Nissan Qashqai J11. Manual — part 368

ECK-32

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SYSTEM

Depending on the engine components, ECM activates the fail-safe mode of the torque limitation level 1 (low
limitation), the level 2 (mean limitation), or the level 3 (strong limitation function of vehicle speed).

FAST SET-POINTS TO COMPLETE TORQUE REQUEST

For each combustion mode (the normal combustion mode, the regeneration combustion mode, and the pro-
tection combustion mode), a torque model is designed to calculate the total fuel mass quantity, the estimated
mean effective torque, the combustion efficiency and the current fuel consumption for the final torque set-point
and the engine current speed.
The total fuel mass quantity is corrected to take into account the main injection advance deviation and the
mass air flow deviation.
For each combustion mode, the after and the post injection relative efficiencies are calculated to determine the
fuel mass quantity needed to perform the engine inner torque.
The after injection relative efficiency is equal to one in normal combustion mode and to zero in a regeneration
combustion mode or in a protection combustion mode.
The post injection relative efficiency is function of the post injection timing and the difference between the cur-
rent and the basic post injection timing.

FINAL TORQUE REQUESTS SETTING

The final torque requests are computed by the arbitration with the driver request, the intersystem torque
request (VDC/ESP), the torque limitations and the curative anti-jerk correction.
The set-point torque is used for fuel mass calculation. It is filtered by the preventive anti-jerk and corrected by
the curative anti-jerk.

COMBUSTION CONTROL

COMBUSTION CONTROL : System Description

INFOID:0000000010471226

SYSTEM DESCRIPTION

The torque set-point is converted into a total fuel quantity injected. This quantity is split in various injections
according to a mapped injection pattern. Thus, a fuel quantity and an initial phasing of injection are allocated
for each injection. The choice of the number of injection (limited to five maximum) is given with different con-
straints such as acoustic, performance and emissions.
In the DPF (Diesel Particulate Filter) regeneration phase, post injections do not contribute to the torque elabo-
ration but to the increase of the DPF temperature. Therefore, the fuel consumption increases in the DPF
regeneration phase.

FUEL SUPPLY AND PRESSURE CONTROL SYSTEM

Fuel Supply System

The fuel supply system consists of two circuits: the fuel low and high-pressure circuit.
The fuel low-pressure circuit brings fuel from the tank to the high-pressure fuel pump through the fuel filter
(with fuel heater).
The high-pressure circuit function is to put the fuel under pressure and distribute it to the injectors:
• High-pressure fuel pump
• Fuel flow actuator
• Common rail
• Fuel injectors
The low-pressure fuel (coming from low-pressure circuit) is transferred to the high-pressure pump part via the
fuel flow actuator, which regulates the fuel flow quantity. The high-pressure fuel pump consists of a three-pis-
ton pump.
The fuel under pressure goes to the common rail, which distributes the fuel equally to each injector.
Finally, the commanded injectors deliver the fuel flow entering the cylinder.

Fuel Pressure Control

The combustion quality is influenced by the size of the droplets sprayed into the cylinder. In the combustion
chamber, smaller fuel droplets will have enough time to burn completely and will produce less smoke and less
unburnt particulate matter. To meet pollution requirements, the size of the droplets needs to be reduced and
hence so too do the injection orifices.
Since these orifices are smaller, less fuel can be injected for a given pressure, which in turn limits the power.
To counter this drawback, it is necessary to increase the quantity of injected fuel, which involves raising the
pressure (and the number of orifices on the injector nozzles). The pressure is continuously regulated to 160
MPa (1600 bar, 1632 kg-cm

2

, 23200 psi) in the rail. The measurement circuit consists of an pressure sensor

on the rail and transmits the pressure signal to ECM.

SYSTEM

ECK-33

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The high-pressure pump is self-supplied by an integrated gear pump. This supplies the rail, whose pressure is
controlled for loading by the fuel flow actuator. The flow regulation actuator allows the high-pressure fuel pump
to supply only the necessary quantity of diesel for maintaining pressure in the rail.

INJECTION CONTROL

The injection control parameters are the quantities to inject and their respective advances. The system per-
forms one to six injections.
An electrical current (impulse or pulse) is sent to each injector holder based on the previously computed data.
The piezoelectric injectors ensure injected fuel quantity with an excellent repeatability of the injection process.
Piezoelectric actuators work like capacitors. To control the injector, ECM punctually drives energy resulting in
the actuator deformation and injector opening.
During the injection time, piezoelectric actuator stores this energy, the length of electrical pulse is computed
with the fuel flow demand and injectors characteristics. At the end of the injection time, ECM recovers energy
to send at the start of control. Piezoelectric actuator then discharges and returns to its initial shape. The injec-
tor nozzle closes.

