 AUSTIN, Texas--BUSINESS WIRE--Hyliion Holdings Corp. NYSE: HYLN Hyliion, a leader in electrified powertrain solutions for Class 8 commercial semi-trucks, has announced that Dennis M. Gallagher has joined the company as Chief Operating Officer. Gallagher brings over 20 years of experience leading high-performing business units with a focus on global manufacturing and commercial vehicles. He will oversee aspects of Hyliions commercialization process. Dennis experience in the heavy-duty 