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THINGS TO KNOW ABOUT THE
ENGINE'S RUNNING
Principles of Transmission System
The conveyance of the power developed by the engine to the driving wheels at the rear of the car involves the use of three main components--the clutch, the gear- box, and the rear axle.
These units, together with the sharts which connect them, form the transmission system.
The clutch is a device for dis- connecting the engine from the gear-box and, therefore, the re- mainder of the system. It is also designed to be capable of picking up the drive smoothly, so that the car moves off from rest without Jerking or shuddering.
Single Plate Cinteli
There are a number of types of clutches now in use, and many more are being developed, but the one most commonly employed is the single plate.
The comparatively thin centre, plate. has 1 ring of ric tlon' fabric riverted to each Oa face near, the periphery. the one side the friction fabric presses against a flat formed on the flywheel, and on the other gainst a heavy dise known as the presser, plate.
The centre plate (known as the single plate) is mounted on short shaft connected to the gear- box, but in a manner which per- mits it to slide along the shaft lengthways though not to revolve Independently of the shaft. This short connecting shaft is carried in what is known as a spigot bearing là recess in the centre of the flywheel) at its forward end, and to one of the constant mesh pinions within the gear-box at its rear end.
When the clutch pedal is push- ed down by the driver the presser plate is drawn backwards along the shaft, and the single plate. being relieved of the pressure of the springs acting on the presse plate, and being. no longer held flywheel, in contact with the comes to rest. The engine is then disconnected from the gear-box.
3
The Gear-Box Itself The gear-box has always been
As the beginner's bugbear. writer of motoring notes it has always been minc, for there is no part of the car so difficult to ex- plain to the novice.
First of all, let us consider why a gear-box is necessary. Briefly.. the gear-box is necessary because the engine which would be requir- ed to propel a car over all kinds of roads without using a gear. " box would be so large as to ren-. der its use prohibitively costly.
Again, the internal combustion engine develops its power very largely in direct ratio to the num ber of revolutions of its crank- shaft in a given time: In other. werds, the faster it revolves (with- in limits). the greater its power output.
The use of a small or a mo- derately sized engine, therefore. involves the use of an arrange- ment of gears 'which will enable the driver to select the ratio best sulted to road conditions, In other words, the gearing should be used in a way which enables the engine to run at its best speed (not necessarily its fastest), both on the level and on hills, as well as when setting the car in motion from rest,
Low: gears meán high engine speeds and relatively low road speeds: high gears mean the op- posite. The toothed wheels in- side the gear-box are of different sizes, and by 'meshing the different wheels the gear ratio is altered. Changing gear is affected by means of a lever.
Top Gear
The first thing to grasp, in con- nection with gears, is that when running on top gear the engine drives straight through the box to the rear axle, without any change. In the number of revolutionā.
That is to say, that if the crankshaft is revolving at 3,000 s ninute, the propeller shaft is do- lug the same.
Why then do we talk of a top gear of five to one? The reduc- tion of five to one takes place in the rear axle itself, the crown' wheel revolving only once to -every five revolutions of the bevel pinion at the end of the propeller shaft. To put it in another way, the propeller shaft is revolving five times for every revolution of the road wheels.
Now, if third gear la ten to one the engine will be revolving tên times for every orice of the road Wheels. You see therefore that a reduction of five to one takes place in the gear-box and another of the same ratio in the rear axle. More Power for His Now let us consider briefly why It is necessary to change gear when cilimbing stiffish hills,
Assume that at a road speed of 30 miles an hour, the engine, with a crankshaft speed of 1,000 r.n.m., develops 20 horse-power; and that the top gear is five to one. The bill is too steep for the engine to propel the car over the hill, so we assist itt do something to
By changing the gear ratio to 10 to one the power output of the
engine is increased because it will. develop more revolutions. The road speed of the car may or may not be affected; that depends on whether the driver "stands on it" hard enough and whether the en- gine will "revy" fast enough to drive the car at 30 m.ph, on the lower gear.
In this case the lowering of the gear ratio will mean approximate- if 2,000 r.p.m., and that is a very, moderate crankshaft speed for 30 m.p.h.
Of course these road and crank- shaft speeds, and the gear ratios,
are not what you will And your car. but they will serve make the point clear.
On to
The Propeller Shaft Few people realise the import- ance of the propeller shaft, or ap- preciate the amount of thought which has been given to this sEN- ple-locking unit. When you ap- preclate that rear axle does all kinds of things, such as rising and falling and jumping up and down at either end, the need" for some kind of flexible joining in the shaft becomes apparent..
But when It is also rememberzo that when the rear springs flatten " out under load the axle varies its distance from the gearbox. It will be seen that there is more about A propeller shaft than meets the eye of the uninitiated.
