1.static balancing of the rotating parts
(轉動部份的靜態平衡)
2.partial balancing of the reciprocating parts
(活塞運動部份的平衡)
3.dynamic balancing of the reciprocating parts
(轉動部份的動態平衡)
4.reducing bearing presure
(減低培林(軸承)(日文發音被ㄚ令故)的壓力)
^^^^^^^^
1.static balancing of the rotating parts
1.它的意思是指曲軸部份在不轉動的時候達到靜力平衡
也就是當你將曲軸拿起將其兩端的曲軸端放在架子上
時,你將其任意轉動至任意位置,它都會固定住,不會因
為重力的關係而轉動,在多缸車的設計時可以利用其他缸
的位置將其人工化(contrived)的平衡掉,但對於單缸車
而言因為其先天上的缺陷(inherent lack of crankshaft
static balance)所以此時設計上必須多了一個配重(
counterbalabce weight) 使其能夠達到此平衡,而其配
重必須均勻的放在曲軸之兩側否則會有couple出現,這將在
第三點時講到,而其配重重量須為一半得曲軸柄重量
(rotating mass of crankpin)..這個平
衡是最重要的,因為當你的重心並非在旋轉的軸線上時
它的離心力會是速度的平方倍,即當你的轉速為兩倍時
它所造成的離心力會為四倍,所以對於摩托車這一種低
扭力高馬力型引擎,因它於行走時必需要將轉速拉的很高
所以對於曲軸的平衡是相當重視的,如果這一項平衡沒做好
的話車子騎起來感覺不會很明顯,但是曲軸與曲軸箱之間的
軸承會很容易壞掉,造成機油外洩出去,普力(傳動箱)珠or電盤(速客達)
變速箱or電盤(擋車),另外一點當轉速拉太高時會造成曲軸變形
到時曲軸打到曲軸箱.就好玩了.
2.partial balancing of the reciprocating parts
2.這一個平衡就是將活塞上下的運動所造成的重心偏移利用配重
(counterbalance weight)將其平衡掉,但是利用配重並無法百
分之百的將其抵消掉因為直線運動並無法利用旋轉運動將其抵消掉
因為這兩個它是作用在不同的方式上(because a reciprocating
mass can never be completely balanced by a rotating mass
on the crankshaft owing to the resultant forces acting
along different path)而剩餘的部份將利用另一種機構將其平衡
這我稍後在po,而這一種配重設計在曲軸上時,且是為單缸車種時
它會造成過度的矯正對於靜力平衡,但是不夠的矯正對於活塞直線運動
the counterbalance weights added to the crankshafts of single and
in line twin-cylinder engines generally over correct for static balance
and under correct for reciprocating balance.
對於這一個棘手的問題,設計者(designer)採用了折衷的辦法:使配重
所產生的力量剛好為一半得活塞最大產生力量,所以直立缸的車較容易
產生垂直的震動如野狼,巡弋150,由於垂直的震動透過車架經由懸吊
傳到人身上,所以感覺較大,而水平設計的的引擎其震動會由車架吸收掉
較不易傳到人身上,故感覺較小,如jog系列,採取完全水平的設計,而dio
採垂直設計,所以騎乘時感覺騎jog較舒服,因人體感覺震動小,而騎dio較累
如果有機會可以做一個小實驗,將狀況一樣(最好是一樣好,如果是一樣爛
多多少少還是看得出來)的dio和jog立起中柱原地給它大灌油門你會發覺
jog會跳動的很嚴重,但dio卻會在原地維持小震動,因jog引擎震動被車架吸收
後會在中柱直接消耗掉,而不會傳到懸吊上,而dio會有一部份的震動被
懸吊吸收掉所以較不會在地板上跳動,看起來水平缸較好,但是它也有缺點
就是在氣態流體力學,液態流體力學,與空間利用上(維修方面) 氣態流體力學
就是指油氣部份,在吸入時如果其進氣口做在上方則其化油器最好做成
FZR的那一顆一樣吸氣直接由上而下吸入,在岐管部份直通而下,
會有較小得轉折角度,但是這樣其化油器的成本就較高,但是jog考慮成本
的因素其化油器仍然做水平的,所以岐管整整轉了90度,這對於引擎的
吸氣效率影響很大,但是如果吸氣口做於左右測那車子做出來又會使得左右兩
邊加的很寬使得車子成為怪物,而液態流體方面就是指機油,水平引擎較
容易吃機油,因汽缸與活塞環之間留有一定的間隙而水平缸因重力
的關係不易將卡在缸壁上的機油刮下,但是如果減小其間隙又容易縮缸
至於維修空間方面,有拆過jog的引擎和dio引擎的人我想就知道其中的道理
因為單缸車配置在車上都為前後水平,而前後水平在空間上的利用
就已經相當的浪費了,所以相關的零組件就必須設計的剛剛好擠的進去車子
所以目前的國產車都採取較折衷的方式前頃數度的汽缸設計,在搭配懸吊設計
使車體震動減小,至於多缸車方面,採取水平對臥的引擎又稱拳擊手引擎
boxer engine 其對於balancing of the reciprocating
的平衡會利用對向的汽缸將雙方的直線力量抵消掉,使引擎最平順,如摩托車
bmw車系.像汽車的impezra但是空間方面仍是其最大的問題,有看過civic的直四引擎室
和impezra的引擎室就會明顯感覺出其間擁擠與簡單的極大差異,
而另一種折衷的方式就是利用
v缸,將震動巧妙的利用其他缸將之予以抵消掉.
3.dynamic balancing of the reciprocating parts
There are three points. First, nitrous oxide is comprised of 2 parts
nitrogen and one part oxygen (36% oxygen by weight). When the nitrous
oxide is heated to approximately 572oF (on compression stroke), it
breaks down and release extra oxygen, However, it is not this oxygen
alone which creates additional power, but the ability of this oxygen
to burn more fuel. By burning more fuel, higher cylinder pressures are
created and this is where most of the additional power is realized.
Secondly, as pressurized nitrous oxide is injected into the intake
