15-150000-00
A fourth correction is made according to the pressure error.
This correction is used to reduce the injection timing advance when the pressure in the rail is
higher than the pressure demand.
A fifth correction is made according to the rate of EGR.
This correction is used to correct the injection timing advance as a function of the rate of
exhaust gas recirculation. -
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When the EGR rate increases, the injection timing advance must in fact be increased in order to
compensate for the fall in termperature in the cylinder.
A. Main Flow Control
The main flow represents the amount of fuel injected into the cylinder during the main injection.
The pilot flow represents the amount of fuel injected during the pilot injection.
The total fuel injected during 1 cycle (main flow + pilot flow) is determined in the following manner.
When the driver depress the pedal, it is his demand which is taken into account by the system
in order to determine the fuel injected.
When the driver release the pedal, the idle speed controller takes over to determine the
minimum fuel which must be injected into the cylinder to prevent the enigne from stalling. -
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It is therefore the greater of these 2 values which is retained by the system. This value is then
compared with the lower flow limit determined by the ESP system.
As soon as the injected fuel becomes lower than the flow limit determined by the ESP system, the
antagonistic torque (engine brake) transmitted to the drive wheels exceeds the adherence
capacity of the vehicle and there is therefore a risk of the drive wheels locking.
The system thus chooses the greater of these 2 values (main flow & pilot flow) in order to prevent
any loss of control of the vehicle during a sharp deceleration.
As soon as the injected fuel becomes higher than the fuel limit determined by the ASR trajectory
control system, the engine torque transmitted to the wheels exceeds the adhesion capacity of the
vehicle and there is a risk of the drive wheels skidding. The system therefore chooses the smaller
of the two values in order to avoid any loss of control of the vehicle during accelerations.
The anti-oscillation strategy makes it possible to compensate for fluctuations in engine speed
during transient conditions. This strategy leads to a fuel correction which is added to the total fuel
of each cylinder.
A switch makes it possible to change over from the supercharge fuel to the total fuel according to
the state of the engine.
Until the stating phase has finished, the system uses the supercharged fuel.
Once the engine changes to normal operation, the system uses the total fuel. -
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(5) Fuel Control
The main fuel is obtained by subtracting the pilot injection fuel from the total fuel.
A mapping determines the minimum fuel which can control an injector as a function of the rail
pressure. As soon as the main fuel falls below this value, the fuel demand changes to 0 because
in any case the injector is not capable of injecting the quantity demand.
01-113680-01
1. OVERVIEW
The six speed automatic (M78) transmission
is available in two variants: four wheel drive
and two wheel drive.
The transmission has the following features:
Six Forward Speeds
One reverse gear
A torque converter with an integral converter lock-up clutch
Electronic shift and pressure controls
A single planetary gear-set
A double planetary gear-set
Two hydraulically controlled brake bands
Three multi-plate clutches
All hydraulic functions are directed by electronic solenoids to control: -
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Engagement feel
Shift feel
Shift scheduling
Modulated torque converter clutch applications ·
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The transmission contains fully synthetic automatic transmission fluid (ATF) and is filled for life;
therefore it does not require periodic servicing.
Engine power reaches the transmission via a torque converter with integral converter lock-up
clutch.
The six forward gears and one reverse gear are obtained from a single planetary set, followed by
a double planetary set. This type of gear-set arrangement is commonly known as Lepelletier type
gear-set.
The automatic transmission is electronically controlled. The control system is comprised of the
following elements:
External transmission control unit (TCU)
Internal embedded memory module (EMM)
Input and output speed sensors
Valve body unit comprised of four on/off solenoid valves and six variable bleed solenoids
Torque converter -
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