UNIT3
FUEL INJECTION SYSTEMS
TEXT B
Functions of the Motronic Systems
PROFESSIONAL ENGLISH
UNIT 3
FUEL INJECTION SYSTEMS
TEXT B
Functions of the Motronic Systems
Ignition Timing Control
Control Unit
Dwell-Angle Control
Idle Speed Control
本次课学习内容本次课学习目标
掌握 Motronic系统的主要功能及其作用原理
掌握常用术语
了解相关术语
提高翻译能力
NEW WORDS
coordinate [kou'?:dineit] v.调整，整理
model ['m?dl] n.模型，典型，圆形，车型； v.模拟
troubleshoot ['tr?bl∫u:t] v,排除故障
condenser [k?n'dens?] n.冷凝器，电容器
patch [p?t∫] v.修补，补缀
interpolate [in't?:pouleit] v.窜改
fall-off [f?:l-?f] n.衰退，减少，逐渐下降
conserve [k?n's?:v] v.保存，保藏，守恒
dwell time 闭合时间，初级电路接通时间
short of 缺乏，缺少，不够 … （标准）
at the moment of 在 … 一刻，当 … 时
idle-speed control 怠速控制
be derived from 由 … 得来，来源于
all the while 一直，始终
lambda closed-loop control λ闭环控制
idle-speed stabilizer 怠速稳定器
PHRASES AND EXPRESSIONS
Functions of the Motronic Systems
In simple terms,Motronic is an engine-management system
with a single control unit for control of ignition timing as well as
fuel-injection,Many of the sensors important for fuel injection
are also needed for ignition-system control,so the integration
of the two systems can accomplish many things:
· Integrated control of fuel injection and ignition can manage
the engine better than control of either one alone,That is,
timing is sometimes dependent on the air-fuel ratio,and vice
versa; also,emissions can be reduced by coordinated control.
· Engine control can be based on actual needs of each
engine model based on large amounts of engine-test data
during different operating conditions stored in the Motronic
Read Only Memory (ROM)[1]
[1] 根据 Motronic系统的只读存储器（ ROM）中所存储的大量试验数据，就能够按照每个发动机机型的实际需要，对发动机进行控制。 Motronic系统的只读存储器（ ROM）中所存储的这些试验数据是在发动机不同工况期间通过试验而得到的。
· Many additional operating functions can be provided,
Important from the standpoint of service are the adaptive
functions,and the self-diagnostics for troubleshooting
· Motronic advantages are better driveability and fuel
efficiency,and reduced emissions,More specific benefits,
a,fuel savings achieved from best combination of
mixture and timing
b,dependable starting,cold or hot
c,stable idling at reduced rpm
e,relative freedom from maintenance
f,good torque characteristics,allowing longer gear ratios
Ignition Timing Control
I'm talking here about more than electronic ignition-the systems
that have replaced the points and condensers of yesterday,I'm
talking about microcomputer control of ignition advance angle for
every plug firing,or at most,every two plug firings,The millisecond
response time of electronic ignition advance control is far faster
than the traditional mechanical flyweight/vacuum advance systems.
In a mechanical system (and that includes electronic ignition),as
rpm increases,centrifugal weights advance timing,Changing load
(manifold pressure) can further change timing advance with a
vacuum diaphragm,As rpm increases,there is less dwell time for
the coil to charge when perhaps the engine needs more spark
energy.
Traditional curves for distributor timing show the limited control
of timing advance possible,A timing point that is proper for one
combination of rpm and load is probably wrong for other
combinations of centrifugal weight position and vacuum diaphragm
action,Once the vacuum control or the centrifugal weights reach
their limits,advance control is fixed,
Mechanical timing has been patched with more vacuum hoses,
temperature and delay valves,and other servicing headaches;
it's still a compromise,Even at its best,this control fails far short
of the precise and rapid timing needed by today's cars.
In Motronic systems,however,the control unit processes a
number of inputs,and then adjusts timing for all conditions
based on its internal data map.
