Mack Trucks, Inc.

Joseph H Schmidt

Jeffrey S Zsoldos

John B Bartel

Timothy Suder

An engine exhaust braking method and apparatus bypasses intake air around the intercooler from the turbocharger while simultaneously injecting a minimum amount or greater of fuel per stroke into an engine cylinder during engine brake operation. The minimum amount of fuel is determined such that it is the smallest amount of fuel which will fully combust when the engine is operating at a particular speed. The apparatus includes a combustion engine, a turbocharger, an intercooler, and a compression release braking system. The compression release braking system includes an engine or vehicle electronic control unit, a compression release brake controller, a fuel injector, and an intercooler bypass assembly, wherein while the engine brake is engaged, a small amount of fuel is injected into the cylinders during the compression stroke, and engine intake air is bypassed around the intercooler from the turbocharger and directly into the engine.

Method and apparatus for compression brake enhancement using fuel and an intercooler bypass

A two-cycle compression brake apparatus and braking method is provided according to the invention. The apparatus includes a positive power hydraulic lash adjuster positioned in a travel path of a power rocker arm and being capable of opening an associated at least one valve when a hydraulic fluid is held in the positive power hydraulic lash adjuster, and a compression brake hydraulic lash adjuster positioned on a compression brake rocker arm and positioned over the associated at least one engine valve and being capable of opening the associated at least one valve when a hydraulic fluid is held in the compression brake hydraulic lash adjuster, wherein in a compression braking mode the hydraulic fluid is held in the compression brake hydraulic lash adjuster to actuate the at least one associated valve while the positive power hydraulic lash adjuster does not actuate the at least one associated valve so that at least one exhaust valve is opened near a top dead center position of an associated piston while at least one intake valve is opened near a bottom dead center position of the associated piston to perform the two-cycle engine compression braking.

Two-cycle compression braking on a four stroke engine using hydraulic lash adjustment

An engine exhaust braking method and apparatus. The method includes injecting a predetermined amount of fuel per stroke into an engine cylinder during engine braking, wherein the predetermined amount of fuel cools the fuel injector nozzle, thereby allowing the engine braking to be performed without damage to the fuel injector nozzle due to excessive heat. The apparatus includes a fuel injector having a nozzle and capable of injecting a predetermined amount of fuel into an engine, and a processor connected to the fuel injector, with the processor monitoring engine operation and capable of causing the fuel injector to inject the predetermined amount of fuel into the engine, wherein a predetermined amount of fuel is injected into the engine to cool the fuel injector nozzle, thereby allowing the exhaust braking to be performed without damaging the fuel injector nozzle due to excessive heat.

Method and apparatus for controlling nozzle temperature during engine braking

An engine exhaust braking method and apparatus is provided according to the invention. The engine exhaust braking method includes the steps of actuating an exhaust valve during an intake stroke of the engine, holding the exhaust valve open during a first portion of a compression stroke of the engine, and closing the exhaust valve when a corresponding piston of the engine is more than one-half way through a compression stroke, wherein a cylinder corresponding to the exhaust valve is precharged by higher pressure air from the exhaust manifold.

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Hagerstown, MD, United States of America

Joseph H Schmidt