An engine system includes a charge air cooler assembly that is configured to direct air to different parts of the engine system and to reduce overall void volume within the air intake system. The charge air cooler assembly includes a first stage air-to-air cooler arranged to direct a first charge air along a first direction from an inlet to an outlet of the first stage air-to-air cooler. The charge air cooler assembly also includes a second stage air-to-air cooler arranged to direct a second charge air along a second direction from an inlet to an outlet of the second stage air-to-air cooler that is different from the first direction. In some embodiments, the first stage air-to-air cooler and the second stage air-to-air cooler are each disposed in a parallel flow arrangement relative to an air driver of the engine system.

This diesel engine includes a turbocharger which compresses intake air by utilizing a flow of exhaust gas, and an exhaust gas after-treatment device which purifies the exhaust gas, wherein an exhaust pipe connects the exhaust gas after treatment device and the turbocharger, and is connected upwardly to the exhaust gas after-treatment device. The exhaust pipe can have a curbed portion, and have one end and another end, and both ends can face towards a front direction of the diesel engine. The exhaust pipe can be extended to a rear side in the engine front-rear direction, then bent by 180 degrees, and after being extended to a front side in the engine front-rear direction below the turbocharger, can be bent upward and is connected to the exhaust gas after-treatment device. The turbocharger can have an intake ejection pipe which ejects the gas and faces towards the front direction.

A method of operating a forced induction gaseous-fueled engine includes mixing gaseous-fuel and engine intake air to form a mixture at a fuel mixer. The method includes delivering the mixture to an intake manifold by at least partially bypassing a charge air cooler.

An engine system includes a charge air cooler assembly that is configured to direct air to different parts of the engine system and to reduce overall void volume within the air intake system. The charge air cooler assembly includes a first stage air-to-air cooler arranged to direct a first charge air along a first direction from an inlet to an outlet of the first stage air-to-air cooler. The charge air cooler assembly also includes a second stage air-to-air cooler arranged to direct a second charge air along a second direction from an inlet to an outlet of the second stage air-to-air cooler that is different from the first direction. In some embodiments, the first stage air-to-air cooler and the second stage air-to-air cooler are each disposed in a parallel flow arrangement relative to an air driver of the engine system.