The inline engines of the D 2876 LF series underwent major modification for the heavy-duty MAN Trucknology Generation (TGA):
- New grading with higher power and torque plus high torque gradients
- Substantial improvement of engine efficiency and fuel consumption over wide ranges of the operating map through an increase of engine peak pressure and the new common rail (CR) technique
- Adaptation of the cylinder head, cylinder head packing, cylinder liner and crank case bolt fit to the higher gas pressures
- Reduced engine weight through omission of the secondary acoustic measures and use of a lighter crank case yoke
- Use of the second-generation Bosch common rail injection system (1600 bar)
- Engine management by EDC 7 and communication with the vehicle management computer on the CAN bus
- Depending on conditions of use and lubricants, oil change intervals of maximally 100,000 km can be achieved and thus lower operating costs for the user
- High reliability through adherence to the proven D 2876 LF 12.8 liter engine concept
- Increase of exhaust brake performance in conjunction with the upgraded, pressure-controlled exhaust valve brake (EVB) as special equipment
- Further increase of exhaust brake performance through use of the entirely new, innovative primary braking system water retarder (PriTarder) in conjunction with the pressure controlled EVB as special equipment
In Europe the 13-step test to ECE R49 is used for commercial vehicles of more than 3.5 t permissible overall weight. This means measuring the engine's exhaust emissions in 13 ready defined, stationary operating states. Then the mean emissions are calculated. In the procedure for Euro 3 engines, in contrast to Euro 2, measurements will probably also be conducted in the subdynamic and, depending on the engine version, in the full dynamic state.
MAN Engine EXTRA EQUIPMENT
The following extra equipment is possible depending on how the customer intends to use a vehicle:
- Gear wheel driven power takeoff at engine end with 600 Nm (temporarily 720 Nm) torque
- Refrigerant condenser, driven by Poly V-belt, firmly attached to intermediate case, for vehicles with air-conditioning
- Possibility of adding hydro geared pump to cam shaft power takeoff
- Possibility of adding steering pumps and hydraulic pumps on air compressor front and rear
- Cooling water preheater from Calix (220 V, 1100 W)
- Ready for attachment of Frigoblock generators G12/G17/G24 (WR is not possible here)
- MAN PriTarder combination of water retarder and EVB-ec
MAN Trucks BASICS OF TORQUE
- TORQUE: Power and torque increase with speed. After overcoming the friction loss and greater heat losses at low speeds, the engine achieves its maximum torque with optimum filling of the cylinder. If speed increases further, the torque drops because of the greater flow resistance and short valve opening times.
- POWER: Power is the product of speed and torque. Seeing as the drop in torque is slower than the increase in speed, there is initially an increase if the power output of an engine. Between the maximum torque and the maximum power there is an elastic range in which power is kept constant by increasing torque although the speed is dropping.
- SPECIFIC FUEL CONSUMPTION: The full-load consumption curve in the diagram can be explained by the fact that you get less than good fuel consumption in the low range of speed because of the poor pressure mix of the fuel particles (14.5:1). At high speeds, combustion is imperfect because of the short time that is available. And fuel consumption increases.
MAN Trucks D 2876 LF ENGINE BLOCK – CRANK CASE
The crank case is cast in one piece together with the cylinder block from special GJL-250 cast iron. The wet cylinder liners of highly wear-resistant, special centrifugal cast GJL-250 are exchangeable. The sealing between the cylinder liner and the crank case coolant jacket at the top is by a oval elastomer moulded washer and at the bottom by two elastomer round sealing rings.
Optimized wall thicknesses and functional ribbing of the crank case side walls optimized by the finite element method (FEM) produce rigidity of form and low noise emission. The crank case was matched to the higher ignition pressure (160 instead of 145 bar) by reinforcing the partitions and geometrically optimizing the cylinder liner fitting, but for the same crank case weight.
To improve the oil supply to the valve gear, extra oil holes were provided in the crank case across from the main oil duct through the partitions to the cam shaft bearing (and on to the valve gear). The crank case was matched externally for compact attachment of the new EDC 7 control unit, rail and cam shaft engine speed sensor. The casting and machining of the crank case were also optimized.
The crank case is closed off at the rear by the flywheel/timing case of GJS-400 ductile cast iron, with the rear crank shaft sealing ring, and at the bottom by the crank case yoke of permanent mould cast aluminium (Loctite 518 sealing). Apply a track with a maximum width of 1 mm. The crank case venting gases are fed back into the combustion air by way of a wire-knit oil trap with pressure regulating valve attached to the rear left of the crank case to avoid emission on the intake side of the turbo charger.