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TTANSMISSION
Although modern automobile transmission used on automotive vehicles vary in details, they all in a similar manner. They have a torque converter and planetary-gear sets which are controlled by brakes and clutches to provide two or three forward gear ratios.
The transmission provides different gear ratios between the engine, since the engine produces little power at low speed . Thus, for accelerating the car from a standing start, considerable power is required; the engine should be running at a fairly high speed. The driver, therefore, shifts the transmission gears into first; this gear position permits the engine to run at a fairly high speed. A typical first-gear ratio would be that the engine develops high power, and the car moves away from the curb and accelerates quickly. Next, the driver shifts to second (momentarily declutching to permit moment of the gears in the transmission . In second, the car accelerates to a higher speed. In second, a typical ratio would be 8:1. Finally, the driver shifts to third. In this gear position, there is a direct drive through the transmission; the propeller shaft turns at the same speed as the engine crankshaft. In third, a typical ratio would be 1:1.there is another gear position, reverse. In this position, the propeller shaft is made to rotate in a reverse direction so that the car goes backward.
FOUR-WHEEL-DRIVE
In the USA, while more consumes are moving away from sport utility vehicles and opting for cars and crossovers, they still are not willing to part with all-wheel-drive systems. For them, it's a safety system.
In a recent survey of current SUV owners, 73 percent said they want all-wheel-drive on their next vehicle. In the luxury market, 50 percent of owners say they want all-wheel-drive on their cars or trucks.
A recent report from industry research firm JD Power forecasts that four-wheel-drive vehicles will make up 37 percent of all vehicles produced for the US by 2008.The growth is expected to come from increased sales of AWD systems based on front-wheel -drive vehicles. Their market share is expected to more than double to 32 percent from the current 13 percent in the next two years.
Seeing its SUV sales slipping away, carmaker Ford wants to be in a position to exploit this trend. The carmaker has introduced AWD versions of the Ford Fusion , the Mercury Milan and the Lincoln MKZ midsize sedans and the Ford Edge and Lincoln MKZ crossovers. Ford now has 36 vehicles that offer either four-wheel drive or AWD.
Unlike four-wheel-drive, which the drive must manually activate, an AWD system is either permanently on or it continuously monitors the vehicle's condition and takes action independently. To wheel is seamless.
The system monitors the vehicle's condition 100 times a second, analyzing what's happening with the wheels on the road, the drive's inputs such as turns of the steering wheel and the pressure on the accelerator. It then varies the torque sent to the wheels.
"A major advantage of all-wheel-drive is the flexibility to shift torque or apply raking to any wheel," says marketing manager Robert Parker." In the past we could either shift torque from back to front or from front to rear. With advances in AWD technology, we can shift torque to the exact wheel or wheels with the best traction
In the AWD technology for he 2007 models, a vehicle like the Fusion or MXZ is typically front-wheel-drive. Torque goes to the front wheels in effect pulling the vehicle along. Because the engine rests over the front of the vehicle, the weight provides greater traction to the wheels both pulling and steering the car.
If, however, the system senses a loss of traction it shifts torque to any or all of the wheels. The most obvious benefit occurs on slippery road conditions, but the AWD system improves traction in a number of less obvious situations.
A common problem with front-wheel-drive vehicles is their under steer, typically seen in cornering. If a front-wheel-drive vehicle accelerates into a turn, too much weight can be shifted to the rear, causing loss of traction in the front wheels. The front of the vehicle can go towards the outside of the turn when the driver is aiming to turn the car sharply. AWD automatically compensates either by adjusting the torque to the wheels, altering engine speed or both.
Starting in 2007, Ford expects to sell around 500000 AWD-equipped vehicles annually, of which 400000 will be cars and crossovers. It sounds like a tall order, but Ford says the numbers should be easy to reach, as it is making the technology more affordable.
It plans to sell AWD models for between USD 3100and 5400 less than competitors, in some cases undercutting the prices for their front-wheel-drive models. Competition in the US industry is about to reach a new level of intensity.
