trailer world issue Two 2008

Rubrik 20 Ausgabe Zwei 2008 basic element in its hybrid Sprinter, where it is installed compactly in a line in the drive train between the engine and gearbox. A signiﬁcantly more complete conﬁguration stage was the proto- type of a Nissan Cabstar light truck, which ZF retroﬁtted with a hybrid drive train: a motor/generator unit, an automatic gearbox (“iTronic”) with automatic clutch and the corresponding control electronics were combined with the diesel power plant of the Nissan. The third conﬁguration stage was produced by ZF in co-operation with MAN. This is a hybrid drive train ﬁtted into a MAN TGL 12- tonner, again equipped with the standardised components from ZF. Except with the diﬀerence that this concept is equipped with an ELECTRODYNAMIC ACCELERATION ELEMENT (EDA), instead of a clutch. In technical terms, the hy- brid concept with EDA is based on the fact that in this case, the electric motor is not installed directly between the combus- tion engine and gearbox, but is connected by means of a single- stage planetary gear. It still gets by however with taking up very little space. Three drive solutions can therefore be accommodated in the identical installation space of a vehicle: a conventional drive train with manual gearbox, with automatic AS-Tronic gearbox plus acceleration clutch of a hybrid system with EDA. The highlight of replacing the clutch with the electric motor is both very elegant technically, and nothing more than consistent: hardly any other power plant is better suited for getting a heavy truck on the move than an electric motor. Its enormous torque is available practically 100% with the switch-on pulse. The electric motor – with correspondingly intelligent controls – can therefore be used like an extremely sensitive clutch, with all the character- istics of a torque converter. Applications which require extremely slow driving speeds, such as communal use or waste disposal can therefore be realised with very low wear and above all quietly on the environment. Volvo is pursuing a very independent path towards the hybrid truck. The Swedes have the heaviest hybrid distribution truck so far in trial service. The twin-axle Solo truck from the medium-heavy FM series is also equipped with a parallel hybrid and gets by with a smaller diesel engine than usual. This DOWNSIZING of the possible diesel power plant is incidentally a core feature of modern hybrid systems: in the parallel hybrid, the electric mo- tor contributes to covering short- term peak performance require- ments. This “booster” function enables the use of signiﬁcantly smaller diesel engines. And that in turn reduces weight and fuel consumption. Since the Volvo trial vehicle, in service as a waste collection truck, must be able to service in- ner-city routes under purely elec- tric power, all peripheral units which are normally driven by the combustion engine must also be powered electrically. Other- wise the servo-steering pump, air compressor, oil pump, fuel pump and auxiliary drive would all be inoperable in the purely electric mode. This constitutes a substan- tial requirement, which signiﬁ- cantly increases the power consumption in electric operation, and which must be compensated for by recharging during transit in op- eration with the diesel engine. The fact that Mercedes for example has already designed a PLUG-IN SOCKET CHARGING solution for its hybrid Sprinter points out the problem: it is by no means the case that the electrical energy require- ment can be covered over the working day of a hybrid distributor ex- clusively by recuperation, i.e. the recovery of braking energy in pro- pulsion operation. It requires additional charging current to top up 20 Issue Two 2008 Technology The best of two technologies: Diesel engine and electric motor  Use of the high torque of the electric motor for accelerating  Use of the efficiency of the diesel engine for speed  Smaller diesel engines required  Zero exhaust and noise emissions when stopped  Significant savings potential for fuel and harmful emissions  Energy efficiency and practicability by charging the batteries during braking (recuperation)  Combination of “stop-and-go” capability and long-distance capability

trailer world issue Two 2008

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