Diesel – Electric Parallel Hybrid Traction

For vehicles that live and work in the city and never leave, pure electric traction provides excellent benefits, for the operator and for society as a whole. Where the vehicle is required to leave the city, where range and performance are key operational needs, the Diesel-electric hybrid drive provides an excellent solution. With traction either wholly by electric motor, wholly by Diesel engine or by a combination of the two, what appears at first sight to be a compromise is nonetheless an exciting innovative solution. It brings outstanding benefits both in ease of driving and in fuel economy savings of up to 30%, depending on mission, compared to conventional power train solutions. This is achieved in three important ways:

• Regenerative braking system. The electric traction motor under overrun conditions or vehicle braking functions as a generator and the kinetic energy of motion is converted to electrical energy to charge the traction batteries.
• Stop and Start function. When coming to rest the Diesel engine is automatically switched off. Starting from rest is initially by electric motor only and the Diesel engine is started automatically according to vehicle road speed and driver acceleration demand (indicated by the accelerator position).
• Down-sized Diesel engine. Like most mechanical devices, engine efficiency increases as a function of power demand or load. Usually, the Diesel engine chosen for a particular application will have sufficient power to cater for all needs. With a Diesel-electric parallel hybrid, the use of a down-sized engine covers most needs but the extremes of power required for high rates of acceleration or for the steepest of hills can be met by the Diesel engine working in parallel with the electric motor.

With these features, urban driving in which there is a high degree of stopping and restarting provides the greatest fuel economy savings while the vehicle is equally at home on the motorway between cities, functioning with the flexibility that is expected of a commercial vehicle.

ECODaily Hybrid
The ECODaily Diesel-electric parallel hybrid vehicle is equipped with the 16-valve 2.3 litre 4 cylinder FPT Diesel engine of 116cv (85kW) together with a three-phase synchronous electric motor-generator with a maximum power rating 43cv (32kW). The Agile gearbox acts as an interface between the engine and the electric traction control systems and automates gear and clutch shifts on the basis of driver requirements. The vehicle actually drives in a very similar way to a conventional vehicle with automated transmission. The electric traction is powered by high specific energy batteries and the system operating features include the three key operating parameters considered above. With a maxi-mum speed of 130 km/h, the parallel hybrid Daily is suitable for both urban and extra-urban work and gives a vehicle range limited only by the capacity of the Diesel fuel tank.

Eurocargo Hybrid
The new Eurocargo Hybrid, available at 7.5t and 12t maximum permitted mass, has a Diesel-electric parallel hybrid driveline, making it possible to do goods distribution and collection work in towns without sacrificing high-speed performance on motorways, with fuel consumption savings of up to 30% compared to conventional Diesel engined vehicles, depending on vehicle mission. The 7.5t version uses the 16-valve, 4-cylinder Tector Euro V Diesel engine with maximum rated power of 160cv (118kW) working in combination with a 60cv (44kW) maximum rated power electric motor-generator, a 6-speed automated gearbox and a lithium ion battery pack of rated capacity 1.9 kWh. System operating features include starting from a standstill in electric mode only, automatic starting of Diesel engine on the basis of driver performance requirement, power assist from electric motor during acceleration and climbing, Stop & Start function and regenerative braking. The 12t version uses the 16-valve, 4-cylinder Tector Euro V Diesel engine with maximum rated power of 180cv (134kW) with transmission and battery specifications as for the 7.5t version. The payload is only 200 kg less than conventional Diesel engined models. A further innovation in this vehicle is the automatic engagement of the engine brake during deceleration, in advance of the application of the foundation brake.

Diesel – Electric Series Hybrid Traction
Ideal for passenger transport in urban areas without limitations on range is the Diesel-Electric series hybrid power train; essentially an electric traction system with an on-board battery charger. Sharing the energy saving features of the pure electric versions such as kinetic energy recovery, the series hybrid power train achieves fuel consumption savings in excess of 30% compared to a conventional Diesel engined vehicle, depending on vehicle mission. Ideally suited to urban public passenger transport operating on fixed routes permits an optimised calibration of the power train to achieve the greatest savings. Iveco is active in this field since the mid 1990s with many examples of both 6m, 7.4m and 12m buses operating in French, Italian and Spanish cities. 6m versions use a 1.2 litre Diesel engine with 43 kW electric motor while 7.4m and 12m versions use a 2.8m Diesel engine with 150kW electric motor for 7.4m versions and 164kW electric motor for 12m versions.