Renault partners show research prototypes: 2-cyl. 2-stroke diesel, 48V mild-hybrid diesel, delivery EV

13 December 2014

POWERFUL two-cylinder, two-stroke diesel. Click to enlarge.

At its recent Innovations@Renault event, the France-based automaker presented three research prototypes developed in tandem with its partners as cooperative projects: a mild-hybrid diesel produced as part of the HYDIVU (Hybrid Diesel for LCVs); a two-cylinder, two-stroke diesel from the POWERFUL (POWERtrain for FUture Light-duty vehicles) project (earlier post); and an electric light commercial van developed as part of the du VELUD (Electric Vehicle for Sustainable Urban Logistics) project.

HYDIVU is a 48V mild-hybrid diesel solution to bring down consumption and emissions in LCVs. The objective of this project is to reduce the consumption of LCVs for business customers who travel long distances. Developed on the base of the Renault Master, this prototype is fitted with a powertrain that integrates an electric motor (mild hybridization), Twin-turbo technology and a downspeeding design. The combination of these three technologies results in a in a fuel consumption saving of up to 10% when used over long distances.

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48V mild-hybrid diesel LCV Click to enlarge.

This powertrain is derived from the Energy dCi 165 Twin Turbo engine, to which the engineers have applied the following enhancements:

• A 48-Volt (10-12kW) starter motor/alternator-type electric motor mounted on the gearbox: this delivers additional torque, thereby reducing the load on the internal combustion engine. With an advantageous position in the powertrain as close as possible to the wheel, it is able to benefit from greater mechanical efficiency, allowing it to recover more energy during periods of deceleration and braking. This recuperated energy is stored inside the 48V battery and can be-used in the form of additional torque, which in turn reduces to a similar degree the load on the internal combustion engine.

• Downspeeding: this reduces the running speed of the internal combustion engine by lengthening the gear ratios. This reduction in engine revs results in less friction which is directly beneficial to consumption.

• An improvement in the engine’s thermo-mechanical efficiency has been achieved through the use of a Twin-Turbo concept with variable geometry adapted to downspeeding. The objective is to strike a balance between sufficient torque available from the very lowest revs (from 1,000rpm) and consistent driveability across the entire operating range.

  Further, the engine features a reduction in friction thanks to downspeeding and the use of innovative technologies such as steel pistons.

• Fuel-injection pressure was increased to 2,500 bar (compared with 2,000 bar) for a reduction in polluting emissions while at the same time ensuring the necessary power output.

Partners on this project are LMS, IFPEN, Valeo, and Continental.

POWERFUL two-stroke diesel. The project led by Renault, in collaboration with the Czech Technical University in Prague, IFP Energies Nouvelles, Delphi, Le Moteur Moderne (LMM) and Universitat Politècnica de València developed an advanced two-cylinder, two-stroke compression ignition (CI) engine integrating LTHC (low temperature homogeneous combustion) as part of the European project POWERFUL (POWERtrain for FUture Light-duty vehicles).

The 2-stroke, two-cylinder 730 cm³ engine uses a valve scavenging architecture, with the combustor head defined to optimize the scavenging. Injection pressure is up to 2,000 bar, delivered by the latest common rail generation combined with a high performance HP pump designed to limit the weigh to contribute to the CO₂2 reduction. A new generation of fast solenoid injector was proposed with improved multiple injection control and limited leakage.

The efficiency of two-stroke engines is close to 50%, while four-stroke automotive diesels struggle to achieve 35%, Renault said. The efficiency gains of the two-stroke cycle offer other benefits: compactness and a reduction in weight, given that it involves halving the engine size and number of cylinders (here a twin-cylinder). The engine is 40 kg lighter and more compact, thereby making it ideally suited to small vehicle platforms.

The two-stroke, two-cylinder engine produces the same sound as a four-stroke, four-cylinder unit, Renault said.

Twizy Delivery Concept is a research prototype that forms part of the du VELUD (Electric Vehicle for Sustainable Urban Logistics) project. The VELUD initiative aims to run a pilot delivery scheme in Paris with an electric LCV in order to reduce the impact of urban deliveries on air quality. Based on the Renault Twizy, this prototype explores an alternative for deliveries in built up areas.

The main foci of this project are:

• Experimenting in the sphere of new uses for ‘final kilometres’ logistics.

• Testing the adaptive potential of modular cargo zones in accordance with the goods on-board.

• Defining an intelligent management of the fleet to achieve optimum activity and an efficient delivery
  service.

This project is intended to help establish the blueprint for a future system of urban logistics, incorporating the criteria of the towns and cities with the changing demands of transport linked to the development of e-commerce.

The prototype consists of a small electric-powered vehicle to which is attached a trailer, which is capable of holding up to 15 adjustable containers depending upon the load in a total space of one cubic meter.

Partners include Industrial Systems Engineering School (EIGSI, La Rochelle), AIRPARIF, La Petite Reine Groupe Stars Service, and the City of Paris.