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Exhaust-powered Braking

18th March 1960, Page 84
18th March 1960
Page 84
Page 84, 18th March 1960 — Exhaust-powered Braking
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Which of the following most accurately describes the problem?

DATENT No. 827,067 describes a

scheme by which exhaust gas is used to operate a brake servo as well as providing engine-braking, when throttled by an exhaust obturator. (Clayton Dewandre Co., Ltd., Titanic Works. Lincoln.) The exhaust pipe (I) is fitted with a throttle valve (2). When this is closed the engine decelerates and the gas passes through a one-way valve (3) to a reservoir (4). The reservoir can be primed initially by compressed air.

The pressure side of the servo (5). for the normal brake system receives .gas from the reservoir through a pipe (6). A branch pipe controlled by a valve (7) works a smaller servo (8) which operates the exhaust throttle. The brake pedal actuates both braking systems simultaneously.

Alternatively the exhaust throttle can be operated by a solenoid (9). This is controlled by a separate switch or by one mounted on the pedal as shown. The latter device brings the exhaust brake into action ahead of the main system. In another layout the switch is closed by upward movement of the accelerator pedal. •

Another. servo (10) cuts off the fuel supply when the exhaust brake is applied. This too could be controlled electrically.. Reference is made to an earlier patent numbered 732,829.

FUEL-COOLED INJECTOR

ANinjector, cooled by circulated fuel, is shown in patent .No:7827,900. The assembly issufficiently compact' to be used in the engine of a road vehicle. (Maschinenfabrik Augsburg N Urn berg, A.G., Nurnberg, Germany.)

Referring to the drawing, the fuel from the injection pump arrives through the connection (1) and passes down the duct (2) to reach the pressure space (3) and lift the needle-valve.

Fuel for cooling enters at the union (4) and flows down a duct (5) into an annular space (6) around the nozzle body. After traversing this, it leaves through a cross-slot (not shown) and flows upwards through the space (7) between the needle and its bore to emerge from a connection (8) into the overflow pipe.

POROUS LINED COMBUSTION CHAMBER

DATENT No. 823,714 describes a corn

bustion chamber for "oil engines which is designed so that injected fuel adheres to the walls of the space. This is said to promote clean, quiet running. (Maschinenfabrik Augsburg Ntirnberg, A.G., NUrnberg, Germany.) The drawing shows the combustion chamber in the crown of the piston. It has a porous lining (1) made of an unspecified sintered material. The injector (2) is positioned so that its fuel jets are directed over the lining, when dispersed by the swirling air charge.

The lining has an absorptive factor of 60 per cent. and the fuel is forced into it by compression. As combustion proceeds, the fuel seeps out and evaporates to bring the combustion process nearer to a constant-pressure cycle.

TWO-STROKE FUEL CONTROL

A FOUR STROKE fuelinjection PA engine can have fuel intake contro led by the quantity of air taken in, but in a two-stroke this method does not work well because of the extra air taken for scavenging. Patent No. 826,994 describes a device which controls the injectionpump setting on a two-stroke engine according to the pressure of the air drawn in rather than the quantity. (S. A. Andre Citroen, 117-167 Quai de Javel. Paris.)

In the diagram, I and 2 represent two cylinders of a two-stroke engine. They are charged by a blower (3) and the quantity of air is regulated by linked throttle-valves (4) in the intake ducts.

'Fuel from the injection pump passes through a metering valve (5) and .a distributor (6) before it reaches the cylinders. The metering valve is operated by the'pressure of . the Scavenging air which is applied through the pipe (7).

An increase in air pressure raises the rate of fuel delivery. The patent states that the same degree of control can' be obtained by sensing the pressure drop across a venturi in the exhaust pipe, SNOW CHAIN

ADETACHABLE tyre band for improved traction in mud or snew is shown in patent No. 827.180. The bind is built up from identical units which can he assembled to form any required length. (0. Pizzuti, Via P. Reti 63r. Genoa-Sampierdarena, Italy.) The drawing shows the basic unit from which the tread is constructed. it consists of a pair of side-plates (1) of stirrup form, strengthened by ribs (2). A double hinge (3) on one end interleaves with a triple hinge on the neighbouring link, the assembly being completed by pins.

An assembled length is laid on the ground, the wheel is run on to it, and the last pin inserted to form a complete circle. The tread band can be used also to protect tyres from damage on bad surfaces.

TWO-SPEED AXLE -rt

A DRIVING axle with two ratios is

shown in patent No. 827,116 by Daimler-Benz A.G.. Stuttgart Untertiirkheirn, Germany. The differential gear includes an epicyclic unit which, in one position, locks the sunwheel and, in the other, couples it to the planet-carrier. The shape of the teeth on the dog-clutch employed forms part of the patent.


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