1. Fuel Efficient Engines
Engine Technologies and how they affect our economy in terms of fuel conservation and ecology

2. How do we define efficiency?
Definition
How do we define efficiency?
In terms of fuel economy in km/L or L/100 km for cars and trucks
In terms of load carrying capacity for commercial vehicles
In terms of bsfc for other engines
In terms of low emissions for all engines

3. Main Technologies available today To improve Efficiency
Variable Valve Timing and Lift,
Cylinder deactivation,
Turbochargers and Superchargers,
Integrated Starter and Generator Systems,
Direct or Indirect Fuel Injection with Turbo-charging/Supercharging,
Charge Stratification,
HCCI

6. Variable Valve Timing and Lift
Also called Variable Valve actuation, variable cam timing, Variable Valve Timing (VVT)
Variable-valve Timing-and-lift Electronic Control (VTEC)®

7. Cylinder deactivation
Some refer to it as Variable Displacement or Displacement on Demand or Multiple Displacement System
It was first introduced by GM in the 1980s
In 2003 Cadillac built a V hp engine of size 13.6L. It could run on 8 or even on 4 cylinders “on demand” to give economy.
A GM V-6 could run on 3 cylinders at light load to improve fuel economy by 6-8%
In 2004, Honda introduced an i-VTEC V6 (an update of the venerable J-series), but in this case, i-VTEC had nothing to do with cam phasing. Instead, i-VTEC referred to Honda's cylinder deactivation technology, which closes the valves on one bank of (3) cylinders during light load and low speed (below 80 mph) operation.

8. Supercharging and Turbo-charging
Requires reduction in compression ratio or change in spark timing to reduce knock.
When provided with after cooling, the reduction in compression ratio is less
Either increased power can be obtained with the same size engine or it is possible to reduce the size for the same power and hence reduce fuel consumption

10. Integrated Starter/generator Systems
These systems automatically turn the engine off when the vehicle comes to a stop and restart it instantaneously when the accelerator is pressed so that fuel isn't wasted for idling.
In addition, regenerative braking is often used to convert mechanical energy lost in braking into electricity, which is stored in a battery and used to power the automatic starter.

11. Fuel Injection Applied to the S.I.Engine
There are three possible locations: 1. Inlet Manifold.
2. Inlet Port.
3. Direct Cylinder.

13. Direct Cylinder Injection
Fuel is injected directly into the cylinder
Possible to operate ultra lean – one report claims 65:1 air-fuel ratio under normal running – stratified charge
Stoichiometric operation under normal running - homogeneous charge
Rich mixture for full power operation – homogeneous charge

15. Semi-direct Injection or Port Injection
Injectors Positioned in Each Induction Manifold Branch Just in Front of Inlet Port
Injection at Low Pressure (2-6 Bar)
Need Not Be Synchronized With Engine Induction Cycle
Fuel Can Be Discharged Simultaneously to Each Induction Pipe Where it is Mixed and Stored Until Inlet Valve Opens
Need Not Be Timed – Requires Low Discharge Pressures – Injectors Not Exposed to Combustion Products so Complexity Reduced – Less Cost

17. Charge Stratification

18. THE HCCI ENGINE