Adrian Clenci

National University of Science and Technology "POLITEHNICA" · Department Automobiles and Transport

This paper presents an original continuously variable intake valve lift (ViVL) mechanism designed for the automotive spark ignition engines. The paper first presents the analytical kinematic synthesis of the ViVL mechanism, which consists in finding out the required intake cam profile starting from an imposed intake valve lift law. Then, by using t...

This paper assesses the effect of the Miller cycle upon the internal aerodynamics of a motored transparent spark ignition engine via CFD simulation and particle image velocimetry. Since the transparent Miller engine does not allow for measurements in the roof of the combustion chamber, the extraction of information regarding the aerodynamic phenome...

Today, the greenhouse gas (GHG) emissions (specifically, CO2) represent the greatest challenge of the internal combustion (IC) engine and consequently, now, more than ever, the passenger car industry is looking for technologies meant to address this issue. Since CO2 emission is related to the combustion process occurring inside the engine, its redu...

Future passenger cars must comply with whatever regulations will be created to mitigate greenhouse gas emissions (GHG) and pollution. Regarding the pollutants of an internal combustion (IC) engine, they are dealt with by using an exhaust after-treatment system (EATS). Yet, catalytic converters encounter light-off problems after cold start: their af...

Given the increased concern for environmental protection and the need for finding viable alternatives for replacing fossil fuels in internal combustion engines, the research carried out in the recent past on the use of biodiesel has increased. Out of the physico-chemical characteristics of fuels, the volatility has a great influence on the combusti...

Individual road mobility comes with two major challenges: greenhouse gas emissions related to global warming and chemical pollution. For the pollution reduction in the spark ignition engine vehicle, the standard and reliable aftertreatment technology is the three-way catalytic converter (TWC). However, the TWC starts to convert once an optimal temp...

The lubricating oil of an internal combustion engine (i.c.e.) performs several functions having a major contribution to the reliability of the system, implying proper operation during the period of exploitation. Replacing the engine oil ahead reaching the turnover / time corresponding to preventive maintenance it turns out to be sometime an imperat...

The lubricating oil of an internal combustion engine (I.C.E.) performs several functions with a major contribution to the reliability of the system, which involves proper operation during the operating period. Changing the engine oil early or late could generate additional costs and/or damage the engine’s performance. Thus, it becomes necessary to...

Articol publicat in Revista INGINERIA AUTOMOBILULUI (http://siar.ro/publicatii/) Nr. 68/september 2023 A journey in time to explain the terms MODEL/MODELLING/SIMULATION... Un periplu prin timp pentru a explica termenii MODEL/MODELARE/SIMULARE... "Îți place să formulezi matematic un fenomen fizic, să găsești ecuația diferențială care-l descrie și...

http://siar.ro/wp-content/uploads/2023/06/rIA_67.pdf (pages 5-13) ENGLISH: Today, despite its drawbacks, the internal combustion engine is still the most convenient choice for road mobility. Historically, engine selection for light vehicles is about choosing either the spark ignition engine, or the compression ignition engine. Of the two engines,...

#𝗜𝗻𝘁𝗲𝗿𝗻𝗮𝗹𝗖𝗼𝗺𝗯𝘂𝘀𝘁𝗶𝗼𝗻𝗘𝗻𝗴𝗶𝗻𝗲 𝗮𝗻𝗱 #𝗦𝘂𝘀𝘁𝗮𝗶𝗻𝗮𝗯𝗹𝗲𝗥𝗼𝗮𝗱𝗠𝗼𝗯𝗶𝗹𝗶𝘁𝘆 at the Romanian Academy on Tuesday the 28th of March, 10h00 - 14h00. Tough subject these days... "Everything is connected. We are bond together… and by each of our actions we birth our future…" P.S. The presentation is, in fact, an invitation to reflection. I will not speak from the position...

Articolul este o încercare de a înțelege nuanțele termenului "digitalizare" si a fost publicat in revista Ingineria Automobilului nr. 66/martie 2023. În încercarea de a înțelege nuanțele acestui termen, primul pas trece prin diferențierea față de digitizare. În analiza acestui cuplu de termeni (digitizare / digitalizare) de mare interes pentru soc...

Articolul prezintă o cercetare asupra circulației termenilor utilizați în limbile engleză, franceză, germană și română pentru a desemna renunțarea la sursele de emisii de gaze cu efect de seră. Scopul acestei cercetări este extragerea unor concluzii cu privire la pertinenţa și particularităţile statutului și utilizării termenului consacrat în limb...

