Download presentation

1
**Measuring Engine Performance page 91**

Chapter Brian Measuring Engine Performance page 91

2
**Basic Terminology Bore & Stroke Engine Displacement Compression Ratio**

Force Work Power Energy Horsepower

3
Bore Diameter of cylinder 2 X Radius

4
Stroke Distance TDC-BDC Distance piston travels up or down

5
**Cylinder Displacement**

x D2 x stroke or Π x r2 x Stroke

6
**Engine Displacement 0.7854 x D2 x stroke X # of cylinders or**

Π x r2 x Stroke # of cylinders in3 / 62 = Liters

7
**Compression Ratio Area of cylinder at BDC compared to**

Area of cylinder at TDC 63 in3 to 9 in3 = 7:1 compression ratio

8
**Force pushing or pulling stationary force moving force**

Centrifugal force spinning FORCE does NOT = Pressure

9
**Pressure Pressure is force per given area or Force/Area PSI**

Force = psi X area Area = force / psi Area = Π R2

10
**Work force applied resulting in movement Work = Force x Distance**

W = F x D Mechanical advantage (lever, ramp, etc) Effort distance / resistance distance = Mechanical advantage

11
**Mechanical Advantage 10’ / 2’ = 5 = MA E(effort) = R(resistance)/ MA**

500# 2’

12
**Power Power is time taken to do the work P = work/time P=W/T**

Power = feet x Pounds / time or Foot pounds per second?

13
**Energy Energy can not be created or destroyed**

Potential—has the potential to . . . Kinetic Mechanical Chemical Thermal (heat) Light

14
**Horsepower Power = work / time P= w/t**

Hp = 33,000 ft-lb (work) / 1 minute (time) or Hp = 550 ft-lb / 1 second

15
**Horsepower Formula 100 ft x 330 lb / 6 seconds = 5500 ft lb / sec**

dividing this by 550 ft lb / sec (1hp) = (5500 ft-lb /sec) / (550 ft lb / sec) = 10 hp thus 1 hp = rate of work in ft-lb/sec / 50 ft-lb / sec

16
**Kinds of Horsepower Brake Horsepower Indicated Horsepower**

Frictional Horsepower Rated Horsepower Corrected Horsepower

17
Brake Horsepower bhp actual hp delivered what we can use

18
**Indicated Horsepower ihp (perfect world)**

power developed by the burning fuel average of power on 4 strokes (mean) PLANK / 33,000 P = mep in in lb/in2 L = length of stroke A = Cylinder Area N = power strokes per minute or RPM / 4 K = # of cylinders

19
**Frictional Horsepower**

fhp HP lost because of drag fhp = ihp-bhp

20
Rated Horsepower rhp 80% of bhp

21
**Corrected Horsepower corrected for elevation (sea level)**

corrected for temperature barometric pressure quality of fuel humidity

22
Torque Twisting force force x distance ft - lb in – lb Newton - Meters

23
**Torque is not Constant Torque will change w/ engine speed**

More pressure on piston = more torque

24
**Torque and Horsepower Unlike torque. . .**

Horsepower increases with engine speed Torque measure of engine’s twisting force Hp measures engine’s ability to do work

25
**Volumetric Efficiency**

How well an engine breathes draws air/fuel into cylinder Can decrease as engine speed increases many factors

26
Practical Efficiency how efficiently an engine uses the fuel

27
**Mechanical Efficiency**

% of power developed in cylinder (ihp) compared to power delivered to crankshaft (bhp) friction, Mechanical efficiency = bhp/ihp

28
**Thermal Efficiency Heat efficiency**

how much power produced is used to push the piston down Power is lost to : cooling exhaust 20-25% efficient Exhaust 35% . . . Cooling & Lubrication 35%

29
**Brake thermal efficiency**

= Brake horsepower (bhp x 33,000) 778 Fuel heat value x weight of burned fuel per minute 778 is Joule’s equivalent it is a constant

Similar presentations

OK

1 Undirected Breadth First Search F A BCG DE H 2 F A BCG DE H Queue: A get Undiscovered Fringe Finished Active 0 distance from A visit(A)

1 Undirected Breadth First Search F A BCG DE H 2 F A BCG DE H Queue: A get Undiscovered Fringe Finished Active 0 distance from A visit(A)

© 2017 SlidePlayer.com Inc.

All rights reserved.

Ads by Google

Ppt on power system harmonics books Ppt on artificial intelligence in machines Download ppt on fundamental rights and duties pictures Ppt on history of internet free download Ppt on peak load pricing electricity Ppt on harmful effects of fast food Ppt on grease lubrication intervals Download ppt on square and square roots Ppt on silicon controlled rectifier Ppt on online shopping in php