Fuel Consumption Improvement Research Articles

The influence of acetylene black microparticles as a fuel additive in pure palm oil and its performance characteristic on diesel engine

Fuel additives are recognized for their potential to make diesel engines cleaner and more efficient. However, the use of Pure Palm Oil (PPaO) as a fuel faces challenges due to its inherent combustion inefficiencies. This study explores how Acetylene Black (AB), as an additive, affects the combustion performance and spray characteristics of a diesel engine. Observations of spray phenomena were conducted using a High-Speed Camera Phantom C110. The addition of AB to PPaO resulted in an increase in engine power and torque by 11.43 % at a 60 % load, averaging a 2.97 % improvement over diesel fuel (DF). PPaO demonstrated the most significant improvement in Specific Fuel Consumption (SFC) by 17.2 % at a 40 % load, averaging an 8.2 % increase. For PPaO with AB (PPaOAB), the greatest enhancement in SFC occurred at a 10 % load, showing a 9.2 % improvement over DF, with an average increase of 2.1 %. The study also found that thermal efficiency was optimally enhanced with PPaOAB at a 20 % load, achieving a remarkable 17.7 % improvement compared to DF. Notably, the inclusion of PPaOAB significantly reduced the thickness of carbon deposits on the pistons and cylinder head by 51.8 % and 3.9 %, respectively, and improved spray angle and penetration compared to PPaO. These findings suggest that AB could be a promising additive for PPaO, sparking further research interest in the application of AB in other fuels.

Water-in-Biodiesel Emulsion with Hydroxy (HHO) Gas Fuel Enrichment for Single-Cylinder Diesel Engine Application

The rising issue of the depletion of fossil fuels opened a new pathway to seek alternative fuels to fulfil World Sustainable Development Goals (SDG). The application of high-blending biodiesel is possible however, it causes the diesel engine to perform poorly due to high viscosity, high fuel consumption, and increased NOx emission. To comply with the strict regulation, the idea of combining alternative fuels of high blending biodiesel, water-in-biodiesel emulsion, and hydrogen is seen as possible to solve the issue of each alternative fuel. Therefore, this study focused on the effect of high blending of biodiesel, water-in-biodiesel emulsion with hydroxy (HHO) enrichment in single-cylinder diesel engines on engine performance and exhaust emission. The fuel tested for this study are B10, B50, and an emulsion of B50 with the addition of HHO known as B50H and tested on engine speeds of 2400rpm under various loading conditions of 1kW, 2kW, 3kW, and 4kW. The result showed the B50H showed improvement in Fuel Consumption (FC) by 4%, 5% for Brake Thermal Efficiency (BTE), and reduced Nitrogen oxide (NOx) by 23% compared to B10 fuel. Thus, the combination of high blending of biodiesel, water-in-biodiesel emulsion, and HHO gas successfully improved diesel engine performance and reduced harmful exhaust emissions to promote clean and renewable energy, without depending on current diesel fuel.

The heat transfer potential of compressor vanes on a hydrogen fueled turbofan engine

Hydrogen is a promising fuel for future aviation due to its CO2-free combustion. In addition, its excellent cooling properties as it is heated from cryogenic conditions to the appropriate combustion temperatures provides a multitude of opportunities. This paper investigates the heat transfer potential of stator surfaces in a modern high-speed low-pressure compressor by incorporating cooling channels within the stator vane surfaces, where hydrogen is allowed to flow and cool the engine core air. Computational Fluid Dynamics simulations were carried out to assess the aerothermal performance of this cooled compressor and were compared to heat transfer correlations. A core air temperature drop of 9.5 K was observed for this cooling channel design while being relatively insensitive to the thermal conductivity of the vane and cooling channel wall thickness. The thermal resistance was dominated by the air-side convective heat transfer, and more surface area on the air-side would therefore be required in order to increase overall heat flow. While good agreement with established heat transfer correlations was found for both turbulent and transitional flow, the correlation for the transitional case yielded decent accuracy only as long as the flow remains attached, and while transition was dominated by the bypass mode. A system level analysis, indicated a limited but favorable impact at engine performance level, amounting to a specific fuel consumption improvement of up to 0.8 % in cruise and an estimated reduction of 3.6 % in cruise NOx. The results clearly show that, although it is possible to achieve high heat transfer rate per unit area in compressor vanes, the impact on cycle performance is constrained by the limited available wetted area in the low-pressure compressor.

