Engine Rpm Research Articles

N-butanol and isobutanol as alternatives to gasoline: Comparison of port fuel injector characteristics

The paper reports on an experimental investigation of the relationship between the pulse width of a gasoline engine port fuel injector and the quantity of the fuel injected when butanol is used as a fuel. Two isomers of butanol, n-butanol and isobutanol, are considered as potential candidates for renewable, locally produced fuels capable of serving as a drop-in replacement fuel for gasoline, as an alternative to ethanol which poses material compatibility and other drawbacks. While the injected quantity of fuel is typically a linear function of the time the injector coil is energized, the flow through the port fuel injector is complex, non ideal, and not necessarily laminar, and considering that butanol has much higher viscosity than gasoline, an experimental investigation was conducted. A production injector, coupled to a production fueling system, and driven by a pulse width generator was operated at various pulse lengths and frequencies, covering the range of engine rpm and loads on a car engine. The results suggest that at least at room temperature, the fueling rate remains to be a linear function of the pulse width for both n-butanol and isobutanol, and the volumes of fuel injected are comparable for gasoline and both butanol isomers.

Considerations Regarding Validation through Simulation of Some Board System Information’s for Powertrain Performance Optimization

The authors present in this paper the opportunities offered by the use of software platforms (MULTISIM) in the validation of informational systems for optimizing economical consumption. So after some research (based on identification methodology system type) a physical-mathematical model can be developed that offers the possibility to optimize fuel consumption in the economy pole depending on specific correlations of operating regimes. Resulted relationships allow designing of information systems by proposing solutions which acquire information on movement speed, engine RPM in load (by determining the actual torque through correlations of exhaust gas temperature, moment and torque).Having these relationships we can design, for example, system version with discrete components or with digital system for surveillance engine operation.

Design and Development of OBD-II Compliant Driver Information System

Background/Objectives: On-Board Diagnostics, or OBD, in a vehicle connection, is a term alluding to a vehicle's logical toward oneself and reporting ability. OBD systems give the vehicle proprietor or a repair expert access to condition of origin data for different vehicle sub-systems. Methods/Statistical Analysis: The driver data framework (DIS) is connected in a vehicle through OBD-II connector. Initially, live information undertaking that gives real time gauges reading. The live information is constrained to show an ambient temperature, Throttle position, Intake manifold absolute pressure, MAF air flow rate, calculated engine load value, intake air temperature, Engine coolant temperature, RPM and vehicle speed (km/h). Second assignment is DTC filtering framework that offers diagnostic trouble codes. Findings: The point of this venture is to get a completely useful Programmable System on Chip (PSoC) platform working with observing live data monitoring and DTCs corresponds with all present day vehicles. Correspondence to and from the ECU will be done utilizing the On-Board Diagnostics two (OBD-II) standard. The correspondence with the ECU must be taken care of utilizing a surveying sort system as information programmed overhauling of information from the ECU isn't possible sporadically. Rather a cyclic process or string will need to run ceaselessly to do a question to the ECU took after by the perusing of the answer. The product will need to work with the returned hexadecimal information in a manner that gives the client or driver valuable information. Conclusion/Improvements: Driver Information System (DIS) helps effective and efficient use of vehicles and can assist a relatively inexperienced drive to shift to proper gears or proper acceleration according to the load on the engine and there by achieve better fuel economy and better emission performance.

열방출량 (Heat Rejection Rate)을 이용한 PTC (Powertrain Cooling) 성능 추정

Abstract It is important to consider powertrain cooling performance, when engine is applied to new vehicle. If theperformance is poor, engine will be damaged by overheating. But, the development timing of engine is faster thantiming of vehicle, it is difficult to test the cooling performance of new engine and vehicle. In this study the powertaincooling performance was estimated with some test and calculation data. First, the heat rejection test was conducted. From this test, the heat rejection data at required rpm and load was acquired. Second, coolant flow test was conducted.From this test coolant flow rate to radiator was measured. Then engine torque and rpm was calculated from vehicle load and speed. Vehicle load and speed was calculated from test mode. Then by comparing these data, the powertraincooling performance was estimated. Key Words : Coolant Flow Data, Heat Rejection Rate, PTC (Powertrain Cooling Performance) * Corresponding Author : Sunki Min(Ajou Motor College)Tel: +82-10-9072-2658 email: skmin@motor.ac.krReceived January 29, 2015 Accepted May 7, 2015Revised (1st March 20, 2015, 2nd May 6, 2015)Published May 31, 2015

