Partial EGR Cooling Circuit Temperature Control
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Solution Overview
Problem
Current cooling systems for engine systems with partial exhaust gas recirculation devices, such as EGR, face challenges in effectively managing temperature to reduce nitrogen oxide emissions and prevent clogging, especially during start-up when temperatures are low and hydrocarbon levels are high, leading to potential fouling issues.
Innovation Solution
A mixed-loop cooling circuit management system that dynamically controls the circulation of heat transfer fluid between the engine, radiator, and EGR exchanger using a decoupling device and pumps to optimize cooling based on temperature thresholds, ensuring the EGR device operates within optimal temperature ranges to minimize nitrogen oxide emissions and prevent clogging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the EGR device is cooled using a hot loop cooling circuit with temperature of 70-95°C, then the engine cooling is maintained, but nitrogen oxide emissions increase
Solution Approach 1:
The patent implements dynamic control of the EGR cooling system by switching between hot loop and cold loop modes based on operating conditions. The system dynamically adjusts coolant temperature to the EGR device, using lower temperatures (below 70°C) during conditions that promote NOx formation, while maintaining higher temperatures for engine cooling when needed. This dynamic switching resolves the contradiction between maintaining engine cooling temperature and reducing nitrogen oxide emissions.
2Object-generated harmful factors
If the EGR device is cooled to reduce nitrogen oxide emissions, then emissions decrease, but clogging occurs during start-up when temperatures are low
Solution Approach 1:
The patent changes the temperature parameter of the coolant supplied to the EGR device based on operating conditions. During start-up or low-temperature operation, the system maintains higher coolant temperatures to prevent condensation and clogging. During normal operation, the system lowers the coolant temperature to reduce nitrogen oxide emissions. This parameter change strategy resolves the contradiction between emission reduction and clogging prevention.
3Object-generated harmful factors
If a separate cold loop cooling circuit is used for the EGR device, then nitrogen oxide emissions are reduced, but device complexity increases
Solution Approach 1:
The patent designs the cooling circuit to serve multiple functions through a unified system. The same cooling circuit infrastructure is used for both engine cooling and EGR device cooling, with the ability to switch between hot loop and cold loop modes. This multi-functionality approach reduces the need for completely separate cooling systems, thereby limiting the increase in device complexity while still achieving nitrogen oxide emission reduction.
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 better temperature control of the EGR device and engine, reducing nitrogen oxide emissions while preventing clogging by maintaining the EGR device at suitable temperatures, thus adhering to anti-pollution standards and extending the lifespan of components.
Implementation Method 1
a radiator device capable of lowering the temperature of a heat transfer fluid
Implementation Method 2
an air heater device located in the passenger compartment
Implementation Method 3
a cooler (or exchanger) of the recirculation device partial exhaust gas, to cool said partial exhaust gas recirculation device
Data Source
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AI summary
A method for managing the cooling of an engine system equipped with a partial exhaust gas recirculation device using a cooling circuit comprising a hybrid circuit with a first and second loop for the circulation of heat transfer fluid for cooling a unit heater and an engine respectively, and a third loop for circulating heat-transfer fluid for cooling the partial exhaust gas recirculation device, the method involving: receiving (201) at least one value of a parameter relating to the engine system (TM, state_EGR, pedal_pos, engine_speed), formulating (202, 203, 204) a control signal for the third loop (S) dependent on said at least one value received, so as to reduce the cooling of the partial exhaust gas recirculation device, and sending (205) the control signal to the third loop so as to adapt the cooling to the engine system situation.