Timing Data "Maps"
To determine precise timing-advance requirements,each
family of engines is tested to learn the best timing for each
condition of speed,load,and other variables in heat and cold,
on the dynamometer and in the mountains,The goal is to find
the timing for best power,for best economy,all the while
meeting emission limits.
Fig,3-3 Ignition advance map shows electronic timing control
according to engine load and speed,The maps are symbolic
of thousands of data points stored in control unit memory.
The result of these tests is a series of data "maps",as
shown in Fig,3-3,Literally thousands of data points from these
tests are stored in the computer memory of the Motronic
control unit ROM (Read Only Memory) for readout during
engine operation,As you may know,a ROM cannot be
changed,For any combination of engine load and rpm,the
control unit can supply the best ignition timing,For example,
for an rpm-input signal of 2000 rpm,at a load signaled by the
air-flow sensor,the computer would look up the timing
advance angle,let's say it should be 22 degrees BTDC.
But control is even more precise,Suppose the rpm were
2050,and the memory contained only data points for 2000 and
2100; then the computer would look up both 2000=22 degrees
BTDC,and 2100=24 degrees BTDC,and interpolate,It would
calculate an advance for the 50 rpm difference between 2000
and 2050,and would output timing of 23 degrees BTDC.
In the control unit,timing is computed so fast that Motronic can
adjust timing for every firing of each spark plug!
Distributor
Because it does not control timing or signal rpm,the
Motronic distributor's only job is to distribute the secondary,that
is,to send the control-unit-timed spark to the proper cylinder.
While timing and dwell were formerly dependent on each
other,Motronic memory provides separate dwell-angle data,
based on battery voltage and rpm,Later,we'll see how timing
and dwell control improve starting and other variations,but
here are the principles.
Dwell-Angle Control
As engine rpm increases on mechanical advance systems,
there is less dwell time for the coil to charge between firings,
resulting in a fall-off of coil voltage,In Motronic systems,dwell
angle is electronically controlled so the coil receives the proper
current at the time of plug firing,The more battery voltage,the
less dwell angle needed,On the other hand,as rpm increases,
more dwell angle is needed for the time to charge the coil,
Fig,3-4 Dwell angle is controlled for battery voltage and
engine speed,according to memory map in control unit.
By controlling dwell angle,the coil is charged properly for each
ignition firing,no more,no less,The objective is to provide the
required secondary power at the plug at the moment of firing
with minimum losses in the ignition output transistor and the coil.
To reach the nominal value of primary current at the moment
of firing,the dwell angle is changed according to the battery
voltage as shown in Fig.3-4,When battery voltage is less,dwell
time is increased,In effect,the dwell control answers the
question,"When should the primary circuit be closed for the
optimum time for the coil primary current to rise to proper value
at moment of opening primary circuit?" In addition,the control
unit output stage limits current so that if,due to rapid engine
speed changes as in acceleration,current reaches the nominal
value before the ignition point,current is held constant.
So engine rpm and battery voltage are inputs to the control
unit,From dwell-angle data in the ROM,control unit output is the
dwell,or charge-time control,that conserves energy and
prevents overheating the coil,Also,if the rpm signal indicates
less than 30 rpm,as when the engine stops or the key is left on
with the engine stopped,primary cut-off prevents coil overheating,
Now that you understand the basics of Motronic ignition control.
