The document discusses engine geometry and piston motion. It defines key terms like cylinder clearance volume, swept volume, compression ratio, and average and instantaneous piston speeds. It then covers topics like engine torque, power, indicated work, mechanical efficiency, power and torque curves, fuel consumption, combustion efficiency, and volumetric efficiency. Key parameters discussed include mean effective pressure, specific fuel consumption, thermal efficiency, and air-fuel ratio.
in this presentation , the different engine inefficiencies has been discussed including all sort of friction losses which affects the brake power of the engine. It includes volumetric efficiency, thermal efficiency, IMEP, BMEP, brake power etc.
The various forces acts on the reciprocating parts of an engine.
The resultant of all the forces acting on the body of the engine due to inertia forces only is known as unbalanced force or shaking force.
in this presentation , the different engine inefficiencies has been discussed including all sort of friction losses which affects the brake power of the engine. It includes volumetric efficiency, thermal efficiency, IMEP, BMEP, brake power etc.
The various forces acts on the reciprocating parts of an engine.
The resultant of all the forces acting on the body of the engine due to inertia forces only is known as unbalanced force or shaking force.
Spring Design, Helical Springs, compression & Extension springs, spring design procedure leaf spring, multi-leaf springs design process and analysis, Role of Spring index in spring design. Springs for Fluctuating loads.
Unit 5- balancing of reciprocating masses, Dynamics of machines of VTU Syllabus prepared by Hareesha N Gowda, Asst. Prof, Dayananda Sagar College of Engg, Blore. Please write to hareeshang@gmail.com for suggestions and criticisms.
Spring Design, Helical Springs, compression & Extension springs, spring design procedure leaf spring, multi-leaf springs design process and analysis, Role of Spring index in spring design. Springs for Fluctuating loads.
Unit 5- balancing of reciprocating masses, Dynamics of machines of VTU Syllabus prepared by Hareesha N Gowda, Asst. Prof, Dayananda Sagar College of Engg, Blore. Please write to hareeshang@gmail.com for suggestions and criticisms.
This slideshow contain a detailed explanation of the following topics:
(1) Condition of generation of net torque.
(2) Concept of Electrical & Mechanical Angle
(3) Equation of induced emf
(4) B-wave
(5) B-wave for uniform and non-uniform air gap
(6) Distributed winding
(7) Short pitched winding
PHP Frameworks: I want to break free (IPC Berlin 2024)Ralf Eggert
In this presentation, we examine the challenges and limitations of relying too heavily on PHP frameworks in web development. We discuss the history of PHP and its frameworks to understand how this dependence has evolved. The focus will be on providing concrete tips and strategies to reduce reliance on these frameworks, based on real-world examples and practical considerations. The goal is to equip developers with the skills and knowledge to create more flexible and future-proof web applications. We'll explore the importance of maintaining autonomy in a rapidly changing tech landscape and how to make informed decisions in PHP development.
This talk is aimed at encouraging a more independent approach to using PHP frameworks, moving towards a more flexible and future-proof approach to PHP development.
GraphRAG is All You need? LLM & Knowledge GraphGuy Korland
Guy Korland, CEO and Co-founder of FalkorDB, will review two articles on the integration of language models with knowledge graphs.
1. Unifying Large Language Models and Knowledge Graphs: A Roadmap.
https://arxiv.org/abs/2306.08302
2. Microsoft Research's GraphRAG paper and a review paper on various uses of knowledge graphs:
https://www.microsoft.com/en-us/research/blog/graphrag-unlocking-llm-discovery-on-narrative-private-data/
Le nuove frontiere dell'AI nell'RPA con UiPath Autopilot™UiPathCommunity
In questo evento online gratuito, organizzato dalla Community Italiana di UiPath, potrai esplorare le nuove funzionalità di Autopilot, il tool che integra l'Intelligenza Artificiale nei processi di sviluppo e utilizzo delle Automazioni.