OBD-II 시스템을 활용한 자동차 고장진단 프로그램 개발

This paper develops an OBD Diagnostic Program (Program) using Visual Studio (C#), which was used to diagnosis malfunction information from OBD-II system vehicles. We accomplished this using the Program, Diagnostic tests, Board (STN1110), FTDI Basic Cable, Mini USB Cable, OBD Data Cable, and both hybrid and regular vehicles. The Program tests real-time data output, DTC output, sensor value output, engine RPM, waveform data, OBD type check, PID inspection, and whole monitoring. We found vehicles used in this research had 19 PIDs, which was within OBD-II regulations. We also gathered data on control and diagnostic code regulated by OBD-II system, such as, sensor output value, engine RPM, DTC output, each PID analytic value, OBD type, fuel mode, and whole monitoring result value. Using the data collected through the Program appropriately can lead to more effective diagnostic practices and contribute to education.

전자제어 디젤엔진의 연료압력 레귤레이터 고장에 따른 진단 및 성능 연구

Abstract To cope with exhaust gas regulation, Diesel engine applied to electronic control system. As it accuratelyregulated the injected fuel mass and the fuel efficiency and the output are increased but the noise and the vibrationare decreased. In order to keep the performance of Electronic Diesel Control System, it is important to accuratelycontrol the fuel pressure. However, when the regulator of fuel pressure is not controlled properly, the failure phenomenons(starting failure, staring delay, accelerated failure, engine mismatch et al.) occur because the fuel pressureis not stabilize. In this study, effects on a fuel pressure, engine rotating speed according to the control rate of fuel-pressure regulator are investigated in order to analyzed the performance variation with failure of fuel-pressureregulator. As a result, when the control rate of a fuel-pressure regulator is 4%~6% lower than that of standard condition, the variation of engine's rpm and return fuel flow is increased, and the abnormal condition was occurred.Besides, it is possible to diagnose the failures on fuel-pressure regulator under these conditions.

Performance and emission characteristics of Tertiary Butyl Alcohol gasoline blends on a spark ignition engine

The aim of this study is to investigate the effect of gasoline and tertiary butyl alcohol (TBA) blends on the performance and emission features of a spark ignition engine. In this study, a four-stroke three-cylinder carburetor type spark ignition engine was used for leading the experiments. Exhaust emissions were analyzed for carbon dioxide (CO2), oxides of nitrogen (NOx), carbon monoxide (CO), and unburned hydrocarbons (HC) using gasoline TBA blends with different proportions ranging from 0%, 3%, 5%, and 10% blends at 1500, 2000, and 2500 engine rpm. The results depict that the changing of the gasoline TBA blends leads to a decrease in brake specific fuel consumption as the blend percentage increases with respect to the change in rpm, and the brake thermal efficiency increases as the blend percentage increases. The engine exhaust emissions concentration of CO, NOx, and HC decrease.

Flow-pattern switching in a motored spark ignition engine

Cycle-to-cycle variability of intake-jet flow in an optical engine was measured using particle image velocimetry, revealing the possibility of two different flow patterns. A phase-dependent proper orthogonal decomposition analysis showed that one or the other flow pattern would appear in the average flow, sampled from test to test or sub-sampled within a single test; each data set contained individual cycles showing one flow pattern or the other. Three-dimensional velocity data from a large-eddy simulation of the engine showed that the particle image velocimetry plane cuts through a region of high shear between the intake jet and another large flow structure. Rotating the measurement plane ±10° revealed one or the other flow structure observed in the particle image velocimetry measurements. Thus, it was hypothesized that cycle-to-cycle variations in the swirl ratio result in the two different flow patterns in the particle image velocimetry plane. Having an unambiguous metric to reveal large-scale flow cycle-to-cycle variability, causes for this variability were examined within the possible sources present in the available testing. In particular, variations in intake-port and cylinder pressure, lateral valve oscillations, and engine RPM were examined as potential causes for the cycle-to-cycle flow variations using the phase-dependent proper orthogonal decomposition coefficients. No direct correlation was seen between the intake-port pressure, or the pressure drop across the intake valve, and the in-cylinder flow pattern. A correlation was observed between dominant flow pattern and cycle-to-cycle variations in intake-valve horizontal position. RPM values and in-cylinder flow patterns did not correlate directly. However, a shift in flow pattern was observed between early and late cycles in a 2900-cycle test after an approximately 5 r/min engine speed perturbation.

