GF54.10-P-1040FL Energy management for engine start/stop function 2.5.
12
MODEL 212.0 /2 28.2.13 with CODE (B03) ECO start/stop function fuse box
The "energy management for engine start/stop function" System diagnosis completed
subfunction is viewed from an energy management point-of-view. Outside temperature T = -10 up to 40 °C
Information on the "engine timing Start-Stop function" subfunction is (except model 212.095/098/298)
documented in the "Common-Rail Diesel Injection (CDI) function" Outside temperature T = -40 up to 60 °C
description (with diesel engine) or "gasoline injection and ignition (model 212.095/098/298)
system with direct-injection function" (with gasoline engine). Battery temperature T = 0 up to 60 °C
(except model 212.095/098/298)
Function requirements, general Battery temperature T = -40 up to 60 °C
Engine running and at operating temperature (model 212.095/098/298)
Engine hood closed A/C regulated
One-time overspeeding
of v = 15 km/h in forward travel Energy management for engine start/stop, general
For a stationary vehicle, the engine Start-Stop function switches the
engine off automatically and starts it again, as soon as the driver
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Switching of the engine during standstill periods of the vehicle Immediately after the cold start of the engine the CDI control unit or
reduces the fuel consumption and therefore the carbon dioxide the ME-SFI [ME] control unit runs a system diagnosis [SD] and
emissions. evaluates the functional capability of the start/stop function. In
The master control unit for the engine start/stop function is the CDI addition the front SAM control unit with fuse and relay module
control unit (N3/9) (with diesel engine) or the ME-SFI [ME] control (N10/1) checks the function of all affected components for isolating
unit (N3/10) (with gasoline engine) that records and evaluates all the on-board electrical system battery and connecting the additional
influencing factors. battery for ECO start/stop function.
The conventional switching off and starting the engine with the
transmitter key (A8/1) or via the KEYLESS-GO start-stop button The additional battery for ECO start/stop function is actuated by
(S2/3) (with code (889) Keyless-Go) continues to be possible. the additional battery relay for ECO start/stop function (K114). For
vehicles with manual transmission, this is designed as a mechanical
Through the use of the additional battery for ECO start/stop function relay and for vehicles with automatic transmission as an electronic
(G1/13) with a capacity of 12 Ah the starting voltage dip is avoided relay.
while the engine is being started. The on-board electrical system battery is decoupled from the on-
The additional battery for ECO start/stop function then assumes the board electrical system on vehicles with manual transmission through
power supply for the active consumers in the process while the on- the on-board electrical system decoupling relay (K19/7) and for
board electrical system battery (G1) is isolated from the on-board vehicles with automatic transmission by the ECO start/stop function
electrical system (at engine start). Active comfort functions are not diode (V19).
switched off.
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The engine start/stop function encompasses the following The on-board electrical system management provides information,
subfunctions: which describes the on-board electrical system management status
Function sequence for engine stop or the requirements for the on-board electrical system.
Function sequence for engine start
Function sequence for a forced engine start The following on-board electrical system management information is
Function sequence for determine condition of additional provided by the rear SAM control unit with fuse and relay module
battery for ECO start/stop function (N10/2):
Function sequence for charge ECO start/stop function - State of on-board electrical system battery
additional battery - State of additional battery for ECO start/stop function
- On-board electrical system status
Additional function requirement for engine stop - Requirements for load-intensive consumers (e.g. A/C)
Stop enable issued by the CDI control unit or
the ME-SFI [ME] control unit The CDI control unit or the ME-SFI [ME] control unit evaluates all the
relevant data and then issues the stop enable. The engine is
Function sequence for engine stop switched off as a result of this.
As the master control unit for the engine start/stop function, the CDI
control unit or the ME-SFI [ME] control unit checks the various
influencing factors for the stop enable. -----------------------------------------------------------------------------------------
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The blower output is reduced when the automatic blower system The front SAM control unit reads in this hot start signal over a direct
of the A/C is active. In high ambient temperatures the system line and actuates the on-board electrical system decoupling relay
changes into air circulation mode depending on the specified (manual transmission) or the ECO start/stop function diode (A/T) in
temperature adjusted. the front prefuse box (F32) and the ECO start/stop function additional
© Daimler AG, 12/13/13, G/09/13, gf54.10-p-1040fl, Energy management for engine start/stop function Page 1 of 4
MODEL 212.0 /2 28.2.13 with CODE (B03) ECO start/stop function fuse box
battery relay on the additional battery for the ECO start/stop function.
After an engine stop a maximum of three engine starts is permitted The additional battery for the ECO start/stop function is then
without exceeding the speed threshold of v = 8 km/h. switched through to the on-board electrical system. Shortly after this
the on-board electrical system decoupling relay (manual transmission)
or the ECO start/stop function diode (automatic transmission)
Function sequence for engine start
disconnects the on-board electrical system battery from the on-board
During the starting procedure the on-board electrical system battery is
electrical system during the start procedure.
isolated from the on-board electrical system. The power supply for
The energy requirement of the on-board electrical system is now
the active consumers is now provided by the additional battery for
powered by the additional battery for ECO start/stop function.
the ECO start/stop function.
The on-board electrical system battery now supplies the energy
This serves to prevent any voltage dip as perceived by vehicle required for the engine starting process. As soon as the ME-SFI [ME]
occupants when starting the engine (e.g. during radio or ventilation
control unit or CDI control unit detects an engine rpm of
operation).
n = 400 to 700 rpm, it stops the starting process and transmits
The CDI control unit or the ME-SFI [ME] control unit evaluates all
a corresponding signal to the front SAM control unit.
relevant influencing factors and then issues the start enable (hot start
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signal).