Control Unit
Motronic systems make extensive use of other data maps
stored in ROM for many of the control unit functions,including:
·fuel injection
·lambda closed-loop control
·warm-up
·acceleration
·ignition timing
·dwell angle
·EGR
·idle-speed control
Lambda memory map
The main map in the control unit is a set of lambda memory-
points used to determine the desired air-fuel ratio for the fuel
injection pulses,The lambda memory map,shown in Fig.3-5,is
derived from lab and road tests,and modified for the
requirements of the vehicle and the country where it will operate:
·at part load,maximum economy and minimum emissions
·at wide-open throttle,maximum torque while avoiding
knocking
·at idle,maximum smoothness
·during throttle opening,maximum driveability
Air quantity and the requirements for control of injected fuel
can vary due to many factors such as manifold-pressure
variations resulting from individual piston pumping,and intake-
valve opening/closing [2],Idling manifold absolute pressure can
vary by 5 kPa from an average 42,over more than 10% plus or
minus [3],For this and other variations,the lambda map insures
the best possible adjustment of the air-fuel ratio as corrected by
inputs that control fuel injection,and without affecting other
operating points,Air flow and rpm set up basic pulse time,
[2] due to 意思为,归因于 …”,,由于 … 所引起,。 Pumping与 opening/closing并列，
均为动名词。本句可译为：各个活塞的泵吸作用以及进气门的开、闭动作引起了进气歧管的压力波动，像这种压力波动之类的诸多因素都将导致空气量和喷油量的控制要求发生变化。
·at part load,maximum economy and minimum emissions
·at wide-open throttle,maximum torque while avoiding
knocking
·at idle,maximum smoothness
·during throttle opening,maximum driveability
Air quantity and the requirements for control of injected fuel
can vary due to many factors such as manifold-pressure
variations resulting from individual piston pumping,and intake-
valve opening/closing [2],Idling manifold absolute pressure can
vary by 5 kPa from an average 42,over more than 10% plus or
minus [3],For this and other variations,the lambda map insures
the best possible adjustment of the air-fuel ratio as corrected by
inputs that control fuel injection,and without affecting other
operating points,Air flow and rpm set up basic pulse time,
[3]当句子中有表示增减意义的动词或分词出现时,by后面的数值表示净增减的数。介词 from此处表示,距离,,,离开,,,间隔,之意。所以句中 vary by 5 kPa from
an average 42意思为,偏离平均值 42kPa的变动量达 5kPa”。本句可译为：怠速时的进气歧管压力会偏离平均值 42kPa，变动量达 5kPa，即上、下变动 10%以上。
Fig,3-5 Lambda "map" establishes lambda,or
air-fuel ratio for each load/speed point
Sequential Fuel Injection
Sequential injection means delivering fuel separately from
each injector in sequence— in firing order,With an increase
in computing power,and an increased demand for idle
smoothness and reduced emissions,Bosch Motronic ML.3
can provide sequential injection,Each injector is timed to cut
off just before the intake valve opens,During acceleration,
the ECU can deliver additional enriching pulses,cylinder by
cylinder for the rapidly changing conditions.
In spite of its increased cost,you'll see more pulsed
Motronic sequential injection because:
·each individual injector pulse can be much longer than
simultaneous injection,as long as 720° crankshaft rotation
·less intake valve opening,permitting lower idle speeds
·less variation between cylinders in air-fuel ratio for
smoother idle and reduced emissions
·injector fuel-rail pressure is more constant because only
one injector opens at a time,meaning smoother operation
·improved acceleration enrichment because it can be
applied to the "next cylinder"
·soft rpm limitation by reducing fuel flow cylinder by
cylinder
Some people think "sequential" means injecting the fuel
just as the intake valve opens,but it is not that simple,
Depending on the engine,the injection may be timed
before the valve opens,It is all based on the desired
stratification in the manifold,swirl effects in the cylinder,
emissions,and other considerations.
Idle Speed Control
Most Motronics control idle rpm by a combination of the
idle-speed stabilizer and ignition timing,Inputs include rpm,
closed-throttle signal,and engine temperature,The control
unit sends on-off,or digital signals to the idle-speed
stabilizer,Early Motronics use the auxiliary air vane to
increase air flow during warm-up,In these,cold-engine idle
rpm is increased according to temperature; it is an open-
loop system.
Ignition Timing
Even before the idle-stabilizer acts on air flow,Motronic
idle rpm is first stabilized by changing ignition timing,If idle
rpm falls,the control unit advances ignition timing to
increase rpm,On the other hand,if rpm rises,it retards
timing to cut back rpm,Ignition timing handles small rpm
changes,handles them in milliseconds,The idle-speed
stabilizer handles larger changes and takes a bit longer.
