Cummins natural gas engines are spark ignition engines and have unique features of better fuel economy, better emissions, durability, extended oil and filter change period. Engines are available in both types of aspirations, naturally aspirated and turbocharged-aftercooled versions. Cummins QSV product has been designed to combine the compact size, low emission levels and excellent performance characteristics of high-speed technology with the medium speed benefits of water-cooled exhaust valve seats, steel-crown pistons & combustion control.