The objective of this project is to reduce the warm-up time of an Exhaust Aftertreatment System (EATS) by 30% in order to improve nitrogen oxide conversion efficiency at cold start through the retrofitted implementation of an electric heater.
Sponsored by: Volvo Group Trucks Technology
Team Members
Andre Baadsvik John Belinsky Xitao Liu Joshua Wildonger
Project Poster
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Project Video
Project Summary
Overview
The Exhaust Aftertreatment System (EATS) of Volvo’s semi-trailer trucks converts the exhaust produced by the engine into more environmentally friendly products. In order to do so, the EATS has several stages through which the exhaust passes. The Selective Catalytic Reduction Stage (SCR) is the focus area for this project as it uses catalysts to convert nitrogen oxides to nitrogen and water. The catalysts in the SCR have an activation temperature of 250°C and the heat of the exhaust can make the system reach this temperature in about 10 to 13 minutes during a regulatory emissions test. However, prior to that time, the harmful molecules are exhausted from the system. Therefore, the team was tasked with retrofitting the system with heaters to accelerate the warm-up time.
Objectives
The primary objective for the student team was to reduce the warm-up time by 30% in order to improve NOx conversion efficiency at cold start.
Approach
– Gathered customer needs and project requirements from our sponsor contact
– Researched products that already exist on the market
– Researched heaters and found which would heat up fast enough and hot enough
– Developed four concepts that differed in heater type and location of installation in the EATS
– Built a Pugh concept scoring matrix and narrowed down our concepts to our top choice
– Received test data and the physical EATS from Volvo
– Constructed an alpha, beta, and final prototype
– Performed testing once the final prototype was constructed
– Used test results to calculate the wattage added to the system by the heaters
– Combined heater wattage with wattage provided by exhaust to determine the reduction in time to reach the target temperature
– Presented results on a graph comparing original data to two versions of test data
Outcomes
– Using an optimal flow rate of 60 grams per second, the heating solution presented by the team produced a 43% reduction in warm-up time of a 13 minute test using a 2-minute pre-heat cycle for the heaters where the heaters were on with no mass flow
– Allowing the heaters to pre-heat for 2 minutes prior to initiating mass flow, caused their initial temperature to be double that of the ambient temperature (25°C)
– Using the same flow rate, but instead starting the heaters and the blower at the same time resulted in a 16% reduction in warm-up time
– The reduction in warm-up time correlates to fewer harmful molecules exhausted out the tailpipe and entering the atmosphere