THE HONGKONG TELEGRAPH, MOTORING SUPPLEMENT. SATURDAY, APRIL 20, 1929.
POWER EFFICIENCY OF PETROL.
Two Important Factors for Motorists.
fiatoful "pink" "Knocking", behaviour of the exploded petrol means loss of power and economy. | mixtures) in the Internal- The spark has to be rolarded and obmbustion engine. Every ex- the mixture enriched, which planation of a knock" Jo means that the engine gets hotter in the nature of a theory and more petrol is consumed, Mr. HR. Ricardo's theory is, per Freedom from "knoclding.” (on the hupe, the ond generally accepted. other hand, "implies that the car In more or less his own words: will stand an advance spark, even when the mixture of petrel vapour
Fow people, as they gazo at mixture in the internal combustion up hills, so that the engine koops and air is compressed to a high their ideal car, have a thought for engine. The Empire Motor Fuela relatively cool and less potrol is pressure and to a temperature ap- that necessary complement the Committee has had similar re- consumed. In other words, moro proaching that of Its self-ignition fuol that makes the wheels go searches carried out on the power la obtained at loss, cost. tomperature, and is then Ignited round. Yet it is just as important behaviour of alcohol and alcohol- Clearly, the tendency to "knock" by the spark, the flame at first to have a perfectly produced fuel ether mixtures. Some review of is the one outstanding factor de spreads by tho, normal process of as it is to have a perfect manufac- the results of these fascinating termining the practical value of combustion, compressing before it tured car. Fortunately, with the experiments may help petrol con- potrol, Compared with this all the unburnt portion of the charge. advance in automobile engineer-sumers to appreciate the problems other considerations are of second- When the consequent riso in tem- ing has gone an even more marked of the petrol producers.
ary importance. But what exactly perature of this unburt partion is advance in the science of oll- However little motorists may is a "knock" or "pink". Probably more rapid than the rate at which roaning and the blending of motor know about the potrol they use, not one in a hundred motorists to heat can be given off, then fuels. Much valuable research they will judge it, quite rightly, could give a correct answer. work has been carried out at the by the degree of its tendency to Instance of the largo oll com- "knock." The joy goes out of panies on the behaviour of petrol motoring when one hears that
Only Theory Available, The truth is that there is little exact knowledge even now of the
AUTO
SUPPLY HEADQUARTERS
The most complete stock of Auto Acces-
F.
sories in the City are here at lower than elsewhere prices.
No matter what you might want in acces sories we have it.
The Republic Motor Co. of China
(Successors A. LUNG & Co., Auto Dept.)
30-32 Des Vœux Road, Central.
spontaneous ignition takes placo, and an explosivo wave is set up. which strikes the walls of the cylinder with a hammer-like blow causing the familiar “pinking" or "knocking," which the scientista call"detonation." It is quito, different from pre-ignition pro- por-that is, from self-ignition of the mixture of petrol vapour and. alr boford the passage of · the spark." But "knocking," if persist- ed in, will so raise the temperature of the points of the sparking | plug as to cause preignition. How, then, is "knocking" to be avoided?
"A Means' of Correction. Mr. Ricardo has proved that "knocking" is loss the lower the rata of burning of tho fuel. The reason for this, according to his theory, is that if the rate of spread of the flame is sufficiently slow thei unburnt portion which la being compressed can get rid of its hent quick enough to avoid self- ignition. In all cases it seems
that a low rate of burning la advantageous. No motor fuel has yet boen found of which the rate of burning was too low to permit of maximum eMeloney Being obtained in the highest-speed engine yet tested. Mr. Ricardo next showed that the rate of burn- ing was affected by the chemical composition of the petrol-that is, by the relative proportions of aromatics, naphthenes, and para- fing it contains; that the sinaller the proportion of paraffins the better from almost every point of view; and that a certain propor tion of aromaties, estimated at about 20 por cent for the majority of commercial motor engines, prac- tically eliminated the tendency to "knock."
