Exhibit 1
JOINT FILING AGREEMENT

The undersigned, Emerald Energy Fund I LP, EEF I Management LP, Emerald Cleantech Fund I LP, ECF I Management LP, Emerald Partners I Ltd., Pascal Mahieux, John Bridle and Walter Locher,  hereby agree that the Schedule 13G with respect to the Common Stock, par value $0.01 per share, of Clean Diesel Technologies, Inc., dated as of February 3, 2011, is, and any amendments thereto (including amendments on Schedule 13D) signed by each of the undersigned shall be, filed on behalf of each of us pursuant to and in accordance with the provisions of Rule 13d-1(k) under the Securities Exchange Act of 1934.

Dated:  February 3, 2011
Emerald Energy Fund I LP
 
By:
EEF I Management LP, its General Partner
 
By:
Emerald Partners I Ltd., its General Partner
 
 
By:
Sean P. McGuinness, Attorney-in-Fact*
     
 
EEF I Management LP
 
By:
Emerald Partners I Ltd., its General Partner
 
 
By:
Sean P. McGuinness, Attorney-in-Fact*
     
 
Emerald Cleantech Fund I LP
 
By:
ECF I Management LP, its General Partner
 
By:
Emerald Partners I Ltd., its General Partner
 
 
By:
Sean P. McGuinness, Attorney-in-Fact*
     
 
ECF I Management LP
 
By:
Emerald Partners I Ltd., its General Partner
 
 
By:
Sean P. McGuinness, Attorney-in-Fact*
     
 
Emerald Partners I Ltd.
 
 
By:
Sean P. McGuinness, Attorney-in-Fact*
     
 
Pascal Mahieux
 
 
By:
Sean P. McGuinness, Attorney-in-Fact*
   
 
John Bridle
 
 
By:
Sean P. McGuinness, Attorney-in-Fact*
 
 
Walter Locher
 
 
By:
Sean P. McGuinness, Attorney-in-Fact*
_____________________

*Signed pursuant to at Power of Attorney included as an Exhibit to the Schedule 13G of which this Exhibit is a part.