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ELECTRONIC CONTROL SYSTEM
TNV DI Service Manual
13-5
Introduction
INTRODUCTION
None of the components of the electronic control
system can be individually repaired. When any
component is faulty and needs repair, the entire
assembly must be replaced.
ELECTRONIC CONTROL
SYSTEM
Model 4TNV84T-Z, 4TNV98-E, 4TNV98-Z and
4TNV98T-Z engines come with the Exhaust Gas
Recirculation (EGR) system to conform to the next
engine emission regulations (EPA 2008 rules). The
EGR system and an electronic governor (Eco-
governor) constitute an electronic engine control
system.
The electronic engine control system regulates the
exhaust gas recirculation flow rate and the fuel
injection volume depending on the engine load and
speed signals from the engine controller (E-ECU),
so that the exhaust gas is kept clean according to
the emission control regulations. Figure 13-1
illustrates the electronic engine control system.
Features of the electronic engine control system
include:
• Engine speed control schemes
Droop control / Low-idling speed up / Auto
deceleration / High-idling speed down / Black
smoke suppression
• Starting aid
Auto preheating / After heating
• Engine failure detection
• CAN communication with the control system of
the driven machine
Although these features are described in section 4-
7, whether they are available as options differs
among machines/vehicles; for more information,
see the instruction manuals for the respective
machines/vehicles.
Figure 13-1
E-ECU
CSD
Engine speed
sensor
Rack position
sensor
Eco-governor
Fuel injection pump
Actuator
Intake
Exhaust
EGR-Valve
Piston
Liner
Inj.Nozzle
Re-circulation
EGR
Starting aid
Coolant temperature
sensor
Starter
Operator's console
Stop switch
Key switch
OFF
Accelerator sensor
CAN
Engine
ON
START
TNV_DI_SM_A4.book 5 ページ 2007年12月6日 木曜日 午前9時23分