📕 Vedremo insieme alcuni esempi dell'utilizzo di Autopilot in diversi tool della Suite UiPath:
Autopilot per Studio Web
Autopilot per Studio
Autopilot per Apps
Clipboard AI
GenAI applicata alla Document Understanding
👨🏫👨💻 Speakers:
Stefano Negro, UiPath MVPx3, RPA Tech Lead @ BSP Consultant
Flavio Martinelli, UiPath MVP 2023, Technical Account Manager @UiPath
Andrei Tasca, RPA Solutions Team Lead @NTT Data
A tale of scale & speed: How the US Navy is enabling software delivery from l...sonjaschweigert1
Rapid and secure feature delivery is a goal across every application team and every branch of the DoD. The Navy’s DevSecOps platform, Party Barge, has achieved:
- Reduction in onboarding time from 5 weeks to 1 day
- Improved developer experience and productivity through actionable findings and reduction of false positives
- Maintenance of superior security standards and inherent policy enforcement with Authorization to Operate (ATO)
Development teams can ship efficiently and ensure applications are cyber ready for Navy Authorizing Officials (AOs). In this webinar, Sigma Defense and Anchore will give attendees a look behind the scenes and demo secure pipeline automation and security artifacts that speed up application ATO and time to production.
We will cover:
- How to remove silos in DevSecOps
- How to build efficient development pipeline roles and component templates
- How to deliver security artifacts that matter for ATO’s (SBOMs, vulnerability reports, and policy evidence)
- How to streamline operations with automated policy checks on container images
Encryption in Microsoft 365 - ExpertsLive Netherlands 2024Albert Hoitingh
In this session I delve into the encryption technology used in Microsoft 365 and Microsoft Purview. Including the concepts of Customer Key and Double Key Encryption.
Key Trends Shaping the Future of Infrastructure.pdfCheryl Hung
Keynote at DIGIT West Expo, Glasgow on 29 May 2024.
Cheryl Hung, ochery.com
Sr Director, Infrastructure Ecosystem, Arm.
The key trends across hardware, cloud and open-source; exploring how these areas are likely to mature and develop over the short and long-term, and then considering how organisations can position themselves to adapt and thrive.
DevOps and Testing slides at DASA ConnectKari Kakkonen
My and Rik Marselis slides at 30.5.2024 DASA Connect conference. We discuss about what is testing, then what is agile testing and finally what is Testing in DevOps. Finally we had lovely workshop with the participants trying to find out different ways to think about quality and testing in different parts of the DevOps infinity loop.
State of ICS and IoT Cyber Threat Landscape Report 2024 previewPrayukth K V
The IoT and OT threat landscape report has been prepared by the Threat Research Team at Sectrio using data from Sectrio, cyber threat intelligence farming facilities spread across over 85 cities around the world. In addition, Sectrio also runs AI-based advanced threat and payload engagement facilities that serve as sinks to attract and engage sophisticated threat actors, and newer malware including new variants and latent threats that are at an earlier stage of development.
The latest edition of the OT/ICS and IoT security Threat Landscape Report 2024 also covers:
State of global ICS asset and network exposure
Sectoral targets and attacks as well as the cost of ransom
Global APT activity, AI usage, actor and tactic profiles, and implications
Rise in volumes of AI-powered cyberattacks
Major cyber events in 2024
Malware and malicious payload trends
Cyberattack types and targets
Vulnerability exploit attempts on CVEs
Attacks on counties – USA
Expansion of bot farms – how, where, and why
In-depth analysis of the cyber threat landscape across North America, South America, Europe, APAC, and the Middle East
Why are attacks on smart factories rising?
Cyber risk predictions
Axis of attacks – Europe
Systemic attacks in the Middle East
Download the full report from here:
https://sectrio.com/resources/ot-threat-landscape-reports/sectrio-releases-ot-ics-and-iot-security-threat-landscape-report-2024/
De-mystifying Zero to One: Design Informed Techniques for Greenfield Innovati...
