All wheel drive? Do you need that? If so, are there differences in technology? This article is intended to provide an orientation in the jungle of technology and at the same time explain what makes the 4 × 4 technology of the Mitsubishi Plug-in Hybrid Outlander so special.
For a car to drive around a bend, you need a differential in the middle of the axle. This differential takes over the compensation of the speed differences between the wheels. When cornering, the outside wheel must travel one more distance than the inside of the bend. If you did not have a differential between the wheels, the car would be reluctant to drive around the corner under heavy tension and tires. At the same time, the differential also ensures that power that can not be brought to the ground goes the path of least resistance. When cornering with a front-wheel drive vehicle, this would be the inside wheel. Wheel slip or a spinning wheel is the result.
Modern SUVs often have a so-called hang-on all-wheel drive. A “PTU (Power Transfer Unit)” ensures decoupling of the all-wheel drive and only “suspends” the rear axle when the driven front axle slips. The force is then distributed between the two axles in the same way as it would otherwise be between the two wheels on an axle. However, here too a speed difference must be compensated for. In this case between the axes. Because the rear axle covers a shorter distance than the front axle.
A rigid distribution of force would also lead to tension in the drive train here. The use of the all-wheel technology also leads to an extra weight. More drive shafts, more transfer cases, more differentials and possibly even hydraulic components.
Differences in the all-wheel technology
All-wheel drive allows the transmission of driving forces and thus the progress even in adverse weather conditions. What a bike can not do on its own, four wheels make it. So far the theory. However, the necessary differentials stand in the way of success. An all-wheel drive, in which the force between the front and rear axles is distributed, must have three differentials. As long as these can not be controlled, however, this also ensures that a single spinning wheel paralyzes the system. The force goes the path of least resistance and the four-wheel drive would be useless. Classic off-road vehicles have that's why mechanical differential locks, With these you can lock the speed-compensating effect of the differential, the power is distributed in equal proportions to both wheels. The more serious the off-road use, the more barriers.
However, modern SUVs do not need this expensive technology. They are spared the harsh off-road use. And so the manufacturers save on the expensive technology of differential locks. Thanks to ABS and ESP controls, it is also possible to brake a wheel using the brakes. The function of a mechanical differential lock is simulated here. And since you rarely really need the advantages of all-wheel drive in everyday life on dry roads, manufacturers are now also saving on permanent all-wheel drive. In everyday life, many SUVs are purely front-wheel drive vehicles and only in the event of “slip” does the all-wheel drive system react and engage the rear axle.
In contrast to permanent all-wheel drive vehicles, any slip that occurs must first be recognized, only then will the system react and deliver a power output to the rear axle, often by means of a slat lock. To drive up a snowy slope, that may be enough and to turn around in the dry at the next supermarket parking lot, anyway. But - it's actually just a fake all-wheel drive.
Permanent four-wheel drive
Technology, car freaks and engineers agree that an all-wheel drive only becomes really exciting when it is in constant use. If he is always active, it is best to be cleverly controlled and with active torque distribution. Like in All-wheel rally star from Mitsubishi, the EVO for example.
Differences between the rally star and the plug-in hybrids
While the Mitsubishi Evo, like other four-wheel drive vehicles, requires a connection between the front-mounted engine to the transmission and then to the two axles, has the Plug-in Hybrid Outlander two electric motors, which were installed directly between the wheels. A rigid connection between the axles is history. A differential to compensate for the speeds between the front and rear axles not necessary. And yet, the plug-in Hybrid Outlander has a permanent four-wheel drive. Smart control over the power control of the electric motors. Fully variable in power output at all times. Sometimes in front, sometimes in the back, sometimes both axles - just as the driving condition requires. The power flow is controlled by the control technology of the World Rally Champion Mitsubishi. Decades of experience, programmed into the control electronics of the Plug-in Hybrid SUV.
And so just the eco-SUV is the SUV with the most honest and effective four-wheel drive for everyday use.