Numerical Simulation of Hatchback Car with Modified Vehicle Design for the Improvement of Fuel Consumption

The continuous demand and fuel depletion in the automobile industries cause a reduction in fuel consumption, especially in a car which is a classic problem to focus on vehicle body design. The formation of drag force in the car body demands tractive force and significantly affects the engine performance and fuel consumption rate which is not advisable for enhancing aerodynamic efficiency. This paper discusses the methodology to reduce the fuel consumption rate in hatchback cars using a ‘basebleed method’. The hatchback car model with and without basebleed is numerically simulated for the various speed to study the aerodynamic coefficients. The numerical simulation is performed with the k-ε turbulence model for predicting the wake region of both car models with and without basebleed. The numerical study witnessed the hatchback car model with basebleed arrived 6% reduction in the coefficient of drag (CD) compared to without basebleed, which results in a reduction of fuel consumption rate of up to 4.33 %. The research evidence that the stability of the car is not affected while using this basebleed drag reduction method and it is studied from the resultant parameters such as coefficient of lift (CL) and coefficient of side force (CS) and for the varying yaw angle (φ). Further, the research recommends the integration of basebleed at the underbody structure in Hatchback cars to improve the engine fuel consumption without affecting its stability.

A short Literature Review on Sawlog and Pulpwood Transport Efficiency and Fuel Consumption

Timber transport is one of the main components of woody supply chain, which causes high costs and considerable emissions depending on truck size, type, transport distance, and payload. A cradle-to-gate life cycle assessment of Softwood plantations and regrowth hardwood native forests estimated that the most significant contributor to total greenhouse emissions per unit of wood production in softwood plantation was log haulage at 37%. For regrowth native hardwood forests, log transportation contributed 23% of greenhouse gas emissions. This research, built on existing literature, focused on how timber harvesting transportation costs and emissions to the environment can be reduced, specifically, the transport of the industrial timber logs from the Forest Stockpile to the processing facility or unloading points. The review summarized the data and highlighted that the efficiency and emissions data could be categorized into five themes: Higher Capacity Transportation (HCT), Road Networks & Surfaces, Logistics and Planning, Fleet Replacement, and Fuel efficiency technologies. Fuel efficiency improvements across these themes ranged from 3% to 43% within the reviewed case studies. Several studies researched the fuel efficiency of High Capacity Transport indicated that the fuel consumption in liters per ton kilometer was 8-11% lower in the 92-tonne combination HCT compared to a 72-tonne combination HCT due to the increased payload for High Capacity Transport. Road networks and the composition of the surfaces have been shown to have a strong correlation to emissions. Studies have shown a 16.7% increase in emissions from a network of predominantly highways to a higher proportion of Forrest and Gravel roads. Studies that included data on vehicle age found efficiency improvements of up to 26% when new vehicles’ fuel consumption was compared to older vehicles. Newer truck fleets incorporate newer technologies, with reports showing fuel consumption improvements of up to 43% with less than a two-year payback period.

Energy conversion analysis for mild hybrid electric vehicles equipped with an electric supercharged SI engine via multi-domain acausal modeling

Mild hybrid electric systems, which are highly dependent on engine performance and use less scarce resources, are powertrain systems that can promote immediate vehicle electrification worldwide while taking advantage of existing infrastructure and facilities. In this study, a 12-V mild hybrid electric vehicle (MHEV) with an electric supercharged spark ignition (SI) engine, which is a complex system that integrates an engine, supercharger, electric motor, and battery, was physically modeled using Modelica, a multi-domain acausal modeling language, for a small and light-weight vehicle (vehicle mass: <1000 kg) that aims to make effective use of regenerated power. Additionally, the developed model was used to simulate driving cycle in realistic time and to quantitatively analyze and understand the regenerative power energy conversion process across multiple physical domains and the fuel consumption improvement mechanism in detail and dynamic performance improvement of the electric supercharger. As a result, in the target compact 12-V MHEV with an electric supercharged SI engine, although the intake enthalpy increase due to the intake air compression by the electric supercharger is negligible, the increase in engine speed can be suppressed as the engine torque increases due to supercharging, reducing the engine friction work, in turn resulting in a fuel consumption improvement of approximately 2.5 % under the WLTC mode driving cycle. Furthermore, the electric supercharged SI engine dynamic performance improved by more than 20 %.