THE WORLD HAS A NEW
1
The Nash "400" Advanced Six Phacton
AND FINER MOTOR CAR
EVERY WORD you hear about the new Nash "400"is a Good Word!
MUC
UCH talk about the new motor Easy steering, too, features the Nash "400". People everywhere are saying ("it's the easiest steering, car they have
ever driven.
cars, many things being said both "pro" and "con"--"
But every word you hear about the new Nash "400" is gondd
No one can look at the slender grace, the smart modern style of the new "400" Salon Body without a feeling of genuine admiration.
See its new Twin Ignition engine! Here is the engineering marvel of the year. You'll be amazed at the difference between this and older engine types→
MARINA,
Here is the motor car industry's great. est value! It has Bijur.chassis lubrica- tion; Houdaille bydraulic shock ab sorbers; bumpers front and rear; and a long list of other impartint features." The whole world is saying-and meant every word of it—Nash has built. the car of the year. Be sure to see it, Be sure to drive it.
NASH 400"
Leads the World in Motor Car Value
IMPORTANT FEATURES-NO OTHER CAR HAS THEM ALL
Twin-Ignition engine
12 Aircraft-type spark.
plugs.
High comprenion Hondaille and Lovejoy
shock absorbers Grxcinsive Nash mamuting)
Telephone C, 1474.
Salon Bodies'
Aluminium alloy
plutoni
(Inver Stents). New double drop frame Torsional vibration
damper World'scasieststeering
7-bearing crankshaft
· (bollow crankzina) Bijur centralized'
chassis lubrication Electric clocks. Exterior metalware
chrome plated over Dickel
WONG SIU WOON,
Short turning radius Longer wheelbases One-piece Saloh
fenders
Nash Special Desiga
Itoot and rec
bumpete
Sole Agents for Hongkong and South China. 21, Pottlager Aires, SERVICE STATION:-76, Dea Your Road Central-Telephone G.644,
De Sata
Multum pro parue!
The Difference
Is Important.
THE two machines pictured here show the difference between Supertwist cord used in Goodyear Tyres and the cord used in ordinary tyres.
On each machine one cord stands out, intact and taut. That is Supertwist, a distinct Goodyear development used only in Goodyear tyres,
On each machine one cord is broken or hangs slack. This is the cord used in'ordinary tyres.
ALLODY
"EA.
On one machine Supertwist and an ordinary cord were stretched equally. Supertwist hold firm the ordinary cord broke. On the other, when the tension was relaxed, the Supertwist sprang back, like a rubber band, to its original measure. But the ordinary cord was left limp and distended. The elasticity and durability of Supertwist cord in Goodyear tyres have reduced blowouts and similar trouble to the vanishing point. Supertwist is one of the reasons why the present Goodyear Balloon with the tractive All-Weather Tread is called "Goodyear's Greatest Tyre."
GOOD YEAR
DISTRIBUTORS
ALEX. ROSS & Co. (China), Ltd.
PRINCE'S BUILDING, HONGKONG.
New
نا
De Soto 4-Door Sedan
and already in the field of low-priced sixes.. De Soto Six-
a sensation
་
the new Chrysler sensation-car brings Chrysler's dashing style and speed and colourful individuality into the field of low- priced sixes within one month of its advent is recognised as today's most vivid expression of the new quality and value standards in modern motor car manufacture.
New Mechanical Excellences for a Popular-Priced Six
New Chrysler-designed "Silver Dome" high-compression enȚ gine, using any grade petrol. New-type rubber insulation of engine to wipe out the last yeù- SOLE AGENTS-
4
tige of torque and vibration. New-type Isotherm-inrar-strat „pistams with piston ringu of new tongue and groove construction, New-type 4-wheel hydraulic ins
termal expanding brakes, with squenkless moulded brakelining. New type smaller wheels, com bining greater safely with cailer riding and smarter appearance,
THE REPUBLIC MOTOR CO., OF CHINA.
(Successors A. LUNG & Co. Auto Department.)
30, 32 Des Vœux Road.
DE SOTO SIX
PRODUCT
CHRYSLER
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