Performance evaluation of air assisted orchard sprayer

Field evaluation of an air assisted orchard sprayer was carried out to determine the distribution pattern of the sprayer based on droplet density and volume of spray deposition using droplet analyzer on Indian gooseberry (Phyllanthus emblica) and kinnow (Rutaceae) orchard. Preliminary evaluation was conducted at 800, 100, 1200, 1400, 1600 and 2000 engine rpm and pressure was set at three different levels of pressure at minimum (4 kg/cm2), middle (10 kg/cm2) and maximum (12, 18, 20, 22, 24 kg/cm2). It was found that with increasing engine rpm and pressure, swath width, height of spray and discharge rate increased for both the nozzles. Based upon preliminary evaluation results, the sprayer was evaluated in orchard of Indian gooseberry at pressure of 22 kg/cm2 and at an engine rpm of 1600, the maximum spray height and swath width was found to be 6.0 m of 13.8 m respectively. The sprayer was operated at pressure of 10 kg/cm2 and an engine rpm of 1000, the maximum spray height and swath width was found to be 4.0 m and 11 m for kinnow plants respectively. The average volume median diameter (VMD) and average number median diameter (NMD) was found to be 152.12 μm and 51.71 for Indian gooseberry and 223.12 μm and 51.71 for kinnow respectively. The saving of labour and saving in cost of spraying was found to be 91.2%, 96.3%, 71.5% and 64.08%, 17.64%, (−3%) respectively as compared to tractor operated gun type sprayer, foot operated sprayer and tractor operated aero blast sprayer.

Analysis of Power and Broadcasts of Gases with Obstruction of the Air Filter

In this project it seeks to meet varying power and gas emission that occurs in a vehicle Chevrolet Corsa to reduce income of air into the intake manifold which also cause a change of pressure therein, and due to this pressure change, the voltage signal emitted by the MAP to the ECU will be affected. The experiment was carried out at different speeds regime as it tries to simulate the operation of an automobile to the topography of Ecuador, which is required to reach high engine rpm to overcome the pending there. While the experiment was carried during no real operating conditions, due that a car would never come to an obstruction of 75%, the data and analysis gives an idea of the seriousness of this is when there the obstruction in the air intake of the engine, and these are reflected directly in the engine performance.

An experimental investigation on the performance characteristics of a hydroxygen enriched gasoline engine with water injection

In this study, effect of hydroxygen (H2 + O2) addition on performance and emissions of a gasoline engine was experimentally investigated. Flow rate of hydroxygen gas mixture was adjusted to 0%, 3.75% (2.5% H2 + 1.25% O2) and 7.5% (5% H2 + 2.5% O2) by-volume of intake charge for entire speed range of the engine. Then, water was injected into the intake manifold of the SI engine to decrease NOx emissions which were significantly increased with hydroxygen addition. Mass flow ratio of water with respect to gasoline was kept constant as 0.25/1. The original electronic control unit (ECU) wasn't modified and a self-developed ECU was used to control gas injectors (for hydroxygen) and water injector. Initially, gasoline injection rate and intake air flow rate were measured with 50% constant throttle position for entire speed range (1500–5000 rpm) of the test engine and then, calculated hydroxygen and water flow rates were introduced into engine. Total hydrocarbons, oxides of nitrogen and carbon monoxide were measured and COVimep, brake power, brake thermal efficiency and BSEC were calculated. According to test results, brake power, brake thermal efficiency and oxides of nitrogen of the test engine were increased up to 11.7%, 5.9% and 141.1% respectively with hydroxygen addition, whereas COVimep, BSEC, total hydrocarbons and carbon monoxide were decreased up to 15.2%, 5.6%, 74.5% and 59.5% with hydroxygen addition. The maximum increase of NOx emission with hydroxygen addition was decreased from 141.1% to 82.7% with water injection. However, the improvements in cyclic variation, brake power, brake thermal efficiency, BSEC, THC and CO emission with hydroxygen addition were reduced with water injection.

