Volvo Turbo Engines 1971

8/3/2019 Volvo Turbo Engines 1971

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Turbo - a technically snperior solutionAs long ago as the early 1950's, Volvo chose a differentmethod. To give the increased output Volvo started tobuild supercharged engines which gave the required

power without any increase in displacement. As a pioneerin the field, Volvo was obliged to solve the manypractical problems coupled to turbo-supercharging. Themany years which have passed since then and thethousands of engines manufactured have allowed Valvoto develop an engine programme which builds on themany advantages provided by supercharging. One resultof this long lead in supercharging techniques has enabledVolvo to develop an engine which will meet futurerequirements without departing from the reliable andeconomical six-cylinder in-line engine.

Whymore powerfu l engin es?The development of both road networks and automotivetechniques has made possible the manufacture of truckswhich can carry much heavier loads. Sirnlrltaneous tothe increases in vehicle and vehicle combination weights

grows the need for higher average speeds for reasonsof transport economy and adaption to traffic rhythm.It is, therefore, necessary to increase truck engine powerat a rate corresponding to these developments.

Many of the world's truck manufacturers still solvethis problem by building bigger and bigger engines. Thisof course, gives the required increase in output but oftenat the price of increased engine weight and higher fuelconsumption.

Compressor -+

Volvo TD 100 "Engine X"

Turbo yes no

Displacemen t 9.6 litres 13 litres

Output at2200 r.p.m. 325 h.p. 355 h.p.

Inner frictionallosses 65 h.p. 95 h.p.

Net output 260 h.p. 260h.p.

Comparing the Turbo and normally-aspirated enginesIn order to achieve the same net output without turbo itis necessary to increase displacement by about 35 7 0 ascan be seen in the table above. The larger engine has,

+- Turbine

however, larger internal frictional losses amounting toroughly 30 h.p. which must be compensated by ahigher fuel consumption. '

More fuel +more oxygen = igher outputThe idea behind supercharging with a turbo unit is toattain higher output from an engine with a givendisplacement by feeding it more fuel. In order that theextra fuel can be burnt and converted into power acorresponding amount of air is required. This is achievedby forcing in air under pressure with the help of acompressor. This compressor is powered from a turbinewhich, in turn, derives its power from the stream ofexhaust gases. The turbine and compressor sit on thesame shaft and together form a Turbo unit.


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b.h. p. (DIN)220

Five vita l adv n tag e sw ith tu rboHigher output from a given displacement.The increase in power on Volvo engines is about 35 r o .

Better fuel economy.The combustion phase in a turbo engine is more effective.Because of the surplus of air pumped into the enginecombustion is much more complete than in a normally-aspirated unit. In addition, the increase in pressurebrought about by the compressor lifts the temperature ofthe air. When the fuel is injected the compressed air inthe cylinders has a high temperature which contributesto quick and complete combustion. The inevitableignition delay is therefore cut considerably in a turbosupercharged DieseL These factors give a lower fuelconsumption.

Cleaner exhaust gases.The almost complete combustion gives the addedadvantage of clean exhaust emissions.

ever engine noise.The reduction in ignition delay also gives a slowerbuild-up of pressure. For this reason a turbo-superchargedDiesel runs quieter and smoother. Since a turbo engineis smaller than a normally-aspirated engine with the sameoutput it also has a lesser expanse of "noise-generating"surface. In addition, both the induction and exhaustnoises are damped by the turbo unit- the pressurewaves are, so to speak, cut to ribbons.

Full output even at high altitudes.Because of the lower air pressure a normally-aspiratedengine gives reduced output at high altitudes. On the

} other hand, however, a turbo-supercharged engine givespractically the same output up to heights of about 2,000metres above sea leveL At this height a normally-aspiratedengine would have lost about 20 r o of its output.

e

200, ."'

___ T070B If/

-- 070B /

"I

I /'/

out P/V

/I

/I1 1 //i V/,

/1II - _ ,I 1;.... - _~ --~ torque, , ',_ r---..

