From 23 July 1941 to date, Jeep brand has been a symbol of true four-wheel-drive performance, innovation and continuous improvement. Today, Jeep has not only a household name, it is more than a technical off-road vehicle with a synonym. For more than half a century, it has successfully across borders reach the heart of many people in the car. Precisely because of this, Jeep vehicles have been sold in nearly 100 countries, with many Jeep enthusiasts. Open Jeep family history, we find that it is on the Jeep tradition and innovation unique personality forged the blood of the Jeep brand’s glory.
1. Jeep Jeep four-wheel drive technology Introduction
From 23 July 1941 to date, Jeep brand has been a symbol of true four-wheel-drive performance, innovation and continuous improvement. Today, Jeep has not only a household name, it is more than a technical off-road vehicle with a synonym. For more than half a century, it has successfully across borders reach the heart of many people in the car. Precisely because of this, Jeep vehicles have been sold in nearly 100 countries, has many Jeep enthusiasts. Open Jeep family history, we find that it is on the Jeep tradition and innovation unique personality forged the blood of the Jeep brand’s glory.
2.Freedom-Drive Introduction
“Freedom-Drive I” this four-wheel drive system in the country to be equipped on the guide’s freedom and passengers, this JEEP brand sets of four-wheel drive system is developed for urban traffic, it is timely four-wheel drive, electronically controlled center differential is a multi-plate clutch in terms of structure, front and rear axles are open differential, no lock mechanism four-wheel also no electronic brake assist. When
Daily running (mainly refers to driving on paved road), the driving force is transmitted only to the front wheels, the wheel drive traction vehicle running mode, then the computer monitor at any time where adhesion four wheels if wheel slip occurs, the computer will automatically distributing power to the front and rear wheels at the same time, the torque can be adjusted within a certain range. In order to ensure that urban wet pavement or hard acceleration state guidelines are still safe and reliable performance. When complex road, open the “four-wheel drive lock” function may be constant in the driving force distribution to front and rear wheels of 50:50.
3.Freedom Drive II describes
Freedom Drive II with a simple point that is timely four-wheel drive low gear, the maximum wheel-drive system with Freedom Drive I except that a second-generation stepless transmission (CVT2 ) setting, this CVT transmission having a 19: 1 ratio of the difference, that is to say it can be simulated low speed ratio, to reduce the speed of the torque amplification effect.
Freedom Drive II Freedom Drive I and method of operation is substantially the same, the center armrest is pulled below 4WDLOCK switch, torque lock in 50:50, then switch the shift lever L to stop, low speed can be realized, this when the ESP system is automatically shut down, and converted to an auxiliary braking for the off-road sections.
In driving off-road sections, Freedom Drive II is significantly higher than the advantages Freedom Drive I. Simply put, if the Freedom Drive I is to improve road safety and handling, then the Freedom Drive II system is on this basis, by gear ratios and brake electronic aids for CVT intensity of the off-road capability pricey.
Since the low-speed gear position having a simulation, so the difficulty climbing sections is decreased, the throttle can be controlled more accurately to climbing.
Further, the electronic brake assist strength Freedom Drive II also better in Freedom Drive I, so for a general road intersecting axes, the passenger may be freely deal! Further, hang gear and begins 4WD LOCK L after the function, hill descent feature is automatically turned on, do not hit the brakes when going downhill can be guaranteed a safe range, this is the gospel for junior players, cross-country, in reducing the risk factor of technically retain a certain amount of fun.
4.Quadra-Trac II Introduction
Quadra-Trac II four-wheel drive system is a four-wheel drive, it is suitable for general road and off-road driving. Its front axle, a rear axle structure for the open differential, the transfer case is equipped with a central limited slip mechanism of the multi-plate clutch, this configuration allows front and rear axles rotate at the same or different speeds.
Quadra-TracII equipment in the four-wheel drive system is mainly Grand Cherokee 3.6 models, the advantages of this system is simple in structure, very intuitive and convenient operation, the driver does not need to remember complicated driving mode switching step, In most cases Quadra-Tra II four-wheel drive system can cope with their own, if only want to use the low-speed four-wheel drive mode needs to pull a switch light.
However, since the front and rear axle differential not with any limited-slip function, the power distribution between the left and right wheels rely Jeep BTCS brake assist system to achieve that effect certainly not as limited slip speed is obvious.
Quadra-TracII operation and performance of the Grand Cherokee
Grand Cherokee four-wheel drive system has a normal four-wheel drive AWD and two low-speed mode is selected, under normal driving conditions, the engine after two front drive shaft system output torque, upon needs additional traction, the electronic system will automatically reflect made by combining different strength multi-plate clutch of the central group, the percentage of the maximum engine power 100 assigned to the front axle or rear axle enhanced rescue capability of the vehicle.
