Engine Design and Operating Parameters

• Thermodynamic Parameters– Define indicated, brake, and friction quantities.

– Define net and gross quantities

– Calculate sfc, AF, vol. eff. and engine efficiency

– Correct performance data for atmospheric conditions.

• Geometric & Kinematic Parameters.– Define and use the different rated conditions

– Calculate engine volume, piston speed, and cylinder surface area as a function of crank angle

– Draw a cylinder schematic and identify the bore, stroke, crank radius, TDC, BDC, and crank angle

List of Laboratory Experiments

• Study of Anatomy of A Single Cylinder Diesel Engine.

• Study of Anatomy of A Multi-cylinder Diesel Engine.

• Disassembly and assembly of A single cylinder Diesel Engine.

• Measurement of Valve Timing of A Single Cylinder Diesel Engine.

• Performance study of Single cylinder Diesel Engine.

• Performance study of Multi cylinder Diesel Engine.

• Performance study & Morse Testing of Multi cylinder (MPFI) Gasoline Engine.

• Performance study of Dual Fuel Engine.

• Measurement of p- diagram on a diesel engine.

• Measurement of coefficient of discharge of Valve as function of valve lift.

Division of Sub Groups : Allocation of Experiments

Simplified View of An Engine

Anatomy of A Multi-cylinder Diesel Engine

LUBRICATION SYSTEM

Lubrication Networking

Exhaust Valve : Operation Schedule

Pcyl

Patm

Inlet Valve : Operation Schedule

PcylPatm

Valve Actuation Diagram

Cold Period of Operation Hot Period of Operation

Geometry of Flow Passage through Valves

Geometry of Valve

Stages of Valve Lifting

Instantaneous Valve Events

• For low lift valves, the minimum flow area corresponds to a frustum of right circular cone.

• The conical face between valve and seat is, perpendicular to the seat, defines the flow area.

0cossin

vLw

The minimum area is:

2sin

22cos v

vvm

LwDLA

• For the second stage, the minimum area is still the slant surface of a frustum of a right circular cone.

• However, this surface is not perpendicular to the valve seat.

• The base angle of the cone increases from (900- toward that of a cylinder.

• For this stage:

cossintan

42

22

wLww

D

DDv

m

sp

2/122tan wwLDA vmm

Dm is mean diameter of seat : wDD vm

•When the valve lift is sufficiently large, the minimum flow area is no longer between the valve head and seat.•It is the port area minus the sectional area of the valve stem.

tan4

2/1

222

wwD

DDL

m

spv

Then,

22

4 spm DDA

Valve Lift Curves

Frictional Compressible Flow Through Inlet Valve

• The real gas flow effects are included by means of an experimentally determined discharge coefficient CD.

• The air flow rate is related to the upstream stagnation pressure p0 and stagnation temperature T0, Static pressure just down stream of the valve and a reference area AR.

• AR is a characteristic of the valve design.

12

1

2/12/1 1

2

inlet

inletRD

RT

pACm

2

1

0

1

2/1 11

2

p

p

p

p

RT

pACm cyl

inlet

cyl

inlet

inletRD

When the flow is chocked:

Discharge Coefficient:

idealf

actf

d

m

mC

,

,

The value of CD and the choice of reference area AR are linked together.

The product CD . AR is the effective flow area of the valve assembly, AE.

In general valve head area or port area or curtain area are used as reference areas.

INLET VALVES

12 3

EXHAUST VALVES