1
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[Door opens, footsteps]

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[Jazzy music: 'The Russians Are Coming' - Val Bennett]

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[rattly engine revs several times]

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Tim: It's hard to imagine the modern world without the internal combustion engine

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it's used to drive such a vast variety of machines, including, of course, the car.

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[engine stops]

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It was the engine that made the whole idea of the car possible.

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The principle on which it works is really quite simple: It's really just like a canon,

9
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the explosive fuel forcing out whatever's inside the barrel.  This is actually a firework mortar...

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And it forces out this cylindircal shell, and the explosive fuel is the gunpowder in the bottom.

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Put it in here...  [strikes match]

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[fuse fizzles] [BANG-Whoompf!]
[whistling of shell]

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The internal combustion engine is really just the same, except it has a captive piston, instead of the shell,

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and it uses an explosive vapour instead of the gunpowder.

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Athough the idea's very simple, it hasn't been easy to tame the violent energy of all these explosions, thousands of times a minute.

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In this programme, I'm going to look at this wild, unlikely contraption, and also at its fuel.

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Almost all internal combustion engines use a fuel based on crude oil.

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This naturally seeps out of the ground in places, and has been known about since ancient times.

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It had a variety of uses, but not as a fuel.

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[bubbling of oil well]

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It's mentioned several times in the Bible: Noah was instructed by God, to use it for waterproofing his ark.

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[thunder]
[distant shouting of ark-builders]

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It was only in the 19th century that oil's potential as a fuel was realised, and people started drilling and refining it.

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One of the products of the refining was a volatile gas-oil, or petrol.

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The petrol was at first regarded as a completely useless byproduct;

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its vapour was so dangerously inflammable.  But it was also realised that it was an enormously potent source of energy.

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We can show this with this modified firework mortar...

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This obviously isn't an experiment to do at home, but if Rex puts a teaspoonful of gunpowder down the mortar...

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[tapping of spoon]

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And, er, using the lager can as the projectile...

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[can rattles down tube]
[fuse fizzles] [dull pop]

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Hehehe, ohdear.  Well, it's not very powerful.

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Ah, well now we're going to compare this with the, er, a teaspoon full of petrol, we'll see how far that goes...

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This time we're igniting it with a spark plug in the side.

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[spoon taps on tube]

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[can rattles down tube]
[muffled bang]

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You can see what an enormous amount of energy there is in the petrol.
[splash]

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Although it's hard to believe, this isn't actually an explosion.  It's just a very rapid combustion; a vary rapid fire.

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The early internal combustion engines were often called explosion engines, though,

40
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and I think it's really a much more appropriate name.

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The great attraction of the explosion engine, is the enormous power it has for its size and weight.

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This is the smallest engine we could find, complete with fuel tank behind; used for model aeroplanes.

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[loud mosquito-like buzzing]

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Even this has enough power to pull Rex round at quite a speed, though it takes a bit of time to get the momentum.

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[engine buzzes loudly]

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The power of a modern car engine is quite awesome - even a basic one is rated at about 60 horsepower.

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That's literally equivilant to the power of 60 horses.

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[buzzing fades out]

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[bang!]
The first successful explosion engine was built by an inventor called Etienne Lenoir in 1859.

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He simply threw away the boiler of a steam engine, and modified it so it would ignite the piped gas supplied for lighting.

51
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Unfortunately the violence of the explosions tended to damage the piston and valves.

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And it was much less efficient than the original steam engine.

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Lenior: Ooph!  [mutters in French]

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[Bang!]
Lenoir: Arrgh!

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[passers-by abuse Lenoir in French]

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Tim: However his engine inspired other inventors, including a German wholesale grocery salesman called Nicolaus Otto.

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[puffinging of gas-engine]
Lenoir: Herr Otto!

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[Bang!]
Otto: Ooogh!  [horse neighs]

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[puffing of engine]
Tim: Otto came up with an engine which was much more efficient.

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His engines were immediately successful, and he sold over 35,000 to power factories and workshops.

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One of the first Otto engines to be built in britain was the 1895 Hornsby-Ackroyd.

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[roar of burner]
It all still looks very like a steam engine, but it runs on paraffin; another product of refining crude oil.

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It first has to be heated to make it an inflammable vapour.

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[Hiss!]

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It's a two-man job to start it, and it never goes round faster than 100 times a minute.

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[Puff-puff-puff of vapour through valves]

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What's going on inside is that first the vapour is sucked into the cylinder...

