TOD four-wheel drive system
TOD is the abbreviation Torque-On-Demand, meaning ldquo; on-demand four-wheel drive torque rdquo; technology, it power can be allocated according to needs of the vehicle and road conditions. Under normal conditions, TOD rear-wheel drive system is primarily, but road conditions change, it will be necessary, the torque transmitted to the front wheels to provide sufficient grip.
The system Borg Warner from 1994 to begin production, it has been equipped with a variety of models, while Harvard is equipped with the earlier system of domestic models. The following will Haval H5 equipment TOD introduce four-wheel drive system as an example.
“Great Wall Hover”
the TOD means of a plurality of sensors to detect the operating status of each axle, the vehicle speed parameter detected, an axle speed, the throttle opening degree, ABS brake system state and the like, in order to prevent loss of adhesion of the tire. TOD device is installed at a front end position of the drive shaft of the vehicle, controlled by the electronic control unit ECU. Is determined by the electronic control unit according to the running condition of the vehicle front wheel skid, to provide adequate current to the electromagnetic coil, the first stage of the driving cam plate clutch mechanism, a second compression stage wet clutch which bound it, whereby the torque of the rear axle assigned to the front axle. When the current wheel slip badly, i.e., front and rear wheels when the rotational speed difference becomes large, the ECU by increasing current, so that the torque amplifier further pressing the multiple disc clutch, so more torque distribution to the front axle.
is less than 70 km / h and it can switch the AWD 2H
AWD system TOD schematic structure: 1, the transfer case input shaft; 2 , front propeller shaft; 3, the propeller shaft; 4, drive chain; 5, a main cam; 6, a second stage clutch; 7, the coil; 8, a first stage clutch.
a schematic view of the TOD mounting position
Compared with the conventional fluid coupling, such as timely four-wheel drive technology, TOD can acquire an engine speed signal by wheel speed sensors mounted on the vehicle signal analysis and calculation signals, to actively adjust, reasonable distribution torque, thereby improving the vehicle behavior, the response ratio of the hydrodynamic couplingTime is greatly reduced. In addition to the fluid coupling is quite sensitive to temperature, and does not start TOD delay at low temperatures. Further, TOD system with ABS, ESP, TCS matching system, compatible with (for example, when working ABS, TOD will cut off the power in the wheel 60ms, for better braking effect), advantageously
to increase active safety of the vehicle.
TCS TOD can collaborate and work will help enhance the vehicle’s handling performance. And because they do not have the manual locking feature is turned on, in four-wheel drive road required to be turned by sand or the like in advance and maintaining speed, TOD system is not as useful.