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Valeo and Ricardo team for 42-V diesel vehicle

The 42-V mild hybrid diesel vehicle that Valeo and Ricardo are developing will integrate a range of Valeo 42-V systems, such as its integrated starter-alternator system (shown), with a 1.2-L, four-cylinder diesel engine from Ricardo.

Valeo and Ricardo announced at the Frankfurt Motor Show that earlier this year the two companies entered a technical and strategic partnership to develop a 42-V mild hybrid diesel vehicle. The goal of the venture is to produce a vehicle in which fuel consumption is reduced by up to 30% while simultaneously surpassing Euro IV levels of exhaust emissions by 50%. The jointly developed mild hybrid vehicle, currently called i-MoGen (Intelligent Motor Generator), will integrate some of Valeo's 42-V systems with a high-output, downsized 1.2-L diesel engine that will constitute the core of the powertrain system together with a supervisory controller to coordinate system operation, both developed by Ricardo.

The Valeo/Ricardo systems will be installed on a "C" category production vehicle as a practical demonstrator for future mass-market powertrain technologies. The first demonstration vehicle is expected to be complete by the end of the year, with customer presentations already planned for 2002. The companies have set for the vehicle ambitious goals to be achieved before then, including a 4-L/100 km (59-mpg) fuel economy, the ability to accelerate from 0 to 100 km/h (0 to 62 mph) in 10 s, and production-vehicle refinement and driveability.

At the heart of the i-MoGen vehicle will be the Ricardo-developed four-cylinder HSDI diesel engine capable of delivering 74 kW (100 hp). This engine reduces fuel consumption by 20% compared to a conventional 2.0-L diesel engine. It also offers a possible total mass savings of up to 30%, which compensates for the additional mass normally associated with mild hybrid vehicles.

Valeo's high-efficiency integrated starter-alternator system, which will be mounted on the crankshaft between the engine and the transmission, performs a number of key functions. The integrated unit uses electronic control to crank the engine, providing stop-and-go capability. When a driver stops at a traffic light, for example, the engine is automatically cut, both saving fuel and reducing emissions. As soon as the driver engages a gear again, the engine automatically and quietly restarts. NVH improvements are inherent when at standstill because of the absence of engine noise. The quiet starting is realized through the use of the integrated starter-alternator in motor mode. Since this unit is fully integrated into the powertrain and replaces the traditional starter motor, engaging the starter's gear on the ring gear is no longer. The starting time is 0.3 s as opposed to 1 s with a conventional starter motor, leading to further reduction in emissions.

The special design of the Valeo integrated starter-alternator means it can provide additional torque into the powertrain over the full range of engine speeds. During acceleration, the starter-alternator is used as an electric motor to give an extra boost to the engine; despite the smaller engine size, the i-MoGen powertrain can supply similar torque to the much larger and heavier 2.0-L diesel engine.

In a conventional vehicle, the kinetic energy of a vehicle is lost as heat when the driver applies the brakes. With the high-output starter-alternator, a part of this energy can be saved, using the alternator to generate electric energy. As soon as the driver presses the brake pedal, an electronic communication is sent to the integrated starter-alternator that immediately converts kinetic energy from the vehicle to electrical energy that can be stored in the battery. It is then possible to re-use this energy, which is the basic principle behind regenerative braking.

The maximum electrical output power from the Valeo integrated starter-alternator unit—when running in alternator mode—is 6 kW, which is three times higher than conventional alternators. This high output is necessary to allow the operation of high- power electrical components such as the electrical HVAC compressor or the electrically heated diesel particulate filter, a Ricardo solution that efficiently destroys harmful diesel particulate.

As part of the integrated starter-alternator system, Valeo will integrate a dc/dc converter to supply 14 V to the low-power electrical components that are not converted to 42 V. Such a high capacity dc/dc converter is expected to be a requirement in future 42-V vehicles where specific components will require lower voltage.

A key requirement for 42-V systems is the reliability of available power. Valeo is collaborating with a battery expert to develop and integrate fault-tolerant batteries with a battery state-of-charge function to guarantee the reliability of all its 42-V systems.

Valeo's THEMIS (THErmal Management Intelligent System) manages and optimizes engine temperature according to the driving conditions and will be central to i-MoGen's engine-cooling system. With this system, which features an electrical variable water pump, electronically controlled variable speed fans, and an electronic coolant valve that replaces the conventional thermostat, engine warm-up time is reduced by up to 50%. The result is less engine wear and lower emissions, and fuel consumption can be reduced by up to 5% at low engine loads.

As an additional benefit, the THEMIS system enhances cabin comfort, providing heat even after the engine has been switched off. Electronic control of the cooling function allows easy diagnosis and failure-mode management.

Valeo has developed a 42-V electrical HVAC system, based on an electrical compressor, which will be integrated into the demonstration vehicle. This innovative HVAC system only uses energy "on demand," and since HVAC systems are notorious power consumers, this new system is set to bring significant fuel-economy benefits. Additionally, the system is equipped with a 42-V, 1.3-kW cabin air heater that compensates for the low heat rejection of a high-efficiency, downsized diesel engine under warm-up conditions from a cold start.

The jointly developed demonstrator vehicle will also be subject to rigorous systems tuning, NVH testing, and objective driver evaluations to ensure that the final vehicle will fulfill the needs of the driver and will feel similar to a production car. The combination of Valeo/Ricardo systems interfaces with nearly every generic engineering aspect of the vehicle. In addition to exhaustive and applied engineering expertise in the powertrain, advanced electronics, and interior systems area, the system also connects with important chassis systems. This makes the partnership unique in its jointly accumulated knowledge base and numerous systems synergy benefits.

Behind the partnership with Ricardo lies Valeo's new approach to customer-led innovation, called "Domains," demonstrated and explained at its booth in Frankfurt. Valeo believes its Domains will enable the company to anticipate and exceed customer expectations more efficiently and effectively as well as continuously identify and exploit technology integration possibilities.

Valeo's Electrical Energy Management Domain centers the technologies and products required to enable the generation, storage, control, and distribution of electrical energy within the vehicle and is key to implementing many new electrical and electronic functions, many with customizable features, especially when linked to the introduction of powerful 42-V networks. Its Thermal Energy Management Domain offers solutions to generate, control, and dissipate the thermal energy generated within the vehicle. This domain includes thermal management in the vehicle interior and seeks to provide climate comfort for the vehicle occupants. Many of the typical systems in this domain are the powerful energy systems that make 42-V solutions favorable.

"The technical and strategic agreement we have signed with Ricardo was actively driven by our market-led domain approach to innovation," said Thierry Morin, Chairman of Valeo's Management Board. "The joint development work with Ricardo will strengthen our understanding of customer and consumer needs in both the Electrical Energy Management Domain and the Thermal Energy Management Domain."

- Jean L. Broge

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