0001172661-11-000027 SC 13G 1 20110204 20110204 CLEAN DIESEL TECHNOLOGIES INC 0000949428 2810 061393453 DE 1231 SC 13G 34 005-51147 11575470 4567 TELEPHONE ROAD SUITE 206 VENTURA CA 93003 805 639 9458 4567 TELEPHONE ROAD SUITE 206 VENTURA CA 93003 Allen & CO LLC 0001303053 134193615 NY 1104 SC 13G 711 FIFTH AVENUE NEW YORK NY 10022 212-832-8000 711 FIFTH AVENUE NEW YORK NY 10022 SC 13G 1 cdti123110.txt SCHEDULE 13G HOLDINGS REPORT