Electric delivery: Driving the Emerald Automotive t-001 RE-EV prototype van
May 31, 2012 § Leave a comment
Low emissions and low energy consumption are crucial features for the delivery vans of the future – vehicles which clock up large mileages in and between our cities. The UK government’s Technology Strategy Board thus stumped up 50% of the funding needed to develop such a vehicle, with the stipulation that as much of its engineering and components as possible could be sourced within the UK, and the result is the t-001 RE-EV, a range-extended electric van.
Developed by Intelligent Energy of Loughborough and built by Brentwood-based Revolve Technologies, a partner in the project, the t-001 features a Ford-supplied four-cylinder, 1.4-litre diesel engine, a 75kW traction motor and a 54kW generator (from Evo Electric of Woking), and a 25kWh lithium-ion Axeon battery. The t-001’s rear wheels are driven by the motor, which is directly coupled to the differential; the engine acts only as a ‘range-extender’ to run the generator. This gives an all-electric range of up to 66 miles before the engine kicks in, and fuel consumption over a 125-mile route of 138mpg; in simulations, a carbon dioxide output of 22g/km was achieved.
The van’s total possible range between refuelling or recharging stops is over 400 miles, and its battery can be recharged in 30 minutes from a three-phase power supply; different recharging solutions could be adopted in a production vehicle, but this would be adequate for a fleet van returning to a fixed base. Performance remains acceptable for a vehicle of this type – a top speed of 81mph, acceleration 0-62mph in 8.5 seconds – and crucially, it maintains a kerbweight of just 1550kg and a payload of 1400kg, thanks to its lightweight structural components and body panels.
“This was designed to be all about weight, volume adoption and cost of ownership, a real-world application”, says Nick Tebbutt, project director at Ricardo, tasked with developing the powertrain control system, telematics, and initial simulations. “The powertrain was picked to support the above. It gets around range anxiety and is a way of addressing the variability of fleet use, not necessarily doing a fixed route like a bus.”
“The transmission is single-speed, with the motor directly onto the diff”, says chief engineer Andrew Preece, “but we could add in eco modes using standard gearing in a custom casing.” Regenerative braking is yet to be integrated to the t-001 demonstrator, but this will be fitted and tested in the next phase.
A riveted and bonded aluminium spaceframe structure, with composite exterior panels and lightweight seats and interior components, means that the t-001 prototype weighs in at 1550kg and its payload is 1400kg – comparable to that of the similarly-sized short-wheelbase Ford Transit, with which it shares its braking and suspension systems, along with its stock wheels and tyres. The use of carry-over parts is integral to keeping the overall cost of the vehicle down, though for final production, other sources and suppliers could be used depending on the global location and local market requirements.
Affordability has been an important aspect to the project, and whilst the range-extended powertrain and bespoke structure will add to the van’s purchase price, “the selling proposition is the total cost of ownership”, says Intelligent Energy programme director Chris Hiett. “The total cost to a fleet user is reduced, when you take into account the whole life of the vehicle. It is more expensive to buy initially, but over a typical four-year cycle there are net savings, especially with fuel costs in the UK and Europe.” Exemption from levies such as the London congestion charge, and incentives such as CO2-based taxation, all speed up the payback period.
Large fleet operators including the British Post Office and DHL have contributed to the project, inputting data on duty cycles and talking to Intelligent Energy about their needs. The aim is to build the van in batches of 10,000, manufacturing at different locations around a central hub, and to this end, Intelligent Energy has formed a subsidiary division, Emerald Automotive, to further develop and market the vehicle for production. In the next 24-month phase of the programme, more prototypes will be built, and a small number will go out to fleets – initially in the UK and Europe – for field testing.
Emerald Automotive intends for the van to meet a five-star standard in the Euro NCAP crash tests, and for it to meet emissions legislation in both Europe and in North America, where production is also being considered. Further into the future, different powertrains are possible on the same flexible and scalable platform: RE-EV with a petrol engine for selected markets, as well as fuel cell, an intention from the start of the programme.
A further feature which could be integrated into the van – and which could enhance EV capability in passenger vehicles as well – is Ricardo’s Sentience (“consciousness”) technology, which combines telematics and telecommunication, navigation and intelligent mapping, for forward planning of the route. Using topographical data about the road ahead and real-time information on traffic conditions, it analyses the best points in the route to engage electrical power, to modulate the engine load to best effect on different gradients and in different conditions, to control acceleration and deceleration to smooth out progress, and to maximise the energy recuperation from the regenerative braking system, as well as to control the air conditioning.
“You can schedule the powertrain, for example, if it knows that there is a zero-emissions zone coming up”, says Tebbutt. “You can look at the journey profile, rearrange the strategy to deploy the engine earlier to ensure you have sufficient charge to go through the EV zone. You can work out the most fuel-efficient delivery route and pre-programme it: when you turn the engine on, the use of the battery. The usual fleet tracking and distribution software looks to do minimum mileage, but this has the potential to put an extra level on that: the most efficient way to drive it.”
Engineers from Ricardo have been carrying out the final validation and calibration work at a test track facility, and this phase of the programme is now effectively over. Though some elements of the t-001 prototype may yet be changed for production, and its cabin, its interior TFT-screen displays and driver interface will all be further developed, its powertrain is functioning smoothly; a simple drive/neutral/reverse selector takes the place of a conventional gearbox, and the motor pulls away strongly from a standstill. Fine-tuning of the suspension and power-assisted steering is still ongoing, but this is a very complete concept ready to move into its next phase of development.
Motor: 75kW (nominal); 167kW (peak); 600Nm (launch)
Generator: 54kW (nominal); 120Nm
Range-extender engine: 1.4-litre I4 diesel
Battery: 25kW total, lithium-ion
EV range: 66 miles*
Total range: 463 miles*
Top speed: 81mph (limited)
Acceleration 0-62mph: 8.5 seconds
Fuel consumption: 138mpg over first 125 miles*
Carbon dioxide emissions: 56 g/km over first 125 miles; 22g/km average*
Gross vehicle weight: 2950kg
Rear cargo space: 5.2 cubic metres; will accommodate 3 Euro standard pallets
(*figures based on NEDC cycle in Ricardo’s simulation)
*A full version of this story will appear in the summer 2012 edition of rQ, Ricardo Quarterly.