MAN Truck & Bus

MAN Engines Head of Development Werner Kübler explains the special features of the engine.

This motor simply has many advantages.

Narrower, lighter more efficient: MAN designed its R6 D4276 engine specifically for harvesters. Werner Kübler, development manager at MAN Engines, explains the special features of this engine that is used among other things in the new CLAAS JAGUAR 900 forage harvester series.


Werner Kübler

is development manager at MAN Engines in their Nuremberg Engine Competence Centre. Their premises extend over some 40 hectares and it is where MAN currently has 4000 employees producing almost 100,000 engines a year; around 10 percent for use outside the brand's own truck and bus programme. So all MAN engines for CLAAS combine harvesters and forage harvesters are also developed and manufactured in Nuremberg.

Mr Kübler, the new CLAAS JAGUAR 970 series is equipped with a six-cylinder in-line engine. The previous series had a V8, why now an R6?

KÜBLER The R6 D4276 simply has many advantages. It is narrower and lighter than the previous V8 engine – with the same cubic capacity. It is also more efficient and smooth running with significantly better performance. In addition to these plus points, the 6-cylinder in-line engine has fundamental thermodynamic advantages over a V8 at the same cubic capacity. The more compact design of the R6 also creates more installation space for additional components, like an exhaust gas after-treatment system, which is a further benefit.

What are the applications for which MAN designed the new R6?

KÜBLER We developed this engine specifically for use in harvesters. It has a cubic capacity of 16.2 litres and builds on the D3876 truck engine with 15.3 litres capacity. We have further optimised all the essential components, however, or redesigned them for the higher output of 790 HP. So the bores were enlarged from 138 mm to 142 mm, the turbocharger was adapted to 790 HP and we further developed the common rail injection system. We also developed a completely new high-pressure pump; combined with optimised diesel injectors it ensures greater injection efficiency. The D42 has been very well received in the harvester sector, by the way. That's why we're currently adapting it for other sectors.

Was the V12 in the JAGUAR 980 and 990 also specifically developed for agricultural use?

KÜBLER MAN initially brought the D28 V-engine into series production as eight and twelve cylinder versions for marine applications. Based on its robust design, we then developed it further and brought it into series production for various other applications, such as in the railway sector, for power generation and combined heat and power generation, for vehicles and also for agricultural use. The engine is now so advanced and further developed that it can deliver up to 2000 HP for yacht applications.

MAN-Motor R6 D4276 bei CLAAS Feldhäckslern
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Power machine What is especially in demand is a broad performance plateau and a noticeable increase in torque at lower revs.

Both engines are standing here side by side. What are the crucial differences – apart from the number and arrangement of their cylinders?

KÜBLER Both MAN's V12 and R6 are engines using the latest technology and available in exhaust class V. The V12 is designed for the power range above 800 HP, the R6 for the range up to 800 HP. So the V12 still has greater potential, but is also 600 kg heavier. Both engines are specifically designed for good overall economy and their fuel consumption is below 190 g/kWh over a wide range of running conditions. That's a very low level in comparison to our competitors. The torque curve, torque behaviour and running smoothness are comparable for both motors.

What are the special features that distinguish the harvester engines?

KÜBLER What is especially in demand is a broad performance plateau and a noticeable increase in torque at lower revs, so that power still increases when engine speed is reduced. We succeeded in doing this well in both the V12 and the R6. Both engines produce their maximum torque at 1350 rpm.

What "adjusting screws" do designers have to optimise an increase in torque? And how do they minimise an engine's fuel consumption?

KÜBLER When it comes to torque behaviour, the art lies in optimising the air supply to the turbocharger. In the case of fuel consumption, on the other hand, this primarily involves appropriate tuning of the turbochargers, fuel injection and exhaust gas after-treatment system. Optimum adjustment of the gas exchange and combustion air flow is important. That's what gives the engine the ability to "breath more easily".

Landtechnik des Unternehmens CLAAS
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Agricultural technology CLAAS, founded in 1913, is one of the market and technology leaders in harvesting technology.

Does MAN only supply the "bare" engines to CLAAS or also all other engine component?

KÜBLER We supply important components from our portfolio that are required for engine operation, such as the exhaust after-treatment system, the AdBlue® tank and the diagnostic software.

Who is responsible for electronic engine management – MAN or CLAAS?

KÜBLER The electronic engine management is developed at MAN. We use hardware and basic software from Bosch and supplement it with application-specific functions developed in-house. This is how we developed the control system for exhaust gas after-treatment, for example, or the option of integrating fan control into the engine management system, which is why we refer to this as full EDC (electronic diesel control – an electronic diesel management system).

Did MAN also develop the new CEMOS AUTO PERFORMANCE for the JAGUAR?

KÜBLER No, that's an engine and traction drive management system specially developed by CLAAS. It is used for application-specific engine control via the CAN BUS without altering full load detection. It is, so to speak, an automatic accelerator for the partial load range to save power and fuel.

This interview first appeared in the CLAAS customer magazine "Trends", 2/2020 edition.

Text   Georg Döring (Claas)
Photos   Peter Dörfel

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