Performance parameters
1. Engine Geometry
VC
TC
B
L (
s = a cosθ + l − a sin θ
2 2 2
)1/ 2
Cylinder volume when piston at TC (s=l+a)
BC
defined as the clearance volume Vc
The cylinder volume at any crank angle is:
l
s
πB 2
V = Vc + (l + a − s )
4
Maximum displacement, or swept, volume:
θ
πB 2
a Vd = L
4
Compression ratio:
VBC Vc + Vd
For most engines B ~ L (square engine) rc = =
VTC Vc
2. Mean and Instantaneous Piston Speeds
VC
TC
( 2
s = a cosθ + l − a sin θ 2 2
)
1/ 2
B
Average and instantaneous piston speeds are:
L
U p = 2 LN
BC ds
Up =
dt
l Where N is the rotational speed of the crank shaft
s in units revolutions per second
Up π cosθ
= sin θ 1 +
θ
Up 2
(
( l / a ) 2 − sin 2 θ )
1/ 2
a
Average piston speed for standard auto engine is
about 15 m/s. Ultimately limited by material
strength. Therefore engines with large strokes run
at lower speeds those with small strokes can run
at higher speeds.
4. Engine Torque and Power
Torque is measured using a dynamometer.
b
Stator Force F
Rotor
N
Load cell
The torque exerted by the engine is: T = F b with units: J
The power Wdot delivered by the engine turning at a speed N and
absorbed by the dynamometer is:
Wdot = ω T = (2π N) T w/units: (rad/rev)(rev/s)(J) = Watt
Note: ω is the shaft angular velocity with units: rad/s
5. Indicated Work
Given the cylinder pressure data over the operating
cycle of the engine one can calculate the work done
by the gas on the piston.
The indicated work per cycle is Wi = ∫ PdV
WA > 0
WB < 0
Compression Power Exhaust Intake
W<0 W>0 W<0 W>0
6. Indicated Power
Indicated power:
Wdoti = Wi N / nR w/units: (kJ/cycle) (rev/s) / (rev/cycle)
where N – crankshaft speed in rev/s
nR – number of crank revolutions per cycle
= 2 for 4-stroke
= 1 for 2-stroke
Power can be increased by increasing:
• the engine size, Vd
• compression ratio, rc
• engine speed, N
7. Mechanical Efficiency
Some of the power generated in the cylinder is used
to overcome engine friction. The friction power is
used to describe these losses:
Wdotf = Wdoti - Wdotb
Friction power can be measured by motoring the engine.
The mechanical efficiency is defined as:
ηm = Wdotb / Wdoti = 1- (Wdotf / Wdoti )
Mechanical efficiency depends on throttle position, engine
design, and engine speed. Typical values for car engines
at WOT are 90% @2000 RPM and 75% @ max speed.
8. Power and Torque versus Engine Speed
Rated brake power There is a maximum in the brake power
versus engine speed called the rated
brake power.
1 kW = 1.341 hp
At higher speeds brake power decreases as
friction power becomes significant compared
to the indicated power
Max brake torque There is a maximum in the torque versus
speed called maximum brake torque (MBT).
Brake torque drops off:
• at lower speeds do to heat losses
• at higher speeds it becomes more difficult
to ingest a full charge of air.
9. Indicated Mean Effective Pressure (IMEP)
imep is a fictitious constant pressure that would produce the same
work per cycle if it acted on the piston during the power stroke.
imep = Wi / Vd = (Wdoti nR) / (Vd N)
so Wdoti = imep Vd N / nR = imep Ap Up / (2 nR)
imep does not depend on engine speed, just like torque.
imep is a better parameter than torque to compare engines for design and
output because it is independent of engine speed, N, and engine size, Vd.
Brake mean effective pressure (bmep) is defined as:
Wb 2π ⋅ T ⋅ nR bmep ⋅ Vd
bmep = = → T=
Vd Vd 2π ⋅ nR
10. Maximum BMEP
Wb 2π ⋅ T ⋅ nR
bmep = =
Vd Vd
• The maximum bmep is obtained at WOT at a particular engine speed
• Closing the throttle decreases the bmep
• For a given displacement, a higher maximum bmep means more torque
• For a given torque, a higher maximum bmep means smaller engine
• Higher maximum bmep means higher stresses and temperatures in the
engine hence shorter engine life, or bulkier engine.
