Fuel injectors deliver fuel directly into an engine's combustion chamber or intake port. They require precise nozzle design to properly atomize fuel for efficient mixing and combustion. Common nozzle types include single-hole, multi-hole, and pintle nozzles. Modern electronic fuel injection systems use either an electronic unit injector (EUI) or hydraulic electronic unit injector (HEUI) to precisely control fuel injection timing and quantity electronically for improved performance and emissions.

1. FUEL INJECTORS
A PRESENTATION BY
PUSHPAJEET
A2326215006

2. WHAT IS A FUEL
INJECTOR?
• Fuel injectors are electromechanical valves,
usually one per cylinder, situated so that they
deliver fuel either directly into the engine’s
combustion chamber (direct injection) or into
the intake plenum port (indirect port
injection).

4. REQUIREMENT?
• Atomization
• Distribution of fuel
• Prevention of impingement on walls
• Mixing

5. NOZZLES
• Nozzle is the part of an injector through which the liquid fuel
is sprayed into the combustion chamber.
DESIGNE OF NOZZLE
• The design of the nozzle must be such that the liquid fuel
forced through the nozzle will be broken up into fine droplets .
• It must spray fuel in such a manner as to minimize the
quantity of fuel reaching the surrounding walls.
• The non turbulent type of combustion chamber depends
almost entirely on both the nozzle design and injection
pressure .

6. TYPES OF NOZZLES
1. SINGLE HOLE NOZZLE
• This is simplest type of nozzle and is used in open combustion
chambers.
• It consists of a single hole bored centrally through the nozzle body
and closed by the needle valve . It’s size is usually larger than
0.2mm.
• It’s spray cone angle varies from 5 deg to 15 deg.
ADVANTAGES
• Simple in construction and operation.
DISADVANTAGES
• High injection pressure required
• Tendency to dribble
• Not good mixing due to narrow cone angle.

7. 2. MULTI HOLE NOZZLE
• Extensive use in open combustion chamber as fuel gets properly mixed
even there is slow movement of air .
• Number of holes varies from 4 to 18 , diameter lies between 0.25 to 0.35
mm and hole angle lies between 20 to 45 degree .
ADVANTAGES
• Good atomization
• Proper distribution of fuel .
DISADVANTAGES
• Holes are small and liable to clogging.
• Dribbling between injections.
• Very high injection pressure .
• Close tolerance in manufacture and costly.
3.PINTLE NOZZLE
• The stem of the nozzle valve is extended to form a pin or pintle which
protrudes through the mouth of the nozzle body.
• Spray cone angle is generally 60 degree ,and spray is hollow conical.

8. ADVANTAGES
• Self cleaning type and avoid carbon deposits at end.
• Avoids dribbling.
• Good atomization
DISADVANTAGES
• Distribution and penetration is poor hence not suitable in open
combustion chamber
4. PINTAUX NOZZLE
• It’s a type of pintle nozzle with an auxiliary hole.
• Small amount of fuel come from auxiliary hole before main injection.
ADVANTAGES
• Good cold starting characteristics
DISADVANTAGES
• Tendency of auxiliary hole to choke.
• Less effective than multi hole nozzle

10. ELECTRONIC UNIT INJECTOR
• the Delphi Diesel Systems electronic unit injector
(EUI) both the quantity and the timing of injection
are controlled electronically through a Colenoid
actuator.
• The Colenoid is a solenoid of patented construction
that can respond very quickly (injection periods are
of the order 1 ms), to control very high injection
pressures (up to 1600 bar or so).
• The Colenoid controls a spill valve, which in turn
controls the injection process.
• The pumping element is operated directly from a
camshaft (or indirectly via a rocker), and the whole
assembly is contained within the cylinder head.

11. Benefits
• High speed dual valve operation for accurate control
of injection events
• High pressure injection for optimized combustion and
reduced after treatment
• Lightweight, compact design for enhanced efficiency
• Available with a wide range of high pressure nozzle
options
• Multiple injection capability with programmable shot-
to-shot injection control
• Programmable variable nozzle opening and closing
pressure
• On board diagnostic and dynamic trimming capability
(glitch control)
• Cost effective technology
• Proven reliability and durability

13. HYDRAULIC ELECTRONIC UNIT
INJECTOR• It uses a hydraulic pressure intensifier system with a
7: 1 pressure ratio to generate the injection
pressures
• The hydraulic pressure is generated by pumping
engine lubricant to a controllable high pressure.
• The HEUI uses a two-stage valve to control the oil
pressure, and this is able to control the rate at which
the fuel pressure rises, thereby controlling the rate
of injection, because a lower injection rate can help
control NOx emissions.
• The HEUI uses engine oil under high pressure to
power the plunger rather than a fuel injection pump
camshaft lobe to power the plunger.
• The HEUI fuel system provides infinite control of
injection pressure.

15. REFERENCE
• Automobile Engineering , by R.K RAJPUT
• I C ENGINE by V GANESHAN
• Automotive engineering fundamental by RICHARD STONE &
JEFFREY K.BALL
• DELPHI E3 fuel injector :
http://www.delphi.com/manufacturers/cv/powertrain/injecti
on-systems-and-components/e3-diesel-electronic-unit-
injector
• HEUI : http://generators.tpub.com/TM-9-6115-729-24/TM-9-
6115-729-240063.htm
• Kamo R, Bryzik W, Reid M, Woods M. Coatings for improved
engine performance. SAE technical paper 970204; 1997.