
                                                                    Exhibit 4g

           50,000 Shares of Series B Convertible Preferred Stock

                      CLEAN DIESEL TECHNOLOGIES, INC.

      Series B Convertible Preferred Stock (par value $0.05 per share)

                    Initially Offered Pursuant to Rights
                        Distributed to Shareholders



To Securities Dealers, Commercial Banks,
  Brokers, Trust Companies and Other Nominees:

     Enclosed  are  a  Prospectus,   dated   ___________  ____,  1998  (the
"Prospectus"),  and  Instructions  as to Use of  Rights  Certificates  (the
"Instructions"),  relating to the offering of up to 50,000 shares of Series
B  Convertible  Preferred  Stock,  par value $0.05 per share (the "Series B
Preferred Stock"), of Clean Diesel Technologies,  Inc. (the "Company), at a
subscription price of $_______ per share in cash,  pursuant to transferable
subscription rights ("Rights")  initially  distributed to holders of record
("Record Date Holders") of the Company's  outstanding  common  shares,  par
value $0.05 per share (the "Common  Shares") as of the close of business on
_______ __, 1998 (the "Record Date");  provided,  however, that Rights will
not be  distributed to and may not be exercised by, Record Date Holders who
reside in jurisdictions  where the Rights have not been registered or where
an exemption from registration is not available, as described more fully in
the Prospectus. The Rights are described in the Prospectus and evidenced by
a Rights  Certificate (a "Rights  Certificate")  registered in your name or
the name of your nominee.

     Each  beneficial  owner of the Company's  Common Shares  registered in
your name or the name of your  nominee is entitled to one Right for each 50
Common Shares so owned by such beneficial owner on the Record Date and each
share of Series B Preferred  Stock will be immediately  convertible,  at no
cost to the holder thereof,  into 33 Common Shares. No fractional Rights or
cash in lieu thereof will be distributed or paid.

     We are  asking  you to  contact  your  clients  for  whom you hold the
Company's  Common  Shares  registered  in your name, or in the name of your
nominee to obtain  instructions  with  respect to the  Rights.  You will be
reimbursed for customary  mailing and handling  expenses incurred by you in
forwarding any of the enclosed materials to your clients.  The Company will
pay all  transfer  taxes,  if any,  applicable  to the  sale  of  Series  B
Preferred  Stock to a Rights  Holder upon  exercise  of Rights,  subject to
certain exceptions described in the Prospectus and the Rights Certificate.

     Enclosed are copies of the following documents:

     1.   The Prospectus;

     2.   The Instructions;

     3.   A form  letter  which  may be  sent  to your  clients  for  whose
          accounts  you  hold  shares  of  the   Company's   Common  Shares
          registered in your name or the name of your  nominee,  with space
          provided for obtaining such clients'  instructions with regard to
          the Rights;

     4.   Rights Certificates;

     5.   A Nominee Holder Oversubscription Certification; and

     6.   A Notice of Guaranteed Delivery.

     Your prompt action is  requested.  The Rights will expire at 5:00 p.m.
Eastern  Standard Time, on  ___________  __, 1998,  unless  extended by the
Company (the "Expiration Date").

     TO  EXERCISE   RIGHTS,   PROPERLY   COMPLETED   AND   EXECUTED   RIGHT
CERTIFICATE(S)  (UNLESS THE  GUARANTEED  DELIVERY  PROCEDURES  ARE COMPLIED
WITH) AND PAYMENT IN FULL FOR ALL RIGHTS EXERCISED MUST BE DELIVERED TO THE
SUBSCRIPTION  AGENT AS INDICATED IN THE PROSPECTUS  PRIOR TO THE EXPIRATION
DATE.   EXERCISE  OF   OVERSUBSCRIPTION   PRIVILEGES  (AS  DEFINED  IN  THE
PROSPECTUS)   MUST   BE   ACCOMPANIED   BY  A   COMPLETE   NOMINEE   HOLDER
OVERSUBSCRIPTION CERTIFICATION.

     THE RIGHTS  WILL ONLY BE GRANTED  TO,  AND MAY ONLY BE  EXERCISED  BY,
INVESTORS  RESIDING IN THE  FOLLOWING  JURISDICTIONS  WHERE THE  SECURITIES
OFFERED  HEREBY  HAVE  BEEN  REGISTERED  WITH  THE  APPROPRIATE  SECURITIES
REGULATORY  AUTHORITIES  OR WHERE AN EXEMPTION  FROM SUCH  REGISTRATION  IS
AVAILABLE:  OUTSIDE THE UNITED  STATES AND IN  COLORADO,  CONNECTICUT,  THE
DISTRICT OF COLUMBIA,  ILLINOIS,  INDIANA,  IOWA, KANSAS, MAINE,  MARYLAND,
MASSACHUSETTS,  NEVADA, NEW JERSEY, NEW YORK, NORTH CAROLINA, RHODE ISLAND,
VERMONT, VIRGINIA AND WASHINGTON. RIGHTS WILL NOT BE DISTRIBUTED TO HOLDERS
WHO RESIDE IN STATES  WHERE THE  SECURITIES  OFFERED  HEREBY  HAVE NOT BEEN
REGISTERED OR WHERE AN EXEMPTION FROM  REGISTRATION  IS NOT  AVAILABLE.  IN
ADDITION,  THE SERIES B PREFERRED STOCK MAY NOT BE TRANSFERRED TO RESIDENTS
OF  ANY  OF  THE  FOLLOWING  STATES:  ARIZONA,   FLORIDA,   GEORGIA,  OHIO,
PENNSYLVANIA OR TEXAS.

     Additional copies of the enclosed  materials may be obtained from, and
Rights  holders   requesting   assistance  or  information  may  call,  the
Information Agent,  ChaseMellon Shareholder Services at 888-224-2745 in the
U.S. or Computershare Services, P.L.C. at 1179-370-672 in the U.K.

                                    Very truly yours,

                                    CLEAN DIESEL TECHNOLOGIES, INC.


                                    -------------------------------

                                    Jeremy D. Peter-Hoblyn
                                    President and Chief Executive Officer

     NOTHING HEREIN OR IN THE ENCLOSED  DOCUMENTS  SHALL  CONSTITUTE YOU OR
ANY PERSON AS AN AGENT OF THE COMPANY,  THE SUBSCRIPTION AGENT OR ANY OTHER
PERSON  MAKING  OR  DEEMED TO BE MAKING  OFFERS  OF THE  COMMON  STOCK,  OR
AUTHORIZE  YOU OR ANY OTHER PERSON TO MAKE ANY  STATEMENTS ON BEHALF OF ANY
OF THEM WITH RESPECT TO THE OFFERING,  EXCEPT FOR STATEMENTS EXPRESSLY MADE
IN THE PROSPECTUS OR THE SUBSCRIPTION DOCUMENTS.

