BS 5th semester – EXERCISE – Fuel injection & Efficient combustion
DEVELOPMENT OF NEW TECHNOLOGIES FOR FULFILLING IMO REQUIREMENTS
IMO requirements and other regulations on the reduction of exhaust emissions (ispušne emisije) and
environment protection are becoming increasingly tighter (stroži) and the allowed limits are getting lower.
IMO societies have laid down guidelines (odredila smjernice) for future limits on emission contents
(ispušnih komponenti), taking into consideration different applications and exploitation conditions of
marine engines. The trend is to completely eliminate pollutants. The world's leading engine manufacturers
have developed technologies able to meet (zadovoljiti) the new requirements and regulations. Increasing
the number of injectors, ACERT and slide-valve technologies, together with application of water-in-fuel
emulsion (emulzija goriva s vodom), selective catalytic reduction (SCR - selektivna katalička redukcija),
and biodiesel fuels represent comprehensive and efficient solutions. Some of them are presented here.
ACERT® technology.
Caterpillar has developed the ACERT technology
(Advance Combustion Emission Reduction Technology)
that involves fuel delivery, electronics, air management
(razvod zraka), and combustion management. One of
the key breakthroughs (iskorak / proboj) in ACERT
technology has been the development of fuel delivery
into the combustion chamber through multiple injections
(višestruko ubrizgavanje). The multiple-injection process
introduces fuel into the combustion chamber in a number
of precisely-controlled microbursts (mikro ubrizgavanja).
Injecting fuel in this way allows for precise shaping of the combustion cycle. A controller (an electronic
unit) directs the injector system to deliver precise quantities of fuel at exactly the right time during
combustion. In addition to enhanced combustion and fuel saving, the ACERT technology enables
optimum performance, i.e. maximum output and efficiency with minimum emissions at a wide range of
load and engine rating (širokom rasponu brzina vrtnje). It is one of the best and most comprehensive
technologies aimed at reducing harmful emissions of air pollutants from vessels, and it represents one of
the solutions to the existing and future IMO regulations on exhaust emissions.
MAN B&W slide valve (injector).
In order to reduce harmful emissions from their slow-speed engines, MAN B&W has launched a new slidetype valve for fuel injection. This valve type has minimised the risk of subsequent penetration (naknadni
prodor) of fuel into the combustion chamber after the fuel injection. This directly results in reduction of
emissions of carbon monoxide (CO) (ugljičnog monoksida) and volatile organic compounds (VOC) (štetnih
organskih komponenti) as, in the engines featuring this type of valve, there is no incomplete combustion.
In addition to the development of slide-type fuel valves, MAN B&W has also optimised the nozzle for
achieving lower NOx emissions (emisija dušičnih oksida). Compared to conventional fuel valves and
nozzles, in this way a 25% NOx reduction at 90% engine load has been achieved, with an increase in fuel
consumption of only 1%. Likewise (također / isto tako), these engines have a reduced smoke emission.
Slide valves fitted to MAN marine
engines ensure optimised combustion
and
cleaner
engines.
Enhanced
combustion decreases the amount of
non-burnt hydrocarbons (around 30%)
and particulate matter (PM) (krute
čestice), which results in less smoke.
Furthermore (nadalje), the piston top
ends suffer less load and wear, resulting
in minimum wear of the exhaust valve
seats. Most importantly, the slide valve,
i.e. the fuel valve nozzle, entirely
complies with the IMO requirements on
NOx emissions reduction.
Modified fuel injectors (courtesy of MAN B&W)
EXERCISES
1. Use the following words to complete the text: associated, costs, decrease, however, research,
therefore
Change in number of injectors.
There has been some _______________ into increasing the number of injectors per cylinder.
Increasing the number of injectors enables the combustion process to be better controlled and
_______________ more efficient combustion. It has been reported that a _______________ in
NOx from 30% is achievable, _______________ there is a considerable cost associated with the
need to have additional injectors, piping and _______________ equipment. As well as additional
equipment, a significant increase in maintenance _______________ can be expected.
2. Answer the following questions:
a) Name some of the world's famous engine makers.
b) Name some technologies and applications aimed at reducing harmful emissions from vessels.
c) What harmful components do the exhaust emissions contain?
d) What is the major drawback (mana / loša strana) of increasing the number of injectors for
achieving efficient combustion?
e) What does ACERT stand for?
f) How is enhanced combustion achieved by ACERT technology?
g) How is incomplete combustion prevented in new MAN engines?
h) Besides efficient combustion and meeting IMO requirements, name some other advantages
of these new technologies.
3. Translate into English.
a) Proizvođači motora prisiljeni su razvijati nove tehnologije, za zadovoljavanje IMO propisa.
b) MAN B&W je uveo klizne ubrizgače kao standardnu opremu (standard feature) svakog novog motora.
c) Da bi se postigli bolji rezultati u smanjenju ispušnih emisija (exhaust emissions reduction), MAN
razvijaja i sekundarne metode kao što su primjena emulzije goriva s vodom (water-in-fuel emulsion) i
selektivna katalička redukcija.
d) Standardni motor dozvoljava emulziju goriva s 20% vode pri punom opterećenju.
e) SCR je trenutno najefikasnija metoda za smanjivanje emisije NOx-a, a smanjenje iznosi 85%-95%.
f) Urea, reducirajuće sredstvo (means of reduction), se ubrizgava u ispušne plinove pri temperaturi od
290-450°C.
g) Prije ulaska u Područje kontroliranih emisija (Emission Control Area), količina goriva u svakom tanku,
kao i (as well as) datum, vrijeme i pozicija broda moraju se unijeti (be recorded) u Knjigu o uljima (Oil
Record Book) i brodski dnevnik.
h) Optimalno izgaranje rezultira smanjenjem emisija ugljičnog monoksida (CO), štetnih organskih
komponenti (VOC), dušičnih oksida (NOx), neizgorenih ugljikovodika (non-burnt hydrocarbons) i krutih
čestica (PM).
i) Kod teških dizelskih goriva, moguća je čista emulzija vode i goriva, dok je kod benzina moguća samo uz
primjenu emulgatora (emulsifier) kao što su biljni proteini (plant proteins).
j) U brodskim dizel motorima, biodizel (biodiesel) se može upotrebljevati u različitim postocima uz (with)
nekoliko manjih preinaka (minor conversions) na motoru.
2