Geely Emgrand X7. Manual part — 25

2.2.3 System operating principle

2.2.3.1 Electronic Throttle Body (ETC) Operating Principle

油门踏板位置

传感器总成

发动机

控制模块

电子控制

节气门体总成

NL02-2014b

Electronic throttle body assembly must be used dedicatedly to the engine electronic control
module (ECM) with ETC system-driven feature hardware as the core control element. System
control software usually uses the computer algorithms mode, basing on the engine torque output
control. At the same time, due to the cancellation of the traditional mechanical throttle valve
control of mechanical pull cables, ETC is equipped with a acceleration pedal position sensor (APP)
with a resistive potentiometer device, in order to provide vehicle handling demand information
and other information for the driver to control the vehicle to the engine electronic control module
(ECM).

Electronic throttle body opening is determined by ECM according to the acceleration pedal control
input signals. With other engines and vehicles sensor input signals, ECM analyzes the driver's
intention in advance and calculates the needed engine output power and accordingly adjusts the
engine throttle opening and fuel supply (injection) amount. At the same time, the electronically
controlled throttle position sensor can detect the actual throttle opening and send the feedback to
ECM. ECM then, based on this feedback signal, adjusts the vehicle control parameters. This
control process ensures that the engine and vehicle work in the ideally controlled conditions. Due
to the rapid development of modern science and technology, High-Speed ECM can quickly
analyze the driver's intention and calculate the basic throttle opening parameter values, based on
the throttle pedal signal, the signal variation and signal change rate. At the same time, ECM
adjusts and optimizes the throttle opening parameter, based on various sensors input signal status,
so that the system further calculates the optimum throttle opening control parameters and
implements the actual throttle control. ECM sends the output control signal to the ETC motor
drive circuit to open the throttle according to the calculated opening parameter, based on the
revised throttle opening and pre-determined control strategy. Because of the high speed calculation,
the system enables smooth engine speed changes under transition engine operating conditions. The
whole control process only requires a few milliseconds, achieving excellent vehicle performance.

The application of automotive electronic technology makes it difficult to directly judge the
electronic drive control throttle valve body assembly diagnosis by conventional visual inspection
method. In the event of electronic controlled throttle body malfunction, the system needs to
provide a Jolt-limited function. It allows the driver to drive the vehicle to a repair station for
repair.

Accelerator position

sensor assembly

Engine control

module

Electric control throttle

body assembly

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Jolt-limited control has the following two kinds of control modes

1. Jolt-limited control with the system unable to control the engine power

ECM will limit the engine power output, and the system can not control the throttle opening and
closing. The throttle opening is automatically adjusted to the system pre-determined position.

ECM will shut down the engine ignition output. At this time, the ECM internal fault occurs and
the system can not control the engine torque output. The throttle body adjusts the opening to (zero
position) off status. The system will fully turn off the ignition control function.

2. Jolt-limited control with the system unable to monitor the driver's intention

ECM will limit the engine power output. At this point, the system loses the ability to determine
and monitor the driver's intention. In order to prevent damage to the engine, ECM will limit the
engine power output and lower engine power increment and velocity increment. When braking,
ECM will adjust the engine speed to idle speed and adjust the throttle opening to the system
pre-determined position.

ECM will force the engine working at idle running status. When the system loses the ability to
determine and monitor the driver's intention, ECM will force the engine working at idle running
status, and system will work at pre-determined position controlled the idle speed.

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2.2.3.2 ECM Controlled Fuel Supply System

1. Fuel Pump Control

When the ignition switch is turned on, the fuel pump will run for 2 s. At this moment, if ECM does
not detect the engine speed signal, fuel pump stops running. Once the engine rotates, ECM detects
the engine speed signal and then controls the fuel pump running. 0.6 s after the engine speed
signal is lost, or the anti-theft device requests to shut down the fuel pump, the fuel pump stops
running.

2. Start-up Fuel Injection Control

Pre-injection of starting fuel injection control can inject once during the normal starting procedure.
The pre-injection starts when the following conditions are satisfied:

Actuation of oil pump relay

–

Fuel pump running longer than the accumulation of pressure’s delay time.

–

The pre-injection has not yet occurred.

–

Once all the above conditions are met, the pre-injection will start in all cylinders at the same
time.

3. Fuel Injection Pulse Width Control

A. Air-Fuel

Ratio

The startup air-fuel ratio, the normal
startup air-fuel ratio, the air-fuel ratio
of clearing flooded-cylinder, the
air-fuel ratio when the engine is
running, the air-fuel ratio in cooling
state, the air-fuel ratio in the warm-up
state, the theoretical air-fuel ratio, the
power enriched air-fuel ratio, the
catalytic overheating protection
air-fuel ratio and the engine
overheating

Keep the air-fuel ratio.

B. Intake

Manifold

Absolute

Pressure

Intake manifold pressure is read
directly by the MAP sensor installed
on the intake manifold.

C. Volumetric

Efficiency

Volumetric efficiency is the ratio of
actual air flow into the cylinder to the
ideal air flow.

充气温度

歧管压力

喷嘴常数

空燃比

喷油脉宽

喷油量计算

空气流量

充气效率

自学习修正

过渡工况
燃油控制

充气温度

电压修正

减速断油

配气相位的

充气效率补偿

FE02-8038b

D. Valve Timing Volumetric Efficiency

The valve timing changes affect the engine's volumetric efficiency. The basic volumetric
efficiency form is set when the valve timing control system has not started to work and the
camshaft and the crankshaft are at the initial positions. After port timing control system starts to
operate, system carries out corresponding air charging efficiency compensation to ensure accurate
calculation of air inlet volume.

E. Self-Learning

Air fuel

ratio

Manifold

pressure

Inflation

temperature

Air

flow

Charging

efficiency

Self-learning

correction

Nozzle

constant

Injecting

pulse width

Voltage

correction

Charging efficiency

compensation of

valve timing

Decrease

fuel cut off

Fuel control of

transient operation

Inflation

temperature

Fuel charge

calculation

101

Self-learning does not amend the changes as the engine running time increases, or the engine and
vehicle manufacturing errors.

F. Close-loop Feedback Correction

Close-loop feedback correction controls the actual Air-Fuel ratio close to the theoretical Air-Fuel
ratio through the oxygen sensor feedback signals.

G. Transition Condition Fuel Control

System uses more complex algorithms to establish the fuel evaporation model to calculate
Air-Fuel mixing conditions, taking into account the engine coolant temperature, intake air
temperature and engine working condition and the best fuel injection amount. It greatly improves
fuel control under various transitional working conditions, including sudden
acceleration/deceleration and other working conditions.

H. Protective Fuel Cut-off Control

When any one of the following conditions is met, the system will stop fuel injection:

–

Cutting off when the engine speed is higher than 6,500 rpm and resume fuel supply when the
engine speed drops below 6,000 rpm.

–

When the system detects an ignition system malfunction, it stops the fuel supply.

– When the system voltage is more than 18V, the function of electric valve body will be

limited.

Mode (Forced idling mode)

I.

Basic Fuel Injection Constant

Whether the basic fuel injection constant indicates the relationship between engine displacement
and nozzle fuel flow rate.

J. Battery

Voltage

Amendment

When the battery voltage changes, the voltage will be amended to ensure the correct amount of
fuel injection.

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