Abstract: In an internal combustion engine equipped with a turbocharger and a compression release engine brake, excessive stress in the engine and engine brake during operation of the engine brake at relatively high engine speeds is prevented by limiting the intake manifold pressure increase produced by the turbocharger, particularly at higher engine speeds. When the engine brake is turned on, a pressure sensor is enabled to sense the gas pressure in the intake manifold. When the pressure sensor detects that the intake manifold pressure is above a predetermined threshold level, the pressure sensor applies gas from the intake manifold to a pneumatic actuator. The pneumatic actuator opens a pressure relief valve which releases gas from the intake manifold to the ambient atmosphere.

Abstract: In a compression release engine braking system for a turbocharged internal combustion engine, excessive stress associated with opening the exhaust valves of the engine near top dead center of engine compression strokes when the engine is turning at high speed is prevented by reducing the intake manifold pressure from what it otherwise would be at that high speed. This is done by retarding the turbocharger so that its speed is less than it otherwise would be at high engine speed. Turbocharger retarding can be accomplished in any of several ways such as by restricting the flow of engine exhaust gas to or from the turbocharger, or by allowing a portion of the exhaust gas to bypass the turbocharger.

Abstract: Increased engine braking is available from a system including an internal combustion engine equipped with a compression release engine brake, a turbocharger, and an intercooler by having the engine inlet air compressed by the turbocharger bypass the intercooler during operation of the compression release engine brake.

Abstract: In a compression release engine brake, electrically controlled mechanisms are provided to partly selectively control the positions or motions of the engine brake slave pistons which periodically open the exhaust valves in the associated internal combustion engine when engine braking is desired. The electrically controlled mechanisms can be used for such purposes as controlling the "lash" of the engine brake or controlling the timing and duration of exhaust valve openings. Because these mechanisms are electrically controlled, they can be made to operate substantially instantaneously.

Abstract: The slave piston drive train in a compression release engine braking system includes a slave piston with a rigidly connected extension. The end of the extension remote from the main body of the slave piston is spherically convex. A bearing pad or foot fits in swivel fashion on this spherically convex end. The outer surface of the foot opposite the spherically convex extension end is substantially flat and bears on a substantially flat surface on an exhaust valve rocker arm.

Abstract: A mechanical component has a recess for receiving a ceramic insert. The insert is held in the recess by a retainer member which preferably resiliently biases the insert inwardly into the recess. The insert provides a hardened bearing surface for the associated mechanical component. For example, the mechanical component may be a piston for use in an engine brake (especially as a master piston in the engine brake), and the ceramic insert may be the portion of the piston assembly which contacts a moving part of the internal combustion engine with which the engine brake is used.

Abstract: In order to make the use of compression release engine brakes on the internal combustion engines of vehicles more acceptable in areas (e.g., urban areas) where high levels of engine exhaust noise are undesirable, the operator of the vehicle can adjust the "lash" of the engine brake to reduce engine exhaust noise whenever desired. The "lash" of the engine brake is the "at rest" clearance between engine brake slave piston and the engine exhaust valve mechanism operated on by the slave piston to produce engine braking. Engine exhaust noise associated with engine braking is reduced by reducing this lash or clearance so the engine brake opens exhaust valves in the engine at lower engine cylinder pressures, thereby reducing the associated exhaust noise. Despite the reduced exhaust noise, the engine brake still provides a substantial amount of engine braking horsepower.

Abstract: Two members which initially have a very loose, complementary dovetail relationship to one another are firmly secured together by causing the material of a ductile locking member to flow into the space which initially exists between the complementary dovetail shapes. This technique is especially suitable for joining materials which are otherwise difficult to unite. For example, this technique can be used to secure an insert of tungsten carbide or ceramic in a main member of steel. Wear or bearing inserts of hard material can be secured in this way to the hydraulic pistons (especially the master pistons) used in compression release engine brakes.

Abstract: An improved clip valve for use in a compression release engine retarder is disclosed. The clip valve assembly incorporates an improved mechanism for arresting the downward motion of a clip valve plunger by using a retaining ring. The apparatus is more robust than previous designs and is easier and cheaper to manufacture. In accordance with another feature of the invention, the new design allows a reduction in the portion of the adjustable screw which is hollow.

