One of the simplest yet most effective CO2 -reducing features highlighted on the Land_e is the ISG Integrated Starter-Generator. The ISG package replaces the conventional alternator and continues to take its drive from the normal ancillary belt. It 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 engine stop-start function of ISG, plus the regenerative braking function, provided by the Integrated Electric Rear Axle Drive offer the potential of a 20 per cent reduction in CO2 emissions. The outstanding multi-terrain ability that is at the core of Land Rover is also enhanced.
Seamless re-connect is a system that significantly reduces fuel consumption by cutting mechanical losses. Drive to the rear wheels is automatically disconnected when conditions allow, such as cruising on a dry surface. Yet unlike hybrid and selectable 4x4 systems, there is instant access to Land Rover’s full range of four-wheel drive abilities. The Propshaft with Seamless Re-connect allows the Propshaft and rear drive components to come to rest, avoiding unnecessary rotational losses.
When rear drive is required – when, for instance, the system detects slippery conditions – the system reconnects the rear axle automatically and virtually instantaneously. The system not only re-engages full 4x4 much faster than rivals, it also offers much better 4x4 capability when connected. Re-engaging drive seamlessly also has safety benefits. It does not affect the car’s dynamic balance in the same way as a slower and less progressive re-connection.
The technology also reinforces Land Rover’s fundamental principle to ‘Tread Lightly’. 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.
----
Land_e shows six Terrain Response modes:
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 optimised 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.
The other five modes are already available on some Land Rover products – General Driving; Sand; Mud and Ruts; Grass, Gravel and Snow; and Rock Crawl. In the Land_e, 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.
In Sand mode, primary power is supplied by the engine; the Integrated Electric Rear Axle Drive system monitors torque to detect either wheelspin or bogging-down, and intervenes as necessary, either to stop tyre slip or to provide additional torque to deal with soft, deep sand.
In Mud and Ruts mode, primary power is again supplied by the engine, while additional torque is available from the Integrated Electric Rear Axle Drive system for heavier mud or deeper ruts.
In Grass, Gravel and Snow mode, control is more important than power, so engine power is fed in only once the vehicle is underway. Integrated Electric Rear Axle Drive is used for driving away without wheelspin even on very slippery surfaces – by constantly monitoring torque and intervening rapidly to prevent tyre slip. In this mode, the Integrated Electric Rear Axle Drive can respond to wheelspin even more quickly than the engine management, and can cancel the initial slippage within one-eighth of a wheel rotation – a critical figure that is small enough to regain grip and prevent permanent damage even on wet grass. No other system achieves this.
In Rock Crawl mode, speeds are typically below 5mph/8kph. Integrated Electric Rear Axle Drive now provides the primary power source, boosted as necessary by normal engine torque. In all cases, the great advantage of Integrated Electric Rear Axle Drive is that an electric motor offers maximum torque at the lowest wheel speeds, for the ideal mix of power with control.
An increasing emphasis on diesel power is clearly important to overall CO2 reductions, and bio-diesel capability extends the potential advantages. Bio-diesel is a fuel derived from renewable and sustainable sources, such as natural oils from soya beans or other easily cultivated vegetable or cereal crops. It is currently commercially available as a blend of bio-derived diesel and petroleum-derived diesel, in varying proportions, and bio-diesel offers reduced emissions compared with petroleum-derived diesel.
Currently, a five per cent bio-derived content is typical with forecourt diesel. Potentially, a vehicle could operate on a 25 per cent bio-diesel mix, which is a realistic goal within a few years, and one supported by the oil industry and governments. A vehicle running on 25 per cent bio-diesel mix could potentially reduce its CO2 emissions by up to 25 per cent. Next generation bio-fuels made from crop wastes are also being developed, and these will deliver even greater CO2 reductions, as well as being more sustainable.
----
Beyond the efficiency-enhancing drivetrain technology, the Land_e showcases other fuel saving technologies.
The ITP Intelligent Thermal Programme controls engine parameters including exhaust heat management and cooling system function. Through heat exchangers, the EHRS (Exhaust Heat Recovery System) utilises 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 – on off-road terrain, for example.
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 10 degrees C. It also regulates high electrical loads until the alternator is operating at high efficiency, which gives a further reduction in CO2 emissions.
| Integrated Electric Rear Axle ... | |
Picture Gallery
Post a comment
RSS -
Webmaster free news |
Forgot your password?