小结
Ignition Timing Control
Control Unit
Dwell-Angle Control
Idle Speed Control
作业
熟记相关专业词汇
P67 EXERCIES Ⅰ & Ⅱ
FUEL INJECTION SYSTEMS
TEXT B
Functions of the Motronic Systems
PROFESSIONAL ENGLISH
UNIT 3
FUEL INJECTION SYSTEMS
TEXT B
Functions of the Motronic Systems
Ignition Timing Control
Control Unit
Dwell-Angle Control
Idle Speed Control
本次课学习内容本次课学习目标
掌握 Motronic系统的主要功能及其作用原理
掌握常用术语
了解相关术语
提高翻译能力
NEW WORDS
coordinate [kou'?:dineit] v.调整，整理
model ['m?dl] n.模型，典型，圆形，车型； v.模拟
troubleshoot ['tr?bl∫u:t] v,排除故障
condenser [k?n'dens?] n.冷凝器，电容器
patch [p?t∫] v.修补，补缀
interpolate [in't?:pouleit] v.窜改
fall-off [f?:l-?f] n.衰退，减少，逐渐下降
conserve [k?n's?:v] v.保存，保藏，守恒
dwell time 闭合时间，初级电路接通时间
short of 缺乏，缺少，不够 … （标准）
at the moment of 在 … 一刻，当 … 时
idle-speed control 怠速控制
be derived from 由 … 得来，来源于
all the while 一直，始终
lambda closed-loop control λ闭环控制
idle-speed stabilizer 怠速稳定器
PHRASES AND EXPRESSIONS
Functions of the Motronic Systems
In simple terms,Motronic is an engine-management system
with a single control unit for control of ignition timing as well as
fuel-injection,Many of the sensors important for fuel injection
are also needed for ignition-system control,so the integration
of the two systems can accomplish many things:
· Integrated control of fuel injection and ignition can manage
the engine better than control of either one alone,That is,
timing is sometimes dependent on the air-fuel ratio,and vice
versa; also,emissions can be reduced by coordinated control.
· Engine control can be based on actual needs of each
engine model based on large amounts of engine-test data
during different operating conditions stored in the Motronic
Read Only Memory (ROM)[1]
[1] 根据 Motronic系统的只读存储器（ ROM）中所存储的大量试验数据，就能够按照每个发动机机型的实际需要，对发动机进行控制。 Motronic系统的只读存储器（ ROM）中所存储的这些试验数据是在发动机不同工况期间通过试验而得到的。
· Many additional operating functions can be provided,
Important from the standpoint of service are the adaptive
functions,and the self-diagnostics for troubleshooting
· Motronic advantages are better driveability and fuel
efficiency,and reduced emissions,More specific benefits,
a,fuel savings achieved from best combination of
mixture and timing
b,dependable starting,cold or hot
c,stable idling at reduced rpm
e,relative freedom from maintenance
f,good torque characteristics,allowing longer gear ratios
Ignition Timing Control
I'm talking here about more than electronic ignition-the systems
that have replaced the points and condensers of yesterday,I'm
talking about microcomputer control of ignition advance angle for
every plug firing,or at most,every two plug firings,The millisecond
response time of electronic ignition advance control is far faster
than the traditional mechanical flyweight/vacuum advance systems.
In a mechanical system (and that includes electronic ignition),as
rpm increases,centrifugal weights advance timing,Changing load
(manifold pressure) can further change timing advance with a
vacuum diaphragm,As rpm increases,there is less dwell time for
the coil to charge when perhaps the engine needs more spark
energy.
Traditional curves for distributor timing show the limited control
of timing advance possible,A timing point that is proper for one
combination of rpm and load is probably wrong for other
combinations of centrifugal weight position and vacuum diaphragm
action,Once the vacuum control or the centrifugal weights reach
their limits,advance control is fixed,
Mechanical timing has been patched with more vacuum hoses,
temperature and delay valves,and other servicing headaches;
it's still a compromise,Even at its best,this control fails far short
of the precise and rapid timing needed by today's cars.
In Motronic systems,however,the control unit processes a
number of inputs,and then adjusts timing for all conditions
based on its internal data map.