Abstract: In a compression release engine retarder of the type in which the reciprocating motion of a hydraulic piston in the retarder is coupled to arcuate motion of a point on a pivoting element in the associated engine by a push rod between the piston and the pivoting element, the end of the push rod in contact with the piston is made convex and the piston surface contacted by the push rod is made flat so that the convex push rod surface rolls on the flat piston surface. This rolling motion replaces sliding motion in the prior art, thereby reducing or eliminating the need for expensive surface treatments and/or lubrication.

Abstract: In a compression release engine brake, the starting point for the forward stroke of the slave piston is automatically adjusted when the engine brake is turned on, e.g., to remove the clearance which is typically provided between the slave piston and the associated internal combustion engine exhaust valve mechanism. Two elements in the engine brake move apart during the first forward stroke of the slave piston. Hydraulic fluid enters a chamber formed between these two members and is tarpped there when the returning slave piston closes the aperture through which the fluid entered that chamber. The return strokes of the slave piston are thus foreshortened. The closing of the above-mentioned aperture by the slave piston constitutes the sole means by which hydraulic fluid is trapped in the chamber. No other check valve element is required.

Abstract: An improved master piston assembly for use in a compression release engine retarder. The improved master piston provides increased reliability and reduced manufacturing costs due to a reduction in complexity over the prior art, as well as a redesigned type of contact between the master piston and the associated push rod or rocker arm.

Abstract: An improved slave piston for use in a compression release engine retarder is disclosed. The piston incorporates a self-clipping mechanism whereby, when appropriate, the escape of the high-pressure fluid that drives the slave piston is allowed, clipping the slave piston's displacement. The apparatus is more robust than previous designs and easier and cheaper to manufacture. In accordance with another feature of the invention, an improved fit is provided between the slave piston and the means for controlling the exit of high pressure hydraulic fluid.

Abstract: A process and apparatus are provided to maximize the retarding horsepower of a compression release engine retarder driven from the intake or exhaust valve pushtubes or the fuel injector pushtubes throughout the operating speed range of the engine without exceeding the maximum allowable loading of the pushtubes. The apparatus includes a timing advance mechanism incorporated into each slave piston comprising a biasing means responsive to the hydraulic pressure above the slave piston which determines the position of a moveable stop means whereby the timing advance of the slave piston is continuously varied in response to the hydraulic pressure above the slave piston.

Abstract: An engine retarding system of a gas compression release type is provided for an engine equipped with a high pressure hydraulic fluid supply system. The retarder comprises an hydraulically driven exhaust valve actuator, a solenoid actuated servo valve controlling the flow of high pressure hydraulic fluid from the supply to the actuator and an electronic controller which provides a signal to operate the solenoid as a function of the engine speed and crankshaft position.

Abstract: An improved control valve for use in a compression release engine retarder is disclosed. The control valve for the high pressure hydraulic fluid circuit of the retarder is arranged in series with a check valve so that the pressure drop in the circuit is taken principally across the check valve and the control valve is exposed only to the pressure of the low pressure hydraulic fluid supply system. In accrdance with another feature of the invention, the control valve is provided with a relief port which is opened in response to excess pressure in the low pressure hydraulic fluid supply to limit the quantity of hydraulic fluid introduced into the high pressure circuit and thereby prevent excess motion or "jacking" of the slave piston and its associated exhaust valve.

Abstract: Apparatus is provided to increase the retarding horsepower of a compression release engine retarder driven from the exhaust valve pushtube or the fuel injector pushtube which includes a plenum communicating with the exhaust valve slave piston and the master piston driven by a remote exhaust valve pushtube or the fuel injector pushtube. A trigger check valve is located between the master piston and exhaust valve slave piston so that the initial motion of the master piston delivers energy to the plenum. At a predetermined point in the travel of the master piston, the trigger check valve is opened by the master piston to permit the delivery of the energy stored in the plenum to the slave piston. Additional pumping capability is provided by a second master piston while a control check valve communicating with the second master piston limits the intake of hydraulic fluid into the system after working pressures have been attained to that hydraulic fluid which may leak from the system.