A study on performance and exhaust emissions of the steam injected DI diesel engine running with different diesel- conola oil methyl ester blends

Although biodiesels have low emission profiles, the main drawback of using biodiesel in diesel engines is higher NOx. Nowadays, the electronic controlled steam injection is a promising method for NOx control. This study investigates the effects of steam injection with diesel fuel-canola oil methyl ester (COME) blends on the performance and emissions characteristics of a direct injection (DI) single cylinder diesel engine. Steam is injected into the inlet manifold during inlet period. The combustion of diesel-COME blends has been modeled using two zone combustion model. The results have been compared with each other in terms of performance and emissions. The maximum increments in engine torque and power were measured as 2.5% for 10% COME (B10) at 1200 rpm, 2.8% for 20% COME (B20) at 2200 rpm. The effects of steam injection on performance and emissions of the diesel engine running with B10 and B20 COME blends were also investigated. Satisfaction improvements have been obtained with the combination of steam injection and COME blends. The maximum torque of the engine running with B10 and 10% steam ratio combination (B10 + S10) and B20 and 10% steam ratio combinations (B20 + S10) were found as 2.4% at 1400 rpm and 0.6% at 1400 rpm, respectively. Significant reduction has been observed in NOx emission with B10-S10 combination. The reduction rate in NOx emissions were 22% with B10-S10 and 18% with B20-S10 at 1200 rpm. The study showed that steam injection is an effective tool for controlling NOx emissions without performance degradation in the diesel engines fueled with COME blends.     

Experimental study of combustion performances and emissions of a spark ignition cogeneration engine operating in lean conditions using different fuels

This work presents an experimental study describing a six-cylinder spark ignition engine running with a lean equivalence ratio, high compression ratio, ignition delay and used in a cogeneration system (heat and electricity production). Three types of fuels; natural gas, pure methane and methane/hydrogen blend (85% CH₄ and 15% H₂ by volume), were used for comparison purposes. Each fuel has been investigated at 1500 rpm and for various engine loads fixed by electrical power output conditions. CO, CO₂, HC, and NOx emissions values, and exhaust gas temperature were measured. The effect of fuel composition on engine characteristics has been studied. The results show, that the hydrogen addition increased HC emissions (around 18%), as well as performance, whilst it reduced NO_x (around 31%), exhaust gas temperature, CO and CO₂.     

Using HHO (Hydroxy) and hydrogen enriched castor oil biodiesel in compression ignition engine

Hydrogen and HHO enriched biodiesel fuels have not been investigated extensively for compression ignition engine. This study investigated the performance and emissions characteristics of a diesel engine fueled with hydrogen or HHO enriched Castor oil methyl ester (CME)-diesel blends. The production and blending of CME was carried out with a 20% volumetric ratio (CME20) using diesel fuel. In addition, the enrichment of intake air was carried out using pure HHO or hydrogen through the intake manifold with no structural changes – with the exception of the reduction of the amount of diesel fuel – for a naturally aspirated, four cylinder diesel engine with a volume of 3.6 L. Hydrogen amount was kept constant with a ratio of 10 L/min throughout the experiments. Engine performance parameters, including Brake Power, Brake Torque, Brake Specific Fuel Consumption and exhaust emissions – including NOx and CO, – were tested at engine speeds between 1200 and 2600 rpm. It is seen that HHO enriched CME has better results compared to pure hydrogen enrichment to CME. An average improvement of 4.3% with HHO enriched CME20 was found compared to diesel fuel results while pure hydrogen enriched CME20 fuel resulted with an average increase of 2.6%. Also, it was found that the addition of pure hydrogen to CME had a positive effect on exhaust gas emissions compared to that adding HHO. The effects of both enriched fuels on the engine performance were minimal compared to that of diesel fuel. However, the improvements on exhaust gas emissions were significant.     

