Hino N04C-T Service Manual
Diesel Injection Pump
SERVICE MANUAL
Common Rail System for HINO Dutro /
TOYOTA Dyna N04C-T# Type Engine
OPERATION
November, 2003
00400058E
TABLE OF CONTENTS
1. Product Application List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1-1. Vehicle Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1-2. Component Part Numbers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
2. Common Rail System Outline . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
2-1. Background to Development . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
2-2. System Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
2-3. Comparison to The Conventional System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Outline of TOYOTA / HINO Small Truck Common Rail System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
3-1. Main System Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
3-2. Outline of Composition and Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
3-3. Fuel System and Control System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
4. Description of Main Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
4-1. Supply Pump (HP3) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
4-2. Rail . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
4-3. Injector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
4-4. Engine ECU (Electronic Control Unit) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
4-5. EDU (Electronic Driving Unit) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
5. Description of Control System Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
5-1. Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
5-2. Description of Sensors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
6. Various Types of Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
6-1. Common Rail System Outline . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
6-2. Fuel Injection Quantity Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
6-3. Fuel Injection Timing Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
6-4. Fuel Injection Rate Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
6-5. Fuel Injection Pressure Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
7. Other (ECU Related) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
7-1. ECU External Wiring and Terminal Layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
7-2. Diagnostic Trouble Code . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
1. Product Application List
1-1. Vehicle Specifications
Vehicle Name Engine Model Exhaust Volume
HINO DUTRO / TOYOTA DYNA N04C-TF 4.0L
1-2. Component Part Numbers
Product Name HINO Part Number DENSO Part Number
Supply Pump 22730-1261B 294000-0191
Rail 22760-1170A 095440-0490
Injector 23910-1271A 095000-5321
Engine ECU 89660-37460 101758-6580
EDU 89870-37030 101310-5391
APM (Accelerator Pedal Module) 78100-37550 198800-3150
NE Sensor 89411-1630A 029600-1361
TDC Sensor 89410-1570A 949979-1310
Coolant Temperature Sensor 83420-1250A 071560-0110
AFM (Mass Airflow Meter) 22204-21010 197400-2000
Intake Air Temperature Sensor 89441-4310A 071500-2490
Turbo Pressure Sensor 89390-1080A 079800-5890
EGR-V 17350-1170A 135000-7051
Exhaust Gas Temperature Sensor 89441-37020 (IN) 265600-0600 (IN)
89441-37030 (OUT) 265600-0530 (OUT)
-1-
2. Common Rail System Outline
2-1. Background to Development
• The common rail system was developed primarily to cope with exhaust gas regulations for diesel engines, and is a diesel
injection control system with the following aims:
• To further improve fuel economy;
• To reduce noise;
• To achieve high power output.
2-2. System Characteristics
•
The common rail system uses a type of accumulation chamber called a rail to store pressurized fuel, and injectors that
contain electronically controlled solenoid valves to inject the pressurized fuel into the cylinders. Because the engine ECU
controls the injection system (injection pressure, injection rate, and injection timing), the injection system is independent,
and thus unaffected by the engine speed or load. This ensures a stable injection pressure at all times, particularly in the
low engine speed range, and dramatically decreases the amount of black smoke ordinarily emitted by a diesel engine
during start-up and acceleration. As a result, exhaust gas emissions are cleaner and reduced, and higher power output
is achieved.
A. Injection Pressure Control
• Enables high-pressure injection even at low engine speeds.
• Optimizes control to minimize particulate matter and NOx emissions.
B. Injection Timing Control
• Enables finely tuned optimized control in accordance with driving conditions.
C. Injection Rate Control
• Pilot injection control injects a small amount of fuel before the main injection.
