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SERVICE DEPARTMENT0111-IT-180 Printed in Japan

QAANC-03

SERVICE BULLETINFUEL INJECTION PUMP

NEW PRODUCTSECD 01-06

November, 2001

DENSO AUTHORIZED ECD SERVICE DEALER ONLY

SUBJECT: New ECD-V4 Type Pumps

1. IntroductionA new ECD-V4 type pump has been introduced for direct-injection engines. Compared to the con-ventional type, the most characteristic feature of this pump is the addition of the pre-stroke control.This control improves the drivability of the vehicle by improving the low-speed torque during start-offs.

Pump Type Part Number Customer Vehicle Model Engine Type Destination

ECD-V4 098000-033# TOYOTA LAND CRUISER 100 1HD-FTE Europe

QC0826

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2. Pre-stroke ControlWith respect to the injection pumps in which the op-erating pressure increases year by year, the conven-tional ECD-V4 type has also been meeting theperformance levels required by the engines, includ-ing high power, high torque, and low exhaust emis-sions. The pre-stroke control has recently beenadded in an effort to improve the operation perfor-mance of the vehicle at low speeds.Specifically, the SPV actuating current from the EDUis varied at low speeds, which effectively varies thepressure and regulates the injection volume.

QC0827

Actuationpulse

Actuationcurrent

Solenoid valve

Highpressure

Spill

ECU EDU

SPV

Suction

QC0828

Pump cam anglesignal

SPV

Cam

Injection pressure

Injection rate

Open

Closed

with pre-stroke

without pre-strokeInjection volume controlled by SPV open duration

Pre-stroke volume

0 1 2 3 4 5 6 7 8 9 A B 0 1 2

Pre-stroke volume controlled by SPV closed duration

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Reference:To address the needs for lowering the pressure in the idle-speed range and raising the pressurein the low-speed, high-load range, the pressure control achieved with the pre-stroke control effec-tively enhances the drivability of the vehicle in the low-speed range.

QC0829

Exhaust mode range Reduced emissions through high pressure

Low-speed, high-load range Increased torque through high pressure

High-speed, high-load range Increased power through high pressure

Low-speed rangeEngine speed

Inje

ctio

n vo

lum

e

Vehicle start-off

Idle-speed range Reduced noise through low pressure