An air boost system for a two-cycle engine, such as an EMD engine, which operates with one or more roots blowers, or for similar engines that use gear-driven roots blowers or centrifugal blowers. At least one of the roots blowers is equipped with a variable transmission, which allows airflow into the engine to be varied in accordance with load or other engine operating conditions.

An internal combustion engine includes a cylinder case that includes a first geartrain disposed on a front end of the cylinder case and a second geartrain disposed on a rear end of the cylinder case. The first geartrain drives a first camshaft, and the second geartrain drives a second camshaft, the first and second camshafts having respective rotational axes that are parallel.

Various methods and systems are provided for an intake manifold for an engine. In one example, the intake manifold comprises a first passage for supplying intake air to a plurality of cylinders of the engine and a second passage for supplying gaseous fuel to the plurality of cylinders.

Methods and systems are provided for a 2-port integrated exhaust manifold for an inline-3, inline-6, V-6, and/or V-12 engine. In one example, a system may include an exhaust manifold integrated within a cylinder head of an engine block. The integrated exhaust manifold may include a first set of two runners from a first outer cylinder coupled to a first manifold exhaust port, a second set of two runners of a second outer cylinder coupled to a second manifold exhaust port, and one runner of an inner cylinder coupled to the first manifold exhaust port and another runner of the inner cylinder coupled to the second manifold exhaust port.

An exhaust-gas turbocharger arrangement, including: three exhaust-gas turbochargers, for being arranged above an engine top side, being a high-pressure exhaust-gas turbocharger, a first low-pressure exhaust-gas turbocharger, and a second low-pressure exhaust-gas turbocharger; a high-pressure stage, with the high-pressure exhaust-gas turbocharger; a low-pressure stage, with the first and second low-pressure exhaust-gas turbochargers; and an exhaust-gas conduit, which includes a high-pressure conduit, a low-pressure conduit, and a high-pressure stage bypass, the low-pressure conduit including a bifurcated pipe between the high-pressure exhaust-gas turbocharger and the first low-pressure exhaust-gas turbocharger and the second low-pressure exhaust-gas turbocharger, the high-pressure conduit including an engine exhaust-gas conduit and a high-pressure stage bypass line, the high-pressure stage bypass line being connected at a first end to the engine exhaust-gas conduit and at a second end to the bifurcated pipe, the high-pressure stage bypass line including a part running below the bifurcated pipe.