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...then it's compressed, ignited, and finally the exhaust gasses are pushed out.

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[click of valves] [puff of ignition]

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This sequence... suck, squash, bang, blow...

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is called the four-stroke cycle.

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Otto's big improvement was squashing the vapour up before igniting it, which gave the engine much more power.

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Although, from the outside, a modern car engine looks completely different, and it's obviously got more than one cylinder,

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inside it's really quite similar.  If you start turning it over...

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The piston goes in and out.... the crankshaft goes round and round...

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And this is the exhaust valve, with the strong spring keeping it closed, and the cam pushing it open.

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The other valve, the inlet valve, is tucked away behind on this engine.

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The rusty space around the edge is full of water; essential for cooling the heat of the explosions.

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All these fundamental features have remained unchanged.

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[puffing]
Otto's engines were much too large and clumsy for a car.

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But one of his employees, called Gottleib Daimler, developed a much smaller engine in 1883.

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This ran much faster, and used the volatile petrol as the fuel.

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It produced nearly as much power as Otto's, but weighed 10 times less.

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Daimler's high-speed engine finally made the idea of a car practical.

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And it was quickly realised that cars could do some quite remarkable things.

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The early engines did still have their drawbacks, though.

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This is a 1902 Wolsey, owned by Jack Howes.

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Under the bonnet... the bonnet really just contains the enormous cooling system and radiator

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the engine's tucked away right underneath.

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It's not entirely easy to operate, there are 20 operations you have to do before you can start it.

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Where do you start?

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Jack: First thing I do is to connect the battery, then I turn on the petrol tap.

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And just give the carburettor a touch to draw the petrol through.

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[bonnet clicks shut]
My next operation after that is to turn on the 12 oilers...

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...for the total-loss oiling system.

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Now the most important job of all:  Having inserted the starting-handle as you can see...

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...in the side of the engine, is to put it on half-compression.  Otherwise there's a great risk of breaking your wrist.

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Turn on the switch, adjust the throttle and ignition controls.

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[click-click-click-buzzzt...  click-click-click-buzzzt...]

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[Clunk!  click-click-click-buzzzt...]

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[click-click-click-buzzzt...]

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[click-click-click....click-click-click-click-click...]

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[clicking speeds up as he increases compression]
Jack: (inaudible over engine)

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[loud rattly engine noise]

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Tim: It's not just tricky to get it going: The two leavers controlling fuel and ignition have to be skillfully adjusted as you drive along.

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One false move, and the thing stalls.  Also the engine's very inefficient by today's standards, only doing about 12MPG

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And the total-loss oiling system leaves a trail of oil along the ground wherever it goes.

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[honk.....honk.....honk]
Engines haven't changed radically since this time.

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But their design has been continuously refined.  Arguably the biggest single improvement has been in the oil

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...and how the engine puts it to use.

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An engine wouldn't last for long without oil.  The oil's fed through holes in the castings to all the bearings.

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There's actually an enormous amount of oil being pumped round all the time.

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I can show you this if I knock a hole in the oil filter... this may be a bit messy...

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[rattly idle]
[tapping of hammer]

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[engine noise]
The oil doesn't just lubricate, but it gets all black and filthy like this because it's also a detergent.

116
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It cleans up the deposits left by the exploding gasses.

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Before this detergent was added in the 1940s, you had to strip down the engine and clean everything out,

118
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or decoke it, every few thousand miles.  Now you just have to change the oil and the filter.

119
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I'm going to turn it off, actually.  Whoops!

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[engine stops]
[Tim laughs]

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Many of the improvements in oil, and petrol, have been made possible by the ever-more-sophisticated refining of the crude oil.

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Today, almost everything the refinery produces can be used by the car industry.

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Besides petrol and oil, it provides the chemicals which are the basis of plastics, paints and synthetic rubbers.

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And even the bitumen that the roads are made of.

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[Uplifting music]
Voiceover: Gasoline!  The liquid power to run millions of automobiles everywhere!

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Yet how many know what happens to the gas after it is poured into the gas tank?

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Or realise the care that motor car engineers have taken to give each drop an equal chance to do its duty.

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Gasoline is powerful.  But each drop can give a 100% account of himself only when he finds the most efficiently designed gasoline system,

129
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to help him along his journey.  For a successful life, every drop of gasoline

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depends entirely on what happens to him after he gets in the swim.