Dear Colleagues, As we all know, today, the road mobility comes with two major challenges: (1) greenhouse gas (GHG) emissions related to global warming and (2) chemical pollution (especially in cities). Since worldwide the road mobility is vastly ensured with internal combustion engine vehicles, to put it straightforward, the very existence of th...

The article presents the results of a 1D numerical simulation of a spark ignition engine developed to operate in Miller cycle. Miller cycle offers better thermal efficiency compared to Otto cycle due to higher volumetric expansion than compression, which in the current context is of paramount importance. In an engine with fixed geometric compressio...

Surge is an unstable phenomenon appearing when a valve closing reduces the compressor flow rate. This phenomenon is avoided for automotive turbochargers by defining a surge margin during powertrain system design. This surge margin established with measurements in steady state testing regime limits the maximal engine torque at low levels of output....

The lubricating oil fulfills several purposes, such as: reducing friction processes, protecting the parts of the engine mechanism from wear, preventing the occurrence of corrosion phenomena, taking over and transporting or transferring impurities to the oil filter, lubricating the moving parts as well as their cooling. The lubrication fluid of the...

As argued in many papers, from the road mobility point of view, today, there are three major problems facing humanity: (1) greenhouse gas (GHG) emissions, global warming and city pollution; (2) renewable or sustainable sources of energy; and (3) energy security. The above listed 3 problems generated intense discussions at international level on the...

Termenii care au determinat scrierea acestui articol sunt concepție și proiectare. Sunt sau nu sinonimi? Dacă nu, atunci ce-i distinge, care sunt nuanțele ce îi diferențiază? Iată, deci, câteva întrebări cărora vom încerca să le găsim răspuns în acest articol http://siar.ro/wp-content/uploads/2021/06/rIA59.pdf

Assessment of the impact of the intake valve masking and piston stroke increasing on the Miller engine’s internal aerodynamics In order to comply with the future emissions regulations, at this point, it seemed that more and more automotive manufacturers will use the Miller over-expanded cycle. In our past research, we highlighted the fact that the...

https://automotive.upit.ro/ - Open Access Journal of University of Pitesti Scientific Bulletin - Automotive Series As air pollution and global warming become a priority in sustainable mobility, the evolution of vehicles is facing many regulations that are becoming increasingly stringent in terms of reducing greenhouse gas (GHG) emissions, forcing...

https://automotive.upit.ro University of Pitesti, Scientific Bulletin - Automotive Series (open access journal) https://automotive.upit.ro/index_files/2021/2021_5_.pdf "Temporary downsizing" in the form of deactivation of the cylinders is used as an attractive compromise, as it allows to improve fuel consumption and at the same time, it allows suf...

The automotive electric supercharger provides high torque at low engine speeds. During accelerations, it fills the power gap due to the turbocharger’s inertia and avoids turbo lag. Its operation is of short duration because once this deficit has been juggled, it must be stopped in order not to generate unnecessary electricity consumption and to avo...

Termenul pe care-l aducem acum în discuție este șasiu cu variantele (mai mult sau mai puțin) echivalente din franceză (châssis), engleză (chassis), germană (Chassis, Fahrwerk). După cum vom arăta, folosirea acestui termen generează, uneori, confuzie. Acesta este motivul pentru care am decis abordarea sa.

https://www.techniques-ingenieur.fr/base-documentaire/mecanique-th7/combustion-dans-les-moteurs-thermiques-et-environnement-4216621

Termenul care face obiectul analizei în numărul de faţă al publicaţiei este cel de demaraj/ demarare, care va fi explorat atât individual cât şi ca parte a sintagmei rezistenţa la demaraj/ demarare, noţiune care suscită interes atât ştiinţific cât şi didactic în domeniul ingineriei autovehiculelor. Am încercat, mai întâi, să răspundem întrebării da...

Currently, the internal combustion engine is facing tough regulations regarding pollution and CO2. In order to comply with the latest constraints concerning the CO2 emission, the automotive manufacturers must increase the thermal efficiency of the combustion engine. One way which seems to be preferential for the manufacturers is to implement the Mi...

Rubrica noastră continuă... În numărul actual, am discutat despre driv(e)ability, un termen foarte cunoscut, foarte uzitat în limba engleză și, foarte frecvent, preluat ca atare și în limba română. Driv(e)ability (en) - Agrément de conduite (fr) - Fahrbarkeit (ger) - Draivabilitate (ro)

The tightening of pollution and greenhouse gas regulations generated a change in the homologation procedure, i.e., a far more dynamic driving cycle and the testing of the vehicle in real driving conditions are now part of the type approval procedure. In order to cope with these new challenges, the car manufacturers must adopt new technologies such...