The arrangement at either end of the shaft is known as a univer-
in sal joint, but
some cases (where a tube is used to take up the torque reaction) there is only
a joint at the front end.
What is Torque Reaction?
I have mentioned torque reac- tion. What is it?
am дом
Torque reaction (I speaking only of reaction) in the rear axle is the tendency for the axle casing, to revolve on its own axis in a direction opposite to that of the rear wheels.
Note that this tendency has a force equal to that applied to the rear wheels themselves, and the need for meeting it in some ade- quate way will be understood,
When you let in the clutch with a bang and the car "buck- jumps" just think of torque renc- tion and its power.
TRANSMISSIONS Hydraulic Without
Gearbox
There is only one example of hydraulic transmission without
a gearbox for though the fluid flywheel is a form of hydraulic transinission, it is not intended to displace a gearbox, but to form a hydraulic coupling between en- gine and gearbox. The one ex- ample of the type of transmission under review is avaliable to bu- yers of Leyland 'buses and coa-
ver-
ches, though it could be applied to Cars no less appropriately There are, however, other sions of the underlying idea now being developed, and one or more of these may, or may not, be offered to car buyers in the near future.
As developed for Leyland pas.. "senger vehicles the hydraulic transmission...may be viewed 28 an elaborate form of fald fy. wheel. But it is more correctly considered as a three-stage tur- bine operated by all pressure In- stead of steam Driven by the engine through a double-acting friction clutch 1 the shaft of a rotary pump,,, a kind of paddle wheel in a sealed casing contain ing of. This pump throws of oll from all points of its circum- ference against the blades or ** cells of a circular dise fixed to the driven shaft, and the fas ter the engine rotates the pump the greater the 'oll pressure against the blades of the disc! therefore the more the engine is accelerated the faster the disć: rotates and the faster the vehicle moves if the resistance to motion. is uniform.
When the all goes beyond the blades of the driven disc it still has a lot of the energy or move- ment imparted to to by the pump. This energy-call "It pressure (again is therefore utilised to
drive a second driven dise with blades, and then a third, though between each of the three the of
HONG KONG DAILY PRESS, TUESDAY, MARCH 27, 1934.
MOTOR
JOTTINGS
Motor Notes From Great Britain
The public demand for mea- sures to secure greater safety on Britian roads has met with an early response from the authort- ties. A whole-hearted campaign for the education in caution of all road users is to be embarked upon forthwith,
Such a campaign was strongly recommended in the memoran- the dum recently submitted to Ministry of Transport by the which Automobile Association, maintains that, whilst the moto- rist cannot be absolved from blame, every road user bears a proportionate responsibility, and united effort is therefore re- quired. Further, the Association has pointed out that the curtall- ment of road development along progressive lines has had a mate- rial bearing on this question of road accidents, and emphasized the
of need for the provision continuous non-skid road sur- faces, the elimination of railway level crossings on important main roads and the provision of adequate footpaths and crossing places for pedestrians,
THE IMPORTANCE OF LIGHTING
A much higher standard of street lighting is another need to which attention is directed. As far as trunk road lighting in the London area is concerned, a start has already been made on certain key sections, notably at Wembley, Kingsbury and King ston-on-Thames, where the new all-British Osira system, develop- ed by the G.E.C.." has been in- *stalled.
An Important characteristic of this system is that, while some 6,000 candle-power is thṛown for: ward in the way that trafic is "proceeding, only 3,000 c.p. is thrown in the opposite direction, so that road users can see com- fortably without glare or dazzle. During the -past year this system of lighting has been put into operation in 20 different towns and districts in Britain.: while as many more experimental Installations are being tried out. MONTE CARLO AGAIN Yet another monte Carlo Rally is over. and once
again British cars have acquitted themselves well. In addition to winning the Eight car class in the actual Rally. they swept the board in the coachwork competi- tlon, Mr. C. J. Joyce, with his Talbot "95," won the Grand Prix d'Honneur in the Concours de Confort for closed cars over 1500 c.b.. and was awarded "L'Auto” gold medal. This is the second year in succession that a Talbot has carried off the premier award in this
section. Mr. Townend's "95" being successful in the 1933 event,
35 YEARS' PROGRESS Ancient and modern coachwork appear in close proximity in an interesting photograph recently taken at the Royal Mews, Buck- ingham Palace. The subjects were a 6 h.p, Daimler. but in 1899 for King Edward VII, and one of the latest. 50 h.p. Daimlers with Hooper bodies, built specially for King George.
There is always "slip," and the percentage of slip relative to en- gine speed depends upon the load represented by the laden weight of the vehicle, the gradient and wind resistance, among other things. When the vehicle reaches a steep hill its speed will tend to decrease and yet the engine may run as fast as ever; this is due to an increase of slip, and it is this permissible slipping that gives the counterpart of automatic gear-changing.