Injector Adjustment Value Registration

At the factory, each injector is calibrated for specific pressure needs on a test bench, and the values are indi-
cated on a label attached to the injector holder body. The individual injector correction values are then written
to ECM, enabling the ECM to control the injectors by taking into account the variance from the factory produc-
tion dispersion.
A specific strategy controls fuel injection deviations and dispersion during engine life (called Minimum Fuel
Mass Adaptation strategy).
This function defines individual injector correction to compensate the injector drift to enhance the delivery fuel
accuracy.

TEMPERATURE BEFORE TURBINE CONTROL

Upstream turbine temperature control sequentially uses injection parameters:
• Main injection phasing
• Post injection fuel mass
• Total fuel mass quantity
• Maximum torque
In normal combustion mode (without regeneration), the regulation aims to protect the turbine. when the tem-
perature exceeds the recommended limits, the regulation is able to limit total fuel mass quantity and torque
demand.
In regeneration mode, to increase the temperature in exhaust line, the regulation controls main injection phas-
ing and post injection.
The purpose is to obtain the highest temperature while respecting the recommended limits. In addition, the
regulation protects the turbine when the temperature is too hot.

WATER IN FUEL FUNCTION

The water in fuel detection sensor is an optional sensor integrated in the fuel filter. This function prevents seri-
ous damages on the common-rail system caused by water presence.

AFTER TREATMENT SYSTEM

AFTER TREATMENT SYSTEM : System Description

INFOID:0000000010471227

DESCRIPTION

This system has two main functions:
• Use the present oxygen in exhaust gases to transform the CO in CO2, and the HC in CO2 and H2O.
• Increase the temperature of exhaust gases (with the exothermal energy of the oxidation reaction) to allow

the regeneration in the DPF (Diesel Particulate Filter).

To be effective, the catalytic converter must reach the working temperature of 350 to 400

°

C (662 to 752

°

F).

DPF (DIESEL PARTICULATE FILTER)

The DPF filters up to 99% of the soot particulates that have not been filtered out up to this point. These partic-
ulates consist essentially of micro-spherules of carbon on which hydrocarbons from the fuel and lubricant
have condensed.
The quantity of particulates and their composition depend on:
• The combustion process (an homogeneous air/fuel mixture minimizes particulate formation)
• The quantity of diesel (increasing the cetane index limits the number of particulates formed)
• The post-processing efficiency (only filtration allows the particulates to be removed efficiently)

ECK-34

< SYSTEM DESCRIPTION >

[K9K]

SYSTEM

The DPF is a porous structure with channels set out in such a way as to force the exhaust gases through the
chamber walls.
In normal operation, DPF captures all the particulates emitted by the engine and so fills up progressively. It
therefore becomes necessary to eliminate all the accumulated particulates, which is done by combustion
(regeneration).

REGENERATION

The purpose of regeneration is to burn the particulates accumulated in the filter. In presence of oxygen, the
particulates combustion regeneration occurs naturally when the temperature of exhaust gases exceeds 570

°

C

(1058

°

F). In urban driving conditions, the engine barely reaches high temperature, and the exhaust gas tem-

perature consequently varies between 150

°

C (302

°

F) and 200

°

C (392

°

F). Therefore, it is necessary the DPF

(Diesel Particulate Filter) regeneration system, which does not adversely affect the driving comfort in any driv-
ing condition.
A differential pressure sensor detects filter load status (particulate mass) and triggers the regeneration opera-
tion. This takes place by means of a controlled combustion that raises the exhaust gas temperature up
between 550

°

C (1022

°

F) and 650

°

C (1202

°

F) at the filter intake.

Regeneration is continuously executed according to the following:

Regarding driving conditions:

• Vehicle speed
• Ambient pressure
• Temperature upstream DPF
• Engine coolant temperature

DPF charging level criteria:

• Soot mass [(computed using DPF charging curves (exhaust gas flow according to differential pressure)]
• Simulated soot mass [computed using mapped soot mass emission speed (g/s)]
• Driven distance since last successful regeneration
• Regeneration failures counter
ECM activates many engine management function to ensure good regeneration efficiency:
• Fuel system: A specific injection pattern using post injections is activated.
• Air system: EGR volume control valve is closed and throttle valve (intake) is used to control engine air flow.

In regeneration mode, other boost pressure set points are defined.