Experimental investigation of saturated fogging and overspray influence on part-load micro gas turbine performance

• Part-load MGT performance with water spray at the inlet is studied experimentally. • The ambient temperature impact on MGT performance is varied with its load. • The benefits of inlet fogging and overspray systems deceases with loads. • MGT performance is enhanced with water injection with fixed fuel consumption. • Inlet fogging and overspray reduce NO but increase CO concentrations. Micro gas turbines (MGT) are promising power sources for modern industries, especially in the distributed energy generation market, due to their relatively high projected energy densities. Nevertheless, they suffer from lower thermal efficiency due to the inherent constraint of high- exhaust temperature and the relatively high compression work, especially during hot days and partial load operation. Water injection into gas turbine inlet air is a possible route to improve the MGT performance. As a result of the lack of previous experimental studies related to the study of fog and overspray on turbines at partial load operations, the current study aims to evaluate the influence of saturated fogging (inlet fogging) and overspray on the MGT part-load performance experimentally. Two test benches were installed to implement inlet fogging and overspray on a 10 kW MGT. Droplet size and injected water mass flow were measured at varied spraying pressures and nozzle diameters to determine optimum spray conditions. The output power and specific fuel consumption were measured at different overspray ratios for various MGT loads. The results showed that the enhancement in power output due to inlet fogging and overspray varied according to the applied load. After applying saturated fogging, the output power augmentation corresponding to a 14℃-temperature drop was 9.32% at a load of 30%, while this value decreased to 6.86 and 4.91% for loads 50 and 70 %, respectively. It was also observed that a continuous boost in net power output with an increased overspray ratio. Increasing the load from 30 to 70% reduced the power enhancement by about 42 and 39% for overspray ratios of 1 and 2%, respectively. The maximum output power and specific fuel consumption improvement were achieved at a 2% overspray ratio. Inlet fogging and overspray reduced NO concentrations for all loads, and vice versa for CO concentrations, and emission slop decreased with the load.

Including network level safety measures in eco-routing

Following the most energy-efficient route can have a significant impact on reducing energy consumption. While most eco-routing research has focused on reducing energy consumption and travel time, the safety aspect of route choice is currently neglected. In this paper, a multi-objective optimization methodology is formulated to concurrently minimize fuel consumption, travel time and safety risk, which is quantified using a novel methodology based on network-level safety measures. The proposed optimization framework provides a transparent way to intuitively include driver preferences via “budgets” for time, fuel consumption and safety – which represent the driver’s willingness to sacrifice these factors for fuel consumption improvements. The performance of the proposed method was tested on urban road networks in Brisbane-Australia, with a rear-end collision risk model as the safety measure. The results demonstrate that eco-routing with safety considerations has the potential to improve fuel efficiency while simultaneously reducing safety risks.

A Moment-of-Inertia-Driven Engine Start-Up Strategy for Four-Wheel-Drive Hybrid Electric Vehicles

During the moment-of-inertia (MoI) start-up process, an engine is cranked to ignite at 800 rpm with better fuel efficiency than at 250 rpm in the belt-driven start. As kinetic energy is employed, the work needed to crank the engine is also reduced. This article aims to develop an MoI-driven engine start-up method for a four-wheel-drive (4WD) vehicle. By modeling a 4WD hybrid electric vehicle (HEV) powertrain, a system dynamics model is developed into a state-space equation. The variable operating conditions of the engine and clutch are identified, and an adaptive model predictive controller (MPC) is designed. The goal of multioptimization is to control the engine speed trace, minimize the front and total axle torsion speed, and execute the torque demand. The optimization outputs are the engine torque set points, front electric motor (EM) torque set points, clutch nominal force set points, and rear EM set points. By predicting the engine fluctuation torque and considering the power source component constraints, an optimization algorithm is developed. This strategy is simulated and verified on the vehicle and powertrain models. The results indicate that the proposal achieves distinct fuel consumption improvement with an optimized drivability performance.

