THE DEFINITIVE TRUCKING SITE

August 2008

While petrol-driven engines may have powered the world’s first automobiles, it is the diesel engine that has become the power-plant of choice for commercial vehicles, be they trucks, busses, trains or boats. Invented by Rudolph Diesel in 1897, the diesel engine has evolved over the decades to a point where it can now power performance cars and offer the world the most viable solution to combating harmful vehicle exhaust emissions. One company which remains inextricably linked to this process of evolution, is MAN Nutzfahrzeurge AG, which this year celebrates its 250th year of operations. Paul Collings reports from Germany, discovering where the roots of diesel lie and how far they are expected to extend.

The IAA is Europe’s premiere commercial vehicle expo and every two years in Hanover, Germany, features the very latest technologies from the world’s leading truck suppliers. For MAN, the IAA 2008 exhibition will present a platform to celebrate the 150th birthday of Rudolph Diesel and showcase how the company has nurtured and developed the inventor’s brainchild for more than a century. 

It started in Augsburg 
Prior to the bi-annual IAA, MAN hosts an ‘advance press conference’ which gives trucking journalists from around the world the opportunity to drive the new MAN vehicles that will be featured at the expo. This year, FleetWatch was treated to a trip to the birthplace of the diesel engine, Augsburg, the original home of Maschinenfabrik Augsburg (now known as MAN, from the words Maschinenfabrik Augsburg Nuremburg), the company that backed Herr Diesel’s project back in the late 19th century. 
 

According to MAN’s history book, the first diesel engine was a class-topper, albeit something of an unwieldy beast: “The similarity with a steam engine could hardly be overlooked. The massive steel construction was three metres in height; the A-frame with the cylinder mounted on a crosshead and flywheel at the side, powered by kerosene,managed an impressive 18 horsepower and quite astonishing efficiency of 26.2 percent. Diesel's rational heat engine thus outclassed all other forms of propulsion. It worked without an ignition device, needed no boiler plant and no coal bunker. Compared to the gasoline powered or spark ignition engine, the diesel engine possessed three decisive advantages: it was more robust because it consisted of fewer parts; it was able to burn heavy oil, which was cheaper than gasoline; and its efficiency was far superior.” 

Around the world 
It would take more than 20 years for the world to get its first diesel-powered truck. After the First World War, engineers at MAN increased their efforts to produce a lighter, more powerful and fuel efficient truckmountable engine. In1923, MAN introduced the world’s first diesel truck powered by ‘direct injection’, where fuel is injected directly into the combustion chamber under high pump pressure. Other OEMs were slow to follow but today, most truck diesel engines are powered by direct injection. Throughout the 20th century, MANs pioneering diesel engine development work constantly broke new ground in the world of commercial transport. In 1937, says the history book: “The engine designers in Nuremberg come up with a revolutionary innovation in the spherical combustion chamber and the flat-seat jet. MAN speaks of the G principle (G standing for globe), where the eccentric hollow sphere in the piston head reduces the heat losses, while the rugged flat-seat jet, offset from centre, avoids the elaborate multiple-jet nozzle. More fuel burns in a short time, performance improves from the 100 hp of the forerunner sixcylinder to 120 hp. Plus, the new engine manages with one inlet valve and one outlet valve per cylinder. Despite the simplified construction, the G engine is impressive for its consumption of 155 g/hph (210 g/kWh) and improved cold starting. MAN builds four, six and eight-cylinder models that produce 25 to 160 hp at 1500 to 2400 rpm, meaning a weight/horsepower ratio of only 4.5 to 6 kg.” 

Beyond the war 
During WW2, much of the work at MAN focused on tank development although light trucks were being built for the armed forces. The 4.5 ton, 110 hp direct injection trucks become the prototype of a modern semiforward- control truck and the basis for post-war production. It is claimed these trucks were able to save up to six litres per 100 kilometres compared to competitor models. 

Despite the pressure to meet Hitler’s quotas, MAN engineers were able to set further benchmarks in diesel engine design, unveiling an air-cooled V16 diesel engine with an exhaust turbocharger that produced an unprecedented 900hp at 2200 rpm, “with a remarkable weight/horsepower ratio of only 1.7 kg”, according to the company annals. 
 

“In 1950, MAN presents its first post-war heavy-duty truck in the F8. The nucleus of the imposing 10-tonner (10 tonnes payload) is Germany's first water-cooled V8 diesel, generating 180 hp from 11.6 litres cubic capacity and capable of handling the heaviest truck trains,” explains MAN’s historian. “The cab is just as generously scaled as the engine; a special design feature of the F8 is the headlights integrated in the wings.” 

The 1951 IAA in Frankfurt saw MAN surprise visitors with the launch of the world’s first truck engine with exhaust turbocharging. Although the technology was already being used in marine, rail and stationary diesel engines, the six-cylinder, two-axle MAN D 1546 GT generated 35% more power from its 8.72 litre engine, an impressive 175 hp. In the early 1950s, MAN engineer, Siegfried Meurer, introduced the ‘M’ principle, “the result of intensive study of reactive kinetics and micro operations in the combustion chamber. The soft combustion of the M engine ensures a constant rate in the conversion of thermal and pressure energy. The engine is highly elastic, its exhaust gases are cleaner. Because the fuel burns better, higher specific power is possible,” explain the history files. “Last but not least, the M engine proves to be fairly insensitive to the fuel that is used, consuming everything from light gasoline to lubricating oil.” 