• Auxiliary functions: These functions (e.g. thermoplunger, etc.) are used to increase engine load.
At the same time, two specific exhaust gas temperature controllers are sequentially activated:
• Upstream turbine temperature control: As soon as a DPF regeneration is requested, the regulation is acti-

vated in order to obtain the highest safe upstream turbine temperature for any engine operating point and
without turbine damage risk (over temperature).

• Upstream DPF temperature control: This regulation is activated to heat DPF and to control its regeneration.

REGULATION OF TEMPERATURE BEFORE DPF

Regulation of the exhaust gas temperature before DPF is needed to complete a secure regeneration. This
strategy uses both exhaust line injectors and late post injections.
ECM computes the fuel mass flow injected by injectors (post injection) according to several parameters:
• Exhaust line temperature before DPF
• Atmospheric pressure
• Intake air temperature
• Differential pressure of the DPF
• Minimum level of fuel
• Engine speed
• Engine torque

COOLING FAN CONTROL

COOLING FAN CONTROL : System Description

INFOID:0000000010471228

SYSTEM DESCRIPTION

The cooling of the engine is done by a double speed motor driven fan unit (FAN1: small speed; FAN2: high
speed). The ECM controls cooling fan relays through CAN communication line.

When the engine is running

SYSTEM

ECK-35

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To cool the engine, a request for FAN1 activation is sent when the engine coolant temperature exceeds 99

°

C

(210

°

F) and a deactivated request is sent when the engine coolant temperature becomes lower than 96

°

C

(204

°

F).

When the engine coolant temperature continues to increase, a request for FAN2 activation is sent when the
engine coolant temperature exceeds 102

°

C (215

°

F) and a deactivated request is sent when the engine cool-

ant temperature becomes lower than 99

°

C (210

°

F).

When the engine coolant temperature continues to increase and exceeds the alert threshold calibrated at
115

°

C (239

°

F), ECM judges the engine is over temperature status until the temperature becomes lower than

110

°

C (230

°

F).

In case of an abnormally high engine coolant temperature, the maximum engine torque is reduced; the driver
will then feel a lack of engine power.

When the engine is not running

Only a FAN1 activation request can be sent for anti-percolation purpose (engine stopped with high engine
coolant temperature). The anti-percolation function is active after ignition switch OFF for a defined maximum
time. At ignition switch OFF, a FAN1 activation request is sent if the engine coolant temperature exceeds
100

°

C (212

°

F) and a cutting request is sent when the engine coolant temperature becomes lower than 95

°

C

(203

°

F).

When there is a default on the engine coolant temperature signal, the FAN1 activation is permanently
requested (engine running).
In addition to this, depending on the equipment mounted on the vehicle, the ECM can also send an activation
request for air conditioning needs or automatic transmission needs or DPF (Diesel Particulate Filter) regener-
ation needs.

THERMOSTAT CONTROL

THERMOSTAT CONTROL : System Description

INFOID:0000000010471229

SYSTEM DRAWING

For system drawing of the thermostat control, Refer to

CO-62, "Cooling Circuit"

.

DESCRIPTION

This engine has an engine coolant bypass valve and a thermoplunger and uses them for improving a warm-up
time.

Thermoplunger

The thermoplunger is installed to the engine coolant line and directly warms up engine coolant.
In addition, this system increases the engine load by adding extra consumers to the alternator, in case of DPF
(Diesel Particulate Filter) regeneration (to help the engine load rise).
ECM transmits a thermoplunger operating signal to the thermoplunger control unit when engine coolant tem-
perature is low.
The thermoplunger control unit applies power to the thermoplunger according to the received signal and
warms up engine coolant.
And ECM activates the thermoplunger during DPF (Diesel Particulate Filter) regeneration and increases elec-
tric load for get more engine load to perform normal DPF regeneration.
ECM controls thermoplunger based on the following information.
• Engine coolant temperature
• Battery voltage
• Engine speed
• Alternator load

GLOW CONTROL

GLOW CONTROL : System Description

INFOID:0000000010471230

SYSTEM DESCRIPTION

Glow control system operates at engine starting and after engine starting. The system energizes glow plug
according to engine coolant temperature to improve engine starting function.
When the ignition switch is turned ON, the glow control system starts Pre-glow and the glow indicator lamp
turns ON. When the engine starts, the glow indicator lamp turns OFF and the glow control state changes to
After-glow.
Glow time varies according to engine coolant temperature, barometric pressure and battery voltage.

OIL CONTROL SYSTEM