manifold, it changes from a liquid to a gas (boils). This boiling affect
reduces the temperature of the nitrous to a minus .127 Degrees F.
This "cooling affect" in turn significantly reduces intake charge
temperatures by approximately 60-75 Degrees F. This also helps create
additional power. A general rule of thumb: For every 10 Degrees F.
reduction in intake charge temperature, a 1% increase in power will
be realized. Example: A 350 HP engine with an intake temperature drop
of 70 Degrees F, would gain approximately 25 HP on the cooling affect
alone. The third point, the nitrogen that was also released during the
compression stroke performs an important role. Nitrogen acts to
"buff or dampen" the increased cylinder pressures leading to a
controlled combustion process.
Why Nitrous?
Nitrous oxide injection has become a very popular option for today's
performance enthusiast for several reasons:
1.Nitrous offers you more performance per dollar spent, than any other
performance modification.
2.Nitrous installations are relatively easy to accomplish.
3.Since Nitrous is used only when needed, it offers you the advantages
of complete driveability and normal gas mileage while not "on the button."
4.Systems available for virtually any power need from 25 HP to over 500
extra HP.
5.One of the few performance options available for today's computer
controlled, fuel injected engines.
6.Systems can easily be removed or transferred to another vehicle.
Why NOS?
Through years of involvement with all forms of high performance racing,
NOS has evolved into the world's largest manufacturer of performance
nitrous systems. NOS designs and engineers nitrous systems for virtually
anything with an internal combustion engine from stock to highly modified
cars, motorcycles, watercraft, aircraft and even snowmobiles. NOS has become
synonymous with quality high performance automotive products. Research and
development, engineering and technical support assure you of being part
of the winning NOS team.作者: luyun 时间: 2003-11-19 13:25
汽門的開閉時間
the principles of valve timing
basic considerations
so far in our understanding of the four-stroke principle, we have accepted
that the opening and closing of the inlet and exhaust valves is timed to
coincide exactly with the beginning and ending of the induction and exhaust
strokes. for a variable-speed motor vehicle engine such a tidy approach to
valve timing would result in very inefficient operation. in actual practice
a departure must therefore be made from the basic valve timing implied by the
four-stroke principle, this being early acknowledged by the French automotive
pioneer Fernand Forest who originally patented the idea of valve timing in
1906. let us now examine how this departure can be accounted for in relation
to the factors involved, which may be listed as follows:
1. inertia effects of the incoming and outgoing cylinder gases
2. elastic mature of the incoming and outgoing cylinder hases
3. mechanical stresses imposed by rapidly opening and closing the valves.