SAFETY AND SECURITY
Almost everybody worries about car safety issues. But for an international carmaker it is important to recognise that the reasons for this concern differ from country to country. Swedish carmaker Volvo has established a strong reputation for vehicle safety. But with so many vehicles now offering the highest levels of crash protection, the carmaker is looking at other factors that will make buyers feel safe and secure in their car. The carmaker is looking at a range of preventive vehicle safety and security measures including active safety and "Mayday" systems. In the past carmakers have focused on passive safety, meaning systems and functions that help protect people in the event of an accident. Manufacturers are now broadening their outlook. "We are focusing on technologies that predict and prevent accidents from even occurring, "says lngrid Skogsmo, Volvo's safety director. Safety has three main perspectives: the car, the traffic situation and the human being. The person behind the wheel is still the most important factor, but the electronics are becoming more important than the materials and construction. The driver must stay alert, be able to make quick decisions in stressful situations and not give in to fatigue. But this is often easier said than done.
"Research shows us that often when a car ploughs straight into the rear of another car, the driver never even hits the brakes," says Skogsmo." This is probably because the driver never saw what was going to happen, and so had no chance to prevent the accident. Our electronic safety systems are developed to prevent the accident. Our electronic safety systems are developed to help increase the time the driver has to manoeuvre the car out of danger."
Busy streets, multiple choices and mobile phones all compete with the driver's attention. To help the driver decide which information is more important, vehicles can be equipped with advanced technology that reads traffic quicker than the human eye. The active safety systems warn about threats, and can even step in and act in critical situations if there is not enough time for the driver to avoid them." The system doesn't take over the driving, it just helps the driver to increase safety and make the driving experience more enjoyable," says Skogsmo.
Several developed active safety systems are already in use at Volvo. The firm introduced an Intelligent Driver Information System in 2003. The system sorts incoming information according to relevance and delays phone calls, text message and other non-critical information in situations that demand the driver's full attention. The idea is to prevent the driver from suffering information overload during braking or overtaking.
Safety is not just a matter of avoiding accidents, however. Having a vehicle with a good safety rating makes drivers feel secure. Anything that can contribute to this is a worthwhile addition." We treat this seriously," says Karin Backlund, responsible for Volvo's market intelligence." We try to adapt our customers' preferences. Safety is a Volvo core value and that has to include personal security."
Volvo carried out a survey in nine countries to find out the situations that concern car owners the most. Differences between countries emerged. Swedes are particularly worried about leaving their cars unattended overnight, while the British about leaving their cars unattended overnight, while the British are more concerned about break-ins and the theft of property rather than theft of the vehicle itself. About half of Brazilians, on the other hand, report that they are not concerned about this aspect, focusing exclusively on personal security.
The reasons for anxiety are reflected in the security enhancing features that the respondents would like to have in their cars. In Brazil, a car alarm was mot among the five most wanted security features in the survey, whereas this was top of the list in Sweden. Brazilians and ltalians wanted impact-resistant laminated windscreens, while Swedes preferred lockable wheel trim.
One thing appeared on all wish lists: a Mayday system. People of all countries considered it important to be able to call the police or an ambulance .All of the respondents also agreed that they want to see technologies that assist the recovery of a stolen car. Such systems are costly to develop, however. They require an extensive infrastructure beyond the car to ensure that the vehicle can be tracked and that the emergency services know how to respond to the call. So far, Volvo has launched its" on call" service in seven European countries and plans to add more.
In the meantime, the firm is exploring technologies that give drivers more remote control of their vehicle. The Personal Car Communicator is being offered as an optional in all cars.It's basically a pocket-sized remote control. The device is used to unlock the car door automatically when you pull the door handle. Pressing a button on the PPC can also lock it.
"Wondering if the car is locked is a frequent worry among drivers," says S80 project manager Solvia Gullsdorf." You walk a few metres and then have to check by unlocking and relocking the car" With the PCC, you simply check the key to see if the car is locked. And you do not even have to be near the car; the key just indicates whether your last action was to lock or unlock. It also allows you to start the car without a key.
But keyless entry systems are hardly new. What makes the PCC different is that at a range of 60 to 100m, you can obtain a security status report by pressing the information button. Different LEDs tell you if the car is locked or unlocked, others whether somebody has interfered with the vehicle and caused the alarm to go off. A level meter detects if the car is raised in an attempt to steal the wheels. A flashing red light means that the heartbeat sensor has been activated and that there is an intruder in the car.
"We know that motorists in many countries are fearful of assault, whether going to and from the car in dark and unsupervised parking places , or by somebody who has hidden in the car," says Gullsdorf. However, the darkness can be eliminated. Just one press on the remote control can switch on the car in a dark parking area.
When leaving the car, the headlights can also be switched on for up to 90 seconds by operating the headlamp flasher, allowing you time to get to your front door. The car alarm is activated if somebody.
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