柴油中溶入甲烷对发动机燃烧排放特性的影响

设计了几种不同甲烷含量的甲烷／柴油混合燃料,在实用柴油机上对它们的燃烧和排放特性进行了试验研究。研究结果表明,根据柴油中甲烷含量的不同,溶气对比油耗和热效率有正反两方面的影响;溶有甲烷的柴油与纯柴油相比有较长的着火滞燃期和较低的最大放热率;柴油中甲烷的溶解量越大,滞燃期越长,最高放热率越低;与纯柴油相比,溶有甲烷柴油的NOx排放降低,HC排放增加;在较高的甲烷溶解度时,NOx和烟度排放能够同时降低。     

柴油机掺烧不同比例生物柴油的试验研究

将体积分数为10%2、0%、30%的生物柴油掺混到柴油里组成3种混合燃料,并连同纯柴油共4种燃料,在一台四缸增压中冷柴油机上进行性能、燃烧和排放特性的试验研究.结果表明,柴油机燃用生物柴油与柴油混合燃料的折合油耗率与燃用纯柴油时基本相当;燃用混合燃料的缸内最大爆发压力和压力升高率较低,着火时刻较晚;混合燃料的NOx和碳烟排放与燃用纯柴油时相比均有不同程度的降低,但混合燃料的HC和CO排放只是在1 500r/min时才较纯柴油低,当转速在2 300 r/min时,混合燃料的HC和CO排放更高.     

Hydrogen effects on the diesel engine performance and emissions

In this research, effects of hydrogen addition on a diesel engine were investigated in terms of engine performance and emissions for four cylinders, water cooled diesel engine. Hydrogen was added through the intake port of the diesel engine. Hydrogen effects on the diesel engine were investigated with different amount (0.20, 0.40, 0.60 and 0.80 lpm) at different engine load (20%, 40%, 60%, 80% and 100% load) and the constant speed, 1800 rpm. When hydrogen amount is increased for all engine loads, it is observed an increase in brake specific fuel consumption and brake thermal efficiency due to mixture formation and higher flame speed of hydrogen gas according to the results. For the 0.80 lpm hydrogen addition, exhaust temperature and NOx increased at higher loads. CO, UHC and SOOT emissions significantly decreased for hydrogen gas as additional fuel at all loads. In this study, higher decrease on SOOT emissions (up to 0.80lpm) was obtained. In addition, for 0.80 lpm hydrogen addition, the dramatic increase in NOx emissions was observed.     

Hydrogen addition to tea seed oil biodiesel: Performance and emission characteristics

Compression ignition engines are the dominant tools of the modern human life especially in the field of transportation. But, the increasing problematic issues such as decreasing reserves and environmental effects of diesel fuels which is the energy source of compression ignition engines forcing researchers to investigate alternative fuels for substitution or decreasing the dependency on fossil fuels. The mostly known alternative fuel is biodiesel fuel and many researchers are investigating the possible raw materials for biodiesel production. Also, hydrogen fuel is an alternative fuel which can be used in compression ignition engines for decreasing fuel consumption and hazardous exhaust emissions by enriching the fuel. In this study, influences of hydrogen enrichment to diesel and diesel tea seed oil biodiesel blends (B10 and B20) were investigated on an unmodified compression ignition engine experimentally. In consequence of the experiments, lower torque and higher brake specific fuel consumption data were measured when the engine was fuelled diesel biodiesel blends (B10 and B20) instead of diesel fuel. Also, diesel biodiesel blends increased CO₂ and NO_x emissions while decreasing the CO emissions. Hydrogen enrichment (5 l/m and 10 l/m) was improved the both torque and brake specific fuel consumption for all test fuels. Furthermore, hydrogen enrichment reduced CO and CO₂ emissions due to absence of carbon atoms in the chemical structure for all test fuels. Increasing flow rate of hydrogen fuel from 5 l/m to 10 l/m further improved performance measures and emitted harmful gases except NO_x. The most significant drawback of the hydrogen enrichment was the increased NO_x emissions.     

Numerical and experimental investigation of hydrogen enrichment in a dual-fueled CI engine: A detailed combustion,performance, and emission discussion

An effort has been made to simulation a compression ignition engine using hydrogen-diesel, hydrogen-diethyl ether, hydrogen-n-butanol and base diesel fuel as alternatives. The engine measured for the simulation is a single cylinder, four stroke, direct injection, diesel engine. During the simulation the injection timing and engine speed are kept constant at 23°bTDC and 1500 rpm. Diesel-RK, a piece of commercial software employed for this project, can forecast an engine emission, performance and combustion characteristics. The examination of the anticipated outcomes reveals that adding hydrogen to diesel leads in a small increase in efficiency and fuel consumption. With the usage of hydrogen-blend fuels, the majority of dangerous pollutants in exhaust are greatly decreased. The shortest ignition delay was consistently given by 5H295DEE. The lowest CO₂ (578.61 g/kWh) was given by 5H295nB at CR 19.5. Hydrogen blends increase NOx emissions more than base diesel fuel. In the case of smoke and particulate matter emission, the reduce tendency was seen.     