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First the fuel has to be mixed with air.  The air comes in through the large air filter on the top of the engine.

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00:13:23,699 --> 00:13:26,898
And it's mixed with the fuel inside the carburetor.

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It's easiest to see the principle of the carburetor with this model.

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We've used the vaccum cleaner to represent the engine, because it's sucking in air all the time.

135
00:13:38,200 --> 00:13:43,898
It simply sucks the fuel up and... up this little tube, and mixes it

136
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...with the air in here.  Here we're going to use red ink instead of petrol

137
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so you can see it more clearly.

138
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[vaccum cleaner starts up]

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00:13:52,600 --> 00:13:58,099
Petrol by itself isn't explosive.  Only the mixture of petrol vapour and oxygen from the air.

140
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You can see the petrol being sucked in, looking down a real carburetor.

141
00:14:06,700 --> 00:14:09,199
[vaccum cleaner off]

142
00:14:09,200 --> 00:14:14,099
Unfortunately real engines need different concentrations of fuel for different conditions.

143
00:14:14,100 --> 00:14:16,999
Starting, idling, accellerating, etc.

144
00:14:17,000 --> 00:14:21,298
That's why the 1902 Wolsey had the mixture lever on the steering wheel.

145
00:14:21,299 --> 00:14:30,499
Modern carburetors make all these adjustments automatically, but this is why they're so fiendishly complicated.

146
00:14:33,500 --> 00:14:39,699
Today a completely different system, fuel injection, is becoming more common.

147
00:14:39,700 --> 00:14:43,699
[whine of fuel pump, clicking of injectors]
It's basically simple; there's just a row of electric valves,

148
00:14:43,700 --> 00:14:47,499
one for each cylinder, that squirt a bit of petrol into each inlet.

149
00:14:47,500 --> 00:14:55,398
[roar of flame]

150
00:14:55,399 --> 00:15:04,398
The precise length of time the valve opens, controlled by a computer, varies the amount of fuel injected very accurately.

151
00:15:08,399 --> 00:15:12,798
Once the fuel and air's been sucked into the cylinder and squashed up, it's ignited.

152
00:15:12,799 --> 00:15:17,798
A spark's created by a high voltage jumping across a gap in the spark plug.

153
00:15:17,799 --> 00:15:24,199
The high voltage itself is created by the coil connected to the battery.

154
00:15:24,200 --> 00:15:31,199
Engines don't like getting wet, because water provides an easier path for the electricity than jumping across the gap

155
00:15:31,200 --> 00:15:34,699
...which I think I can show you... [squirting] ...put the spark out.

156
00:15:34,700 --> 00:15:39,398
Fortunately though, you can often get the spark back again simply with a water-repelling oil.

157
00:15:39,399 --> 00:15:42,599
[squirt....squirt...Woomph!]

158
00:15:42,600 --> 00:15:44,599
[quiet sparking noise]

159
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Although the ignition should be started by the spark, petrol's a complicated mixture of chemicals

160
00:15:51,200 --> 00:15:53,199
some of which are quite unstable.

161
00:15:53,200 --> 00:15:56,298
These can ignite spontaneously under heat and pressure,

162
00:15:56,299 --> 00:16:01,499
causing a sort of uneven explosion, called detonation or knock.

163
00:16:01,500 --> 00:16:07,298
As engines have become more powerful over the years, knock has become more of a problem.

164
00:16:07,299 --> 00:16:11,898
It can be overcome, either by damping the unstable compounds with lead additives,

165
00:16:11,899 --> 00:16:16,599
or in lead-free petrol, by refining the unstable compounds out.

166
00:16:16,600 --> 00:16:24,209
The other option, used in diesel engines, is to refine the fuel less, and to compress it more.

167
00:16:24,500 --> 00:16:32,099
The more the fuel's squashed up in the cylinder, the hotter it gets.  It can get so hot that it ignites spontaneously without any spark.

168
00:16:32,100 --> 00:16:37,599
We've blocked the bottom of this cylinder up completely and cut a hole in it...

169
00:16:37,600 --> 00:16:42,699
Um... and if I put a bit of fuel in the side here...

170
00:16:42,700 --> 00:16:46,099
And bash the piston down with a hammer...

171
00:16:46,100 --> 00:16:49,099
It should ignite...

172
00:16:49,100 --> 00:16:50,398
[BANG!]