I made this presentation at the Engineering Trainers' Convention at Renault Bucharest Convention (RBC). Its first part is about what the "superpowers" of a trainer/professor/teacher/educator/instructor are. The second part is about: - the complexity of Automotive Engineering Education nowadays, - the widening gap between industry needs for multi...

Se prezinta evolutia Facultatii de Mecanica si Tehnologie din cadrul Universitatii din Pitesti: educatie, cercetare stiintifica, legatura cu mediul socio-economic

Facem suficient? Se poate mai mult? Ne asumam cu responsabilitate calitatea absolventilor nostri? Prezentarea este de fapt un mic pretext pentru a initia o dezbatere mai ampla... Feedforward vs. Feedback Open loop vs. Closed loop

The use of alternative fuels contributes to the lowering of the carbon footprint of the internal combustion engine. Biofuels are the most important kinds of alternative fuels. Currently, thanks to the new manufacturing processes of biofuels, there is potential to decrease greenhouse gas (GHG) emissions, compared to fossil fuels, on a well-to-wheel...

Joint presentation (University of Pitesti and Renault Technologie Roumanie) at Romanian Automotive Industry Forum, Craiova

Rubrica noastră continuă... Există în industria automobilelor un concept tehnic de o complexitate aparte, întrucât mobilizează, pe lângă datele ştiinţifice, obiective specifice domeniului tehnologiei, un ansamblu de operaţii, informaţii şi procese de largă subiectivitate. Este vorba despre conceptul redat prin termenul englezesc harshness. Asadar...

Increased environmental awareness and depletion of fossil petroleum resources are driving the automotive industry to seek out and use alternative fuels. The most eminent alternative fuels for replacing fossil fuels in internal combustion engines are biofuels (biodiesel and bioethanol).

An engine faulty operation may be the result of improper use of fuels and lubricants, fact that can conduct to a decrease in lubricating characteristics and oil protection. Technical inspection of an engine is important step that cannot be postponed and it is considered an obligatory process in the warranty period, but especially post - warranty...

Lucrarea de faţă este complementară cursurilor universitare de „Termotehnică” şi „Motoare Termice” şi este destinată, mai degrabă, studenţilor programelor de licenţă „Autovehicule Rutiere” şi „Ingineria Transporturilor și a Traficului”. Ea este o sinteză a reflecțiilor autorilor generate de activitățile din acest domeniu derulate la Universitatea d...

Numărul de faţă al publicaţiei va aduce în discuţie termenul utilizat în limba română pentru a reda piesa monobloc căreia îi corespunde în limba franceză sintagma carter semelle, iar în limba engleză bedplate. Deci: carter semelle (fr) - bedplate (en) - semela (ro)

On vehicles equipped with a turbocharged engine, there is a risk of compressor surge. This surge generates instabilities that lead to driving inconvenience, or even mechanical failure of the supercharging system. In general, the surge appears rather in transient operation: sudden closing of the throttle valve on gasoline engine, regulation of the E...

Among many other professions, automotive engineering has significantly evolved in the past couple of decades and is constantly changing to meet the society needs of the 21st Century. As a simple example, what is today "an ordinary car"? In general, a common person using a car for his/her own needs doesn't think at its complexity at the amount of "w...

This page presents the RCR map (i.e., the values of real compression ratio for the whole engine’s operating area) obtained with the method presented in the paper entitled "On the compression ratio definition".

Termenul supus discuţiei în prezenta lucrare se referă la o componentă din structura motoarelor cu ardere internă, care în limba franceză corespunde substantivului linguet, iar în limba engleză sintagmelor echivalente end pivot rocker arm sau finger follower. Deci: linguet (fr) - end pivot rocker arm (en) sau finger follower (en) - langheta (ro)

This article first gives a brief review of heat engines designed for terrestrial transportation since the 1900s. We then outline the main developments in the state of the art and knowledge about internal combustion engines, focusing on the increasingly stringent pollution constraints imposed since the 1990s. The general concept of high-energy perfo...

Plenary presentation at COFRET2018, Strasbourg, 28-29.06.2018

The goal of the study is related to the design of the automotive engineering curriculum in relation to: - what kind of mathematics should be taught to automotive students? - how can be achieved an optimal integration of the math contents with those of the automotive thermodynamics, gas dynamics, vehicle dynamics, etc? - how can teaching and learni...

Conférencier invité au 19e cycle de conférences "Utilisation rationnelle de l'énergie et environnement", Le Cnam Paris

In acest prim articol pe subiectul terminologiei s-au abordat patru termeni de bază ai domeniului Ingineria Autovehiculelor: autovehicul, automobil, autoturism, vehicul

Given that automobiles and their engines are designed to operate in different conditions, getting the right performance and reliability depend on both the technological factors related to their manufacture and the quality of used fuels. So, it is necessary to present the physico-chemical properties of the fuels in accordance with the performances o...