An experimental study on performance,emission and combustion parameters of hydrogen fueled spark ignition engine with the timed manifold injection system

In the present study, a single cylinder spark ignition (SI) engine is modified to operate with hydrogen gas with ECU (Electronic Controlled Unit) operated timely manifold injection system. Performance, emission and combustion parameters are studied at MBT (Maximum Brake Torque) spark timing with WOT (Wide Open Throttle) position. All trials are performed in the speed range of 1100 rpm–1800 rpm. Baseline observations are recorded with gasoline for comparison purpose. Results have shown that maximum brake power is reduced by 19.06% and peak brake thermal efficiency is increased by 3.16% in the case of hydrogen operation. Reduction in NO_x emission is observed for hydrogen at higher engine speed. The maximum net heat release rate is two times higher and the peak cylinder pressure is 1.36 times higher for hydrogen as compared to gasoline at the engine speed of 1400 rpm.     

非直喷式增压柴油机燃用生物柴油的性能与排放特性

研究了非直喷式增压柴油机燃用柴油一生物柴油混合燃料的性能和排放特性。未对原机作任何调整和改动，研究了不同生物柴油掺混比例的混合燃料对功率、油耗、烟度和NOx排放的影响。结果表明：非直喷式柴油机燃用生物柴油后柴油机功率略有下降，油耗有所上升，烟度大幅下降，NOx排放增加明显。油耗、烟度和NOx的变化均与生物柴油掺混比例呈线性关系，合适的生物柴油掺混比例即可以保持柴油机的性能，又可有效地降低碳烟排放，且不引起NOx排放的显著变化。对于该增压柴油机，掺混生物柴油对外特性下的排放影响最大，影响最小的为标定转速下的负荷特性。不论是全负荷还是部分负荷，燃用生物柴油时低速下的烟度降低和NOx上升幅度均比高速时大，而同转速下高负荷时烟度降低和NOx上升更为明显。     

Effect of different volume fractions of ammonia on the combustion and emission characteristics of the hydrogen-fueled engine

Hydrogen internal combustion engines (ICE) will play an important role in reducing carbon emissions, but low power density and abnormal combustion problems are the main obstacles restricting the promotion of hydrogen ICE. Ammonia is a low-reactivity renewable fuel. The purpose of this study is to study the effect of different ammonia-added volume fractions on hydrogen ICE. In this experimental study, the combustion and emission characteristics of an engine fueled by a hydrogen/ammonia mixture were evaluated at part-load operating conditions. The experiment was carried out on a modified engine, the engine speed was 1300 rpm, the absolute pressure of the manifold was 61 kPa, and the volume fraction of ammonia added was 5.2%, 7.96%, and 10.68%, respectively. The test results show that the addition of ammonia changes the combustion characteristics of hydrogen. As the volume fraction of ammonia added increases, the flame development period and flame propagation period are both prolonged, and the peak heat release rate decreases. The addition of ammonia increases the power of the engine and reduces the indicated thermal efficiency. At the ignition timing of the maximum braking torque, as the volume fraction of ammonia added increases, the indicated mean effective pressure and indicated thermal efficiency increase. Adding ammonia volume fraction has little effect on Nitrogen oxides (NOx) emissions, and NOx emissions gradually increase with the delay of ignition timing.     

Combined effect of multi-injection scheme,injector nozzle bore,and biodiesel blends on combustion and performance characteristics of diesel engine