LabVIEW를 이용한 자동차 발전기 전압 계측시스템

본 차량에 장착되는 전자장비의 증가로 인해 교류발전기와 배터리를 이용하여 전기에너지를 공급하고 있으며, 자동차 교류발전기의 수명단축은 교류발전기를 구성하고 있는 부속품들 중에 수명이 한정적이거나, 어떠한 조건에서 사용되느냐에 따라 수명에 영향을 끼치게 된다. 이러한 수명단축의 원인들을 파악하기 위해서는 교류발전기의 전압을 측정하여 분석하는 시스템이 필요하다. 따라서 본 연구에서는 자동차 교류발전기의 수명과 성능을 유지하기 위한 점검 및 정비에 필요한 정밀한 계측 시스템을 개발하였다. PC기반의 모니터링 시스템과 측정데이터를 저장할 수 있는 시스템을 설계하고, LabVIEW SW를 이용하여 계측 시스템을 구동하기 위한 프로그램을 개발하였다. 차동 OP-AMP회로를 이용하여 교류발전기의 발전전압, 여자전압, 램프전압, 배터리 전압, 크랭크 각 센서에 의한 엔진 회전수를 NI DAQ를 통하여 전압을 측정하고 LabVIEW 프로그램을 이용하여 측정데이터를 분석하였다. 기존에 개별적으로 이루어졌던 측정을 5개 채널까지 복합적이고 이동성이 용이한 측정이 가능하였고, 실시간으로 모니터링하며 분석하기 때문에 이상동작 유무 및 고장상태를 예측하기 위한 자료로 활용될 수 있을 것으로 기대된다. Faults in electric power system can be a critical problem for vehicles. The system durability is determined mainly by the durability of their components and operating conditions. Monitoring the conditions of the electric power system may be necessary because it is very difficult to predict precisely when it will fail. Therefore, the aim of this study was to develop a diagnosis system for an electric power system of a vehicle. The alternator voltage, excitation voltage, lamp voltage, battery voltage, and engine rpm from a crank angle sensor are monitored continuously and the system fault can be then detected in real time. NI USB- 9201 DAQ and LabVIEW SW have been used to measure the voltages and analyze the data. Compared to conventional measurements for only each component, an integrated and portable measurement method was developed. In addition to the monitoring the electric power system in real time, the saved data from the measurement also provides valuable information to improve the durability of the components.

Characterization of cycle-to-cycle variations in a natural gas spark ignition engine

In this work a study of the influence of the fuel/air equivalence ratio and engine rotational speed on the cycle-to-cycle variations in combustion in a natural gas spark ignition engine is presented. The study considers both classic estimators of cyclic dispersion and a new one, based on the burned mass and burning rate. The engine experimental conditions were as follows: Intake pressure 0.5bar, while fuel/air equivalence ratio was changed from 1.0 to 0.63, and engine rotational speed was varied from 1000rpm to 2500rpm. For each equivalence ratio and engine speed, a diagnosis model is used to process the experimentally obtained combustion pressure data in order to provide combustion relevant results such as the mass burning rate at a cycle level. A procedure based on the use of genetic algorithms is used to obtain a very accurate and objective (without human intervention) adjustment of the optimum parameters needed for combustion diagnosis: angular positioning and pressure offset of the pressure register, dynamic compression ratio, and heat transfer coefficients. The model allows making the diagnosis of series of 830 consecutive engine cycles in an automatic way, increasing the objectivity of the combustion diagnosis. The paper focuses on using the values of the mass fraction burned computed from the pressure register and especially on the analysis of the combustion cycle to cycle variation in the natural gas fuelled engine. A new indicator for the study of cycle-to-cycle variations is proposed, i.e. the standard deviation of the mass fraction burning rate. The values of this new indicator are compared with other classic indicators, showing the same general trends. However, a deeper insight is provided on the combustion cyclic variation when the values of the new indicator are plotted as a function of the mass fraction burned, since this allows analyzing the cyclic variation along the combustion development in each cycle from a mass fraction burned of zero to one, with a relevant value at mass fraction burned of 0.5. More important is that the consideration of the dependence of the combustion variables (density, flame front surface, combustion speed) on the mass fraction burned allows ensemble averaging of all registered cycles for each value of mass fraction burned. This permits using the ensemble averaged mass fraction burning rate as an estimator of combustion speed.The analysis of the general trends of cyclic dispersion when engine speed and equivalence ratio are modified (1000, 1750 and 2500rpm; 0.7, 0.8, 0.9 and 1.0) indicate that cycle-to-cycle variations show, as expected, a strong dependence on the engine rotational speed, increasing the variation with engine rpm. However, when the standard deviation of mass fraction burning rate is plotted as a function of mass fraction burned, there is a linear dependence on engine rpm, but only a very weak dependence on equivalence ratio. This means that the proposed estimator of cyclic dispersion is sensitive to only flow turbulent intensity and not to equivalence ratio.