Timing Data "Maps"
To determine precise timing-advance requirements,each
family of engines is tested to learn the best timing for each
condition of speed,load,and other variables in heat and cold,
on the dynamometer and in the mountains,The goal is to find
the timing for best power,for best economy,all the while
meeting emission limits.
Fig,3-3 Ignition advance map shows electronic timing control
according to engine load and speed,The maps are symbolic
of thousands of data points stored in control unit memory.
The result of these tests is a series of data "maps",as
shown in Fig,3-3,Literally thousands of data points from these
tests are stored in the computer memory of the Motronic
control unit ROM (Read Only Memory) for readout during
engine operation,As you may know,a ROM cannot be
changed,For any combination of engine load and rpm,the
control unit can supply the best ignition timing,For example,
for an rpm-input signal of 2000 rpm,at a load signaled by the
air-flow sensor,the computer would look up the timing
advance angle,let's say it should be 22 degrees BTDC.
But control is even more precise,Suppose the rpm were
2050,and the memory contained only data points for 2000 and
2100; then the computer would look up both 2000=22 degrees
BTDC,and 2100=24 degrees BTDC,and interpolate,It would
calculate an advance for the 50 rpm difference between 2000
and 2050,and would output timing of 23 degrees BTDC.
In the control unit,timing is computed so fast that Motronic can
adjust timing for every firing of each spark plug!
Distributor
Because it does not control timing or signal rpm,the
Motronic distributor's only job is to distribute the secondary,that
is,to send the control-unit-timed spark to the proper cylinder.
While timing and dwell were formerly dependent on each
other,Motronic memory provides separate dwell-angle data,
based on battery voltage and rpm,Later,we'll see how timing
and dwell control improve starting and other variations,but
here are the principles.
Dwell-Angle Control
As engine rpm increases on mechanical advance systems,
there is less dwell time for the coil to charge between firings,
resulting in a fall-off of coil voltage,In Motronic systems,dwell
angle is electronically controlled so the coil receives the proper
current at the time of plug firing,The more battery voltage,the
less dwell angle needed,On the other hand,as rpm increases,
more dwell angle is needed for the time to charge the coil,
Fig,3-4 Dwell angle is controlled for battery voltage and
engine speed,according to memory map in control unit.
By controlling dwell angle,the coil is charged properly for each
ignition firing,no more,no less,The objective is to provide the
required secondary power at the plug at the moment of firing
with minimum losses in the ignition output transistor and the coil.
To reach the nominal value of primary current at the moment
of firing,the dwell angle is changed according to the battery
voltage as shown in Fig.3-4,When battery voltage is less,dwell
time is increased,In effect,the dwell control answers the
question,"When should the primary circuit be closed for the
optimum time for the coil primary current to rise to proper value
at moment of opening primary circuit?" In addition,the control
unit output stage limits current so that if,due to rapid engine
speed changes as in acceleration,current reaches the nominal
value before the ignition point,current is held constant.
So engine rpm and battery voltage are inputs to the control
unit,From dwell-angle data in the ROM,control unit output is the
dwell,or charge-time control,that conserves energy and
prevents overheating the coil,Also,if the rpm signal indicates
less than 30 rpm,as when the engine stops or the key is left on
with the engine stopped,primary cut-off prevents coil overheating,
Now that you understand the basics of Motronic ignition control.
