[待更新] Cummins Westport Inc. designs, engineers, and markets 6 to 12 litre spark-ignited automotive natural gas engines for commercial transportation applications such as truck and buses. Our dedicated 100% natural gas engines are manufactured by Cummins and available as a factory-direct option from leading truck and bus manufacturers (OEMs).heavy-duty natural gas vehicles. Applications are due Nov 14. Learn more here . " The Cummins 12 li...