The European Commission approved a so-called Real Driving Emission (RDE) test in response to the criticisms to the current driving cycle used at chassis dyno for homologation purpose (NEDC): it is considered outdated and misleading since air pollutants in real driving conditions are considerably higher than the certification thresholds. So, what's...

In this paper we present the synthesis of the cam for a distribution mechanism used for Miller-Atkinson cycle and described in previous works. The input data contain the angles at which the valve opens and closes, respectively, the dimensions of the main parts, the maximum displacement of the valve. and the law of motion of the valve. The authors c...

Increased environmental awareness and depletion of fossil petroleum resources are driving the automotive industry to seek out and use alternative fuels. For instance, the biofuel is a major renewable energy source to supplement declining fossil fuel resources. The addition of alcohols like methanol and ethanol is practical in biodiesel blends due t...

The surge limit on automotive turbocharger needs to be avoided to prevent operations with pressure and mass flow oscillations. Mild surge is accompanied by noise which is disturbing. Deep surge can cause significant loss of engine power and severe drivability issues. It is necessary to know the stationary limit in order to match a turbocharger with...

The mechanism considered in this paper is a VCR one consisting in a crank, a shaft, an intermediate triangular element and a control lever and it was described in previous papers of the authors. The authors start from a classical crank-shaft mechanism for which the extreme positions are known. The first stage of the synthesis consists in determinat...

INTRODUCTION and EXTENDED ABSTRACT Road mobility is the engine of economic development and is one of the fundamental aspects of social cohesion because it allows everyone the freedom of movement, along with the advantages inherent to it: easy access to various jobs, to public services, vacations/leisure etc. Even though it still represents the mo...

This article first gives a brief review of thermal engines designed for terrestrial transportation since the 1900s. We then outline the main developments in the state of the art and knowledge about internal combustion engines, focusing on the increasingly stringent pollution constraints imposed since the 1990s. The general concept of high-energy pe...

The use of biodiesel fuel in compression ignition engines has the potential to reduce CO2, which can lead to a reduction in global warming and environmental hazards. Biodiesel is an attractive fuel, as it is made from renewable resources. A major drawback associated with the use of biodiesel, however, is its poor cold flow properties, which have a...

Today, perhaps more than in the past, we think that the great question for the trinomial " academia-industry-state " is the following: are the graduate engineers " fit for purpose " and capable of operating in an industry that needs multi-and inter-disciplinary skills? In other words, is there a gap between industry needs for multi-skilled engineer...

This is the presentation of the article published in The European Proceedings of Social & Behavioural Sciences further to the participation to Edu World 2016 Conference

Technical inspection of a motor vehicle is an activity that should not be neglected and that is deemed to be binding both within the warranty period, but especially post - warranty. An engine malfunction may be due to unsuitable use of fuels and lubricants, resulting in a decrease in lubricating performances and protection of the oil. On the other...

Increasing energy performance of internal combustion engines is largely influenced by frictional forces that arise between moving parts. Thus, in this respect, the nature and quality of the engine oil used is an important factor. Equally important is the effect of various engine injection strategies upon the oil quality. In other words, it's of utm...

Fuel economy is a prime objective in order to meet regulatory and customer demands. Given this context, engine manufacturers are forced to introduce complex systems such as variable valve actuation (VVA). One of the simplest form of a VVA system is what is usually called as variable valve timing (VVT). What's important in these particular cases is...

The use of biodiesel fuel in compression ignition engines has the potential to reduce CO2, which can lead to a reduction in global warming and environmental hazards. Biodiesel is an attractive fuel, as it is made from renewable resources. Many studies have been conducted to assess the impact of biodiesel use on engine performances. Most of them wer...

DOI: 10.1007/978-3-319-27276-4\

The volume includes selected and reviewed papers from the European Automotive Congress held in Bucharest, Romania, in November 2015. Authors are experts from research, industry and universities coming from 14 countries worldwide. The papers are covering the latest developments in fuel economy and environment, automotive safety and comfort, automoti...

This paper is a consequence of a study on assessing the cold-starting performance of a compression ignition engine fuelled with different blends of fossil diesel fuel and biodiesel. Through experimental investigations, it was found that the engine starting at -20°C was no longer possible in the case of using B50 (50% diesel + 50% biofuel made from...

MOOC - mize si provocari In finalul acestui mic articol de prezentare a ceea ce inseamna MOOC, scriam: Închei acest scurt periplu prin lumea MOOC ... gândindu-mă dacă vom vedea, cândva, vreun MOOC lansat în România de universități românești?...