Unfortunately, slip implies loss of efficiency; in other words, waste of power, Under extraor dinary conditions. (e.g., if the vehicle were sét to cilimb an unclimbable hill) all the power- of the engine would be wasted. or while the engine would con- tinue to run and drive the pump. the latter would not deliver on with sufficient energy to move the protors. The oll would merely, be
churned" while the tellicle re-.. mained unmoved. But that is carrying the point to an extreme. Ordinary, this transmission is rea-
is made to pass through a sta-sonably efficient on hills that do tionary disc with diagonally form- ed"boles which direct the oil at the best" angle on to the blades of the next driven diap. Thess. driven discs, by the way, are call- ed rotors, while the two station- ary ones are termed stators.
After the movement of the oil has thus been used three times It has no longer any pressure or energy 61 briodical use: so the oil is allowed to hail back into the bottom of the casing, whence subsequently it is picked up again by the pump init
Varging Efficiency
As may be imagined, the driven rotors are never rotated quite so fast as the pump or the engine.
not bring down the vehicle speed to less than 8 m.ph, while the system has points of appeal to.. bus and coach operators that -compensate, for its varying löss of efficiency under easier condi- tions.
A feature of the Leyland system is that by means of the dúal frie̟- tion clutch mentioned earlier the driver can cut out the hydraulic transmission and bring into use a direct mechanical drive. This is done when with a gear-box the -top gear would be used, "which.
means at speeds over 10-20 mph with the engine easily able to maintain or increase the vehicle speed.
A lofty canopy which seems to tower above the roof of the modern car was apparently the only attempt on the part of the veteran to "afford any protection from the elements. Yet it is said that, before its Royal owner took delivery. this twin-cylinder ma→ chine travelled from Coventry to Land's End, thence to John o'Groats and back to Coventry, ita average running speed being · 10. m.ph
"CHARGING WITHOUT
FEARS
Automatic regulation of the dynamo output to suit the con- ditions of the battery has been
adopted on the electrical equlp- ment of many 1934 British cars. It is a development representing many years of research work on the part of Joseph Lucas Ltd., and more than 10 year's ex- perlenice gained on commercial vehicles and buses.
IS THIS A RECORD? From time to time there appear in the press references to huge milenges put up by motor vehl- eles, both private and commercial. and some of these are truly phe- nomenal. In this" category must surely be place a' Dennis 6-ton- ner operated for years by a New South Wales concern On A tri- weekly service between: Orange and Sydney. This has achieved 'considerably over 300,000 miles.
And to show its capabilities when nearing the 320,000 miles mark this veteran took a 281- top load 10 miles. On the body of the vehicle was placed a steam winch scaling nearly 4 tons, while a 4-ton trailer carried a cylind- rical tank weighing 18-tons 13 cwt.
Real reluctance is often shown in giving up a trusted vehicle, however old, and there is a' good example of this in the case of 2 4-ton Thornycroft lorry oper- ated by the Birmingham Mint: This gave trouble-free service over at least 150,000 miles, working 54. days a week continuously, and its owners stated definitely that it was only the new and very heavy scale of taxation now in force on.. solld tyred vehicles that made them part:
The new vehicle is a 2-tonner of the same make.
An important Scottish bus oper- ating concern, Yog's Bus Ser-.. vice, decided upon a gruelling test of the first Albion Valiant 32-seater purchased by them. Normally, vehicles in this service are docked for overhaul at 70.- 000 miles, but in this case it was decided to let it rum to 140,000 miles, though, of course, there were the usual inspection dock-.. ings
The engine was found to be in wonderful condition, the average cylinder wear. being only .008 in. and the sole replacements a new set of rings, four exhaust valves and two guides Brake linings of use. were still good after 95,000 miles
These results are particularly good, as the machine had been covering 260 miles a day with heavy traffic at one end and se- vere hills and corners at the other. It is unnecessary to dwell upon the bugbears of over and under- "charged batteries, which for so long have been among the chief causes of trouble on car electrical systems. With the new develop ment no dyname charging switch is necessary and the driver need not worry as to whether his par- ticular running conditions call for 'Suminer · Or "Winter output, as at present. By this system the battery is correctly. charged entirely automatically for all conditions of speed and foad
**
THE GEARLESS BUS AGAIN
One of the outstanding exhibits at the Commercial Vehicle Show in London last November was the Leyland Gearless bus, as it became known; in other words, the Hydraat Torque Converter. It is interesting, therefore, to Icarn that already a number of vehicles of this type have been ordered by bus operating concerns.
