Design and Dynamic Analysis of an Innovative Axial Shift Valvetrain System (ASVS) for Variable Stroke Engine

A variable valvetrain system is the key part of the variable stroke engine (VSE), which could achieve higher power performance and low-speed torque. An innovative axial shift valvetrain system (ASVS) was put forward to meet the air-charging requirements of a 2/4-stroke engine and complete a changeover within one working cycle. Two sets of intake and exhaust cam profiles for both intake and exhaust sides in the 2/4-stoke mode were designed for 2/4-stoke modes. Furthermore, a simulation model based on ADAMS was established to evaluate the dynamic valve motion and the contact force at different engine speeds. The dynamic simulation results show that the valve motion characteristics meet the challenges at the target engine speed of 3000 r/min. In two-stroke mode, the maximum intake valve lift could achieve 7.3 mm within 78°CaA, and the maximum exhaust valve lift could achieve 7.5 within 82°CaA on the exhaust side. In four-stroke mode, the maximum intake valve lift can achieve 8.8 mm within 140°CaA, and the maximum exhaust valve lift can achieve 8.4 mm within 140°CaA. The valve seating speeds are less than 0.3 m/s in both modes, and the fullness coefficients are more than 0.5 and 0.6 in the 2-stroke and 4-stroke mode, respectively. At the engine speed of 3000 r/min, the contact force on each component is acceptable, and the stress between cam and roller can meet the material requirement.

Analisis Bahan Bakar Campuran Methanol dengan Minyak Jarak terhadap Performa Engine 0S 4.6LA Pesawat Terbang Unmanned Aerial Vehicle (UAV)

Technological progress is evidenced by the creation of sophisticated equipment made to simplify human life. One of the advanced equipment continuously developed is an uncrewed aircraft called the Unmanned Aerial Vehicle (UAV). This study used an Unmanned Aerial Vehicle (UAV) Super Heavy aircraft with a two-stroke engine type OS 4.6 LA where the two-stroke engine requires fuel which can also lubricate the piston while operating. The purpose of this research is to make an alternative fuel with a mixture of methanol and castor oil where castor oil has flammable properties like fuel in general but can provide better lubrication. In this research, an analysis of the mixture of methanol and castor oil will be carried out on engine performance and fuel consumption of an Unmanned Aerial Vehicle (UAV) aircraft with an engine type OS 4.6 LA. This research aims to compare methanol and castor oil with a ratio of 3:1 and 4:1, then test engine performance and fuel consumption. The results confirm that a 4: 1 mixture is the best performer with a stationary rotation of 4184 rpm, an idle rotation of 7344 rpm, and an acceleration rotation or the highest rotation of 12649 rpm. Then the fuel efficiency in the idle position with a flight time of 9.00 minutes consumes 100 ml of fuel, or in other words, the fuel consumption is 11.11 ml/minute.

Six-Stroke Cylinder Engine : An Emerging Technology

The requirement for the advancement of internal combustion (IC) engines and enhance methods for the combustion cycle is increasing day by day. The four-stroke combustion engine is extensively used due to better fuel economy and less exhaust smoke. However, the major drawback includes a considerable amount of extra heat energy generation that directly adds up to waste energy. In order to overcome the limitation, the idea of computing two extra strokes in the four-stroke engine to utilize the waste energy has been introduced. The six-stroke engine has significantly improved the fuel working ratio per cycle. Incorporating alternative fuels like hydrogen and HHO into six-stroke technology increases efficiency and minimizes exhaust emissions. A six-stroke engine could be the solution for making hybrid automobile technology more convenient. The review article aims to thoroughly understand the underlying principles behind the improved efficiency of a six-stroke cylinder engine. The researches on the six-stroke cylinder engine are summarized in the literature review. The design configuration of alternative fuels is discussed towards the end of the paper.

Effects of stroke on spark-ignition combustion with gasoline and methanol

Besides electrification of the powertrain, new synthetic alternative fuels with the potential to be produced from renewable sources come into focus. Methanol is the most elementary liquid synthetic fuel and no novelty for use in internal combustion engines. This article presents pathways to achieve high efficiency spark-ignition methanol combustion on a direct injection spark-ignition single-cylinder research engine with two different stroke-to-bore ratios (1.2 and 1.5) and a constant bore. In addition, two compression ratios (CRs) were investigated on each setup: CR = 10.8 using RON95 E10 gasoline fuel and a higher CR = 15 using neat methanol. In contrast to previous studies of stroke-to-bore ratio influences on SI combustion, this article aims at demonstrating how the advantages of a high stroke-to-bore ratio can be exploited by combining a long-stroke engine with increased compression ratios and methanol. The increased stroke enhances the tumble motion due to a higher piston speed and a larger compression volume which improves the mixture homogenization and combustion velocity. Moreover, the lower surface/volume ratio results in a reduced heat transfer. When using RON95E10 gasoline fuel and CR = 10.8, an efficiency gain of up to 1.6% could be achieved with the long-stroke compared to the short-stroke especially at lower engine loads. With methanol and CR = 15, an efficiency gain of up to 1.6% could be achieved with the long-stroke setup compared to the short-stroke engine. Subsequently, lean burn conditions were experimentally investigated with methanol and CR = 15. The longer stroke allowed the lean burn limit to be extended from λ = 1.9 to λ = 2.0 with an efficiency gain of up to 2.2%. A maximum indicated efficiency of 47.4% could be achieved at λ = 1.9 with methanol on the long-stroke engine with CR = 15.

Comparative Study of Combustible Species for 4-stroke Otto Cycle Combustion Motor and 6-stroke MUB-2 Cycle Combustion Motor with Fuel Pertamax

This paper describes the ratio of levels of combustible species (CO, HC, CO2 and lambda) of a four-cycle otto motor with a six-stroke MUB-2 motor with additional combustion duration and two working steps. The increase in combustion duration aims to re-burn combustible species that have not been completely burned in the first combustion. This study used a 4 stroke motor with a capacity of 125 cc and then modified it into a 6 stroke motorbike with twice the duration of combustion. The observed local atmospheric conditions at a relative humidity of about 76% rH, and the ambient temperature and pressure were around 24 ° C and 101.32kPa, respectively. The implementation of data retrieval with crankshaft rotation at intervals of 600 rpm from 2400 rpm to 7200 rpm.Using an anlyser gas, the MUB-2 six-stroke engine showed 12.36% CO levels, 27.30% HC levels, 30.8 CO2 levels % and 1.7% lower lambda than conventional four-stroke engines. This means that in the 6 stroke MUB-2 motor, the combustion process of the air and fuel mixture is more perfect than the conventional 4 stroke motor.