ENGINE CONTROL SYSTEM (4JK1/4JJ1) 6E-359
Mass Air Flow (MAF) SensorThe MAF sensor is an air flow meter that measures the
amount of air that enters the engine. It is fitted between
the air cleaner and turbocharger. A small quantity of air
that enters the engine indicates deceleration or idle
speed. A large quantity of air that enters the engine
indicates acceleration or a high load condition. The
MAF sensor assembly consists of a MAF sensor
element and an intake air temperature (IAT) sensor that
are both exposed to the air flow to be measured. The
MAF sensor element measures the partial air mass
through a measurement duct on the sensor housing.
Fuel System Description
The common rail system uses a type of accumulator
chamber called the fuel rail to store pressurized fuel,
and injectors that contain electronically controlled
solenoid valves to spray the pressurized fuel in the
combustion chambers. The injection system (injection
pressure, injection rate, and injection timing) is
controlled by the ECM, and therefore the common rail
system can be controlled independently, free from the influence of engine speed and load. This ensures a
stable injection pressure at all time, particularly in the
low engine speed range, so that black smoke specific
to diesel engines generated during vehicle starting or
acceleration can be reduced dramatically. As a result,
exhaust gas emissions are clear and reduced, and
higher output is achieved.
AAW46ESH001401
RTW76EMF000401
Supply pump
One-way valve
Fuel tank Fuel filter
Camshaft
position
sensor Crankshaft
position
sensor Various sensors
(accelerator position sensor, coolant temperature,
mass air flow, etc.) Injectors
Pressure sensor
Fuel rail Pressure
limiter valve
ECM
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6E-360 ENGINE CONTROL SYSTEM (4JK1/4JJ1)
1. High Pressure Control• Enables high pressure injection from low engine speed range.
• Optimizes control to minimize particulate matter and NOx emissions.
2. Injection Timing Control
• Enables finely tuned optimized control in accordance with running conditions.
3. Injection Rate Control
• Pilot injection control that performs a small amount of injection before main injection.
The fuel rail system consists primarily of a fuel supply
pump, fuel rail, injectors, and ECM.
Fuel System Component Description
Injector
Legend
1. Fuel injector ID code
2. Leak off pipe
3. Two dimensional barcode
4. Port for mounting the injection pipe
5. O-ring
Electronic control type injectors controlled by the ECM
are used. Compared with conventional injection
nozzles, a command piston, solenoid valve, etc. are
added.
ID codes displaying various injector characteristic are
laser marked on the connector housing, and ID codes showing these in numeric form (24 alphanumeric
figures). This system uses fuel injector flow rate
information (ID codes) to optimize injection quantity
control. When an injector is newly installed in a vehicle,
it is necessary to input the ID codes in the ECM.
QR (Quick Response) codes or fuel injector flow rate
(ID codes) have been adopted to enhance the injection
quantity precision of the injectors. The adoption of
codes enables injection quantity dispersion control
throughout all pressure ranges, contributing to
improvement in combustion efficiency and reduction in
exhaust gas emissions.
RTW56EMH000101
23
1
4
5
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ENGINE CONTROL SYSTEM (4JK1/4JJ1) 6E-363
Along with the employment of a common rail type
electronic control fuel injection system, the fuel rail is
provided to store high pressure fuel between supply
pump and injectors. A pressure sensor and a pressure
limiter are installed on the fuel rail. The pressure sensor
detects the fuel pressure inside the fuel rail and sends
its signal to the ECM. Based on this signal, the ECM
controls the fuel pressure inside the fuel rail via the fuel
rail pressure (FRP) regulator of the supply pump. The
pressure limiter opens the valve mechanically to relieve
the pressure when the fuel pressure inside the fuel rail
is excessive.
Fuel Rail Pressure Sensor
The FRP sensor is installed to the fuel rail and it
detects the fuel pressure in the fuel rail, converts the
pressure into a voltage signal, and sends the signal to
the ECM. The ECM monitors the FRP sensor signal
voltage. Higher fuel rail pressure provides higher signal
voltage while lower pressure provides lower signal
voltage. The ECM calculates actual fuel rail pressure
(fuel pressure) from the voltage signal and uses the
result in fuel injection control and other control tasks.
Pressure Limiter Valve
Legend 1. Valve
2. Valve body
3. Valve guide
4. Spring
5. Housing
6. Fuel rail
7. Fuel return pipe
The pressure limiter relieves pressure by opening the
valve if abnormally high pressure is generated. The
valve opens when pressure in rail reaches
approximately 220 MPa (32,000 psi), and closes when
pressure falls to approximately 50 MPa (7,250 psi).
Fuel leakage through the pressure limiter re-turns to
the fuel tank. Fuel Rail Pressure (FRP) Regulator
The ECM controls the duty ratio of the linear type fuel
rail pressure (FRP) regulator (the length of time that the
current is applied to the FRP regulator), in order to
control the quantity of fuel that is supplied to the high-
pressure plungers. Since only the quantity of fuel that is
required for achieving the target rail pressure is drawn
in, the drive load of the supply pump is decreased.
