channel 26, 28 of the combustion engine 12, a cooler 34 for an exhaust gas turbocharger 20, and/or an EGR cooler 38, 40, which is integrated into an exhaust gas recirculation line 22, 24. It is also provided that during an activated stop function, and consequently when the combustion engine is not in operation, coolant is supplied to the cooling circuit or, if there are multiple cooling circuits, to at least one of the cooling circuits.