180

160

140

120

100

80

60 kpm807060

50

4030

1000 1500 2000 2500 3000rmp

40

20

a 500

___ Turbo Engines

Normally-aspirated engineFuel

gfhph1 8 0

Fuel consumption,A

1-- . . ,-""1 7 0

1 6 0

150

140o 20 40 6 0 8 0

Speed kmhExhaust gases%40

30 " ' - .

f "'t I'" SmokeI" - _ -, . . . . ,20

10

oo 2 0 40 6 0 8 0

Speed kmh

Comparative fuel consumption and exhaust smoke for a7-litre turbo-supercharged engine and a Itl-litre normallyaspirated engine with the same output and maximum speed.:


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T D 120 engine

T h is is h ow V o lv o b u ilda tu r b o e n g in e

J .

Turbo-supercharging does bring certain increasedrequirements to bear on the design of an engine. It istherefore important that the unit is intended forsupercharging from the initial design stages. On thefollowing pages we show you how Volvo has totallyadapted its engines to turbo operation:

1. The higher pressures require utterly reliable sealing.2. Loading on the crankshaft and bearings increases

considerably.3. The engine block is exposed to greater stress.4. Higher output means greater amounts of heat-

requires better cooling.5. Turbo operation is also more requiring as regards

cleaning of induction air, lubricating oil and fuel.

These requirements can be met in two manners: either bylimiting the degree of pressure in the engine or also byreinforcing the actual engine design. Volvo chose acombination of these two factors.


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sufficiently to give full output. For this reason theamount of fuel metered into the engine is controlledby means of a pressure-sensitive governor or smokelimitation device as it is sometimes known. Thisunit senses the partial vacuum in the induction

manifold. It ensures that the engine never receivesmore fuel than it can effectively combust. This ofcourse gives a slight reduction in output but thistakes place within an engine speed range which is

not used in normal operation. e

T h e T u rb o e n g in e inday-to-dayu s e

The 15 or more years of production experiencewhich Volvo has gained in turbo engine manufacturehave resulted in the utter reliability which is todaycharacteristic of these Volvo units. The turbo unitrequires no special service. It is lubricated by the

engine's normal lubrication system. Experience hasshown that it is often economical1y advisable tooverhaul the turbo unit after about 160,000 km butmany run twice that distance without any trouble.At low engine speeds the stream of exhaust gasesis so slow that the turbo unit is not driven


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h e Vo lv o T u rb o p ro g ram m

The "D" in Volvo engine designations stands for DieseL''TD'' means Turbo Supercharged DieseL The figures indicateengine output. The last letter is changed each time the engine isaltered to such an extent that one can speak of a new version.

TD50B

Output:

Torque:

Displacement:

Compression ratio:

Fitted to truck:

165 b.h.p. DIN at 2,800 r.p.m.

170 b.h.p ..SAE at 2,800 r.p.m.45 kgm DIN at 1,900 r.p.m.47 kgm SAE at 1,900 r.p.m.

5.1 litres

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85 series

TD70B

Output:

Torque:

Displacement:

Compression ratio:

Fitted to truck:

207 b.h.p. DIN at 2,400 r.p.m.210 b.h.p, SAE at 2,400 r.p.m.

70 kgm DIN at 1,400 r.p.m,70 kgm SAE at,1,400 r.p.m.

6.7 litres

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86 series

TD 100 A

Output:

Torque:

Displacement:

Compression ratio:

Fitted to truck:

260 b.h.p, DIN at 2,200 r.p.m.270 b.h.p, SAE at 2,200 r.p.m,

96 kgm DIN at 1,400 r.p.m,100 kgm SAE at 1,400 r.. p.m.

9.6 litres

15:1

88 series

TD 120 A

Output:

Torque:

Displacemen t:

Compression ratio:

Fitted to truck:

330 b.h.p, DIN at 2,200 r.p.m.330 h.h.p. SAE at 2,200 r.p.m,

128 kgmDIN at 1,300 r.p.m,127 kgm SAE at 1,300 r.p.m,

12.0 litres

15:1 .

89 series


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Volvo Turbo Engines 1971