Common Rail System
Injection Pressure Control
Optimization, High Pressurization
Common Rail System
Injection Pressure
Conventional
Pump
Speed
Particulate
Injection Pressure
Speed
NOx
Injection Timing Control
Optimization
Common Rail
System
Injection Timing
Conventional
Pump
Injection Rate Control
Speed
Pilot
Injection
Injection Rate
Crankshaft Angle
After-Injection
Post-Injection
Main
Injection
Injection Quantity Control
Cylinder Injection
Quantity Correction
1
3 4
2
Q000518E
-2-
2-3. Comparison to The Conventional System
In-Line & VE Pumps Common Rail System
High-Pressure Pipe
Momentary High Pressure
Timer
Governor
System
In-Line Pump
Nozzle
Supply
Pump
Feed
Pump
Rail
Normally High Pressure
Delivery Valve
SCV (Suction Control Valve)
Injection Quantity Control
Injection Timing Control
Rising Pressure
Distributor
Injection Pressure Control
Dependent upon speed and injection quantity
VE Pump
Pump (Governor)
Pump (Governor)
Pump
Pump
Fuel Tank
Injector
Engine ECU, Injector (TWV)*
Engine ECU, Injector (TWV)*
1
1
Engine ECU, Supply Pump
Engine ECU, Rail
Engine ECU, Supply Pump (SCV)*
2
*1 TWV: Two Way Valve
*2 SCV: Suction Control Valve
Q000387E
-3-
3. Outline of TOYOTA / HINO Small Truck Common Rail System
3-1. Main System Components
Accelerator Position Sensor
Intake Air Temperature Sensor
Variable Nozzle Type Turbo Opening Sensor
Variable Nozzle Type Turbo Motor
Glow Plug
Airflow Meter (With Integrated Ambient
Air Temperature Sensor)
Injector
Crankshaft Position Sensor
Rail Pressure Sensor
Intake Air Pressure Sensor
EGR Valve
Intake Restriction
Step Motor
Variable Nozzle
Controller
Pressure Limiter
Engine ECU (With
Built-In Atmospheric
Pressure Sensor)
EDU
Supply Pump
Fuel Temperature Sensor
Coolant Temperature Sensor
Cylinder Recognition Sensor
Rail
SCV
Items are DENSO products
Q000569E
-4-
3-2. Outline of Composition and Operation
A. Composition
The common rail system consists primarily of a supply pump, rail, injectors, and engine ECU.
Fuel Temperature
Vehicle Speed
Accelerator Opening
Intake Air Pressure
Intake Air Temperature
Coolant Temperature
Crankshaft Position
Cylinder Recognition Signal
Intake Airflow Rate
Engine ECU
Rail
Pressure Sensor
Rail
Pressure
Limiter
Injector
Fuel Temperature Sensor
Supply Pump
SCV (Suction
Control Valve)
Fuel Tank
B. Operation
a. Supply Pump (HP3)
The supply pump draws fuel from the fuel tank, and pumps the high pressure fuel to the rail. The quantity of fuel dis-
charged from the supply pump controls the pressure in the rail. The SCV (Suction Control Valve) in the supply pump
effects this control in accordance with commands received from the engine ECU.
b. Rail
The rail is mounted between the supply pump and the injector, and stores the high-pressure fuel.
c. Injector (G2 Type)
This injector replaces the conventional injection nozzle, and achieves optimal injection by effecting control in accordance
with signals from the engine ECU. Signals from the engine ECU determine the duration and timing in which current is
applied the injector. This in turn, determines the quantity, rate and timing of the fuel that is injected from the injector. QR
codes noting the characteristics of each vehicle are inscribed on the injector, and this data is sent to the ECU when the
engine ECU or injectors are replaced. This enables software to be adjusted to the mechanical characteristics of each
injector.
d. Engine ECU
The engine ECU calculates data received from the sensors to comprehensively control the injection quantity, timing and
pressure.
Q000144E
-5-
3-3. Fuel System and Control System
A. Fuel System
This system comprises the route through which diesel fuel flows from the fuel tank via the rail to the supply pump, and
is injected through the injector, as well as the route through which the fuel returns to the tank via the overflow pipe.
B. Control System
In this system, the engine ECU controls the fuel injection system in accordance with signals received from various sen-
sors. The components of this system can be broadly divided into the following three types: (a) sensors; (b) ECU; and (c)
actuators.
a. Sensors
Detect the engine and driving conditions, and convert them into electrical signals.
b. Engine ECU
Performs calculations based on the electrical signals received from the sensors, and sends them to the actuators in order
to achieve optimal conditions.
c. Actuators
Operate in accordance with electrical signals received from the ECU. Injection system control is undertaken by electron-
ically controlling the actuators. The injection quantity and timing are determined by controlling the duration and timing in
which current is applied to the TWV (Two-Way Valve) in the injector. Injection pressure is determined by controlling the
SCV (Suction Control Valve) in the supply pump.
Sensor
Crankshaft Position Sensor NE
Cylinder Recognition Sensor G
Accelerator Position Sensor
Rail Pressure Sensor
Other Sensors and Switches
Engine Speed
Cylinder Recognition
Load
Engine
ECU
Actuator
Injector
· Injection Quantity Control
· Injection Timing Control
· Injection Pressure Control
Supply Pump (SCV)
· Fuel Pressure Control
EGR, Air Intake Control
Relay, Light
Q000390E
-6-
4. Description of Main Components
4-1. Supply Pump (HP3)
A. Outline
• The supply pump consists primarily of the pump body (camshaft (eccentric cam), ring cam, and plungers), SCV (Suction
Control Valve), fuel temperature sensor, and feed pump.
SCV
Fuel Temperature Sensor
Q000570E
• The two plungers are positioned vertically on the outer ring cam for compactness.
