Exhibit 32.1

CERTIFICATION

In connection with the periodic report of ClearSign Combustion Corporation (the “Company”) on Form 10-Q for the quarterly period ended June 30, 2018 as filed with the Securities and Exchange Commission (the “Report”), we, Stephen E. Pirnat, Chief Executive Officer (Principal Executive Officer) and Brian G. Fike, Interim Chief Financial Officer (Principal Financial and Accounting Officer) of the Company, hereby certify as of the date hereof, solely for purposes of Title 18, Chapter 63, Section 1350 of the United States Code, that to the best of our knowledge:

(1) The Report fully complies with the requirements of Section 13(a) or 15(d), as applicable, of the Securities Exchange Act of 1934, and

(2) The information contained in the Report fairly presents, in all material respects, the financial condition and results of operations of the Company at the dates and for the periods indicated.

Date: August 13, 2018

/s/ Stephen E. Pirnat

Stephen E. Pirnat

Chief Executive Officer (Principal Executive Officer)

/s/ Brian G. Fike

Brian G. Fike

Interim Chief Financial Officer (Principal Financial and Accounting Officer)