Reductant Line Heating Control via Coolant Flow Modulation
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Solution Overview
Problem
Conventional SCR systems for reducing NOx emissions face challenges in accurately controlling the temperature of the reductant, particularly due to reliance on ambient air temperature sensors and the complexity of electrical heaters or coolant control systems, which can lead to overheating or failure to maintain the reductant above freezing point.
Innovation Solution
A reductant heating system utilizing an engine coolant with a flow regulation device and controller that adjusts coolant flow rates based on the temperature of the coolant and reductant, eliminating the need for ambient air temperature sensors and using pulse-width modulation to control a single coolant flow regulation valve.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If electrical heaters are used to heat reductant lines, then heating effectiveness is improved, but system complexity and cost increase due to requiring ambient temperature sensors, controllers, batteries, and control relays
Solution Approach 1:
The patent extracts and eliminates the complex electrical heating system components (ambient temperature sensors, controllers, batteries, control relays) by replacing them with a passive thermal management approach using engine coolant and strategically positioned temperature sensors that directly monitor reductant temperature without requiring complex control systems.
Solution Approach 2:
The system uses the engine coolant's natural thermal energy to heat the reductant tank and lines without requiring external power sources or active control systems. The temperature sensors provide direct feedback that enables the control unit to regulate coolant flow, creating a self-regulating thermal management system that eliminates the need for batteries and complex control relays.
2Use of energy by stationary object
If ambient air temperature sensors are used for electrical heater control, then heating reference is provided, but measurement accuracy deteriorates due to sensor defects and inaccuracy over time
Solution Approach 1:
The patent introduces intermediate temperature sensors that directly contact or closely monitor the reductant temperature in the tank and lines, serving as mediators between the thermal system and the control unit. This eliminates reliance on ambient air temperature sensors and provides accurate direct measurement of reductant temperature for precise control.
Solution Approach 2:
The system implements direct temperature feedback by positioning sensors to continuously monitor reductant temperature in the tank and lines. This feedback is sent to the control unit which regulates coolant flow accordingly, creating a closed-loop control system that maintains accurate temperature control without relying on ambient temperature estimates.
3Use of energy by moving object
If coolant is used to heat reductant tank and lines, then energy efficiency is improved, but temperature control precision worsens without flow rate modulation
Solution Approach 1:
The patent makes the coolant flow rate dynamic by using a control unit that actively modulates the coolant flow based on real-time temperature feedback from sensors monitoring reductant temperature in the tank and lines. This dynamic flow regulation enables precise temperature control while maintaining the energy efficiency of using engine coolant as the heat source.
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 solution effectively maintains the reductant temperature above freezing and below a safe threshold, reducing energy and hardware costs, and system complexity, while ensuring reliable operation across varying ambient conditions.
Implementation Method 1
a coolant line that includes a first portion positionable in heat exchanging communication with reductant in a reductant tank and a second portion positionable in heat exchanging communication with reductant in a reductant line
Data Source
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AI summary
The invention relates to a reductant heating system. The system comprises a coolanfi line comprising a first portion positionable in heat exchanging communication with reductant in a reductant tank and a second portion positionable in heat exchanging communication with reductant in a reductant line, the reductant line configured to receive reductant from the reductant tank, a flow regulation device coupled to the coolant line and configured to regulate the flow rate of coolant entering the first portion of the coolant line, and a controller communicable in signal transmitting communication with the flow regulation device to vary the flow rate of coolant through the first portion of the coolant line to achieve a desired temperature of coolant in the second portion of the coolant line.