CAPÍTULO 2: DESCRIPCIÓN DE LA SOLUCIÓN
2.8 Implementación del Mercado de Datos
2.8.5 Desarrollo de la estructura física de almacenamiento
8 Retarder
8.1 Structure and function of retarder
The ZF Retarder integrated in the Ecomat is a single-staged hydro-dynamic continuous brake fitted between the torque converter and selector trans-mission.
This means that braking force is directly dependent on the gear engaged. Even at low speeds, full braking effect is available (characteristic for the primary retarder).
The retarder consists of the following components:
A rotor and a stator, both of which are fitted with blades. The rotor (the rotating part of the retarder) is connected to the input shaft of the transmission and therefore also to the vehicle’s drive axle when a gear is selected. The stator on the other hand is rigidly connected to the Ecomat housing.
Additionally, the ZF retarder has a special feature in that a vane ring is rotatably fixed in the stator. This reduces losses when the retarder is not engaged to less than 25% of the amount of loss without such a division of the stator.
A proportional solenoid which receives a voltage sig-nal from the transmission electronic unit determines the piston position of the retarder valve. The higher the voltage signal, the greater the oil pressure pres-ented by the control valve in the retarder cycle.
The retarder torque can be controlled depending on the piston position and the oil pressure determined by this. The maximum retarder torque is programmed in the electronic unit.
The basic advantage of the ZF retarder is its infinite-ly variable control. If required, the braking torque can be divided into one or several stages, all limited to a value specified by the customer.
023780
Stator
Grid
Rotor
Retarder ZF-Ecomat 2 plus
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8.2 Retarder action
There are various activation options for a braking procedure using the retarder (see diagram, chapter 8.5). Depending on the type of activation, it may be undertaken in stages or a gradual manner during which a voltage value equivalent to the retarder torque is sent from the appropriate activation ele-ment to the proportional solenoids. Depending on the strength of this signal, the piston of the retarder control valve is moved into a certain position which sets an appropriate level of oil pressure in the retar-der circuit.
The oil filling experiences centrifugal acceleration as a result of the rotor’s rotary motion, which is dri-ven by the coasting vehicle via the axle, propshaft, and transmission in overrun mode. The rotor forces the oil into blades in the non-rotating stator. The direction of oil flow is reversed and slowed (braked).
Due to the reverse of oil flow direction in the stator, the rotation of the rotor is also slowed, as is the vehicle speed.
The friction of the oil flow is converted into heat.
This heat is conveyed to the cooling water by the heat exchanger in liquid cooled engines or radiated into the cooling air in air-cooled engines.
Retarder ZF-Ecomat 2 plus
8.4 Retarder and engine brake
Max. braking torques
Trans- Total of all
mission Max. Torque brake torques Max. TRotor[Nm]
type max. [Nm] at nT= 1900 rpm
650 Nm 900 750
HP 502 C 850 Nm * 950 * 850 *
1100 Nm 1300 1050
HP 592 C 1250 Nm 1300 1050
HP 602 C
1400 Nm 1500 1250
1600 Nm 1500 1250
* up to max. 13 to
8.5 Retarder activation variants hand and foot
Overview of permitted Retarder activation variants
Retarder ZF-Ecomat 2 plus
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TSC1 primary = % of nominal rotor torque
TSC1 sec = % from 1st support point on characteristics field M_output for retarder operation
TSC1 operating element = % of M_output during retarder operation
Hand
No function 1/2 1/3 1/6
2/1 2/2 2/3 2/6
3/1 3/2 3/3 3/6
4/1 4/2 4/3 4/6
5/4
6/5 ED
Analog
EBC1 brake pedal
TSC1 primary
TSC1 sec
No function ED Analog TSC1 primary TSC1 sec TSC1 Bed elem
Foot
1 2 3 4 5 6
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Retarder ZF-Ecomat 2 plus
8.5.1 Permitted variants “foot request” without
“hand request”
Variants 2/1
Activation via footplate in digital manner with max.
3 stages. Any parameters can be set for the retarder request percentage.
