Electronic differential: Difference between revisions

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In automotive engineering the electronic differential is a form of differential, which provides the required torque for each driving wheel and allows different wheel speeds. It is used in place of the mechanical differential in multi-drive systems. When cornering, the inner and outer wheels rotate at different speeds, because the inner wheels describe a smaller turning radius. The electronic differential uses the steering wheel command signal and the motor speed signals to control the power to each wheel so that all wheels are supplied with the torque they need.

Functional description

The classical automobile drivetrain is composed by a single Internal combustion engine providing torque to one or more driving wheels. The most common solution is to use a mechanical device to distribute torque to the wheels. This mechanical differential allows different wheel speeds when cornering. With the emergence of electric vehicles new drive train configurations are possible. Multi-drive systems become easy to implement due to the large power density of electric motors. These systems, usually with one motor per driving wheel, need an additional top level controller which performs the same task as a mechanical differential.

The ED scheme has several advantages over a mechanical differential:^[1]

simplicity - it avoids additional mechanical parts such as a gearbox or clutch;
independent torque for each wheel allows additional capabilities (e.g., traction control, stability control);
reconfigurable - it is reprogrammable in order to include new features or tuned according to the driver’s preferences;
allows distributed regenerative braking;
the torque is not limited by the wheel with least traction, as it is with a mechanical differential.
faster response times;
accurate knowledge of traction torque per wheel.

However, the ED scheme also come with many disadvantages and drawbacks:

errors and glitches are prone to happen, thus giving inaccurate reading and output as compared to conventional differential. These result in the wheels either receiving too much or little power and torque.
increased premature tyre wear due to the inaccurate reading and output as compared to conventional differential.
higher cost to manufacture and maintain the electronic systems.

Applications

Several applications of this technology have proven successful and have increased vehicle performance. The application range is wide and includes the huge T 282B^[2] from Liebherr which is considered the world largest truck. This earth-hauling truck is driven by an electric propulsion system composed by two independent electric motors. These motors providing a maximum power of 2700 kW are controlled in order to adjust their speeds when cornering, thus increasing traction and reducing tire wear. The Eliica is also equipped with electronic differential; this eight-wheeled electric vehicle is capable of driving up to 370 km/h whilst maintaining perfect torque control on each wheel. Smaller vehicles for traction purposes and System on Chip controllers for generic vehicular applications are also available.

References

^ "Future vehicle driven by electricity and Control-research". doi:10.1109/TIE.2004.834944. S2CID 17238431. {{cite journal}}: Cite journal requires |journal= (help)
^ "Liebherr T282B official webpage". Archived from the original on 2007-06-27.

[1] "Future vehicle driven by electricity and Control-research". doi:10.1109/TIE.2004.834944. S2CID 17238431. {{cite journal}}: Cite journal requires |journal= (help)

[2] "Liebherr T282B official webpage". Archived from the original on 2007-06-27.

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[2]