Into the modern era 
The rise in long-haul international transport spurred the development of more powerful diesel truck engines and from the 1960s to the mid-80s, MANs cabover models became class leaders. In 1979, intercooling was introduced, helping MAN win the1980 "Truck of the Year" award with its heavyweight F8 19.280 and 19.320 models, delivering 280 and 320 hp respectively. 

“In 1985 the engine designers at MAN go a step further,” our MAN historian says. “With a little more displacement, supercharging, boost intercooling and new multiple-jet injection, the new six-cylinder engines manage up to 360 hp. These engines also take their place under the cab. The top engine of the series is a mighty V10 diesel of 18.3 litres displacement that produces 460 hp, just right for 40 tonnes, which is now becoming acceptable in Europe. This engine makes the MAN F90 the most powerful long-haul truck on European roads.” 

By the mid-1990s, emissionscontrol legislation was changing the way European manufacturers designed their engines. It was no longer just about power generation and fuel consumption, but also about environmental protection. 

Using increasingly sophisticated electronic engine management systems, MANs engineers were able to drastically reduce toxic levels of particulates, nitrogen oxide, carbon dioxide and carbon monoxide. The F2000, released in 1995, met the Euro 2 exhaust standard with its D28 engines and astounded the trucking world by travelling 2800 kilometres from Edinburgh to Bari with a GVM of 40 tons, delivering consumption figures of 25.15 litres per 100 kilometres. 

MAN today 
The turn of the millennium saw MAN release its Euro 3 heavy-duty TGA model, equipped with electronically controlled slide valve pumps, four-valve design and cooled exhaust gas recirculation (EGR). “With exhaust gas recirculation, which withdraws part of the exhaust gas before the exhaust turbine, cools it and adds it back to the compressed intake air after the intercooler, there is a drop in the combustion temperature. That means reduced nitrogen oxide emissions – 30% less than Euro 2 engines for the same attractive fuel consumption figures,” boasts the history text.

By 2004, MAN had secured its reputation as one of the world’s leading truck technology developers and cemented this with the introduction of the D20 common-rail series. “MAN still holds with the magic formula 6,” our historian explains. “What speaks in favour of maintaining the concept of the sixcylinder inline engine is the entire absence of those inertial forces and moments of inertia that need such elaborate countermeasures in other designs. The new 10.5-litre, fourvalve engines are very much more compact and lightweight than their predecessors.” 

While delivering more power, the new engine was lighter and quieter. Fuel consumption was as much as 5% less than its predecessor. Ranging from 270 to 440 hp, the D20 derivatives were Euro 4 compliant, as were the more powerful D26 engines, generating up to 540 hp.

Today, meeting growing demand for greater truck engine power, MAN now sells its latest diesel engine, the D28. This V8 engine sets new standards delivering 680 hp and 3000 Nm and now powers Europe's most powerful series-manufactured truck, the MAN TGX V8. 

This model, along with stable mates, the heavyweight TGS and TGX series were recently awarded the "Truck of the Year 2008" title by a panel of European trucking journalists. 
 

Tomorrow and beyond 
For truckers in South Africa, the very latest European trucking technology may seem a long way off, perhaps even somewhat irrelevant. But the fact of the matter is, trucking is now very much a global industry and developments in Europe will impact on emerging markets at an increasing tempo. In essence, what is recent history over there is our immediate future over here. 

Environmental legislation is driving truck engine design and MAN has scored something of a coup in developing EGR technology to an extent where it will comply with Euro 6 and EEV (Enhanced Environmentally-friendly Vehicle) standards. While other European truck OEMs ensure Euro 5 compliance with SCR (selective catalytic reduction) technology, which requires a separate tank for the additive Adblue, MAN has focused its R&D on developing its EGR product to make life easier and more profitable for the operator. "We'll be attending IAA 2008 with Euro 5 engines that manage without AdBlue injection,” says MAN’s head of engine development, Dr Wolfgang Held. 

The upshot is this: South Africa will be faced with the same challenges Europe is facing in the near future and the fact that OEMs like MAN spend billions of Euros on making their products safer and more efficient is only half the value – they, along with their European customers, have suffered the teething problems for us. 

For Anton Weinmann, Chairman of the Executive Board of the MAN Nutzfahrzeuge Group, the road ahead is clear: “Environmental zones and driving bans, soaring diesel prices and increasing road tolls are currently having a serious impact on the transport industry. As a manufacturer of commercial vehicles and partner to our customers, we must find answers to these challenges. For this reason, our engineers work under intense pressure day after day to improve the efficiency of our transport solutions even further.” 

On the subject of where the diesel engine is headed in this burgeoning age of alternative power sources, Weinmann asserts: “The clean diesel engine will remain the main power unit in the commercial vehicle in the next 20 to 30 years. At the moment, no alternative which could surpass the diesel engine in terms of reliability, power/weight ratio, efficiency and packaging is in sight.”