Department of Mechanical Engineering: Electronic Injection Systems
Lecture-13
Prepared under
QIP-CD Cell Project
Internal Combustion Engines
Ujjwal K Saha, Ph.D.
Department of Mechanical Engineering
Indian Institute of Technology Guwahati
1
Gasoline Injection
In a multi-cylinder engine with a carburetor, it is difficult to obtain a uniform mixture in each cylinder. The various cylinders receive the airgasoline mixture in varying quantities and richness. This problem is called the maldistribution and can be solved by the port injection system by having the same amount of gasoline injected at each intake manifold.
By adopting gasoline injection each cylinder can get the same richness of the air-gasoline mixture and the mal-distribution can be avoided to a great extent.
2
Typical pattern of mixture distribution in a multi-cylinder engine
3
Reasons for Gasoline Injection
To have uniform distribution of fuel in a multi-cylinder engine
To improve the breathing capacity and hence the volumetric efficiency
To reduce or eliminate detonation
To prevent fuel loss during scavenging in case of two-stroke engines
Types of Injection Systems
Gasoline direct injection (GDI)
Port-Injection
(a) Timed and (b) Continuous
Manifold Injection
4
Groupings
The above fuel injection systems can be
grouped under two heads,viz., single-point and multi-point injection. In the single point injection system, one or two injectors are mounted inside the throttle body assembly.
Fuel sprays are directed at one point or at the center of the intake manifold. This type is also known as throttle body injection.
Multipoint injection has one injector for each engine cylinder, where fuel is injected in more than one location. This is somewhat more common and is often called port injection system.
5
Continuous Injection Systems
This system usually has a rotary pump.
The pump maintains a fuel line gauge pressure of about 0.75 to 1.5 bar. The system injects fuel through a nozzle located in the manifold immediately downstream of the
Prepared under
QIP-CD Cell Project
Internal Combustion Engines
Ujjwal K Saha, Ph.D.
Department of Mechanical Engineering
Indian Institute of Technology Guwahati
1
Gasoline Injection
In a multi-cylinder engine with a carburetor, it is difficult to obtain a uniform mixture in each cylinder. The various cylinders receive the airgasoline mixture in varying quantities and richness. This problem is called the maldistribution and can be solved by the port injection system by having the same amount of gasoline injected at each intake manifold.
By adopting gasoline injection each cylinder can get the same richness of the air-gasoline mixture and the mal-distribution can be avoided to a great extent.
2
Typical pattern of mixture distribution in a multi-cylinder engine
3
Reasons for Gasoline Injection
To have uniform distribution of fuel in a multi-cylinder engine
To improve the breathing capacity and hence the volumetric efficiency
To reduce or eliminate detonation
To prevent fuel loss during scavenging in case of two-stroke engines
Types of Injection Systems
Gasoline direct injection (GDI)
Port-Injection
(a) Timed and (b) Continuous
Manifold Injection
4
Groupings
The above fuel injection systems can be
grouped under two heads,viz., single-point and multi-point injection. In the single point injection system, one or two injectors are mounted inside the throttle body assembly.
Fuel sprays are directed at one point or at the center of the intake manifold. This type is also known as throttle body injection.
Multipoint injection has one injector for each engine cylinder, where fuel is injected in more than one location. This is somewhat more common and is often called port injection system.
5
Continuous Injection Systems
This system usually has a rotary pump.
The pump maintains a fuel line gauge pressure of about 0.75 to 1.5 bar. The system injects fuel through a nozzle located in the manifold immediately downstream of the
References: Crouse WH, and Anglin DL, DL (1985), Automotive Engines, Tata McGraw Hill. 2. Eastop TD, and McConkey A, (1993), Applied Thermodynamics for Engg. 3. Fergusan CR, and Kirkpatrick AT, (2001), Internal Combustion Engines, John Wiley & Sons. 4. Ganesan V, (2003), Internal Combustion Engines, Tata McGraw Hill. 5. Gill PW, Smith JH, and Ziurys EJ, (1959), Fundamentals of I. C. Engines, Oxford and IBH Pub Ltd. 6. Heisler H, (1999), Vehicle and Engine Technology, Arnold Publishers. 7. Heywood JB, (1989), Internal Combustion Engine Fundamentals, McGraw Hill. 8. Heywood JB, and Sher E, (1999), The Two-Stroke Cycle Engine, Taylor & Francis. 9. Joel R, (1996), Basic Engineering Thermodynamics, Addison-Wesley. 10. Mathur ML, and Sharma RP, (1994), A Course in Internal Combustion Engines, Dhanpat Rai & Sons, New Delhi. 11. Pulkrabek WW, (1997), Engineering Fundamentals of the I. C. Engine, Prentice Hall. 12. Rogers GFC, and Mayhew YR, YR (1992), Engineering Thermodynamics, Addison 13. Srinivasan S, (2001), Automotive Engines, Tata McGraw Hill. 14. Stone R, (1992), Internal Combustion Engines, The Macmillan Press Limited, London. 15. Taylor CF, (1985), The Internal-Combustion Engine in Theory and Practice, Vol.1 & 2, The MIT Press, Cambridge, Massachusetts.