Many researchers have conducted extensive experimental and numerical studies to explore the influences of multiple types of fuels. The high demand of energy in the world has led to the growing crisis and depletion of fossil fuels. Therefore, the researchers have focused on investigating renewable energy sources like biodiesel with the aim of suggesting, which energy is more friendly to the environment. Biodiesel has specifications for using it as an alternative fuel to traditional fossil fuels. Whereas, the use of biodiesel fuel in the original design of Diesel engine can emit a higher percentage of nitrogen oxides (NO_x). Therefore, to reduce the harmful emissions of the fuel, the injection schemes and injector nozzle bore (INB) of the engine were modified. The present research combines the effect of the nozzle hole diameters and split injection scheme on the performance and combustion parameters of compression ignition (CI) engine was investigated. The engine was fueled with diesel blended of different proportions (Sp20, Sp40, Sp60, and Sp100) of spirulina biodiesel to prove the suitability of this blend as an alternative fuel. The injector nozzle has three injection holes, and the diameter of the three modified holes of the nozzle is changing (from 0.20 to 0.28 mm, step 0.02 mm) along with two types of scheme injection (double and triple). Furthermore, the influence of the direct injection Diesel-RK model, single-cylinder, four-stroke engine; constant compression ratio (17.5:1), engine speed (1500 rpm), and naturally aspired engine at full load condition are studied. A comparison of the present simulation is compared with published results to validate the present simulation model for conventional baseline Diesel for validation. The simulation was done to investigate and present a comparative study with the conventional baseline Diesel engine. The double injection scheme shows a decrease by 1.8%, 1.7%, and 1.9% for parameters of peak cylinder pressure (PCP), peak cylinder temperature (PCT), and maximum rate of pressure rise, respectively. Whereas, the specific fuel consumption (SFC) and break thermal efficiency are increased by 8.7% and 9.33%, respectively. The results showed a reduction by 2.1%, 20.5%, 22.1%, and 3.2% in PCP, PCT, maximum rate of pressure rise, and break thermal efficiency, respectively. Moreover, the SFC is increased by 3.1% with the modified INB 0.28 (mm).     

Effect of ammonia addition on combustion and emissions performance of a hydrogen engine at part load and stoichiometric conditions

The development of alternative fuels is important in the fight against climate change. Both hydrogen and ammonia are renewable energy sources and are carbon-free combustible fuels. In a recent experimental study, the performance and emission characteristics of a spark-ignition engine burning a premixed hydrogen/ammonia/air mixture were evaluated. The manifold absolute pressure was adjusted to 61 kPa and the engine speed was stabilized at 1300 rpm. The difference between a mixture with a 2.2% volume fraction of ammonia and a pure hydrogen fuel was analyzed in comparison. Specifically, the addition of ammonia increased the ignition delay and flame development periods and reduced the rate of in-cylinder pressure rise. In conjunction with the ignition timing strategy, the addition of ammonia did not affect the engine performance. Nitrogen oxides emissions are increased due to the addition of ammonia. The experimental results suggest that ammonia can be used as a combustion inhibitor, which provides a new reference for the development of hydrogen-fuelled engines.     

Investigation of hydrogen addition to methanol-gasoline blends in an SI engine

In this study, effects of hydrogen-addition on the performance and emission characteristics of Methanol-Gasoline blends in a spark ignition (SI) engine were investigated. Experiments were conducted with a four-cylinder and four stroke spark ignition engine. Performance tests were performed via measuring brake thermal efficiency, brake specific fuel consumption, cylinder pressure and exhaust emissions (CO, CO₂, HC, NOx). These performance metrics were analyzed under three engine load conditions (no load, 50% and 100%) with a constant speed of 2000 rpm. Methanol was added to the gasoline up to 15% by volume (5%, 10% and 15%). Besides, hydrogen was added to methanol-gasoline mixtures up to 15% by volume (3%, 6%, 9% and 15%). Results of this study showed that methanol addition increases BSFC by 26% and decreases thermal efficiency by 10.5% compared to the gasoline. By adding hydrogen to the methanol - gasoline mixtures, the BSFC decreased by 4% and the thermal efficiency increased by 2% compared to the gasoline. Hydrogen addition to methanol – gasoline mixtures reduces exhaust emissions by about 16%, 75% and 15% of the mean average values of HC, CO and CO2 emissions, respectively. Lastly, ?t was concluded that hydrogen addition improves combustion process; CO and HC emissions reduce as a result of the leaning effect caused by the methanol addition; and CO2 and NOx emission increases because of the improved combustion.     