in physics we learn that all bodies possess inertia. no matter whether we are
talking about a cannonball or a column of gas, and that the effect of inertia
is to resist a change of motion. the incoming and the outgoing flows of
cylinder gases are therefore subject to inertia effects. as a consequence
there is an unwelcome reluctance of the gases to commence flowing, followed by
a welcome reluctance of them to cease flowing.
also in physics we discover that the volume of a gas, unlike a liquid, is
not fixed and that this property of great compressibility is possessed by all
gases. the elastic nature of any burnt cylinder gases remaining in the
combustion chamber at the end of the exhaust stroke can, therefore, be such
that they expand and impede the flow of incoming air and petrol mixture at the
beginning of the induction stroke.
in engineering we appreciate that when a material is acted upon by a force,
every particle in the material acts upon every other particle with which it is
in contact and sets up what is termed a state of stress. this imposes definite
limits as to the rapidity with which a valve can be opened and closed, before
breakdown of lubrication and overstressing of the contact surfaces of its cam
and tappet occurs. due allowance must therefore be made for the short time it
necessarily takes to open and close each valve during its open period.
how then can the basic valve timing of the fourstroke principle be modified
in practice to accommodate the various effects mentioned? it is done by
providing for the lead (advance time) and lag (delay time) of the inlet and
exhaust valve periods of opening, or valve events as the American industry
prefers to call them.
anti-lock break system
background to anti-lock braking
one of the most serious hazards of driving and a significant contributor
to the accident toll is the locking of wheels under heavy braking on slippery
surfaces. the consequent loss of braking efficiency will greatly increase the
braking distance and, coupled with this, will be loss of steering response if
the front wheels lock and even worse a loss of directional stability if the
rear wheels lock. furthermore, the veicle will exhibit an unwelcome
sensitivity to road surface irregularities and camber, so that even small
disturbing forces can cause it to slew sideways, making control even more
difficult. in other words, if a wheel is braked to the point of locking its
sideways grip is reduced to zero.
我稍後會提到 how to achieve the shortest emergency stopping distance, all
wheels need to be almost on the point of locking. this is because the rolling
friction(滾動摩擦) developed by a tyre that is still exerting a rotational
grip against the road surface is always greater than the locked wheel friction
developed by a tyre that is simply sliding over the road surface, especially
when this is wet and slippery. experienced drivers have long recognized that
emergency stopping under these conditions is best accomplished by what is
known as cadence braking, the efficacy of which can readily be verified on a
skid pan.this technique involves rapid pumping of the brake pedal, so that
steering control is retained with each momentary release of the breaks, whilst
stopping distance is being shortened as much as possible.
anti-lock braking systems seek automatically to reproduce a similar cycle of
events by means of wheel speed sensors. these detect the point at which a
wheel is about to lock and signal the intention to a control mechanism , which
momentarily either holds constant or actually reduces the braking force to the
wheel concerned, the off-on braking cycle being repeated as long as the wheel
is about to lock. ideally then, an anti-lock braking system should be even
more swiftly acting than an experienced driver ,
not only in minimizing straight-line stopping distances on slippery surfaces,
but also and more importantly in allowing the driver to avoid obstacles by
retaining steering control where otherwise this would be lost with locked
wheels.
