scholarly journals HCCI combustion – a challenge for internal combustion engine

2009 ◽  
Vol 136 (1) ◽  
pp. 3-9
Author(s):  
Andrzej KOWALEWICZ
Keyword(s):  
Combustion Engine ◽  
Valve Train ◽  
Exhaust Gas ◽  
Hcci Engine ◽  
Hcci Combustion ◽  
Particulate Matter Emissions ◽  
Variable Valve Train ◽  
Variable Valve ◽  
Gas Recirculation ◽  
Low Nitrogen

HCCI engine offers a high thermal efficiency combined with low nitrogen oxides and particulate matter emissions. However the key problem: controlled autoignition (CAI) on which is focused this paper is still not solved. Attempts to solve CAI problem as: variable compression ratio (VCR), variable valve train (VVT), exhaust gas recirculation (EGR) and application of fuels having different volatility characteristics and sensitivity to autoignition are disused. Also possibility of fuelling HCCI engine with natural gas (and ignition improver) is presented.

scholarly journals Optimal Degree of Hybridization for Spark-Ignited Engines with Optional Variable Valve Timings

Energies ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 8151
Author(s):  
Andyn Omanovic ◽  
Norbert Zsiga ◽  
Patrik Soltic ◽  
Christopher Onder
Keyword(s):  
Internal Combustion Engine ◽  
Fuel Consumption ◽  
Fuel Economy ◽  
Combustion Engine ◽  
Internal Combustion ◽  
Valve Train ◽  
Effective Measure ◽  
Optimal Degree ◽  
Variable Valve Train ◽  
Variable Valve

The electric hybridization of vehicles with an internal combustion engine is an effective measure to reduce CO2 emissions. However, the identification of the dimension and the sufficient complexity of the powertrain parts such as the engine, electric machine, and battery is not trivial. This paper investigates the influence of the technological advancement of an internal combustion engine and the sizing of all propulsion components on the optimal degree of hybridization and the corresponding fuel consumption reduction. Thus, a turbocharged and a naturally aspirated engine are both modeled with the additional option of either a fixed camshaft or a fully variable valve train. All models are based on data obtained from measurements on engine test benches. We apply dynamic programming to find the globally optimal operating strategy for the driving cycle chosen. Depending on the engine type, a reduction in fuel consumption by up to 32% is achieved with a degree of hybridization of 45%. Depending on the degree of hybridization, a fully variable valve train reduces the fuel consumption additionally by up to 9% and advances the optimal degree of hybridization to 50%. Furthermore, a sufficiently high degree of hybridization renders the gearbox obsolete, which permits simpler vehicle concepts to be derived. A degree of hybridization of 65% is found to be fuel optimal for a vehicle with a fixed transmission ratio. Its fuel economy diverges less than 4% from the optimal fuel economy of a hybrid electric vehicle equipped with a gearbox.

scholarly journals Design of an Electromagnetic Variable Valve Train with a Magnetorheological Buffer

Energies ◽  
2019 ◽  
Vol 12 (20) ◽  
pp. 3999 ◽  
Author(s):  
He Guo ◽  
Liang Liu ◽  
Xiangbin Zhu ◽  
Siqin Chang ◽  
Zhaoping Xu
Keyword(s):  
Electromagnetic Force ◽  
Combustion Engine ◽  
Structure Design ◽  
Valve Train ◽  
Valve Lift ◽  
Soft Landing ◽  
Overall Design ◽  
Variable Valve Train ◽  
Electromagnetic Linear Actuator ◽  
Variable Valve

In this paper, an electromagnetic variable valve train with a magnetorheological buffer (EMVT with MR buffer) is proposed. This system is mainly composed of an electromagnetic linear actuator (EMLA) and a magnetorheological buffer (MR buffer). The valves of an internal combustion engine are driven by the EMLA directly to open and close, which can adjust the valve lift and phase angle of the engine. At the same time, MR buffer can reduce the seat velocity of the valve and realize the seat buffer of the electromagnetic variable valve. In this paper, the overall design scheme of the system is proposed and the structure design, finite element simulation of the EMLA, and the MR buffer are carried out. The electromagnetic force characteristics of the EMLA and buffer force of the MR buffer are measured, and the seat buffering performance is verified as well. Experiments and simulation results show that the electromagnetic force of the EMLA can reach 320.3 N when the maximum coil current is 40 A. When the current of the buffer coil is 2.5 A and the piston’s motion frequency is 5 Hz, the buffering force can reach 35 N. At the same time, a soft landing can be realized when the valve is seated.

Experimental Research of HCCI Combustion Based on Late Exhaust Duct EGR Strategy

2015 ◽  
Vol 713-715 ◽  
pp. 327-330
Author(s):  
Yin Han Gao ◽  
Yu Chao Jiang ◽  
Peng Cheng ◽  
Jun Cheng Chi ◽  
You Kun Wang
Keyword(s):  
Pressure Rise ◽  
Valve Train ◽  
Maximum Pressure ◽  
Hcci Combustion ◽  
Combustion Duration ◽  
Rise Rate ◽  
Exhaust Duct ◽  
Variable Valve Train ◽  
Test Engine ◽  
Variable Valve

Late exhaust duct EGR strategy is one of internal EGR strategies to realize HCCI combustion. Based on a single-cylinder test engine system equipped with an electronic controlled hydraulic variable valve train system, the effects of valve phases in this strategy were studied. The results show that at engine speed 1000r/min, equivalent air-fuel ratio λ= 1, when the IVO phase is put off, EGR ratio increases gradually, CA10 and CA50 are postponed and combustion duration becomes longer. At the same time, peak pressure and maximum pressure rise rate have a tendency to descend. When the SEVO phase is postponed, the parameters of the test engine will also be affected. However, when the phase is postponed above the critical point, the parameters have a backward trend. The property of HCCI combustion is not sensitive to SEVO phase.

Cylinder Deactivation with Mechanically Fully Variable Valve Train

2012 ◽  
Vol 5 (2) ◽  
pp. 207-215 ◽  
Author(s):  
Rudolf Flierl ◽  
Frederic Lauer ◽  
Michael Breuer ◽  
Wilhelm Hannibal
Keyword(s):  
Valve Train ◽  
Cylinder Deactivation ◽  
Variable Valve Train ◽  
Variable Valve

Variable Valve Train Concept for Compliance with Future Diesel Emission Standards

MTZ worldwide ◽  
2021 ◽  
Vol 82 (2) ◽  
pp. 36-41
Author(s):  
Michael Elicker ◽  
Wolfgang Christgen ◽  
Jahaazeb Kiyanni ◽  
Maximilian Brauer
Keyword(s):  
Valve Train ◽  
Emission Standards ◽  
Variable Valve Train ◽  
Diesel Emission ◽  
Variable Valve
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