Systems (100, 200 and 300) and methods (400, 500 and 600) for controlling exhaust gas emissions from naturally aspirated engine are disclosed. The system (100, 200 and 300) includes an open loop exhaust gas recirculation flow to the engine. The system (100, 200 and 300) includes a diesel oxidation catalyst (102, 202 and 302) mounted on or near exhaust manifold (106, 206 and 306) of the engine. Furthermore, the system (100 and 200) includes an exhaust gas mixing conduit (114 and 214) inserted into air intake conduit (104 and 204). The system (100, 200 and 300) further includes an exhaust gas recirculation valve (110, 210 and 310) mounted on cold side or a hot side of EGR cooler. Furthermore, the system (100, 210 and 310) includes an electronic control unit to control exhaust gas recirculation valve (110, 210 and 310) along with various other engine calibration parameters.

An EGR system is configured to allow a part of exhaust gas discharged from an engine to an intake passage to flow as EGR gas to an intake passage through an EGR passage to return to the engine. In the EGR system, a heating film is provided on an inner wall or an outer wall of at least one of the intake passage through which the EGR gas is allowed to flow and the EGR passage. At least a pair of a positive electrode and a negative electrode is provided to energize the heating film.

A gas tube for an EGR cooler has such a structure that a metal plate having a flat plate shape is bent in a tube shape. The metal plate includes a core material, a sheath material clad on one surface of the core material or on both surfaces thereof, and an intermediate material clad between the core material and the sheath material so as to prevent magnesium from diffusing from the core material to the sheath material. The core material includes copper (Cu), silicon (Si), iron (Fe), magnesium (Mg), manganese (Mn), titanium (Ti), and aluminum (Al).

A gas tube for an EGR cooler has such a structure that a metal plate having a flat plate shape is bent in a tube shape. The metal plate includes a core material, a sheath material clad on one surface of the core material or on both surfaces thereof, and an intermediate material clad between the core material and the sheath material so as to prevent magnesium from diffusing from the core material to the sheath material. The core material includes copper (Cu), silicon (Si), iron (Fe), magnesium (Mg), manganese (Mn), titanium (Ti), and aluminum (Al).

An engine with an EGR device includes an engine case, and an EGR pipe that introduces an EGR gas into an intake path. The EGR pipe is arranged to pass through an inside of the engine case. A part of the EGR pipe in the engine case is arranged to face a cooling water path in the engine case. The engine case is defined by a cylinder head. The cooling water path is arranged to surround a whole circumference of the EGR pipe.

An engine with an EGR device includes an engine case, and an EGR pipe that introduces an EGR gas into an intake path. The EGR pipe is arranged to pass through an inside of the engine case. A part of the EGR pipe in the engine case is arranged to face a cooling water path in the engine case. The engine case is defined by a cylinder head. The cooling water path is arranged to surround a whole circumference of the EGR pipe.

An intake system of an engine supplies gas at least containing fresh air to each cylinder. The system includes an EGR passage that communicates with an internal space of a downstream intake passage and introduces some EGR gas into the downstream intake passage. The EGR passage includes a projected section in a substantially polygonal or cylindrical shape that is projected to the internal space of the downstream intake passage. The projected section is formed in such a shape that a projection length H1 in an outer circumferential surface on an upstream side is longer than a projection length H2 in an outer circumferential surface on a downstream side.

A cooling device includes a case delimiting an air circulation enclosure. The case comprises an air intake opening intended to be connected to an air inlet, and an air outlet opening intended to be connected to a heat engine. The cooling device includes an exhaust gas driving device housed at least partially in the air circulation enclosure. The exhaust gas driving device includes at least one exhaust gas flow sensor, each flow sensor being housed entirely in the air circulation enclosure of the case.

An exhaust gas recirculation valve that includes a recirculation passage through which the exhaust gas flows; a valve seat press-fitted onto an inner surface of the recirculation passage; a valve body configured to sit on the valve seat; and a shaft extending through an inside and outside of the recirculation passage and fixed to the valve body and configured to move the valve body relative to the valve seat, in which corrosion-resistant coating is not provided on a portion of the inner surface of the recirculation passage that contacts a peripheral surface of the valve seat, and the corrosion-resistant coating is provided on another portion of the inner surface of the recirculation passage that contacts an end surface of the valve seat in a direction of press-fitting.

An exhaust gas recirculation valve that includes a recirculation passage through which the exhaust gas flows; a valve seat press-fitted onto an inner surface of the recirculation passage; a valve body configured to sit on the valve seat; and a shaft extending through an inside and outside of the recirculation passage and fixed to the valve body and configured to move the valve body relative to the valve seat, in which corrosion-resistant coating is not provided on a portion of the inner surface of the recirculation passage that contacts a peripheral surface of the valve seat, and the corrosion-resistant coating is provided on another portion of the inner surface of the recirculation passage that contacts an end surface of the valve seat in a direction of press-fitting.