Abstract: A method for intentionally imbalancing one or more mass elements of a camshaft assembly to provide overall rotational balance to the assembly, also referred to herein as “zero balance”. Such intentional imbalance may be imparted to any element of a camshaft assembly. In a currently-preferred embodiment, one or more components of an improved camshaft phaser assembly are manufactured as rotationally unbalanced, either by intentionally forming an unbalanced component such as a sprocket wheel having added material or by removing non-functional material from an otherwise standard component. Because the camshaft phaser assembly has a unique and fixed angular relationship to the camshaft, zero balance can be readily and repeatedly achieved for all camshaft assemblies by correct manufacture of parts without requiring separate balancing for each individual camshaft assembly as manufactured.

Abstract: A fast-acting rotor-locking mechanism for a vane-type camshaft phaser. A straight-sided locking pin is disposed in a bushing in the rotor and is urged into a sprocket well by a return spring. A pad disposed at the bottom of the well is a travel stop for the pin. When the pin is fully seated against the pad, the pad covers a portion of the end of the pin. The uncovered portion of the pin end, exposed to oil pressure for unlocking the pin when it is fully seated, is decreased over the prior art pin, permitting use of a lighter locking spring having a lower spring rate. Because of the lighter locking spring, the pin accelerates more rapidly and unlocks significantly faster than in a comparable prior art phaser.

Abstract: A fast-acting rotor-locking mechanism for a vane-type camshaft phaser. A straight-sided locking pin is disposed in a bushing in the rotor and is urged into a sprocket well by a return spring. A pad disposed at the bottom of the well is a travel stop for the pin. When the pin is fully seated against the pad, the pad covers a portion of the end of the pin. The uncovered portion of the pin end, exposed to oil pressure for unlocking the pin when it is fully seated, is decreased over the prior art pin, permitting use of a lighter locking spring having a lower spring rate. Because of the lighter locking spring, the pin accelerates more rapidly and unlocks significantly faster than in a comparable prior art phaser.

Abstract: A camshaft phaser control system including a camshaft target wheel, the target wheel having first and second teeth for measuring camshaft oscillatory instability. The trailing edge of the first tooth coincides with the negative camshaft oscillation peak, and the trailing edge of the second tooth coincides with the positive camshaft oscillation peak. During each camshaft rotation, each tooth initiates an input signal to generate first and second input signals in known fashion. During crankshaft rotation, a third input signal is generated corresponding to the rotational position of the crankshaft. From these signals, operational camshaft oscillatory instability is computed by an engine monitoring system (EMS). Any deviation from the operational instability while the engine is operating is a direct measurement of oscillatory instability of the camshaft about its nominal holding position. A change in oscillatory instability is inferred as system malfunction, permitting defensive action to be taken by the EMS.

Abstract: An improved splined cam phaser includes four assemblies: a sprocket assembly, an inner hub assembly, a cover assembly, and a piston assembly. The joined assemblies provide phaser function at reduced manufacturing cost. The component parts of the assemblies are re-configured from analogous parts in the prior art cam phaser to permit much of the improved phaser to be manufactured inexpensively by powdered metal forming or by stamping or drawing from sheet metal, in contrast with the prior art phaser wherein all parts are formed expensively either by machining from forged blanks or by investment casting. These changes reduce not only the cost of manufacture but also reduce the weight and axial length of the phaser, an important customer acceptance criterion, and improve the speed of response.

Abstract: An improved releasable and reusable self-sealing plug for mechanically sealing a bore. A cylindrical body is formed on its outer surface to retain radial sealing means such as an O-ring. An oversize annular cap at the outer end of the body limits ingress of the plug into a bore, and a pair of opposed, flexible limbs terminating in flanges beyond the inner end of the body are compressed radially during insertion of the plug and spring out at completion of insertion to grip the inner entrance to the bore, thus holding the O-ring and plug in the bore. Insertion may be accomplished manually without the aid of tools. The plug cannot be driven out by pressure on the bore, but is easily removed by recompression of the limbs and flanges and withdrawal of the plug by, for example, needle-nose pliers. The plug may be formed inexpensively and easily by injection molding of a suitable plastic polymer.

Abstract: An improved splined cam phaser includes four assemblies: a sprocket assembly, an inner hub assembly, a cover assembly, and a piston assembly. The joined assemblies provide phaser function at reduced manufacturing cost. The piston assembly is formed, at least in part, of a plastic polymer wherein the seal groove is net formed.