Abstract: A hydraulic brake booster which has an input valve control member acting through a controlled rate spring and through a lever pivoted on the booster housing in the power chamber to move a spool valve in a bore parallel to the power piston so that the input is strictly through the spring. The lever has no connection to the power piston. The control valve is hydraulically unbalanced to a release position and is also urged to the release position by a valve spring. This maintains a proportion between the input force due to the reaction spring, through which input force is applied, and booster pressure. Upon power runout or failure the input and reaction piston overtravels and contacts the output rod to move that rod without moving the power piston.

Abstract: A hydraulic power brake system in which a hydraulic power brake booster has one or more back pressure control valves to produce a restriction downstream of the booster control valve after the booster has been actuated to build up some booster power pressure. This back pressure on the booster control valve is effective to control hydraulic valve noise during booster operation. There is substantially no fluid restriction in the booster when the booster is not actuated. Three back pressure control valve arrangements are disclosed.

Abstract: The hydraulic brake booster power piston has a rectangular cross section seal groove containing a rectangular cross section lathe cut seal having a greater inner diameter than the groove as well as a greater outer diameter. Radial clearance is provided between the piston and the cylinder wall. The groove has one or more holes at its inner diameter opening axially into the booster power pressure chamber. The seal is also axially thinner than the groove. Power pressure holds the seal in sealing relation with the cylinder wall and the piston. When fluid must flow from the exhaust chamber side of the piston to the power chamber side (e.g. during manual no-power operation) the seal moves to the other groove side, allowing flow radially inward in the groove and past the seal inner periphery through the hole or holes to the power chamber.

Abstract: A hydraulic power booster system in which a hydraulic power brake booster has hydraulic ratio changing mechanisms. The ratio is established by trapping hydraulic fluid in a chamber with an input piston having a larger effective area than an output piston forming movable chamber walls. A ratio piston or sleeve exposed to booster power pressure and the trapped pressure is moved upon power runout, causing the booster ratio to change as the ratio of these pressures change, providing a smooth transition from a high ratio toward a 1:1 ratio as the booster shifts to manual operation from hydraulic power operation. These are three booster modifications shown.

Abstract: A hydraulic power booster system in which a hydraulic power brake booster has a hydraulic ratio changing mechanism. The ratio is established by trapping hydraulic fluid in a chamber with an input piston having a larger effective area than an output piston forming movable chamber walls. A ratio piston or sleeve exposed to booster power pressure and the trapped pressure is moved upon power runout, causing the booster ratio to change as the ratio of these pressures change, providing a smooth transition from a high ratio toward a 1:1 ratio as the booster shifts to manual operation from hydraulic power operation. A valve which operates to trap pressure in the chamber upon booster actuation also provides a vent path from the chamber when the booster is fully released so that any air in the chamber may be bled out.

Abstract: A hydraulic power booster system in which a hydraulic power brake booster has hydraulic ratio changing mechanisms. The ratio is established by trapping hydraulic fluid in a chamber with an input piston having a larger effective area than an output piston forming movable chamber walls. A ratio piston or sleeve exposed to booster power pressure and the trapped pressure is moved upon power runout, causing the booster ratio to change as the ratio of these pressures changes, providing a smooth transition from a high ratio toward a 1:1 ratio as the booster shifts to manual operation from hydraulic power operation. A trapped hydraulic fluid link is established between the input piston and the booster output member for manual operation. These are two booster modifications shown.

Abstract: A hydraulic power brake system in which a hydraulic power brake booster has an accumulator operable when there is insufficient power to operate the power brake with hydraulic pressure. The accumulator control valve is actuated by a cylindrical cam normally radially displaced so that its axis is not coincident with the axis of the booster. Sufficient actuating movement of the control portions of the booster cause the cam to move axially and radially so that its axis moves in a direction to be coincident with the axis of the booster, causing the accumulator control valve to be opened in a controlled manner and admit accumulator pressure to the booster power chamber.

Abstract: An engine turbocharger includes a bearing housing, which supports a rotor shaft carrying turbine and compressor impellers on opposite ends of the shaft, and enclosed by turbine and compressor housing members secured to the bearing housing and defining therewith fluid inlet and outlet passages for the turbine and compressor. The turbocharger is provided with an integral wastegate including (1) a poppet valve supported by the turbine housing and controlling bypass passages in the housing between the turbine inlet and outlet passages and (2) an actuating piston in the compressor housing exposed through internal passage means to gas pressure in the compressor outlet and engagable with the poppet valve stem so as to urge the valve in an opening direction as a function of compressor outlet pressure. The shaft bearing lubrication and cooling passages are arranged to also lubricate the wastegate valve stem and spring.

Abstract: A brake actuating pressure proportioning valve is positioned in a vehicle rear brake circuit. The valve is sensitive to vehicle load to change the rear brake pressure point at which proportioning begins. The valve is also sensitive to front brake circuit pressure. If a significant decrease of front brake circuit pressure occurs, a delay piston is moved to follow the proportioner piston to a predetermined extent. In this condition the delay piston keeps the proportioner from operating in a proportioning mode, permitting full rear brake circuit pressure to be delivered without proportioning action. The delay piston is spring loaded to permit a significant pressure delay in proportioning action before it is moved toward its original position with increasing rear brake circuit pressure.

Abstract: A liquid reservoir such as that for a brake master cylinder has a float in the liquid, a magnet and a reed switch secured to the float at a fixed spacing so that normally at high liquid level the reed switch is in a given state. When the liquid level falls, the float approaches a body of magnetic material suspended at a desired level in the reservoir or the bottom of the reservoir which comprises magnetic material. When low liquid level is reached, the body of magnetic material alters the flux field from the magnet to either increase or decrease the influence the magnet on the reed switch to cause a change of state of the reed switch thereby indicating low liquid level.