Abstract: A process for forming a structure of aluminium components comprises pre-treating aluminium sheet to produce an inorganic non-metallic surface coating thereon, forming the pre-treated sheet to produce components of desired shape and applying adhesive to the components and securing them together by means of the adhesive. Generally, an adhesive-compatible press lubricant is present on the sheet when it is formed. The invention also includes aluminium sheet carrying the inorganic non-metallic surface coating and a press lubricant thereon.

Abstract: A process for forming a structure of aluminium components comprises pre-treating aluminium sheet to produce an inorganic non-metallic surface coating thereon, forming the pre-treated sheet to produce components of desired shape and applying adhesive to the components and securing them together by means of the adhesive. Generally, an adhesive-compatible press lubricant is present on the sheet when it is formed. The invention also includes aluminium sheet carrying the inorganic non-metallic surface coating and a press lubricant thereon.

Abstract: A method of determining the state of charge of a motor vehicle battery 1 in which a stabilization load 2 is applied to the battery 1 after the engine is switched off to accelerate the stabilization of the charge distribution within the battery 1. The stabilization load 2 is applied until the terminal voltage of the battery 1 reaches a level corresponding to a predicted value of the state of charge of the battery 1. After a pre-determined delay of 8 hours or less, the terminal voltage of the battery 1 is measured and the state of charge derived therefrom.

Abstract: Transducers 16 detect local vibration of the engine and the signals therefrom can be compared using coherence or correlation functions in the region of the knock frequency to ascertain if the source of the vibrations is the same, indicating knock, or different, indicating random vibration. Two transducers spaced apart can be used, or one can measure cylinder pressure. Alternatively, one sensor could be used, using two signals delayed with respect to each other in time.

Abstract: A leak detector has a gas probe 1 for sensing signal gas escaping from an enclosure containing that gas at a pressure slightly in excess of ambient surrounded by a curtain of barrier gas. The reading of a gas analyzer such as a mass spectrometer depends on the height of the probe from the surface. A height sensor is attached to the leak detector and a programmable amplifier 6 contains information on the characteristic curve of the gas sensor. An output signal from the programmable amplifier compensates for the height of the probe from the surface being detected. The speed of the leak detector can be corrected for in the same way.

Abstract: A leak detector comprises a detector head which is to be scanned across a surface to detect a signal gas eminating from the surface. The opposite side of the surface from the head is supplied with a signal gas under pressure so that signal gas passes through leaks in the surface. Detection of signal gas by the head should then constitute detection of a leak. A curtain 1 of barrier gas is provided around a sample inlet 2 to protect the inlet from spurious signal gas. Orifices 36 provide narrow high velocity jets 38 which impinge on the surface S within curtain 1 and break up jets such as 34 of signal gas which escape under the curtain 1 without allowing the signal gas to reach the sample inlet.

Abstract: The leak detector comprises an annular chamber 11 which leads to a circumferential orifice 14 which in turn leads to an annular duct 21 which is symmetrical about the axis of the detector. Barrier gas is fed to the annular chamber 11, for example from an annular chamber 18 and emerges from the opening 20 to form a substantially laminar flow. Leaks are detected by means of a signal gas within an enclosure at a pressure slightly in excess of ambient, and the signal gas is detected from leaks via a probe 2 which is connected for example to a mass spectrometer. The curtain 1 is stable and enables uneven surfaces to be tracked.

Abstract: A cylinder head 1 has four valves 2, 4 per cylinder and the desirable arrangement whereby the sparking plug 7 electrodes are in the center of the four valves. The sparking plug 7 is housed in a tube 29 to protect it from the oil in the valve gear region of the head. By appropriate choice of dimensions, it has been found possible to operate the valves 2, 4 via rockers 9, 11 by means of a camshaft 18 located in the vee-space between the valves, while still allowing room to accommodate the sparking plug 7. A desirable compactness is thereby achieved.

Abstract: A constant mesh parallel shaft gearbox providing a plurality of ratios has its ratio controlled by having, in place of conventional synchronizer assemblies and dog clutches, rotary positive displacement pumps each having one element (4) connected to the gearbox shaft (2) and another (3) connected to a gear (1). With the pump recirculating fluid the gear (1) freewheels on the shaft (2), a valve ring (9) can prevent recirculation and hence lock the gear for rotation with the shaft. Unidirectional rotation of the gear on the shaft in each direction can be obtained passing pump flow through non-return valves 13 or 14. The invention is equally applicable to epicyclic gearboxes and where brake bands, for example, can be replaced by a rotary pump and valve in accordance with the invention.

Abstract: A valve which is arranged to output from a passage 12 a substantially constant-rate flow of fluid, notwithstanding changes in the flow rate entering the valve by passage 11, is arranged to provide an output from passage 12 which is variable with the static pressure in that passage. Thus when the valve is used to supply a controlled flow to a hydraulic control system an increased flow rate to the system is provided to compensate for increased leakage in the system resulting from a higher static pressure in the system.

Abstract: A method of, and apparatus for, detecting leaks from a surface provides a sampling device (10) making use of an air curtain (C). The body (11) of the device (10), the curtain (C) and a surface (B) to be tested together define a sampler volume (S). Pressure in the sample volume (S) is regulated to draw signal gas from a source thereof to the volume (S) along leak path (L) which exists. Sampled gas is withdrawn from the volume for checking by means of a mass spectrometer (18) for the presence of signal gas.

Abstract: A transmission incorporating a continuously variable ratio unit connected to further gearing, such that a plurality of regimes are available with synchronous shifting between regimes, is controlled such that to avoid hunting between regimes when the transmission is running at or around the synchronous ratio, regime and ratio changing beyond the synchronous ratio is inhibited until the optimum ratio for the prevailing operating conditions differs from the synchronous by a predetermined value.