Power Solutions International (PSI; Wood Dale, Ill.), a designer and manufacturer of emissions-certified alternative fuel power systems, said Oct. 19 that Navistar (Lisle, Ill.), parent company of IC Bus LLC, has extended its engine supply agreement with PSI to run through 2021. The agreement, originally set to run through 2018, covers PSI’s supply of 8.8-liter propane and gasoline engines for IC Bus.

“We’re very excited that Navistar has chosen to extend our supply agreement well into the future,” said Gary Winemaster, PSI’s chairman and CEO. “The decision not only demonstrates the strength of our relationship, but also the satisfaction and confidence Navistar has in our ability to deliver high-performance products that help them achieve their strategic goals. We look forward to a long and successful partnership as bus fleets and local school districts continue to embrace the growing market trend toward alternatives to diesel engines.”

Navistar began partnering with PSI in 2014 in order to expand its IC Bus product line with alternative fuel offerings to meet growing market demand. In November that year, IC Bus launched its PSI-powered CE Series Type C propane school bus at the National Association for Pupil Transportation Summit in Kansas City, Mo. Since production started, IC Bus has produced more than 450 buses powered by PSI’s propane engine. Significant deliveries include 149 buses to Waterbury Public Schools in Waterbury, Conn.; 100 buses to Indianapolis Public Schools in Indianapolis, Ind.; and 63 have been operating for Tuscaloosa City Schools since early 2016.

“We are mindful of the many operational needs of our school bus customers and we take pride in offering them powertrain options that meet those needs while delivering on our promise to build reliable, safe, and efficient buses,” said Persio Lisboa, president of operations at Navistar. “We are excited to continue our partnership with PSI in providing high-performance alternative fuel engines in our buses.”