Experimental and numerical investigation of effects of CNG and gasoline fuels on engine performance and emissions in a dual sequential spark ignition engine

Compared to widening usage of CNG in commercial gasoline engines, insufficient but increasing number of studies have appeared in open literature during last decades while engine characteristics need to be quantified in exact numbers for each specific fuel converted engine. In this study, a dual sequential spark ignition engine (Honda L13A4 i-DSI) is tested separately either with gasoline or CNG at wide open throttle. This specific engine has unique features of dual sequential ignition with variable timing, asymmetrical combustion chamber, and diagonally positioned dual spark-plug. Thus, the engine led some important engine technologies of VTEC and VVT. Tests are performed by varying the engine speed from 1500 rpm to 4000 rpm with an increment of 500 rpm. The engine’s maximum torque speed of 2800 rpm is also tested. For gasoline and CNG fuels, engine performance (brake torque, brake power, brake specific fuel consumption, brake mean effective pressure), emissions (O₂, CO₂, CO, HC, NO_x, and lambda), and the exhaust gas temperature are evaluated. In addition, numerical engine analyses are performed by constructing a 1-D model for the entire test rig and the engine by using Ricardo-Wave software. In the 1-D engine model, same test parameters are analyzed, and same test outputs are calculated. Thus, the test and the 1-D engine model are employed to quantify the effects of gasoline and CNG fuels on the engine performance and emissions for a unique engine. In general, all test and model results show similar and close trends. Results for the tested commercial engine show that CNG operation decreases the brake torque (12.7%), the brake power (12.4%), the brake mean effective pressure (12.8%), the brake specific fuel consumption (16.5%), the CO₂ emission (12.1%), the CO emission (89.7%). The HC emission for CNG is much lower than gasoline. The O₂ emission for CNG is approximately 55.4% higher than gasoline. The NO_x emission for CNG at high speeds is higher than gasoline. The variation percentages are the averages of the considered speed range from 1500 rpm to 4000 rpm.     

Biodiesel production from waste cooking oil using heterogeneous catalysts and its operational characteristics on variable compression ratio CI engine

In the present work, the optimum biodiesel conversion from waste cooking oil to biodiesel through transesterification method was investigated. The base catalyzed transesterification under different reactant proportions such as the molar ratio of alcohol to oil and mass ratio of catalyst to oil was studied for optimum production of biodiesel. The optimum condition for base catalyzed transesterification of waste cooking oil was determined to be 12:1 and 5 wt% of zinc doped calcium oxide. The fuel properties of the produced biodiesel such as the calorific value, flash point and density were examined and compared to conventional diesel. The properties of produced biodiesel and their blend for different ratios (B20, B40, B60, B80 and B100) were comparable with properties of diesel oil and ASTM biodiesel standards. Tests have been conducted on CI engine which runs at a constant speed of 1500 rpm, injection pressure of 200 bar, compression ratio 15:1 and 17.5, and varying engine load. The performance parameters include brake thermal efficiency, brake specific energy consumption and emissions parameters such as Carbon monoxide (CO), Hydrocarbon (HC), Oxides of Nitrogen (NOx) and smoke opacity varying with engine load (BP). Diesel engine's thermal performance and emission parameters such as CO, HC, and NOx on different biodiesel blends demonstrate that biodiesel produced from waste cooking oil using heterogeneous catalyst was suitable to be used as diesel oil blends and had lesser emissions as compared to conventional diesel.     

Evaluation of vibration characteristics of a hydroxyl (HHO) gas generator installed diesel engine fuelled with different diesel–biodiesel blends

There are two main reasons of alternative fuel search of scientists: environmental problems resulted from combustion of fossil fuels and limited reserves of crude oil. Biodiesel and Hydrogen (H₂) are two of the most promising alternative fuels with their environmental friendly combustion profiles. The aim of this study was to evaluate vibration level of a hydroxyl (HHO) gas generator installed and diesel engine using different kinds of biodiesel fuels. In this study, at different flow rates, the effect of HHO gas addition on engine vibration performance was investigated with a Mitsubishi Canter 4D34-2A diesel engine. HHO gas introduced to the test engine via its intake manifold with 2, 4 and 6 L per minute (LPM) flow rates when the engine was fuelled with sunflower, canola, and corn biodiesels. The vibration data was collected between 1200 and 2400 rpm engine speeds by 300 rpm intervals. Finally, artificial neural network (ANN) approach was conducted in order to predict the effect of fuel properties and HHO amount on engine vibration level.     