Up to the present, demonstra tions have, of necessity, been con- fined principally to the northern countries of England, but so-con- vincing has the performance of this bus been that no fewer than 07 vehicles equipped with the de- vice "have been ordered in Lan-- cashire and Yorkshire alone. -
Some extremely interesting vrá ders for Overseas ́have recently been placed with the Associated Equipment Co., builders, or Lon- don's bused Athong these the Arm's ult engines Ogure promin ently. A contract has been plac ed, for instance, for the supply -ot 73 A.E.C. 4-cylinder of engines by a well known Belgian commer- ctal vehicle manufacturer: in an- other case, a 6 cylinder 130 h.p. nil engine is one order for railcar work on the South Manchurian Hallways, ''Simillar work is to be understaken by oul engines to be supplied to the Queensland Rail-
An order for a power unit for
IN STRICKEN NEPAL
on
Lying amongst the foothills of the Himalayas, and brought recently into prominence'in con- nection with the attacks Mount Everest (Both by air and on foot), the State of Nepal has been laid, waste" by the terrific earthquake of January 15th, which had its epl-centre in that region. (In passing, was it not sold by the populace that the Gods of Everest would be wrath if these expeditions were per- mitted?) The city of Kath- mandu, ancient Capital of Nepal, was one of the most picturesque of towns, and although there was no road connecting it with India; there were nevertheless a few very few motor cars in use there.
The owner of one of these-a Hillman--graphically described how his car was transported from the nearest rallhead. First of all, 50 miles of rough "roads" had to
be negotiated through dense jungle, along dry boulder- strewn river beds, to the outpost slopes of the Himalayas, where even these roads cease.
At this stage the wheels and bumpers were removed, and the car was lashed to £ mighty stretcher of stout timber." Sixty- four native porters were then able to "ut the Hillman bodily and actually carry it for a dis tance of twenty miles. Before attaining" the destination "two ranges of hills had to be sur mounted, each some 3,000 feet in height, and in placés "the gradient was as much as 1 in 2. The surface of "the track, more- over. consisted of loose stones, boulders and slippery stone steps. It sounds an amazing feat, but the Hulman seemed no worse for its manhandling, and was the Arst seen in the Kathmandu Valley. Its owner reported that It did good work despite the elementary roads and altitude oi 4,500 feet.
the enterprising Naira Transport Co., which operates the desert service between Haifa, Damascus and Baghdad, is also of more than ordinary interest.
MAKING MOTOR RADIATORS
One of the most interesting processes at the Longbridge fac- tory of the Austin Motor Co, la that of radiator production, ‘and each week 74 miles of tinned" strip are used in the making of Austin radiators. This strip be- gins in rolls, and passes through a series of crimping, planishing; edging and cüfting presses, under the deft guidance of expert girls, before the metal reaches the cor- rugated loop form which, with separating Ans, and in suitable quantities, Can be locked in a frame to reveal for the first time the rudiments of a radiator. This assembly is quickly dipped in flux and solder in turn. then placed under a press to cool, before be- Ing released from the frame and hung on a conveyor which carries It through a hot and cold water. washer. The next stage of pro- duction, after passing through, 'a drying, oven, is the assembly of the top and tank and other at- tings to the block, thèse being mounted for the purpose in a special soldering Jig. An air test at 15 lbs. per square inch pres- sure under water then follows for the detection of leaks, which the radiator, nearing com- pletion, passes on another con- veyor through two drying ovens and the spray painting booth to reach the ultimată · water test. effected at B pressure many
after
LONDON BUS ENGINE SECURES À RECORD
In an entirely new Diesel-ent gined racing car, Capt. G. E. Ť. Byston at' Brooklands; in a down- pour of rain and on a water- covered track, made the first B- tish attempt upon the world's re- cords, In which America has hitherto enjoyed supremacy. He attacked the Diesel car record of 100.75 m.p.h. set up at Daytona in February, 1931, by the Ameri- cán, MP. O. L. Gumimina. Eyston. who raised the speed record to 104.86
m.p.h. for the kilometre, drove a comfortable. saloon cap- able of seating four people, fitted with a six cylinder A.E.C. heavy oil bus engine, of a type identical. to that fitted to many.. London omnibuses. The engine develops 130 brake horse power, weighs only 1,414 lbs, including the By- wheel and all auxiliaries, and was atted in a racing chase's with an over-all width of only 294 inches.
The United Kingdom has held the world standing start recorda for the mile and kilometre for a number of years, the former since 1929, when Kaye Don. with a -four Utre. Sunbeam averaged 100.77 m.p.h., and the latter from 1926. when the late Parry- Thomas with his Thomas Special attained 86.90 m.p.h.
times the maximum ever likely to cccur in normal use.
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