X0306 4 2017-08-08 0001137091 POWER SOLUTIONS INTERNATIONAL, INC. PSIX 0001702521 Weichai America Corp. 3100 GOLF ROAD ROLLING MEADOWS IL 60008 0 0 1 0 0001703367 Weichai Power Co., Ltd. SECTION A 197, FU SHOU EAST STREET HIGH-TECH INDUSTRIAL DEV. ZONE WEIFANG, SHANDONG PROVINCE F4 261061 CHINA 0 0 1 0 0001703252 Shandong Heavy Industry Group Co., Ltd. #40-1 YANZI SHAN WEST ROAD JINAN, SHANDONG PROVINCE F4 250014 CHINA 0 0 1 0 Common Stock 2017-08-08 4 P 0 200000 9.50 A 2928752 I See Explanation of Responses This report is filed jointly by Weichai America Corp., Weichai Power Co., Ltd. and Shandong Heavy Industry Group Co., Ltd. (collectively, the "Reporting Persons"). Weichai America Corp. is the direct owner of the Common Stock referenced in this report and shares the power to vote and the power to dispose of all of such shares of Common Stock with the other Reporting Persons. No individual has beneficial ownership over the Common Stock benefically owned by the Reporting Persons. Each of the Reporting Persons disclaims beneficial ownership of these securities, except to the extent of its pecuniary interest therein. This Form 4 shall not deemed to be an admission that any Reporting Person hereunder is the beneficial owner of any of the reported securities for purposes of Section 16 of the Securities Exchange Act of 1934, as amended, or for any other purpose. /s/Huisheng Liu, Chairman, Weichai America Corp. 2017-08-10 /s/Sun Shaojun, Executive President, Weichai Power Co., Ltd. 2017-08-10 /s/Jiang Kui, President, Shandong Heavy Industry Group Co., Ltd. 2017-08-10