Exploring the potentials of water injection to improve fuel consumption and torque in a small displacement PFI spark-ignition engine

This work deals with the effects of port water injection (WI) on torque and fuel consumption improvements of a port gasoline injection (PFI) boosted Spark Ignition engine. First, an experimental investigation is carried out at high loads and various speeds to acquire performance and combustion data under WI operation. The engine is fully schematized in a 1D commercial code and enhanced by advanced sub-models for the in-cylinder processes description, including refinements for WI impact on flame development and knock onset. The model is validated against experiments at different speed/load points and water amounts. The validated model is utilized in a predictive way for virtual engine re-calibration and re-design aiming to explore WI potentials on the performance increase at full load. A first calibration strategy is proposed with the aim to minimize the brake specific fuel consumption (BSFC) through water injection, with a fixed value of water to fuel mass ratio (W/F = 0.5). The numerical results highlight the potential of water in reducing fuel consumption, reaching a BSFC gain up to 14% at low speed, while greater advantages up to 32% were obtained in the medium/high-speed region, mainly due to suppression of mixture enrichment. Then, a second calibration strategy is conceived to increase the full load torque curve complying with compressor surge, knock and turbine inlet temperature limits, while minimizing the water consumption. The numerical outcomes highlight a maximum increase in torque up to 13.8%, combined with minimal BSFC penalizations compared to the first calibration, and a minimum evaluated W/F≈0.1. The proposed methodology and automatic control strategies prove to be a valid numerical support for an engine recalibration aimed at improving its performance.

Modeling Transient Control of a Turbogenerator on a Drive Cycle

&lt;div class="section abstract"&gt;&lt;div class="htmlview paragraph"&gt;GTDI engines are becoming more efficient, whether individually or part of a HEV (Hybrid Electric Vehicle) powertrain. For the latter, this efficiency manifests itself as increase in zero emissions vehicle mileage. An ideal device for energy recovery is a turbogenerator (TG), and, when placed downstream the conventional turbine, it has minimal impact on catalyst light-off and can be used as a bolt-on aftermarket device. A Ricardo WAVE model of a representative GTDI engine was adapted to include a TG (Turbogenerator) and TBV (Turbine Bypass Valve) with the TG in a mechanical turbocompounding configuration, calibrated using steady state mapping data. This was integrated into a co-simulation environment with a SISO (Single-Input, Single-Output) dynamic controller developed in SIMULINK for the actuator control (with BMEP, manifold air pressure and TG pressure ratio as the controlled variables). Transient verification with WAVE-RT was conducted on WLTP and NEDC drive cycles, estimating dynamic energy recovery and fuel consumption improvement. Hints are given for a more advanced MIMO (Multiple-Input, Multiple-Output) control system architecture and calibration.&lt;/div&gt;&lt;/div&gt;

Thermodynamic analysis of improving fuel consumption of natural gas engine by combining Miller cycle with high geometric compression ratio

The goal of this work is to solve the problem of low thermal efficiency of stoichiometric natural gas engines by combining the Miller cycle with a high geometric compression ratio (GCR). A one-dimensional thermodynamic model of a stoichiometric natural gas engine with turbocharger is established, and its effectiveness is verified by experimental data. On this basis, the influence of the high GCR combined with the Miller cycle achieved by early intake valve closing (EIVC) or late intake valve closing (LIVC) on the fuel consumption is studied in detail. The results show that the reasonable matching of the GCR and intake valve lift profile is beneficial to improve fuel consumption. The upper limit of fuel consumption improvement is determined by the performance of the turbocharger. The EIVC50 + GCR14 and LIVC75 + GCR13.5 solutions can not only ensure that the load and knock level are consistent with the baseline engine (IVC558 + GCR11.5), but also obtain the optimal fuel economy. Thermodynamic analysis further reveals the fuel-saving mechanism. The fuel consumption can be improved by 4.1%, mainly thanks to a good balance between theoretical efficiency and combustion loss. In addition, the reduction in gas exchange loss further improves fuel consumption. Unfortunately, the increase in heat transfer loss and friction loss limits the further improvement in fuel consumption.

