Air-Injection Engine

an internal-combustion engine, usually a diesel, in which fuel is injected into a cylinder by air compressed to 6 meganewtons per sq m (MN/m²), or 60 kilograms-force per sq cm (kgf/cm²). According to their construction they are classified as crosshead and trunk engines and as two-cycle and four-cycle models. In air-injection engines with uniflow scavenging, the indicated mean pressure reaches 0.8–0.9 MN/m² (8–9 kgf/cm²) with smokeless combustion. Air-injection engines have a power of approximately 2.2–3.7 megawatts (3,000–5,000 hp) and speeds of rotation of 180–500 rpm. Air-injection engines are not used in transportation (with the exception of ships) because of their considerable weight and size and the complexity of regulating air pressure at various speeds of crankshaft rotation.