Estimation of Engine Intake Air Mass Flow using a generic Speed-Density method

SHRNUTÍ Měření výfukových emisí spalovacích motorů během reálného provozu přenosnými zařízeními umístěnými na palubě vozidla (PEMS) je důležitou součástí hodnocení dopadu nových paliv a technologií na životní prostředí a lidské zdraví. Znalost aktuálního toku výfukových plynů je jedním z nezbytných předpokladů pro takové provozní měření. Jedním z nejjednodušších způsobů je výpočet z toku nasáveného vzduchu, který je vypočten z měřených otáček motoru a tlaku a teploty náplně v sacím potrubí. V této práci byl obecný algoritmus využívající odhad dopravní účinnosti libovolného běžného čtyřdobého motoru aplikován na tři produkční evropské motory běžně využívané v ČR: těžký a automobilový přeplňovaný vznětový motor, a atmosférický zážehový motor. Vypočtené průtoky nasávaného vzduchu byly porovnány s různými referenčními metodami. Výsledky ukazují, že nejistota stanovení toku nasáveného vzduchu obecným algoritmem je v řádu 10% pro většinu provozních režimů motoru, kromě případů recirkulace velké části výfukových plynů, kdy nejistota vzrůstá na desítky procent. Desetiprocentní nejistota pro motory bez vysoké míry recirkulace výfukových plynů je přijatelná pro mnohá, zvláště průzkumná a orientační, měření emisí za provozu, a může být snížena kalibrací algoritmu pro daný motor.

Progress in electronic fuel injection control systems for automotive diesel engines

The fuel injection timing and the fuel quantity are two of the major parameters to be precisely controlled to optimise diesel engine. This paper presents a new electronic injection timing control based on direct sensing of the start of combustion. Although the injection timing is usually optimised against engine rpm and load, it is also affected by the atmospheric pressure, coolant temperature, fuel properties and injection rate deterioration. By using a start–of–combustion sensor the influence of these parameters on injection timing can be compensated for and the engine performance can be recovered. A new fuel quantity control has been also developed. Instead of 'spill ring' control, an electronic magnetic valve with fast response has been adopted, which enables more precise control of the amount of fuel injected.

Eficiência energética de um trator agrícola utilizando duas configurações de tomada de potência

A tomada de potência (TDP) de um trator agrícola tem por principal finalidade transmitir a potência gerada no motor, para acionamento de órgãos ativos das máquinas agrícolas. Tendo em vista a necessidade de se aumentar a eficiência energética na agricultura, alguns fabricantes disponibilizam para os agricultores uma configuração de TDP que proporciona o acionamento dessas máquinas a um regime de rotação menor do motor do trator. Assim, a rotação da TDP é mantida podendo-se obter uma redução do consumo de combustível. Este trabalho objetivou quantificar o consumo de combustível de um trator agrícola, operando com duas configurações de TDP (normal e econômica) em duas áreas agrícolas de relevo distinto. Como resultado, evidencia-se que, com a utilização da TDP econômica, tanto o consumo horário quanto o consumo operacional de combustível, em ambas as áreas trabalhadas, foi menor quando comparado à TDP normal.

150마력급 선내형 소형 워터제트 추진시스템 개발

Abstract: This study is on the development of 150PS inboard type of compact water jet propulsion system. The water jet is composed of intake, impeller, diffuser, reverse bucket and main shaft. Components of water jet have been manufactured through precision processing after sand casting. Development of water jet pro-pelled engine has been finally completed by processes which are design, production and inspection on each component. The water jet performance characteristics show that 0.29 m 3 /s of maximum flow rate and 37 m/s of flow velocity have been secured in the ground test pool. Field test was performed by 21ft test ship that water jet propulsion equipment developed in this study was installed. As a result, the weight of hull, engine and other parts of the ship has been almost 1.2 ton and 45 km/h of maximum sailing speed has been re-corded with 3700 rpm of engine in the domestic coast test. Keywords: Water Jet, Inboard, Propulsion System 1. 서 론 국내 소형선박의 경우 몰드(mould:선박외형)는 대부분 FRP(fiberglass reinforced plastics:유리섬유강화플라스틱)소재를 적용하여 제작하고 있는 실정이며, 그 외 엔진 및 기타 선박관련 부품은 수입에 의존하고 있는 경우가 많다. 현재 소형선박의 경우 90%가 8m 이내의 선박이며, 이 중에서 5~8m의 선박이 약 50%를 차지하고 있다. 또한, 추진기는 대부분 선외기를 적용하고 있다