Grand Cherokee four-wheel drive low speed switching isCan be performed during running, the vehicle is required to be less than 40 kilometers per hour. Pull the center console box located below the four-wheel drive mode changeover switch, the dashboard indicator lights 4LOW described four-wheel drive low gear ON, then the engine torque in accordance with the 2.72: 1 gear ratio amplified, through the central multi-plate clutch binding, the front and rear drive shaft (not note the front and rear axle drive shaft) lock, assigned to the front and rear PTO 50: 50, ESP also will be closed (and thus identical to the front and rear axle speed), applied in this state in more severe off-road environment, or provide greater torque when dragging heavy objects.
3.6L Grand Cherokee although not the locking device of the front and rear axles, limited slip but an electronic device to a certain extent without up for the lack of the front and rear axle differential lock, the rear of the actual test results is very significant . Electronic Limited Slip is called in the case where the vehicle drive wheels slip, the system automatically adhesion small wheel brake, so that by the action of a differential, so that the torque transmitted to the partially or completely strong adhesion side of the vehicle turning around.
5.Quadra-Drive II Introduction
Quadra-Drive II is a road with excellent properties both, and four-wheel drive system suitable for walking through the wild, can be compared to the Quadra-Trac II respond more poor road conditions, its front and rear axle limited slip differential using a multi-plate clutch, can lock the left and right wheels.
Under normal circumstances, Quadra-Drive II four-wheel drive system with the front of the latter three groups electronic limitedSlip differential can cope with most complex road, or even close to the performance differential lock. And mode of operation is not complicated.
However, the limited slip differential structure is multi-plate clutch torque while providing automatic allocation of convenience, there is also the problem of low durability, the work needed in the face of long continuous high strength, the performance of the system may be compromised.
Quadra-Drive II in the domestic major equipment on the Grand Cherokee and Commander 3.7.
Under normal dry road driving, the front and rear wheels 48 respectively and the percentage of torque distribution 52 percent, once the wheels lose traction, the system senses wheel slip, three electronically controlled limited slip differential ( central, front and rear axles) immediately to the appropriate torque distribution to one or more wheels, in if necessary, or even put all the power of the engine are output to a wheel, greatly enhancing the ability of rescue vehicles.
Open Quadra-Drive II four-wheel drive mode and low-speed large cut Quadra-Trac II equipment is the same, after opening this mode, the electronic control system by locking means (in fact pressing the multiple disc clutch) before and after and the center-center differential bridge movable box, can play a similar role with a mechanical lock, the torque also will be enlarged to 2.72: 1 to enhance the traction capability. In addition, as with the Quadra-Trac II, Quadra-Drive II is also equipped with an electronic limited slip aid system.
6.Command-Trac
Command-Trac four-wheel drive system of the structure, this system is mainly equipped with four-wheel drive on the Wrangler Sahara model. It uses a series of mechanical NV241 transfer case, and with a 2.72: 1 gear ratio is low.
between the longitudinal axis of the Sahara open differential, only a single wheel EDS electronic LSD function, loss of adhesion on one side of the wheel, brake intervention using the electronic system, both sides of the balance the driving force. Limited slip differential available as an option, but imported into the country of the Sahara were not equipped.
7.Rock-Trac Introduction
Rock-Trac structure of four-wheel drive system, this four-wheel drive system is mainly equipped on Wrangler Rubicon model, which are equipped with the Sahara Command -Trac four-wheel drive systems use a series of mechanical NV241 transfer case, except that, using the Sahara 2.72: 1 to a lower speed gear ratio, and can reach Rubicon 4: 1.
compared to the Sahara Command-Trac, Rubicon addition to a greater torque amplification ratio, which is equipped with front and rear axles of the electronically controlled locking differential locks Tru-loc. The system in the face of the most demanding environments, to ensure that the four tires can gain momentum. Even three tire slip, rely on a tire of the vehicle can rescue. Note, however, the front and rear differential lock separation requires a process, and in some cases lock the separation process may not be successful, the vehicle needs to move to completely or H-throttle gear engaging / disengaging. Also in the case of locking the front axle, the vehicle is notSteering operation. Do not have locking differential can also be equipped with a turnaround time of Rubicon EDS electronic limited slip function, without the need for differential locking, relying EDS can achieve the same effect, encounter some simple barriers. This avoids the inconvenience of operating differential lock, also reduces the chances of an accident caused by lower differential locking state.
8. The transfer case Wrangler Use
needs to be switched from the transfer case when 4H or 4L 2H block to block, it is necessary first transmission from shifting to neutral, and then the transfer operation a handle switch case. 2H-4H switched must be less than 88 kilometers per hour, 2H / 4H-4L must be less than five kilometers per hour. No wrong operation according to instructions, but safe, are recommended at a relatively low speed of operation of the safety of the 2H-4H. (At high speed gearbox into neutral inherently dangerous)
Techniques: situ in the transfer case handover success rate is sometimes low, the performance of the transfer case handle large resistance, can not enter the normal gear. Since in a stationary state, the movable gear box component not well engaged. At this point you can allow the vehicle to move slowly, try again. Remember to switch back to the gearbox in neutral.