Potential of Twin Spark Plug Configuration for Scooter Emissions Reduction and Fuel Consumption Improvement

Potential of Twin Spark Plug Configuration for Scooter Emissions Reduction and Fuel Consumption Improvement

Series-hybridisation, distributed electric propulsion and boundary layer ingestion in long-endurance, small remotely piloted aircraft: Fuel consumption improvements

Series hybridisation, distributed electric propulsion (DEP) and boundary layer ingestion (BLI) are some of the most promising approaches for fuel consumption reductions in general aviation and commercial air transport. While these technologies can be also adapted for long endurance and long range, propeller-driven, small remotely piloted aircraft, their beneficial effects are not so clear due to the relatively high increase in propulsion system weight and the reduction in efficiency of the lower Reynolds number propellers. Using weights and efficiencies of off-the-shelf components, this work studies the impact of series hybridisation with and without DEP and BLI in a long endurance, 25 kg of maximum takeoff mass fixed wing aircraft, showing promising results with fuel consumption reductions of more than 15%.

Performance and Emissions of a Spark Ignition Engine Fueled with Water-in-Gasoline Emulsion Produced through Micro-Channels Emulsification

This paper presents an experimental study investigating the effects of water-in-gasoline emulsion (WiGE) on the performance and emissions of a turbocharged PFI spark-ignition engine. The emulsions were produced through a micro-channels emulsifier, potentially capable to work inline, without addition of surfactants. Measurements were performed at a 3000 rpm speed and net Indicated Mean Effective Pressure (IMEP) of 16 bar: the engine point representative of commercial ECU map was chosen as reference. In this condition, the engine, fueled with gasoline, runs overfueled (λ = 0.9) to preserve the integrity of the turbocharger from excessive temperature, and the spark timing corresponds to the knock limit. Starting from the reference point, two different water contents in emulsion were tested, 10% and 20% by volume, respectively. For each selected emulsion, at λ = 0.9, the spark timing was advanced from the reference point value to the new knock limit, controlling the IMEP at a constant level. Further, the cooling effect of water evaporation in WiGE allowed it to work at stoichiometric condition, with evident benefits on the fuel economy. Main outcomes highlight fuel consumption improvements of about 7% under stoichiometric mixture and optimized spark timing, while avoiding an excessive increase in turbine thermal stress. Emulsions induce a slight worsening in the HC emissions, arising from the relative impact on combustion development. On the other hand, at stoichiometric condition, HC and CO emissions drop with a corresponding increase in NO.

Production Forecast of China’s New Energy Passenger Vehicles in 2021–2023 under the Compliance of Dual-Credit Policy

The corporate average fuel consumption (CAFC) and new energy vehicle (NEV) credit policy (2021–2023) was officially released in June 2020. As a mandatory regulation for automobile manufacturers to produce new energy vehicles, its impact on the output of new energy vehicles needs to be systematically evaluated. In this study, we build an enterprise policy compliance model to simulate the dual-credit policy requirements for the production of new energy vehicles from 2021 to 2023 under different scenarios. The results show that the production of new energy vehicles from 2021 to 2023 is required to reach 1.78 to 3.97 million under different scenarios. Three factors, i.e., switching from New Europe Driving Cycle (NEDC) to World Light Vehicle Test Procedure (WLTP) fuel consumption improvement of conventional vehicles, and credit per new energy vehicle, have a more significant impact on the new energy vehicle production than others. Under the minimum guarantee scenario, a 10% change in the above three factors will lead to a 2.5%, 1.5%, and 0.5% reduction in the production requirement for new energy vehicles.