173
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If I blow out the burnt gasses, there may be enough fuel left to make it work a second time.

174
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[compressed air]
[smaller bang]

175
00:17:09,000 --> 00:17:14,999
It was a vicorian cigar lighter working ont his principle, that inspired Rudolph Diesel to design

176
00:17:15,000 --> 00:17:16,999
his first engine in the 1890s.

177
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[clock ticking]
Diesel believed that more compression would make his engine much more efficient.

178
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Diesel: The vision I have, of a better future... machines will free mankind from the slavery of work!

179
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Tim: The higher compression made the engine more dangerous, and a prototype nearly killed him.

180
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[BANG!]
Diesel: What!  Nearly killed me!

181
00:17:43,099 --> 00:17:51,098
Men: Oh, oh, oh... Jah!   JAH!

182
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Tim: By 1895 though, Diesel had an design which ran on cheap fuel and was twice as efficient as any other engine of its time.

183
00:17:57,799 --> 00:18:04,399
Diesel became a millionaire from his invention, and invested very badly, quickly getting heavily into debt.

184
00:18:04,400 --> 00:18:10,499
And decided he couldn't carry on.
Diesel: Ah!  Mein gott!  I cannot pay this.

185
00:18:10,500 --> 00:18:13,699
In May 1913, he set off on a night ferry to Britain.

186
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Diesel: I go!  Goodbye!
[splash!]

187
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Tim: He was never seen again.

188
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[Engine noise]

189
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Today, the diesel engine has been greatly improved, and it's now fitted in many cars.

190
00:18:35,400 --> 00:18:40,899
This contraption, which Rex and I built for a TV series a few years ago, is diesel-powered.

191
00:18:40,900 --> 00:18:46,298
The engine, from a Volkswagen Golf car, hardly looks any different from a petrol one.

192
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However, as Diesel orignally thought, the higer compression does make the engine more efficient, and do more miles to the gallon.

193
00:18:53,400 --> 00:18:58,999
Here, as well as powering the vehicle, the engine's also powering a hydraulic lift.

194
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[engine running]

195
00:19:05,799 --> 00:19:16,298
[fairly quiet engine noise]

196
00:19:16,299 --> 00:19:20,199
The most dramatic change to both diesel and petrol engines in the last 10 years,

197
00:19:20,200 --> 00:19:27,699
has been the addition of sophisticated electronics.

198
00:19:27,700 --> 00:19:31,899
Rex: This modern car engine, compared to the early ones, is horrendously complicated.

199
00:19:31,900 --> 00:19:37,168
For example, there's two computers on board.  One controls the electronic fuel injection,

200
00:19:37,169 --> 00:19:40,999
another one controls the cruise control.

201
00:19:41,000 --> 00:19:46,798
Even thought the engine is much more complicated, this makes the most of every drop of fuel

202
00:19:46,799 --> 00:19:49,199
and gives greater fuel economy and power.

203
00:19:49,200 --> 00:19:53,399
Although the complex electronics would be impossible to repair by the roadside,

204
00:19:53,400 --> 00:19:58,879
I've driven 80,000 miles in it, and even with my poor maintenance, it's never even failed once.

205
00:19:59,000 --> 00:20:02,298
Tim: The engine's improved enormously since 1900.

206
00:20:02,299 --> 00:20:07,499
It starts at the flick of a switch...
[engine turns over, starts and idles]

207
00:20:07,500 --> 00:20:11,699
It's incredibly powerful...
[engine revs]

208
00:20:11,700 --> 00:20:15,499
And it's really very reliable.  But it's still far from perfect.

209
00:20:15,500 --> 00:20:18,499
Despite it's power, it's really very wasteful.

210
00:20:18,500 --> 00:20:24,098
4/5 of the energy released by the petrol is simply lost as heat through the radiator, or the exhaust.

211
00:20:24,099 --> 00:20:29,199
And the exhaust gasses themselves, pose even worse problems...

212
00:20:33,200 --> 00:20:38,899
There's an awful lot of them...

213
00:20:38,900 --> 00:20:44,699
[revs engine]

214
00:20:44,700 --> 00:20:49,298
The average car releases four times its own weight in exhaust gasses during its life.

215
00:20:49,299 --> 00:20:53,798
And it's all pretty horrid stuff!

216
00:20:53,799 --> 00:21:02,499
[engine revs]
This wasn't such a problem when there weren't so many cars around.