it is perhaps of interest to recall that the basic idea of what was then
called an anti-skid control was first employed for railway braking systems by
the Westing-house Air Brake Company in America, but it was in the further
development of this idea and its application to the disc brakes of aircraft
that this same company found the widest demands in the
early 1950's similar anti-
skid controls, such as the Dunlop Maxaret, were also being developed for the
aircraft industry. so it was as a result of the experiemce gained in this
field that the possibility of adapting the Maxaret system for use on motor
vehicles was investigated by the Dunlop company and an installation tested by
the Road Research Laboratory. at this juncture it must be appreciated that
the objectives sought in applying the wheel anti-lock principle to aircraft
and motor vehicle braking systems were somewhat different. with an aircraft
the objectives are to prevent at least expensive tyre damage and at worst a
potentially dangerous tyre burst, by avoiding wheel locking however briefly
it may occur during maximum braking through the landing run. in comparison
with an aircraft tyre, the tyre of a motor vehicle is relatively lightly
loaded and any damage caused to it by wheel locking is far less significant,
but what is really important is any loss of directional control or stability
as already mentioned.
early thinking on anti-lock brake systems for motor vehicles was therefore
directed not only towards passenger car applications, but also for commercial
vehicles with the jack-knifing problem on articulated ones especially in mind.
although the Dunlop Maxaret anti-lock principle was eventually adapted to the
braking system of the specialist Jensen FF four-wheel-drive car in 1966, it
was not until the advent of electronic control systems and electromagnetically
sensed wheel speed, beginning with the introfuction of the Anti Blockier
system (ABS) in 1978 by Robert Bosch working in conjuction with Mercedes-Benz
, that the development of anti-lock braking systems started in earnest and has
led to their to their increasing adoption.
finally, it should be mentioned that not all authorities agree with the
designation 'anti-lock brake system'. the american society of automotive
engineers prefers the term ' wheel slip control system', defining this as ' a
system which automatically controls rotational wheel slip during braking'.作者: luyun 时间: 2003-11-19 13:27
Black-Box
Little Black Boxes, Part One
24 APR 00 - by Matt Carter -- special to MotoGP
Data logging has been a fixture in 500 GP racing for some time, but what do
these electronic black boxes really do, how do they work, and how are they
used? Well, just to set the record straight, 'black boxes'are not always black!
2D Data-Recording equipment is a nice shade of red and Motec boxes are
gold-colored. OK, this is not vital information, so let look at some more
useful stuff, starting with a loose definition.
Data logging is the process of measuring and storing the current state of a GP
motorcycle while it is in operation on the racetrack. This allows the team to
better understand and interpret what the bike is doing, and how that
corresponds with the rider's input and feedback. Data logging quantifies
aspects of bike performance that were previously qualitative. Feel gives way
to fact.
Logging Hardware
At its simplest, a logging system consists of a number of sensors that sample
at a certain frequency and resolution, the consequent data stored for later
retrieval in the pits. Telemetry, or live transmission from the bike to the
pits, is outlawed in GP racing (FIM rule 01.18).
The complexity of data logging systems has increased over recent years. Dirk
Debus from 2D Data-recording gave MotoGP an inside look at its logging system.
The 2D company provides what is possibly the most advanced logging system in
the GP paddock today. This sophistication is demonstrated by the popularity of
the 2D system, and around half the teams in the paddock employ 2D, including
the factory 500 Yamaha and Suzuki teams, as well as most of the privateer
teams.
The 2D system can have up to 64 channels of raw data with sample frequencies
up to 800Hz, at resolutions of 12 bits or more. These raw signals can be
combined, differentiated, and integrated to provide up to 100 channels of data
The entire sensor suite, loggers, and on-bike displays communicate using an
industrial networking protocol (not unlike a conventional office PC network)
that allows very good integration with other bike electronics. This networking
allows the sensors to communicate and share data not only with the logging
controller, but also other sensors, displays, and on-bike electronic systems
such as the engine management electronics.
Data logging has been a fixture in 500 GP racing for some time, but what do
these electronic black boxes really do, how do they work, and how are they
used? Well, just to set the record straight, 'black boxes'are not always
black! 2D Data-Recording equipment is a nice shade of red and Motec boxes are
gold-colored. OK, this is not vital information, so let look at some more
useful stuff, starting with a loose definition.
Data logging is the process of measuring and storing the current state of a GP
motorcycle while it is in operation on the racetrack. This allows the team to
better understand and interpret what the bike is doing, and how that
corresponds with the rider's input and feedback. Data logging quantifies
aspects of bike performance that were previously qualitative. Feel gives way
to fact.