• The engine drives the supply pump at a ratio of 1:1. The supply pump has a built-in feed pump (trochoid type), and draws
the fuel from the fuel tank, sending it to the plunger chamber.
• The internal camshaft drives the two plungers, and they pressurize the fuel sent to the plunger chamber and send it to
the rail. The quantity of fuel supplied to the rail is controlled by the SCV, using signals from the engine ECU. The SCV is
a normally open type (the intake valve opens during de-energization).
Injector
Rail
Discharge Valve
Intake Valve
Plunger
Intake Pressure
Feed Pressure
High Pressure
Return
Return Spring
Return
Fuel Overflow
SCV
Regulating Valve
Filter
Camshaft
Feed Pump
Fuel Inlet
Fuel Tank
Intake Fuel Filter
(With Priming Pump)
Q000392E
• The supply pump in the common rail system with DPNR has a fuel cut valve (FCV). The FCV is provided to enable man-
ual shut-off if a fuel leak occurs in the fuel addition valve passage.
-7-
a. Supply Pump Exploded Diagram
SCV
(Suction Control Valve)
Plunger
Pump Body
Ring Cam
Feed Pump
Regulating Valve
Filter
Camshaft
Plunger
Fuel Temperature Sensor
-8-
Q000393E
B. Supply Pump Internal Fuel Flow
Fuel drawn from the fuel tank passes through the route in the supply pump as illustrated, and is fed into the rail.
Supply Pump Interior
Regulating Valve
Feed Pump
Overflow
SCV (Suction Control Valve)
Intake Valve
Discharge Valve
Pumping Portion (Plunger)
Rail
Fuel Tank
C. Construction of Supply Pump
• The eccentric cam is formed on the camshaft and is attached to the ring cam.
Ring Cam
Camshaft
Eccentric Cam
• As the camshaft rotates, the eccentric cam rotates eccentrically, and the ring cam moves up and down while rotating.
Q000394E
Q000395E
Eccentric Cam
Camshaft
Ring Cam
Q000396E
-9-
• The plunger and the suction valve are mounted on top of the ring cam. The feed pump is connected to the rear of the
camshaft.
Plunger A
Ring Cam
Feed Pump
Plunger B
D. Supply Pump Operation
As shown in the illustration below, the rotation of the eccentric cam causes the ring cam to push Plunger A upwards. Due
to the spring force, Plunger B is pulled in the opposite direction to Plunger A. As a result, Plunger B draws in fuel while
Plunger A pumps it to the rail.
Suction Valve
Plunger A
SCV
Plunger B
Plunger A: Finish Compression
Plunger B: Finish Intake
Delivery Valve
Eccentric Cam
Ring Cam
Plunger A: Begin IntakePlunger
B: Begin Compression
QD0728E
Plunger A: Begin Compression
Plunger B: Begin Intake
Plunger A: Finish Intake
Plunger B: Finish Compression
QD0707E
-10-
E. Description of Supply Pump Components
a. Feed Pump
The trochoid type feed pump integrated into the supply pump, draws fuel from the fuel tank and feeds it to the two plung-
ers via the fuel filter and the SCV (Suction Control Valve). The feed pump is driven by the camshaft. With the rotation of
the inner rotor, the feed pump draws fuel from its suction port and pumps it out through the discharge port. This is done
in accordance with the space that increases and decreases with the movement of the outer and inner rotors.
Quantity Decrease
(Fuel Discharge)
Outer Rotor
To
Pump Chamber
Quantity Decrease
Inner Rotor
Intake Port
From
Fuel Tank
Discharge
Port
Quantity Increase
Quantity Increase
(Fuel Intake)
QD0708E
b. SCV (Suction Control Valve: Normally Open Type)
• A linear solenoid type valve has been adopted. The ECU controls the duty ratio (the duration in which current is applied
to the SCV), in order to control the quantity of fuel that is supplied to the high-pressure plunger.
• The supply pump drive load decreases because intake fuel quantity is controlled to achieve the target rail pressure.
• When current flows to the SCV, the internal armature moves in accordance with the duty ratio. The fuel quantity is reg-
ulated by the cylinder, which moves in connection with the armature to block the fuel passage.
• With the SCV OFF, the return spring pushes the cylinder, completely opening the fuel passage and supplying fuel to the
plungers. (Full quantity intake => full quantity discharge.)
• When the SCV is ON, the return spring contracts and closes the fuel passage.
• By turning the SCV ON/OFF, fuel is supplied in an amount corresponding to the drive duty ratio and then discharged by
the plungers.
External View
Return Spring
-11-
Cylinder
Pump Body
SCV
Cross-Section
Q000050E
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