Standard:
3-stage: 50 %, 75 %, and 100 %.
Inputs:
Pin 65 (ED 2), Pin 12 (ED 15), and Pin 36 (ED 7) Footplate deactivation via S9.
Variants 3/1
Activation using footplate with analog voltage signal on input EU3 EST 146/147 PIN 39.
Voltage spectrum 0 - 5 volts, percentage value of retarder request in ECU 146/147 can be configured.
NOTE
To compensate for pedal zero setting variances, the automatic footplate adjustment function in ECU 146/147 can be activated.
Footplate disengagement using S9 is advisable.
Variants 4/1
Retarder request using brake pedal value output via
“CAN signal EBC1 brake pedal position” as percent of brake pedal travel. Retarder request can be con-figured as % of pedal travel in ECU 146/147.
Footplate disengagement using S9 is advisable.
Retarder ZF-Ecomat 2 plus
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8.5.2 Permitted variants “foot request”
without “hand request”
Variant 1/2
Digital activation using hand lever with max. 3 stages. Percentage value for retarder request can be configured to desired level.
Standard:
3-stage: 50 %, 75 %, and 100 %.
Inputs:
Pin 65 (ED 2), Pin 12 (ED 15), and Pin 36 (ED 7)
Variant 1/3
Hand lever analog, stepped or continuously variable with analog voltage signal on input EU2.
ECU 146/147 PIN 61.
For additional protection of hand lever zero setting (retarder OFF), a digital input can be used. Standard EDM2.
Variant 1/6
Retarder request via TSC 1 as a percentage of the setting of a control element via CAN. The retarder request value is specified by the CAN signal.
For further calculation of the retarder request, the percentage for a given control element can be scaled progressively from software Step 3.
Retarder ZF-Ecomat 2 plus
8.5.3 Permissible retarder activation variants
"Foot" and "Hand" combined
Variant 2/2
If possible, use different digital inputs for the pedal plate and manual lever.
Reasoning:
Requests made by foot and hand may differ and are used for additional logic in the shift program.
Recommendation:
Foot: ED2, ED15, ED7 Hand: Use three unused EDs.
Footplate disengagement using S9 is advisable.
Variant combination of
2/3 for explanation, refer to 2/1 and 1/3 2/6 for explanation, refer to 2/1 and 1/6 3/2 for explanation, refer to 3/1 and 1/2 3/3 for explanation, refer to 3/1 and 1/3 3/6 for explanation, refer to 3/1 and 1/6 4/2 for explanation, refer to 4/1 and 1/2 4/3 for explanation, refer to 4/1 and 1/3 4/6 for explanation, refer to 4/1 and 1/6
Variant 5/4
Retarder request via TSC 1 via CAN as direct specifi-cation for rotor torque.
Additional linking of the TSC1 rotor torque specifi-cation with other controls should not be applied.
Reasoning:
The rotor torque specified e.g. by brake management would no longer be clear. As a consequence, this may affect the control process for a brake system.
NOTE
The TSC1 cannot be assigned to foot or hand. A distinction in the shift program would not then be possible.
Retarder ZF-Ecomat 2 plus
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StTrittplatte Foot plate EU 2EU 3 VV
1
0123n St 2St 3St
Handhebel Manual leverEDM 1 Trittplattenabschaltung Foot plate deactivationRetarderabschaltung Retarder deactivation
max. Max.
1St 2St 3
S9 %% EBC1
EBC1 ABS not fully operational Break Pedal Pos.
%
%%
1 6 7
5
2 34
TSC1 Anforderung [%] Bedienelement TSC1 Request Control ellementEBC1 ABS aktiv EBC1 ABS active TSC1 Anforderung[%] (Retarderreferenzmoment [Nm]) TSC1 Request [%] (Retarder reference torque [Nm])
Rotor-Ist- Moment [Nm] Rotor-actual- torque [Nm] Anforderung [%] Request [%] CAN
Berechnung Rotor-Ist-Moment Caleulation Rotor-actual-torque
8
Retarder activation variants
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