When current flows to the FRP regulator, variable
electromotive force is created in accordance with the
duty ratio, moving the armature to the left side. The
armature moves the cylinder to the left side, changing
the opening of the fuel passage and thus regulating the
fuel quantity. With the FRP regulator OFF, the return
spring contracts, completely opening the fuel passage
and supplying fuel to the plungers (Full quantity intake
and full quantity discharge). When the FRP regulator is
ON, the force of the return spring moves the cylinder to
the right, closing the fuel passage (normally opened).
By turning the FRP regulator ON/OFF, fuel is supplied
in an amount corresponding to the actuation duty ratio,
and fuel is discharged by the plungers.
LNW41ASH001301
12 3 4 5
7
6
RTW56ESH006101
12
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6E-364 ENGINE CONTROL SYSTEM (4JK1/4JJ1)
Fuel Injection System Description
Fuel Injection Quantity Control
This control determines the fuel injection quantity by
adding coolant temperature, fuel temperature, intake
air temperature, barometric pressure, mass air flow and
some switch inputs information corrections to the basic
injection quantity is calculated by the ECM based on
the engine operating conditions (engine speed,
accelerator pedal pressing amount and boost pressure
sensor). More fuel rate indicates if the engine load is
increased as the accelerator pedal is stepped on at
constant engine speed.
Combined with high pressure injection of atomized fuel,
this control improves exhaust gas and ensures proper
fuel consumption. Compared with conventional
mechanical governors, an electronic control system
provides higher degree of freedom of fuel injection
quantity control, thereby presenting high accelerator
response (acceleration feeling and pressing feeling).
Starting Injection Quantity Control
At the engine starting (after the key switch is turned to
the START position to start the engine, up to return of
key switch to the ON position), optimum fuel injection
quantity is controlled based on the information on the
engine speed and coolant temperature. At low
temperature, the fuel injection quantity increases.
When the engine started completely, this boosted
quantity mode at the starting is cancelled and normal
running mode is restored.
Idle Speed Control
A control is made so as to achieve stable idling speed
at all time regardless of engine secular changes or
engine condition variations. The ECM sets target idling
speed and controls the fuel injection quantity according
to the engine conditions (actual engine speed, coolant
temperature and engine load) to follow actual engine
speed to the target idling speed so as to ensure stable
idling speed.
Idle Vibration Control
A control is made so as to reduce the engine vibration
caused by torque variations between cylinders due to
variations in fuel injection quantity of each cylinder or
injector performance. The ECM corrects the injection
quantity between cylinders based on the revolution
signals from the crankshaft position (CKP) sensor.
Normal range of correction quantity between cylinders
is within ±5 mm
3.
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ENGINE CONTROL SYSTEM (4JK1/4JJ1) 6E-365
Exhaust Gas Recirculation (EGR) System Description
Legend1. EGR cooler
2. Engine coolant outlet
3. Engine coolant inlet
4. EGR valve 5. ECM
6. MAF sensor
7. Intake throttle valve
The EGR system recirculates a part of exhaust gas
back into the intake manifold, which results in reducing
nitrogen oxide (NOx) emissions. The EGR control
system uses an electronic control system to ensure
both driveability and low emission. A control current
from the ECM operates a solenoid to control the lift
amount of EGR valve. Also, an EGR position sensor is
provided at the rear of the motor to feed actual valve lift
amount back to the ECM for more precision control of
the EGR amount.
The EGR control starts when the conditions for engine
speed, engine coolant temperature, intake air
temperature and barometric pressure are satisfied.
Then, the valve opening is calculated according to the
engine speed, and target fuel injection quantity. Based
on this valve opening, the drive duty of the solenoid is
determined and the valve is driven accordingly. The
intake throttle valve is provided to adequate intake
manifold depression to ensure EGR gas flow. EGR Valve
RTW56EMF001701
1
4
7 5
6
23
RTW56ESH000801
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6E-366 ENGINE CONTROL SYSTEM (4JK1/4JJ1)
The EGR valve is mounted on the intake manifold. The
ECM controls the EGR valve opening based on the
engine running condition. The ECM controls the EGR
valve by controlling the solenoid. The solenoid is
controlled based on pulse width modulation (PWM)
signal sent from the ECM. A duty ratio change 0% to
appropriate percentage is EGR valve lift control. To
open the valve, duty ratio is increased. To close the
valve, duty ratio becomes small.
The EGR valve position is detected by the position
sensor, and relayed to the ECM. The position sensor
provides a signal to the ECM on the signal circuit,
which is relative to the position changes of the EGR
valve. The ECM should detect a low signal voltage at a
small lift amount or closed position. The ECM should
detect high signal voltage at a large lift amount.
Intake Throttle Valve
The intake throttle valve is located on the intake
manifold inlet. The ECM controls the intake throttle
valve opening based on the engine running condition.
The ECM controls the intake throttle valve by
controlling the solenoid. The solenoid is controlled
based on pulse width modulation (PWM) signal sent
from the ECM. A duty ratio change 0% to appropriate
percentage is intake throttle valve opening angle
control. To open the valve, duty ratio is increased. To
close the valve, duty ratio becomes small.