217
00:21:02,500 --> 00:21:06,399
[uplifting music]
Voiceover: If we are to realise in full the motor car's vast potential for good,

218
00:21:06,400 --> 00:21:09,399
we must use it and care for it wisely.

219
00:21:09,400 --> 00:21:16,199
The motor car has been the key to open new horizons.  Not for the few, but for all.

220
00:21:16,200 --> 00:21:20,298
And all of us share the responsibility of safeguarding the benefits it has brought.

221
00:21:20,299 --> 00:21:26,399
If we plan for the future, if we look ahead to clear all obstacles and roadblocks,

222
00:21:26,400 --> 00:21:31,598
if we recognise the importance of this great individual freedom of movement,

223
00:21:31,599 --> 00:21:37,598
the motor car will be the key to our ever-widening horizons of tomorrow.

224
00:21:37,599 --> 00:21:40,399
[music ends triumphantly]

225
00:21:40,400 --> 00:21:44,798
# Oh beautiful, for spacious skies,

226
00:21:44,799 --> 00:21:50,298
# For amber waves of grain,

227
00:21:50,299 --> 00:21:55,999
# For purple mountain majesties,
[coughs]

228
00:21:56,000 --> 00:22:01,499
# Above the fruited plain,
[coughs]

229
00:22:01,500 --> 00:22:05,298
# America,
[cough-cough]

230
00:22:05,299 --> 00:22:07,298
# America,
[coughs]

231
00:22:07,299 --> 00:22:14,199
# God shed his grace on thee,
Voiceover: If you want sing about America,

232
00:22:14,200 --> 00:22:17,199
you'd better sure you have the breath to sing with!
[singing and coughing continues]

233
00:22:17,200 --> 00:22:21,999
We've been fighting air pollution, but it's time to fight harder.  Help us.

234
00:22:22,000 --> 00:22:34,499
It's a beautiful country [coughs] ...let's not all get choked up about it!
# ...sea! #

235
00:22:34,500 --> 00:22:41,399
In an attempt to clean up the exhaust gasses, catalytic converters are gradually becoming compulsory all over the world.

236
00:22:41,400 --> 00:22:45,298
Child: Oh! Oh Dad!  Dad, Dad, it smells all funny!  Oh Dad!

237
00:22:45,299 --> 00:22:47,399
Dad stop!
[sqeaks to a halt]

238
00:22:47,400 --> 00:22:53,298
Tim: Recent reports from America suggest in practice, catalysts may only remove 30% of the poisonous gasses,

239
00:22:53,299 --> 00:22:57,298
bacause the engine needs carfeul maintenance for them to work properly.

240
00:22:57,299 --> 00:23:01,298
AA man: Don't worry sir, trouble with the catalytic?  Very common these days...

241
00:23:01,299 --> 00:23:03,298
I'll just adjust this screw, and then that'll be alright.

242
00:23:05,400 --> 00:23:12,399
Tim: Even when they do work perfectly, they only convert the gasses to carbon dioxide, the greenhouse gas.

243
00:23:12,400 --> 00:23:15,899
Child: Dad it's getting awfully hot.  I'm boiled Dad!

244
00:23:15,900 --> 00:23:22,899
[bubbling]

245
00:23:23,299 --> 00:23:28,699
Man: Nothing for it, we'll have to go electric, it's the only way to be really green...

246
00:23:28,700 --> 00:23:32,699
Tim: Electric cars aren't perfect either, the electricity to charge their batteries

247
00:23:32,700 --> 00:23:35,798
just transfers a lot of the pollution to the power stations.

248
00:23:35,799 --> 00:23:40,298
I don't think there's any such thing as a completely green car.

249
00:23:40,299 --> 00:23:42,699
[electric motor whine]

250
00:23:42,700 --> 00:23:45,199
The engine's really a victim of its own success.

251
00:23:45,200 --> 00:23:49,798
Despite its disgusting exhaust, it's such a reliable and potent source of power,

252
00:23:49,799 --> 00:23:53,499
it's made the car, and all sorts of other machines, completely indispensable.

253
00:23:53,500 --> 00:23:59,298
It's so central to our modern way of life, that there's almost something rather religious about it.

254
00:23:59,299 --> 00:24:04,699
[Starts engine]

255
00:24:04,700 --> 00:24:12,399
[engine fast-idles]

256
00:24:12,400 --> 00:25:50,399
[Jazzy music: 'Take 5' - Dave Brubeck]