QuickLinks -- Click here to rapidly navigate through this document

Exhibit 23.1

Consent of Independent Registered Public Accounting Firm

Clean Diesel Technologies, Inc.
Oxnard, California

        We hereby consent to the incorporation by reference in the Prospectus constituting a part of this Registration Statement of our report dated March 18, 2015, relating to the consolidated financial statements of Clean Diesel Technologies, Inc. appearing in the Company's Annual Report on Form 10-K for the year ended December 31, 2014. Our report contains an explanatory paragraph regarding the Company's ability to continue as a going concern.

        We also consent to the reference to us under the caption "Experts" in the Prospectus.

/S/ BDO USA, LLP
Los Angeles, California

May 19, 2015

QuickLinks

Exhibit 23.1

Consent of Independent Registered Public Accounting Firm