Land Rover Common Rail System Crs Denso Manual

Operation Section1–66
7. CONTROL SYSTEM
7.1 Fuel Injection Control
(1) General Description
• This system effects more appropriate control of the fuel injection quantity and injection timing than the mechanical
governor or timer used in the conventional injection pump. The engine ECU performs the necessary calculations
based on the signals that are received from the sensors located on the engine and the vehicle. Then, the ECU controls
the timing and duration of the current that is applied to the injectors...

Operation Section1–67
(3) Fuel Injection Quantity Control
General Description
• This control determines the fuel injection quantity by adding coolant temperature, fuel temperature, intake air temper-
ature, and intake air pressure corrections to the basic injection quantity. The engine ECU calculates the basic injection
quantity based on the engine operating conditions and driving conditions.
Injection Quantity Calculation Method
• The calculation consists of a comparison of the following two values: 1....

Operation Section1–68
Set Injection Quantities
• Basic Injection Quantity
This quantity is determined by the engine speed and the accelerator opening. With the engine speed constant, if the
accelerator opening increases, the injection quantity increases; with the accelerator opening constant, if the engine
speed rises, the injection quantity decreases.
• Starting Injection Quantity
This is determined based on the basic injection quantity for when the engine starts up and the added corrections for
the...

Operation Section1–69
• Maximum Injection Quantity
This is determined based on the basic maximum injection quantity determined by the engine speed, and the added
corrections for coolant temperature, fuel temperature, intake air temperature, atmospheric temperature, intake air
pressure, atmospheric pressure, and full Q adjustment resistance (only for the 1st generation HP0 system), etc. 
Corrections
• Cold Engine Maximum Injection Quantity Correction
When the coolant temperature is low, whether during...

Operation Section1–70
• Atmospheric Pressure Correction
The maximum injection quantity is increased and decreased according to the atmospheric pressure. When the atmo-
spheric pressure is high, the maximum injection quantity is increased.
• Injection Quantity Delay Correction for Acceleration
During acceleration, if there is a large change in the accelerator pedal opening, the injection quantity increase is de-
layed in order to prevent black smoke emissions. 
• Full Q Adjustment Resistance (Only for 1st...

Operation Section1–71
(4) Fuel Injection Rate Control
• Although the injection rate increases with the adoption of high-pressure fuel injection, the ignition lag, which is the
delay from the start of injection to the beginning of combustion, cannot be shortened to less than a certain period of
time. Therefore, the quantity of fuel injected until ignition takes place increases (the initial injection rate is too high),
resulting in explosive combustion simultaneous with ignition, and an increase in NOx and...

Operation Section1–72
(5) Fuel Injection Timing Control
• The fuel injection timing is controlled by the timing of the current applied to the injectors. After the main injection period
is decided, the pilot injection and other injection timing is determined.
Main Injection Timing
- The basic injection timing is calculated from the engine speed (engine speed pulse) and the final injection quantity,
to which various types of corrections are added in order to determine the optimal main injection timing....

Operation Section1–73
Split Injection
- The purpose of split injection is to improve the startability of a cold engine. Before the conventional main injection
takes place, this function injects two or more extremely small injections of fuel.
Multi-Injection Control (Only for Some Models)
- Multi-injection control is when small injections (up to four times) are carried out before and after the main injection
in accordance with the state of the main injection and engine operation. This interval (the time...

Operation Section1–74
(7) Other Injection Quantity Control
Idle Speed Control (ISC) System
• The idle speed control system controls the idle speed by regulating the injection quantity in order to match the actual
speed to the target speed calculated by the computer. The ISC can be automatic ISC or manual ISC.
Automatic ISC
- With automatic ISC, the engine ECU sets the target speed. The target engine speed varies with the type of trans-
mission (automatic or manual), whether the air conditioner is ON or...

Operation Section1–75
Manual ISC
- The idle engine speed is controlled by the setting on the idle setting button at the drivers seat.
Idle Vibration Reduction Control
- This control reduces engine vibration during idle. To achieve smooth engine operation, it compares the angle
speeds (times) of the cylinders and regulates injection quantity for each individual cylinder in the event of a large
difference.
ECU
A-GND V-IMC A-VCC
+5V
IMC Volume Terminal Voltage
Q000901E
Target Engine Speed
Q000902E
 t4  t3...