@@ Line 1: / Line 1: @@
+In [[automotive engineering]] the '''electronic differential''' is a form of [[Differential (mechanical device)|differential]], which provides the required [[torque]] for each driving wheel and allows different wheel speeds. It is used in place of the mechanical differential in multi-drive systems. When cornering, the inner and outer wheels rotate at different speeds, because the inner wheels describe a smaller turning radius.  The electronic differential uses the [[steering wheel]] command signal and the [[Electric motor|motor]] speed signals to control the power to each wheel so that all wheels are supplied with the torque they need.
-{| style="float: right"
-| [[Image:Single_drive.png|thumb|400px| One single motor provides torque to all driving wheels by means of a mechanical differential.]]
-|-
-| [[Image: Multi_drive.png|thumb|400px| Multi drive systems allow independent wheel control increasing performance, comfort and security levels.]]
-|}
+==Functional description==
-The main purpose of the electronic differential is to substitute the [[Differential (mechanical device)| mechanical differential]] in multi-drive systems providing the demanded [[torque]] for each driving wheel and allowing different wheel speeds.
-When cornering, the inner and outer wheels rotate at different speeds. This happens because the former describes a smaller turning radius. The electronic differential uses the [[steering wheel]] command signal to control each wheel speed in order to smoothly perform the turning.
+The classical [[automobile]] [[drivetrain]] is composed by a single [[Internal combustion engine]] providing torque to one or more driving wheels. The most common solution is to use a mechanical device to distribute torque to the wheels. This [[Differential (mechanical device)|mechanical differential]] allows different wheel speeds when cornering.  With the emergence of [[electric vehicle]]s new drive train configurations are possible. Multi-drive systems become easy to implement due to the large power density of [[electric motor]]s. These systems, usually with one motor per driving wheel, need an additional top level controller which performs the same task as a mechanical differential.
-==Functional Description==
+The ED scheme has several advantages over a mechanical differential:<ref>{{cite journal | title= Future vehicle driven by electricity and Control-research | doi= 10.1109/TIE.2004.834944 | s2cid= 17238431 }}</ref>
-The classical [[automobile]] [[drive train]] is composed by a single [[motor]] providing torque to one or more driving wheels. The most common solution is to use a mechanical device to distribute torque to the wheels. This device, called [[Differential (mechanical device)| mechanical differential]], is responsible to allow different wheel speed when cornering. With the emerging of [[electric vehicle| electric vehicles]] new drive train configurations are possible. Multi drive systems become easy to implement due to the large power density of [[electric motor|electric motors]]. These driving schemes with one motor per driving wheel need an additional top level controller which is responsible to perform the same task as the mechanical differential. Named electronic differential, it is capable of substituting its mechanical counterpart with significant advantages.
+* simplicity - it avoids additional mechanical parts such as a [[gearbox]] or [[clutch]];
+* independent torque for each wheel allows additional capabilities (e.g., [[traction control system|traction control]], [[stability control]]);
-The ED scheme substitutes the mechanical differential with several advantages:
+* reconfigurable - it is reprogrammable in order to include new features or tuned according to the driver’s preferences;
-*simplicity, it avoids additional mechanical parts like [[gearbox|gearboxes]] or [[clutch]];
+* allows distributed [[regenerative braking]];
-*independent torque for each wheel allows auxiliary functionalities (e.g., [[traction control]], [[stability control]]);
+* the torque is not limited by the wheel with least traction, as it is with a mechanical differential.
-*reconfigurable, it is reprogrammable in order to include new features or tuned according to the driver’s preferences;
+* faster response times;
-*allows distributed [[regenerative braking]];
+* accurate knowledge of traction torque per wheel.
-*does not have the mechanical differential limitation where the torque limited by the lesser traction wheel.
-Moreover, a multi drive traction system with distributed electric motors have main advantages over the traditional solutions<ref>{{cite web | url= http://ieeexplore.ieee.org/search/srchabstract.jsp?arnumber=1339466&isnumber=29535&punumber=41&k2dockey=1339466@ieeejrns&query=%28+uot%3Cin%3Emetadata+%29&pos=1
- | title= Future vehicle driven by electricity and Control-research }}</ref>:
-# faster time response;
-# accurate knowledge of traction torque per wheel.
+However, the ED scheme also come with many disadvantages and drawbacks:
+* errors and glitches are prone to happen, thus giving inaccurate reading and output as compared to conventional differential. These result in the wheels either receiving too much or little power and torque.
+*increased premature tyre wear due to the inaccurate reading and output as compared to conventional differential.
+*higher cost to manufacture and maintain the electronic systems.
 ==Applications==
@@ Line 30: / Line 24: @@
 [[Image:Eliica.jpg|thumb|175px|Eliica shown at [[Intex Osaka]] ]]
-Several applications of this technology proved to be successful and have increased the vehicle performance. The application range is wide and, probably, the most astonishing is the huge [[Liebherr_T_282B| T282B]] <ref>{{cite web | url= http://www.liebherr.com/me/en/40787.asp| title= Liebherr T282B official webpage}}</ref> from [[Liebherr]] which is considered the world largest truck. This earth-hauling [[truck]] is driven by an electric propulsion system composed by two independent electric motors. These motors providing a maximum power of 2700kW are controlled in order to adjust their speeds when cornering thus increasing traction and reducing tire wear.
+Several applications of this technology have proven successful and have increased vehicle performance. The application range is wide and includes the huge [[Liebherr T 282B|T 282B]]<ref>{{cite web |url=http://www.liebherr.com/me/en/40787.asp |title=Liebherr T282B official webpage |url-status=dead |archiveurl=https://web.archive.org/web/20070627104944/http://www.liebherr.com/me/en/40787.asp |archivedate=2007-06-27 }}</ref> from [[Liebherr]] which is considered the world largest truck. This earth-hauling [[truck]] is driven by an electric propulsion system composed by two independent electric motors. These motors providing a maximum power of 2700&nbsp;kW are controlled in order to adjust their speeds when cornering, thus increasing traction and reducing [[tire wear]].
-The [[Eliica]] is also equipped with electronic differential; this 8 wheeled electric vehicle is capable to drive till 370km/h maintaining perfect torque control on each wheel. Smaller vehicles for traction purposes and [[System on Chip]] controllers for generic vehicular applications are also available from WeMoveU company. <ref>{{cite web | url=http://www.wemoveuev.com/_mgxroot/page_10737.html | title= WeMoveU provides System On Chip Electronic Differential controller.}}</ref> <ref>{{cite web | url= http://www.electrictractor.com/html/tow_prod.shtml | title= Electric Tractor’s Electric Ox }}</ref>
+The [[Eliica]] is also equipped with electronic differential; this eight-wheeled electric vehicle is capable of driving up to 370&nbsp;km/h whilst maintaining perfect torque control on each wheel. Smaller vehicles for traction purposes and [[System on Chip]] controllers for generic vehicular applications are also available.
 ==References==
+{{reflist}}
-<references/>
+[[Category:Automotive transmission technologies]]
+[[Category:Vehicle technology]]
+[[Category:Mechanical power control]]