Control Unit
Motronic systems make extensive use of other data maps
stored in ROM for many of the control unit functions,including:
·fuel injection
·lambda closed-loop control
·warm-up
·acceleration
·ignition timing
·dwell angle
·EGR
·idle-speed control
Lambda memory map
The main map in the control unit is a set of lambda memory-
points used to determine the desired air-fuel ratio for the fuel
injection pulses,The lambda memory map,shown in Fig.3-5,is
derived from lab and road tests,and modified for the
requirements of the vehicle and the country where it will operate:
·at part load,maximum economy and minimum emissions
·at wide-open throttle,maximum torque while avoiding
knocking
·at idle,maximum smoothness
·during throttle opening,maximum driveability
Air quantity and the requirements for control of injected fuel
can vary due to many factors such as manifold-pressure
variations resulting from individual piston pumping,and intake-
valve opening/closing [2],Idling manifold absolute pressure can
vary by 5 kPa from an average 42,over more than 10% plus or
minus [3],For this and other variations,the lambda map insures
the best possible adjustment of the air-fuel ratio as corrected by
inputs that control fuel injection,and without affecting other
operating points,Air flow and rpm set up basic pulse time,
[2] due to 意思为,归因于 …”,,由于 … 所引起,。 Pumping与 opening/closing并列，
均为动名词。本句可译为：各个活塞的泵吸作用以及进气门的开、闭动作引起了进气歧管的压力波动，像这种压力波动之类的诸多因素都将导致空气量和喷油量的控制要求发生变化。
·at part load,maximum economy and minimum emissions
·at wide-open throttle,maximum torque while avoiding
knocking
·at idle,maximum smoothness
·during throttle opening,maximum driveability
Air quantity and the requirements for control of injected fuel
can vary due to many factors such as manifold-pressure
variations resulting from individual piston pumping,and intake-
valve opening/closing [2],Idling manifold absolute pressure can
vary by 5 kPa from an average 42,over more than 10% plus or
minus [3],For this and other variations,the lambda map insures
the best possible adjustment of the air-fuel ratio as corrected by
inputs that control fuel injection,and without affecting other
operating points,Air flow and rpm set up basic pulse time,
[3]当句子中有表示增减意义的动词或分词出现时,by后面的数值表示净增减的数。介词 from此处表示,距离,,,离开,,,间隔,之意。所以句中 vary by 5 kPa from
an average 42意思为,偏离平均值 42kPa的变动量达 5kPa”。本句可译为：怠速时的进气歧管压力会偏离平均值 42kPa，变动量达 5kPa，即上、下变动 10%以上。
Fig,3-5 Lambda "map" establishes lambda,or
air-fuel ratio for each load/speed point
Sequential Fuel Injection
Sequential injection means delivering fuel separately from
each injector in sequence— in firing order,With an increase
in computing power,and an increased demand for idle
smoothness and reduced emissions,Bosch Motronic ML.3
can provide sequential injection,Each injector is timed to cut
off just before the intake valve opens,During acceleration,
the ECU can deliver additional enriching pulses,cylinder by
cylinder for the rapidly changing conditions.
In spite of its increased cost,you'll see more pulsed
Motronic sequential injection because:
·each individual injector pulse can be much longer than
simultaneous injection,as long as 720° crankshaft rotation
·less intake valve opening,permitting lower idle speeds
·less variation between cylinders in air-fuel ratio for
smoother idle and reduced emissions
·injector fuel-rail pressure is more constant because only
one injector opens at a time,meaning smoother operation
·improved acceleration enrichment because it can be
applied to the "next cylinder"
·soft rpm limitation by reducing fuel flow cylinder by
cylinder
Some people think "sequential" means injecting the fuel
just as the intake valve opens,but it is not that simple,
Depending on the engine,the injection may be timed
before the valve opens,It is all based on the desired
stratification in the manifold,swirl effects in the cylinder,
emissions,and other considerations.
Idle Speed Control
Most Motronics control idle rpm by a combination of the
idle-speed stabilizer and ignition timing,Inputs include rpm,
closed-throttle signal,and engine temperature,The control
unit sends on-off,or digital signals to the idle-speed
stabilizer,Early Motronics use the auxiliary air vane to
increase air flow during warm-up,In these,cold-engine idle
rpm is increased according to temperature; it is an open-
loop system.
Ignition Timing
Even before the idle-stabilizer acts on air flow,Motronic
idle rpm is first stabilized by changing ignition timing,If idle
rpm falls,the control unit advances ignition timing to
increase rpm,On the other hand,if rpm rises,it retards
timing to cut back rpm,Ignition timing handles small rpm
changes,handles them in milliseconds,The idle-speed
stabilizer handles larger changes and takes a bit longer.
小结
Ignition Timing Control
Control Unit
Dwell-Angle Control
Idle Speed Control
作业
熟记相关专业词汇
P67 EXERCIES Ⅰ & Ⅱ
