Experimental verification of mathematical model of the heat transfer in exhaust system

Petkovic, Snezana; Pešić, Radivoje; Lukić, Jovanka

doi:10.2298/tsci110517102p

Cited by 3 publications

(2 citation statements)

References 4 publications

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“…This would also fulfill the author's main goal here, to give a modest contribution to researchers' current efforts to improve the energetic and ecological efficiency of internal combustion engines [10][11][12][13]. Additionally, an attempt was made for these, and similar engines to find the optimal pre-ignition angles suitable for the majority of the exploitation conditions with the fuels of higher octane values so that the best use of the potentials of the new, higher quality petrol is achieved in order to improve the general performance of the engine.…”

Section: Introductionmentioning

confidence: 79%

Research of combustion in older generation spark-ignition engines in the condition of use leaded and unleaded petrol

et al. 2014

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This paper analyzes the potential problems in the exploitation of the older generation of spark-ignition engines with higher octane number of petrol (unleaded petrol BMB 95) than required (leaded petrol MB 86). Within the experimental tests on two different engines by applying piezoelectric pressure sensors integrated with the engine spark plugs, acceleration sensors and special electronic block connected with distributor, show that the cumulative first and second theoretical phase of combustion when petrol of higher octane number (BMB 95) is used lasts slightly longer than when the low-octane petrol MB 86 is used. For new petrol (BMB 95) higher optimal angles of pre-ignition have been determined by which better performances of the engine are achieved without a danger of the combustion with detonation (also called knocking).when unleaded petrol is used. Simultaneously, 1/3 to 2/3 of the total amount accumulates at the head of the piston [1]. Deposits in the combustion chamber are not only formed from petrol, but also from the used engine oil.Lead oxides in the deposits, as a kind of ceramics and heat insulators, reduce the effect of the convective heat transfer from the mixture to the chamber walls, reducing the level of the thermal load of the engine [1]. In this way, the working process also approaches the adiabatic process, which theoretically implies the better petrol economy of the engine. The part of the deposits accumulated on the valve seat and on the valve head has the role of a shock absorber, too, which is particularly important when the exhaust valves and their seats exposed to the high temperature of exhaust gases are concerned.Deposits formed by the use of unleaded petrol types do not have any of the above mentioned positive features of deposits originating from petrol with the addition of lead alkylates. Due to their chemical composition, deposits provide high-values of convective heat exchange between the mixture and the elements which form the combustion chamber, and their deep black color considerably increases the heat transfer by means of radiation [1]. This means that, in comparison with the deposits in the use of leaded petrol, we have higher temperatures of the elements which surround the engine combustion chamber and the higher temperatures of the cooling medium. These deposits do not have significant lubricating properties, nor the effect of the shock absorber when the valve hits its seat. The damage of the valve seat of engines has shown not to appear in the normal everyday use of the vehicle. The case of the damage of the valve seat which lead to the engine failure was noticed only on the laboratory acceleration tests, when the engine worked under the constantly high operation load [2]. In such conditions, it has been shown that the valve was not considerably damaged. Also, the previous accumulation of lead deposits and an increased amount of burnt oil deposits on the valves and the valve seats in older engines, prevent the occurrence of micro-welds in the contact metal to metal.On t...

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Section: Introductionmentioning

confidence: 79%

Research of combustion in older generation spark-ignition engines in the condition of use leaded and unleaded petrol

et al. 2014

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“…There are three kinds of method to realize the control the fuel flow rate: servo valve, variable pump, and variable-frequency-regulating-speed (VFRS) pump [2]. Petkovic et al [3] researched the modeling of thermal system. Yu et al [4] and Ren et al [5] studied the fuzzy proportional-integral-derivative (PID) control in the temperature system.…”

Section: Introductionmentioning

confidence: 99%

Modeling and control of temperature of heat-calibration wind tunnel

Teng

Cai

2012

THERM SCI

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This paper investigates the temperature control of the heat air-flow wind tunnel for sensor temperature-calibration and heat strength experiment. Firstly, a mathematical model was established to describe the dynamic characteristics of the fuel supplying system based on a variable frequency driving pump. Then, based on the classical cascade control, an improved control law with the Smith predictive estimate and the fuzzy proportional-integral-derivative was proposed. The simulation result shows that the control effect of the proposed control strategy is better than the ordinary proportional-integral-derivative cascade control strategy

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Real driving particle number (PN) emissions from China-6 compliant PFI and GDI hybrid electrical vehicles

Yang

Thomas

et al. 2019

Atmospheric Environment

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11)n this paper the real driving particle number PN emissions from two China compliant hybrid electrical vehicles 12 (EVs were measured using a certification level portable emission measurement system PEMS and strict 13 adherence to the regulatory procedures for real driving emission RDE testing The results show that the trip 14 averaged PN emission factors for the port fuel injection PF) (EV and the gasoline direct injection GD) (EV were 15 E and E km respectively much higher than the engine only counterparts and failing the existing RDE limits Enriched air fuel mixtures and probably lowered catalyst conversion efficiencies as a result of more frequent engine stop and goes of the (EVs are found to be the underlying reasons for the extra PN emissions The test results also suggest the necessity to amend the power management strategy currently widely used in (EVs to deal with the PN issue Key words particle number real driving emission hybrid vehicles port fuel injection gasoline direct injection

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Experimental verification of mathematical model of the heat transfer in exhaust system

Cited by 3 publications

References 4 publications

Research of combustion in older generation spark-ignition engines in the condition of use leaded and unleaded petrol

Research of combustion in older generation spark-ignition engines in the condition of use leaded and unleaded petrol

Modeling and control of temperature of heat-calibration wind tunnel

Real driving particle number (PN) emissions from China-6 compliant PFI and GDI hybrid electrical vehicles

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