IDEAS home Printed from https://ideas.repec.org/a/eee/rensus/v218y2025ics1364032125005064.html
   My bibliography  Save this article

A comprehensive review of emission characteristics and mitigation strategies for non-road small spark-ignition engines

Author

Listed:
  • Ni, Peiyong
  • Dong, Zhen
  • Wang, Xiangli
  • Li, Xiang
  • Zhang, Xuewen
  • Zhang, Jie

Abstract

Despite the global shift toward electrification, non-road small spark-ignition (SI) engines continue to dominate as primary power sources for garden equipment, agricultural machinery and generator sets. However, their operation with the rich air-fuel mixture leads to significant emission challenges. This comprehensive review systematically covers the emission characteristics, regulations and available control technologies for small SI engines. Current analyses indicate that these engines exhibit distinct emission profiles, characterized by elevated hydrocarbon (HC) and carbon oxide (CO) emissions, along with moderate nitrogen oxide (NOx) level. Among various operating and structural parameters, the excess air coefficient is identified as the most critical factor governing emission performance. The review identifies several promising mitigation strategies. Alcohol-gasoline blends consistently reduce HC and CO emissions by 30–40 %, although their impact on NOx emissions remains variable. In contrast, electronic fuel injection (EFI) systems outperform carburetors, improving mixture quality and reducing HC and CO emissions by 50–70 %. Furthermore, the integration of secondary air injection (SAI) with oxidation catalysts reduces HC and CO emissions by 66–88 %, whereas three-way catalytic converters (TWCs) achieve up to 90 % reductions in HC and CO and 75 % in HC + NOx. While many emission control technologies from automotive applications show potential for adaptation, their implementation in small SI engines must consider critical constraints related to cost-effectiveness and spatial limitations. This review establishes a systematic framework for understanding and addressing emission reduction challenges in small SI engines, providing valuable insights for researchers, manufacturers and policymakers in the field.

Suggested Citation

  • Ni, Peiyong & Dong, Zhen & Wang, Xiangli & Li, Xiang & Zhang, Xuewen & Zhang, Jie, 2025. "A comprehensive review of emission characteristics and mitigation strategies for non-road small spark-ignition engines," Renewable and Sustainable Energy Reviews, Elsevier, vol. 218(C).
  • Handle: RePEc:eee:rensus:v:218:y:2025:i:c:s1364032125005064
    DOI: 10.1016/j.rser.2025.115833
    as

    Download full text from publisher

    File URL: http://www.sciencedirect.com/science/article/pii/S1364032125005064
    Download Restriction: Full text for ScienceDirect subscribers only

    File URL: https://libkey.io/10.1016/j.rser.2025.115833?utm_source=ideas
    LibKey link: if access is restricted and if your library uses this service, LibKey will redirect you to where you can use your library subscription to access this item
    ---><---

    As the access to this document is restricted, you may want to search for a different version of it.

    Corrections

    All material on this site has been provided by the respective publishers and authors. You can help correct errors and omissions. When requesting a correction, please mention this item's handle: RePEc:eee:rensus:v:218:y:2025:i:c:s1364032125005064. See general information about how to correct material in RePEc.

    If you have authored this item and are not yet registered with RePEc, we encourage you to do it here. This allows to link your profile to this item. It also allows you to accept potential citations to this item that we are uncertain about.

    We have no bibliographic references for this item. You can help adding them by using this form .

    If you know of missing items citing this one, you can help us creating those links by adding the relevant references in the same way as above, for each refering item. If you are a registered author of this item, you may also want to check the "citations" tab in your RePEc Author Service profile, as there may be some citations waiting for confirmation.

    For technical questions regarding this item, or to correct its authors, title, abstract, bibliographic or download information, contact: Catherine Liu (email available below). General contact details of provider: http://www.elsevier.com/wps/find/journaldescription.cws_home/600126/description#description .

    Please note that corrections may take a couple of weeks to filter through the various RePEc services.

    IDEAS is a RePEc service. RePEc uses bibliographic data supplied by the respective publishers.