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As a result of this the front SAM control unit actuates the decoupling Load-intensive consumers can be requested by the following
relay for on-board electrical system (manual transmission) or the systems:
diode for the ECO start/stop function (A/T) and the additional battery - Supplemental restraint system
relay for ECO start/stop function. The decoupling relay for on-board - PRE-SAFE
electrical system (manual transmission) or the diode for ECO start/ - Brake assist and adaptive cruise control systems
stop function (A/T) connects the on-board electrical system battery to - Air conditioning
the on-board electrical system.
- Steering
The additional battery relay for ECO start/stop function disconnects
the additional battery for ECO start/stop function from the on-board
As soon as the on-board electrical system management is no longer
electrical system.
able to ensure on-board electrical system stability, the rear SAM
The energy requirement of the on-board electrical system is now
supplied again by the on-board electrical system battery. control unit sends an engine start request over the interior CAN
(CAN B), front SAM control unit and the chassis CAN (CAN E) to the
CDI control unit or the ME-SFI [ME] control unit. The CDI control unit
Function sequence for a forced engine start or the ME-SFI [ME] control unit receives this and starts the engine.
To ensure that the on-board electrical system stability is also given If, following this, the on-board electrical system stability can still not
during engine OFF, the CDI control unit or the ME-SFI [ME] control be assured, the engine is no longer switched off.
unit can also force the engine to start. The Start-Stop function is switched off.
A forced engine start is also conducted if, as a consequence of load-
intensive consumers, the on-board electrical system stability can no
longer be assured.
Illustration of power supply at engine start
principle
B95 Battery sensor
G1 On-board electrical system battery
G2 Alternator (except model 212.095)
G1/13 ECO start/stop function additional
battery
K19/7 Decoupling relay for on-board
electrical system
(with transmission 716.6)
(relay open)
K114 Additional battery relay for ECO
start/stop function
(relay closed)
M1 Starter
P54.10-3386-06
© Daimler AG, 12/13/13, G/09/13, gf54.10-p-1040fl, Energy management for engine start/stop function Page 2 of 4
MODEL 212.0 /2 28.2.13 with CODE (B03) ECO start/stop function fuse box
N10/1 Front SAM control unit with fuse and relay module A Mechanical relay
N10/2 Rear SAM control unit with fuse and relay module with transmission 716.6
V19 ECO start/stop function diode B Electronic relay
(with transmission 722) (diode open) with transmission 722
Illustration of power supply when engine
running principle
B95 Battery sensor
G1 On-board electrical system battery
G2 Alternator (except model 212.095)
G1/13 ECO start/stop function additional
battery
K19/7 Decoupling relay for on-board
electrical system
(with transmission 716.6)
(relay closed)
K114 Additional battery relay for ECO
start/stop function
(relay open)
M1 Starter
P54.10-3387-06
N10/1 Front SAM control unit with fuse and relay module A Mechanical relay
N10/2 Rear SAM control unit with fuse and relay module with transmission 716.6
V19 ECO start/stop function diode B Electronic relay
(with transmission 722) (diode closed) with transmission 722
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Function sequence for determine condition of ECO start/stop The additional battery relay for the ECO start/stop function is no
function additional battery longer actuated under the following conditions:
The front SAM control unit runs a battery state recognition - Additional battery for ECO start/stop function deep discharged
immediately after the engine is started. This provides information - Internal short circuit
regarding the availability of electrical power to the additional battery - Short circuit in positive line of additional battery for ECO start/
for the ECO start/stop function. stop function
If the engine is switched off during the battery state recognition, the
SAM control unit switches this off and discards the previous results. In order to establish this, the voltage of the ECO start/stop function
In addition to battery state recognition, the voltage of the additional additional battery is compared with an internal value.
battery for ECO start/stop function mode in the start-stop function A corresponding fault message is shown in the multifunction display
mode is tested after every engine start. (A1p13) of the IC (A1).
The front SAM control unit transmits the data required for this to the
The battery state recognition can be started by means of a instrument cluster via the interior CAN.
diagnosis tester.
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Function sequence for charge ECO start/stop function additional If the voltage dip (U < 11 V) at engine start is too large, an engine
battery stop is deactivated for t = 5 min. (up to 31.5.12), t = 1 min. (as of
The charging strategy of the additional battery for ECO start/stop 1.6.12) to recharge the additional battery for the ECO start/stop
function must take two requirements into account: function.
- The ECO start/stop function additional battery must always be The additional battery for ECO start/stop function is only connected
sufficiently charged. when the alternator's power limit (alternator management) is not
- The number of additional battery relay for the ECO start/stop active and the on-board electrical system voltage (U > 13 V) is high
function actuations and the related load on the additional battery enough.
for the ECO start/stop function must be minimized as far as It is cleared again when the alternator's power limit is active or the
possible. on-board electrical system is severely overloaded.
If the open circuit voltage (U > 12.5 V) of the additional battery for
ECO start/stop function is too low, the alternator's power limit
(alternator management) (except model 212.095) is deactivated so
that the additional battery for ECO start/stop function can be
charged.
© Daimler AG, 12/13/13, G/09/13, gf54.10-p-1040fl, Energy management for engine start/stop function Page 3 of 4
MODEL 212.0 /2 28.2.13 with CODE (B03) ECO start/stop function fuse box
Electrical function schematic for energy PE54.10-P-2070-97DAA
management for engine start/stop
Overview of system components for energy GF54.10-P-9990FL
management
© Daimler AG, 12/13/13, G/09/13, gf54.10-p-1040fl, Energy management for engine start/stop function Page 4 of 4
MODEL 212.0 /2 28.2.13 with CODE (B03) ECO start/stop function fuse box
