Implications of discrete vs. continuously adjustable current for electrically heated catalytic converters

Petkovšek, Marko (author), Zajec, Peter (author), Nemec, Mitja (author), Rihar, Andraž (author), Vončina, Danijel (author), Ambrožič, Vanja (author), Golob, Jure (author), Nedeljković, David (author)

Despite the obvious shift in daily commuting towards electromobility, internal combustion engines (ICEs) still dominate the market, particularly in the transport sector. Their main drawback—cold-start emissions—has driven the development of active control strategies beyond passive exhaust optimizations. An electrically heated catalytic converter (EHC) helps the catalytic converter reach the light-off temperature more quickly through active control; however, it places additional demands on the already strained onboard electrical power distribution network. This paper presents a case study comparing two power supply and control configurations for managing the temperature of the EHC: (i) a smart-switch-based approach using bang-bang control, and (ii) a DC/DC converter with a proportional–integral–derivative (PID) controller. To define key target requirements for a dedicated DC/DC converter suitable for real-world conditions, measurement data such as temperature and electrical power demand were gathered through preliminary pollutant emissions tests performed in a laboratory environment using a programmable bench power supply. For the selected test procedure, engine cold-start emissions using various heater power supply scenarios were reduced by a factor of 6 for Total Hydrocarbons (THC) and by a factor of 5 for Carbon Monoxide (CO). Based on a comparative analysis of power supply parameters, a custom four-leg interleaved Buck converter was developed to meet the target power requirement and to specifically reduce voltage overstress caused by parasitic inductances in the onboard distribution network during rapid load current transients. The efficiency of the proposed DC/DC converter reached 95.8%. Unlike a bang-bang-controlled smart switch, the use of the DC/DC converter reduces both electrical and thermal stress on the vehicle’s cable harness.

• Language: English
• Keywords: DC/DC converter, electric heater, catalytic converter, temperature control, pollutant emissions, battery, internal combustion engine, smart switch, voltage stress
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: FE - Faculty of Electrical Engineering
• Publication status: Published
• Publication version: Version of Record
• Year: 2025
• Number of pages: 23 str.
• Numbering: Vol. 15, issue 23, art. 12483
• PID: 20.500.12556/RUL-176210
• UDC: 621.3
• ISSN on article: 2076-3417
• DOI: 10.3390/app152312483
• COBISS.SI-ID: 258654467
• Publication date in RUL: 25.11.2025

Record is a part of a journal

• Title: Applied sciences
• Shortened title: Appl. sci.
• Publisher: MDPI
• ISSN: 2076-3417
• COBISS.SI-ID: 522979353

Licences

• License: CC BY 4.0, Creative Commons Attribution 4.0 International
• Link: http://creativecommons.org/licenses/by/4.0/
• Description: This is the standard Creative Commons license that gives others maximum freedom to do what they want with the work as long as they credit the author.

Secondary language

• Language: Slovenian
• Keywords: DC/DC pretvornik, električni grelnik, katalizator, regulacija temperature, emisije, baterija, motor z notranjim zgorevanjem, pametno stikalo, napetostna obremenitev

Projects

• Funder: ARIS - Slovenian Research and Innovation Agency
• Project number: P2-0258-
• Name: Pretvorniki električne energije in regulirani pogoni

• Funder: ARIS - Slovenian Research and Innovation Agency
• Project number: L2-2619
• Name: Napredni elektronski napajalni modul za avtomobilski katalizator