The intake throttle valve position is detected by the
position sensor, and relayed to the ECM. The position
sensor provides a signal to the ECM on the signal
circuit, which is relative to the position changes of the
intake throttle valve. The ECM should detect a low
signal voltage at a small opening amount or closed
position. The ECM should detect high signal voltage at
a large opening amount.Turbocharger Description
Legend
1. Exhaust gas
2. Waste gate valve
3. Turbine wheel
4. Compressor wheel
5. Air cleaner
6. Charge air cooler (Intercooler)
The turbocharger is used to increase the amount of air
that enters the engine cylinders. This allows a
proportional increase of fuel to be injected into the
cylinders, resulting in increased power output, more
complete combustion of fuel, and increased cooling of
the cylinder heads, pistons, valves, and exhaust gas.
This cooling effect helps extend engine life.
Heat energy and pressures in the engine exhaust gas
are utilized to drive the turbine. Exhaust gas is directed
to the turbine housing. The turbine housing acts as a
nozzle to direct the shaft wheel assembly. Since the
compressor wheel is attached directly to the shaft, the
compressor wheel rotates at the same speed as the
turbine wheel. Clean air from the air cleaner is drawn
into the compressor housing and wheel. The air is
compressed and delivered through a crossover pipe to
the engine air intake manifold, then into the cylinders.
RTW56ESH001101
RTW56EMH000201
1 3
2 4
5
6
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ENGINE CONTROL SYSTEM (4JK1/4JJ1) 6E-367
The amount of air pressure rise and air volume
delivered to the engine from the compressor outlet is
regulated by a waste gate valve in the exhaust housing.
The position of the waste gate valve is controlled by the
amount of pressure built up on the intake side of the
turbocharger. The diaphragm on the inside of the waste
gate is pressure sensitive, and controls the position of
the valve inside the turbocharger. The position of the
valve will increase or decrease the amount of boost to
the turbocharger. (Standard output engine)
Legend
1. Turbocharger nozzle control actuator
2. Nozzle
The amount of air pressure rise and air volume
delivered to the engine from compressor outlet is
regulated by a turbocharger nozzle control actuator
indirectly. The position of the turbocharger nozzle is
controlled by the ECM. The ECM utilizes a
turbocharger nozzle control solenoid valve and a boost
pressure sensor to control the turbocharger nozzles.
When the engine is not under load, the turbocharger
nozzles are in an open position (A), or no boost
condition (vacuum pressure supply to the actuator is
reduced). When the engine is under load, the ECM
commands the control solenoid valve to close the
turbocharger nozzles (B), thus increasing the boost
(vacuum pressure supply to the actuator is increased).
The ECM will vary the boost dependant upon the load
requirements of the engine. The ECM uses a pulse
width modulation (PWM) on the control circuit to open and control the solenoid valve. (High output engine)
The charge air cooler also helps the performance of the
diesel. Intake air is drawn through the air cleaner and
into the turbocharger compressor housing. Pressurized
air from the turbocharger then flows forward through
the charge air cooler located in the front of the radiator.
From the charge air cooler, the air flows back into the
intake manifold.
The charge air cooler is a heat exchanger that uses air
flow to dissipate hear from the intake air. As the
turbocharger increases air pressure, the air
temperature increases. Lowering the intake air
temperature increases the engine efficiency and power
by packing more air molecules into the same space.
RTW76EMH000201
A
B
1
2
1
2
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6A-12 ENGINE MECHANICAL (C24SE)
Engine - General C24SE
Fuel system Electronically controlled Multi Port Fuel Injection System
Fuel pump type Electric
Fuel pressure kg/cm2 (psi/Pa) 3.4 (48.4/334)
Fuel filter type Cartridge paper element
Air cleaner type Dry paper element
Battery Type/V-Ax No. of units 34B19L/50D20L
Alternator
Capacity V-A(W ) 12-90 (1080), 12-100 (1200)
Starter
Output V-kW 1.4
Exhaust system CO Adjustment (1) Applicable to Open Loop System (Not equipped H2OS)
(2) Not applicable to Closed Loop System (Equipped H2OS)
Compression Ratio (with Tolerance) 9.6:1±0.25
Cylinder Head Material Aluminum Alloy (gravity cast)
Cylinder Block Material Cast Iron
No. of Mounting Points (including trans.) 3
Engine Installation Angles
-Longitudinal 4
° 60'
-Lateral 7° 50' (towards exhaust side)
Overall Dimensions (L ×
××
×
W ×
××
×
H):
- TF (2.4Litre/2W D)610×564 ×708mm
- TF (2.4Litre/4W D) 610×564 ×746mm
Engine Weight
Engine W eight
- TF (2.4Liter/Man) 140kg
Camshaft Type
SOHC
No. of Valves per Cylinder
- Inlet1
- Exhaust
1
Spark Plug Location Side
Port Arrangement Cross Flow
W orking Principle Spark Ignition 4-stroke
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