Investigation of failure in main fuel pump of an aeroengine

There was an accident to a fighter aircraft. Investigation revealed that the accident was caused due to loss of power in the engine as a result of failure in the main fuel pump (MFP). The MFP was multi-plunger type. On dis-assembly, the MFP was found severely damaged and there were fractures in one plunger and four springs. Through systematic metallurgical investigation and analysis, the sequence of events leading to the failure in the MFP was established. The primary failure in the MFP was the fatigue fracture of springs. The fatigue crack initiation could be attributed to pitting corrosion on the surface of the springs. Because of multiple fractures in one of the springs, there was impact load on the corresponding plunger, which resulted in generation of an overload crack. This crack had further propagated progressively by fatigue mechanism culminating in fracture and loss of material from the side wall of the plunger. Subsequently, there was fuel leakage internally in the MFP with the resultant reduction in the fuel delivery pressure. Due to insufficient fuel supply, there was winding down of the engine RPM leading to loss of thrust. After establishing the sequence of failure in the MFP, investigation was carried out to identify the cause for the corrosion on the surface of the springs. It was established that the raw material (wires) used for the manufacture of the springs had developed corrosion pits on the surface due to improper storage.

Study of a Novel Air-augmented Waterjet Boost Concept

This research presents analysis, experiment, and prediction of the performance of a unique marine propulsion concept, the air-augmented waterjet, having a revolutionary potential for significant thrust augmentation and boost capability of waterjet systems. So far, this concept has not been realized in any operational vessel. The air-augmented waterjet propulsion concept is similar to an after-burner in the aeronautical turbojet engine. The thrust augmentation results from the injection of air bubbles into the water flow, converting their expansion work òpdV into additional kinetic energy of the exhaust jet without affecting the pump operation. It can enable substantially augmenting boost capability, overcoming hump resistance, and increasing maximum attainable vessel speed while avoiding cavitation problems. Static tests at the Technion's water tank, using a jetski waterjet engine of a nominal power of 50 kW, have been conducted with and without air injection over a range of motor revolutions per minute (rpm). The addition of air increased the thrust by 20% to 50% depending on the airflow rate and engine rpm. Air expansion work increased the exhaust jet kinetic energy at an efficiency of 70% approximately. Based on the static experiments, prediction of the system behavior for different vessel speeds and engine power levels has been made, revealing a higher relative thrust augmentation for the same pump power and airflow rate at higher vessel speeds. The air-augmented waterjet concept may add a new dimension to marine propulsion as well as upgrade existing vessels.

Study of a Novel Air-augmented Waterjet Boost Concept

This research presents analysis, experiment, and prediction of the performance of a unique marine propulsion concept, the air-augmented waterjet, having a revolutionary potential for significant thrust augmentation and boost capability of waterjet systems. So far, this concept has not been realized in any operational vessel. The air-augmented waterjet propulsion concept is similar to an after-burner in the aeronautical turbojet engine. The thrust augmentation results from the injection of air bubbles into the water flow, converting their expansion work ∫pdV into additional kinetic energy of the exhaust jet without affecting the pump operation. It can enable substantially augmenting boost capability, overcoming hump resistance, and increasing maximum attainable vessel speed while avoiding cavitation problems. Static tests at the Technion's water tank, using a jetski waterjet engine of a nominal power of 50 kW, have been conducted with and without air injection over a range of motor revolutions per minute (rpm). The addition of air increased the thrust by 20% to 50% depending on the airflow rate and engine rpm. Air expansion work increased the exhaust jet kinetic energy at an efficiency of 70% approximately. Based on the static experiments, prediction of the system behavior for different vessel speeds and engine power levels has been made, revealing a higher relative thrust augmentation for the same pump power and airflow rate at higher vessel speeds. The air-augmented waterjet concept may add a new dimension to marine propulsion as well as upgrade existing vessels.