Land Rover Concept Showcases Hybrid System and Other Technologies for 30% Reduction in Fuel Consumption
|The Land_e technology concept|
Ford’s Land Rover is showcasing a range of new technologies including a new mild hybrid drive—collectively known as the e-Terrain System—that, as an integrated system, can reduce both fuel consumption and CO2 emissions by up to 30%.
Packaged into the Land_e concept vehicle, the e_Terrain technologies are targeting sub-150 g/km CO2 figures—equivalent to a combined fuel economy figure of about 5.65 l/100km (41.6 mpg US) in a vehicle similar in size to the current Freelander.
Such CO2 emissions levels are comparable with a typical gasoline B segment or diesel C segment car. Most of the technologies will be available on Land Rover production models starting in the next few years, according to the company.
(The current gasoline-fueled Land Rover models in the US offer fuel economies of between 15 and 16 mpg US (combined). More than 90% of all Land Rover vehicles currently sold in Europe, however, are diesel-powered, with corresponding reductions in fuel consumption and emissions.)
The e-Terrain technologies are practical, feasible, real-world solutions. In every case, they preserve—and in most cases improve—our breadth of capability. We are not prepared to dilute the essence of Land Rover. But we are committed to improving fuel economy and reducing CO2 emissions.—Matthew Taylor, managing director of Land Rove
The technologies that Land_e showcases are:
- A mild hybrid function with the Integrated Electric Rear Axle Drive and ISG Integrated Starter-Generator
- Innovative Propshaft with Seamless Re-connect
- Terrain Response e-Mode
- Biodiesel capability
- ITP Intelligent Thermal Program
- EPAS Electric Power-Assisted Steering
- IMES Intelligent Management of Electrical Systems
The Integrated Electric Rear Axle Drive is used in conjunction with the ISG Integrated Starter-Generator system to deliver mild hybrid function to improve both off-road ability and decrease urban emissions.
Off-road, the Integrated Electric Rear Axle Drive system can provide additional torque as required. Because electric power can offer maximum torque from standstill, it is most effective from virtually zero mph/kph. This offers better low-speed control and enhanced pull-away in difficult situations, such as on slippery surfaces or when towing.
On-road, the additional low-speed torque input from the Integrated Electric Rear Axle Drive allows electric-powered “traffic creep” and low-speed acceleration up to 20 mph (32 km/h) without restarting the engine, benefiting fuel consumption and CO2 emissions.
When quicker acceleration is required, the engine can be restarted immediately, so both the conventional engine and the Integrated Electric Rear Axle Drive system supply power from rest. In this case, the electric torque boost provided by the Integrated Electric Rear Axle Drive significantly improves acceleration without adversely affecting either fuel consumption or CO2 emissions.
The Integrated Electric Rear Axle Drive system draws stored energy from a lithium-ion battery pack it recharges by regenerative braking.
On its own, the ISG Integrated Starter-Generator is a micro-hybrid system that allows the engine to be stopped automatically whenever the vehicle stops, as in traffic, and under the control of the ECU it restarts the engine quickly and smoothly when required. The engine does not idle unnecessarily when the vehicle is stationary, to the further benefit of both fuel economy and CO2 emissions.
Together the ISG and Integrated Electric Rear Axle Drive offer the potential of a 20% reduction in CO2 emissions.
The Propshaft with Seamless Re-connect allows the Propshaft and rear drive components to come to rest, avoiding unnecessary rotational losses, when the drive to the rear wheels is automatically disconnected when conditions allow, such as cruising on a dry surface.
When rear drive is required, the system reconnects the rear axle automatically and virtually instantaneously. By ensuring that front and rear wheel speeds are correctly matched, and with the additional control of the Integrated Electric Rear Axle drive, the drive layout virtually eliminates wheel slippage, which in turn reduces soft-surface damage—for instance on grass.
The ISG Integrated Starter-Generator, Integrated Electric Rear Axle Drive and the Seamless Re-connect propshaft are fully compatible with all Land Rover engine and transmission options, and could be adapted for any model and any market.
The Land_e introduces a sixth Terrain Response mode—e-Mode—to the other five modes available on some Land Rover products: General Driving; Sand; Mud and Ruts; Grass, Gravel and Snow; and Rock Crawl.
The e-Mode is shown for the first time and focuses principally on on-road use. This configures all the vehicle’s e-terrain systems for optimized fuel economy. It always retains instantaneous access to Land Rover’s four-wheel drive capability but adopts soft throttle responses, and delivers early shift points.
In the Land_e, the other five Terrain Modes all use combinations of normal engine and Integrated Electric Rear Axle Drive. In all off-road modes, the engine is never shut down, even if the vehicle is stationary.
The ITP Intelligent Thermal Program controls engine parameters including exhaust heat management and cooling system function. Through heat exchangers, the EHRS (Exhaust Heat Recovery System) utilizes what is normally wasted heat from the exhaust system to promote faster engine and gearbox warm-up from cold, with several advantages.
In a production application, ITP could also control Active Aero Vanes, which would allow specific sections of the radiator aperture to be closed under certain operating conditions. That would reduce high-drag airflow through the radiator core and engine bay when cooling air is not needed—for instance at low ambient temperatures and when running in low-load conditions.
The vanes would also be closed during engine warm-up, again to ensure that the engine reaches optimum operating temperature as quickly as possible. Faster engine and catalyst warm-up significantly reduces emissions in the first minutes after a cold start, and by bringing engine and gearbox oils up to operating temperature more quickly, it reduces mechanical frictional losses.
An electronically controlled thermostat and cooling circuit give far more accurate control of coolant temperature than a conventional system, allowing the engine to run closer to its optimum temperature. The system also incorporates an electric water pump, which, unlike the conventional belt-driven water pump, is driven only on demand, and at variable speeds, avoiding inefficient and unnecessary overspeed running. Mechanical energy savings, optimum temperature control and fast warm-up from start offer the potential for additional CO2 emissions benefits.
Significant benefits are also possible with the use of electric power steering technology, EPAS (Electric Power Assisted Steering). EPAS completely eliminates the pumped hydraulic assistance of a conventional system and powers the steering rack directly, by electric servo motor.
That eliminates pumping power losses, including the significant losses when the pump is being driven at high speed even though assistance is not required, again offering a noticeable CO2 benefit compared to a belt-driven hydraulic system. The higher-voltage electrical supply made possible by ISG also allows the possibility of more powerful assistance for more demanding use.
All electrical system functions are controlled by IMES (Intelligent Management of Electrical Systems), with further efficiency gains. It incorporates a closed-loop system that monitors battery charge, vehicle electrical system demands, and generator speed and load. It uses the monitored data to ensure that the whole electrical system operates in the most efficient way.
It charges the battery only when it needs it, avoiding the over-charging associated with non-intelligent systems, and unless it is absolutely necessary, it avoids charging the battery when it is in low-acceptance states—such as cold ambient conditions, below around 10º C. It also regulates high electrical loads until the alternator is operating at high efficiency, which gives a further reduction in CO2 emissions.