Engine combustion and emission fuelled with natural gas: A review

Natural gas (NG) is one of the most important and successful alternative fuels for vehicles. Engine combustion and emission fuelled with natural gas have been reviewed by NG/gasoline bi-fuel engine, pure NG engine, NG/diesel dual fuel engine and HCNG engine. Compared to using gasoline, bi-fuel engine using NG exhibits higher thermal efficiency; produces lower HC, CO and PM emissions and higher NOx emission. The bi-fuel mode can not fully exert the advantages of NG. Optimization of structure design for engine chamber, injection parameters including injection timing, injection pressure and multi injection, and lean burn provides a technological route to achieve high efficiency, low emissions and balance between HC and NOx. Compared to diesel, NG/diesel dual fuel engine exhibits longer ignition delay; has lower thermal efficiency at low and partial loads and higher at medium and high loads; emits higher HC and CO emissions and lower PM and NOx emissions. The addition of hydrogen can further improve the thermal efficiency and decrease the HC, CO and PM emissions of NG engine, while significantly increase the NOx emission. In each mode, methane is the major composition of THC emission and it has great warming potential. Methane emission can be decreased by hydrogen addition and after-treatment technology.     

Investigation on combustion and emissions characteristics of a hydrogen-blended n-butanol rotary engine

In this paper, a rotary engine equipped with an n-butanol and hydrogen port-injection system was developed to investigate the combustion and emissions characteristics of a hydrogen-blended n-butanol rotary engine at part load and stoichiometric conditions. A self-developed hybrid electronic control unit was adopted to adjust the injection durations of n-butanol and hydrogen. The rotary engine was run under the conditions of 4000 rpm, a manifold absolute pressure of 35 kPa and a fixed spark timing of 45 °CA before the top dead center during the whole testing operation. The hydrogen volumetric fraction in the total intake was varied from 0% to 6.30%. The test results manifested that the brake thermal efficiency and chamber temperature were simultaneously increased with hydrogen addition. The hydrogen supplement obviously shortened flame development and propagation periods. Both chamber pressure integral heat release fraction versus crank angle were increased when the hydrogen fraction was enhanced. HC emissions were reduced by 54.5% when hydrogen volume fraction was raised from 0% to 6.30%, CO and CO₂ emissions were also reduced after increasing hydrogen blending fraction. NOx emissions were mildly elevated due to the improved chamber temperature.     

Effects of hydrogenation of fossil fuels with hydrogen and hydroxy gas on performance and emissions of internal combustion engines

Energy security is an important consideration for development of future transport fuels. Among the all gaseous fuels hydrogen or hydroxy (HHO) gas is considered to be one of the clean alternative fuels. Hydrogen is very flammable gas and storing and transporting of hydrogen gas safely is very difficult. Today, vehicles using pure hydrogen as fuel require stations with compressed or liquefied hydrogen stocks at high pressures from hydrogen production centres established with large investments.Different electrode design and different electrolytes have been tested to find the best electrode design and electrolyte for higher amount of HHO production using same electric energy. HHO is used as an additional fuel without storage tanks in the four strokes, 4-cylinder compression ignition engine and two-stroke, one-cylinder spark ignition engine without any structural changes. Later, previously developed commercially available dry cell HHO reactor used as a fuel additive to neat diesel fuel and biodiesel fuel mixtures. HHO gas is used to hydrogenate the compressed natural gas (CNG) and different amounts of HHO-CNG fuel mixtures are used in a pilot injection CI engine. Pure diesel fuel and diesel fuel + biodiesel mixtures with different volumetric flow rates are also used as pilot injection fuel in the test engine. The effects of HHO enrichment on engine performance and emissions in compression-ignition and spark-ignition engines have been examined in detail. It is found from the experiments that plate type reactor with NaOH produced more HHO gas with the same amount of catalyst and electric energy. All experimental results from Gasoline and Diesel Engines show that performance and exhaust emission values have improved with hydroxy gas addition to the fossil fuels except NO_x exhaust emissions. The maximum average improvements in terms of performance and emissions of the gasoline and the diesel engine are both graphically and numerically expressed in results and discussions. The maximum average improvements obtained for brake power, brake torque and BSFC values of the gasoline engine were 27%, 32.4% and 16.3%, respectively. Furthermore, maximum improvements in performance data obtained with the use of HHO enriched biodiesel fuel mixture in diesel engine were 8.31% for brake power, 7.1% for brake torque and 10% for BSFC.