Sensors
An amazing variety of data is measured on a GP bike from a large variety of
sensors. To ensure reliability of logged data, multiple sensors of different
types are used to measure one related aspect of the GP bike. This ensures
meaningful data if one sensor malfunctions. When youe racing at this level,
the importance of accurate, repeatable measurement of data becomes as
significant as the data itself.
As well has taking information directly from the bike engine management
system, every cylinder will have at least four or five sensors on it, such as
cylinder temperature, cylinder pressure, detonation sensor, power valve
position, exhaust temperature, and more. This range of sensors allows many
different engine parameters to be measured.
For example, cylinder pressure is a direct measure of the power an engine will
produce. By tracking changes in cylinder pressure with any changes made to
the engine, such as porting or exhaust chamber changes, real improvements in
engine performance can be easily detected. Engine sensing is so accurate and
useful that jetting changes are no longer made by tables or rider feel, but
entirely by examining logged engine data.
The chassis is measured very extensively. The obvious measurements, such as
suspension travel and wheel speeds are made, but much more is measured. The
chassis and swingarm have strain gauges to measure chassis flex and vibration.
Throttle position, brake fluid pressure, gear selection, and many other
rider control inputs are measured as well, even including pressure applied to
footpegs!
The rear tire temperature is measured by at least one external infrared sensor
, as well as an internal thermistor. Accelerometers measure all three axis
and a gyroscope allows lean angle to be measured. The combination of these
sensors allows the track to be automatically mapped as the bike travels around
the circuit.
Logging Software
Once the bike is in the pits, the data is downloaded into a database for later
retrieval and analysis using the GUI or front-end of the logging system.
As well as storing the recorded data of the bike on the track, the database
stores the settings and relevant information about the bike when that data was
recorded. Over time, the database builds in size, enabling better
decision-making by the team since bike settings and solutions to previous
problems can be readily recalled.
For example, the 500cc Yamaha teams all have access to the same database of
logged data, accumulated from every race and test since 1994. The data is
available online at every race meeting and totals over 100GB, or the contents
of over 140 CD-ROMS of data. In comparison, the Encyclopedia Britannica CD-ROM
has only three CDs! This helps explain the mountainous challenge every newcomer
to GP faces as they attempt to sort out a new bike while racing against teams
with six years of data.
However, data by itself is useless, as it is simply binary numbers. The GUI
graphically presents this data, using charts, graphs, data overlays,
animations, virtual displays, and more. In addition, the GUI should be able to
make simple analysis (post-processing) of the data to provide useful
comparative statistics such as percentage of time on throttle and on brakes,
or time in each gear, max and minimum speeds, a lap-to-lap comparison, and so
on.The better the graphical display and processing of data, the better the team
decisions.
What's It For?
Data logging is no magical solution to race-bike setup, it is simply a tool,
albeit a flexible and powerful tool, that is used in all facets of GP setup and
testing.
The fundamental advantage of data logging is that it allows accurate,
quantitative feedback. Whilst rider feedback is vital -- after all, they have
to ride these high horsepower machines at brain-shriveling speeds and so need
to feel very comfortable with the bike -- it is qualitative: the rider
interprets what the bike is doing and then explains this to the team. The team
must then interpret what the rider is saying and figure out what the bike is
doing.
This can be complicated by the fact that the GP paddock is full of different
languages and simple and subtle meanings can often be misunderstood. This can
be a huge barrier for riders and teams to overcome. Data logging bypasses this
problem and gives engineers and technicians immediate numerical data in a
universal language. At the very least, data logging allows what the rider is
saying to be better understood.
A rider has a fixed number of sense inputs used to decide what part of the
motorcycle is behaving in a particular way. For example, if the rider feels
the front is diving excessively under braking, is it really the front diving
or is it the back rising too fast? This is difficult for the rider to sense,
especially as they have to think logically and rationally about what the bike
is doing while they are riding at 100 percent physical effort. And if they lose
concentration, just for a moment, very bad things can happen.
