Mack Trucks

About: Mack Trucks is a based out in . It is known for research contribution in the topics: Exhaust gas recirculation & Internal combustion engine. The organization has 251 authors who have published 248 publications receiving 3252 citations.

Variable valve timing system

Abstract: A system for varying the valve timing of an internal combustion engine to increase the retarding effect of the engine for braking purposes, to increase the compression ratio of a relatively low compression ratio engine to enhance starting, and to optimize breathing to improve the engine performance over the useful operating speed range. The valve timing is varied by changing the total valve train length so as to shift the points on the cam profile at which the valve opening and closing events are determined.

Turbocharged engine with exhaust gas recirculation

Abstract: A turbocharged internal combustion engine assembly with exhaust gas recirculation (EGR) includes an air compressor driven by an exhaust turbine, an EGR line that diverts exhaust gases from an exhaust line leading from the engine to an air intake line leading to the engine from the compressor, and a combustion bypass line that conveys compressed air from the compressor to the exhaust turbine without combustion. A pressure adjusting feature disposed along at least one of the air intake line and the exhaust line maintains the pressure at the turbine inlet below the pressure at the compressor outlet and above the pressure at the air inlet of the engine. Examples of suitable pressure adjusting features include a venturi placed in the air intake line at the second point, a power turbine located along the exhaust line downstream of the exhaust turbine, a split exhaust manifold feeding unequal turbine inlets, and an orifice located along the exhaust line between the EGR line and the bypass line.

Fuel injection nozzle holder installation

Abstract: A fuel line installation for a fuel injection nozzle holder comprises two intercommunicating bores formed in the cylinder head, the first of which receives the nozzle holder. A fuel delivery tube, received within the second bore, communicates with the nozzle holder through a conical fitting at the end of the tube. A distance tube encircles the fuel delivery tube and engages the fitting to maintain it in a conical opening in the nozzle holder. The distance tube, in turn, is held against the conical fitting by an elongated annular fitting also encircling the fuel delivery tube and screwed into the free end of the second bore. The second bore and the tubes are dimensioned to provide an annular passage betweeen the distance tube and the interior surface of the bore. In operation, fuel is delivered to the nozzle holder through the fuel delivery tube and return fuel is conducted away from the nozzle holder through the annular passage.

Cooler bypass valve system and method

Abstract: In preferred embodiments, to, e.g., eliminate condensation build-up in the intake manifold and power cylinders, a charge-air cooler (CAC) and/or EGR cooler “bypass” system is provided that can, e.g., control the intake manifold temperature (IMT) above the dew-point temperature of the boosted air. Preferably, a two-port, single valve-body type valve is provided that proportionally controls the amount of charge-air that is “bypassed” (e.g., not cooled), while simultaneously diverting the charge-air cooler return, preferably, inversely proportionally.