• For the same bmep 2-strokes have almost twice the power of 4-stroke
11. Specific Fuel Consumption
• For transportation vehicles fuel economy is generally given as
mpg, or liters/100 km.
• In engine testing the fuel consumption is measured in terms of
the fuel mass flow rate mdotf.
• The specific fuel consumption, sfc, is a measure of how efficiently
the fuel supplied to the engine is used to produce power,
bsfc = mdotf / Wdotb isfc = mdotf / Wdoti w/units: g/(kW hr)
• Clearly a low value for sfc is desirable since at a given power
level less fuel will be consumed
12. Brake Specific Fuel Consumption vs Size
•BSFC decreases with engine size due to reduced heat losses
from gas to cylinder wall.
•Note: cylinder surface to volume ratio increases with bore diameter.
cylinder surface area 2πrL 1
= 2 ∝
cylinder volume πr L r
13. Brake Specific Fuel Consumption vs Speed
• There is a minimum in the bsfc versus engine speed curve
• At high speeds the bsfc increases due to increased friction
• At lower speeds the bsfc increases due to increased time for heat
losses from the gas to the cylinder and piston wall
• Bsfc increases with compression ratio due to higher thermal efficiency
14. Performance Maps
Performance map is used to display the bsfc over the engines full load
and speed range. Using a dynamometer to measure the torque and fuel
mass flow rate you can calculate:
bmep = 2π T nR / Vd Wdotb = 2π N T bsfc = mdotf / Wdotb
bmep@WOT
Constant bsfc contours from a
two-liter four cylinder SI engine
15. Combustion Efficiency
• The time for combustion in the cylinder is very
short so not all the fuel may be consumed or
local temperatures may not support combustion
• A small fraction of the fuel may not react and
exits with the exhaust gas
• The combustion efficiency is defined as actual heat input
divided by theoretical heat input:
ηc = Qin/ (mf QHV) = Qdotin / (mdotf QHV)
Where Qin = heat added by combustion per cycle
mf = mass of fuel added to cylinder per cycle
QHV = heating value of the fuel (chemical energy per unit mass)
16. Thermal Efficiency
ηth = work per cycle / heat input per cycle
ηth = W / Qin = W / (ηc mf QHV)
or in terms of rates…
ηth = power out/rate of heat input
ηth = Wdot/Qdotin = Wdot/(ηc mdotf QHV)
• Thermal efficiencies can be given in terms of brake or indicated values
• Indicated thermal efficiencies are typically 50% to 60% and brake
thermal efficiencies are usually about 30%
17. Arbitrary Efficiency
ηo = Wb / (mf QHV) = Wdotb / (mfdot QHV)
Note: ηo is very similar to ηth, the difference is that ηth takes into
account only the actual fuel combusted.
Recall that sfc = mdotf / Wdotb
Thus ηo = 1 / (sfc QHV)
18. Volumetric Efficiency
• Due to the short cycle time and flow restrictions less than ideal
amount of air enters the cylinder.
• The effectiveness of an engine to induct air into the cylinders is
measured by the volumetric efficiency which is the ratio of actual
air inducted divided by the theoretical air inducted:
ηv = ma / (ρa Vd) = nR mdota / (ρa Vd N)
where ρa is the density of air at atmospheric conditions Po, To for an
ideal gas ρa =Po / RaTo and Ra = 0.287 kJ/kg-K (at standard conditions
ρa= 1.181 kg/m3)
• Typical values for WOT are in the range 75%-90%, and lower when
the throttle is closed
19. Air-Fuel Ratio
• For combustion to take place, the proper ratio
of air and fuel must be present in the cylinder.
•The air-fuel ratio is defined as
AF = ma / mf = mdota / mdotf
• The ideal AF is about 15:1, with homogenous
combustion possible in the range of 6 to 19.
• For a SI engine the AF is in the range of 12 to 18
depending on the operating conditions.
• For a CI engine, where the mixture is highly non-
homogeneous and the AF is in the range of 18 to 70.