Effect of synergistic engine technologies for 48 V mild hybrid electric vehicles

48 V mild hybrid electric vehicles (MHEVs) are considered to the prospective near-term solution for cost-effective vehicle electrification. In this study, the fuel consumption improvement of various synergistic engine technologies was experimentally investigated with a 48 V P0 mild hybridization. The details of application and optimization for each technology were considered and the effect of each technology was quantitatively identified. A combination of synergistic engine technologies including a high compression ratio, late intake valve closing strategy, high tumble flow, electric supercharging and exhaust gas recirculation was applied to a 1.4 L PFI engine. Engine test results confirmed that fuel consumption could be significantly improved by these technologies, and the maximum power and torque were increased as well. The vehicle test results showed that the application of synergistic engine technologies improved vehicle fuel economy by 10%. Engine optimization and EGR could enhance the fuel economy by 5.5% and the effect of electric supercharging and downspeeding resulted in a 4.5% fuel economy improvement. These improvements through the engine technologies were greater than the effect of 48 V mild hybridization which was verified to be 5.5% of the fuel economy enhancement. The result suggests that the application of synergistic engine technologies will be highly effective for improving fuel efficiency of MHEV.

Performance Improvement of a 43 MW Class Gas Turbine Engine with Inlet Air Cooling

In this study, a process of inlet air cooling was implemented in the intake of a land-based gas turbine engine for electricity generation. The motivation behind the study is to improve the performance of the gas turbine engine in hot climate conditions,which causes a significant decrease in the output power and an increase in specific fuel consumption. For inlet air cooling, a refrigeration cycle was attached to the turbo-shaft gas turbine engine,and power required by the refrigeration is extracted from the mechanical engine power output of the gas turbine. A 43 MWclass gas turbine engine which is similar totheGeneral Electric LM6000 engine was modeled in this study. Considering an average coefficient of performance of 3.0 for a refrigeration system, the inlet cooling provided (by supplying cooled inlet air at 15oC) a 22.21% net power increase anda5.2% power specific fuel consumption improvement at 55oCambient conditions.

Utilizing One-Way Valve to Optimize Turbocharger Performance on a Blended EGR Engine

Internal combustion engines will be a part of personal transportation for the foreseeable future. One recent trend for engines has been downsizing which enables the engine to run more favorably over regulatory drive cycles. Another shift due to downsizing is the increase in engine power density which leads to problems with engine knock. One way to reduce the knock propensity of engines is by introducing Exhaust Gas Recirculation (EGR) into the combustion chamber. Exhaust Gas Recirculation also helps improve fuel economy and can reduce NOX emissions. EGR reduces volumetric efficiency which places challenges on the boosting system. LP-EGR helps to lower backpressure and improves scavenging which helps reduce knock and operate at a high efficiency at the low-speed and high-load conditions. At high-speed, and high-load operation however, LP-EGR operation can choke the compressor. This would mean that the turbocharger would need resizing to allow a higher mass flow at these higher speed-load conditions. The HP-EGR helps by reducing the flow rates to the compressor at the higher speed-load conditions which avoids compressor choke and permits a full load performance while retaining a smaller, more transient capable turbocharger. The concept of a one-way valve in the HP-EGR Loop has been explored in this paper. During HP-EGR operation, pressure pulsations drive the intake air back through the HP-EGR Loop and limit the maximum amount of HP-EGR. A one-way valve would prevent any backflow and permit a greater HP-EGR flow for a given average delta pressure. For a given EGR rate, this enables a wider throttle position and thus better controllability at the higher speed-load conditions. Engine testing with the one-way valve suggested that the HP-EGR rate at the high speed/load condition was nearly doubled while reducing the PMEP with an improvement in the Brake Specific Fuel Consumption . Additionally, this led to more reasonable actuator positions in terms of the EGR valve and the intake throttle to ensure better controllability.

Performance of single cylinder diesel engine using triple fuel HSD-LPG-Steam

Fuel system modification techniques to improve engine efficiency could be the way to slow down the energy crisis caused by the lack of new fuel inventions. The Compression Ignition (CI) diesel engine is one of the most preferred engines for both in-land and marine transportation motors. The advantages of compact dimensions and large generated power make CI diesel engine superior to other engine types. The large number of single CI diesel engines use in small fishing vessel engines and agricultural machinery will contribute substantially to fuel consumption in a cumulative manner. Previous researchs on the modification of fuel system with bi-fuel system High Speed Diesel (HSD)oil – Liquified Petroleum Gas (LPG) system capable of reducing Brake Specific Fuel Consumption (BSFC) up to 24% and exhaust gas opacity up to 68%. Subsequent studies focused on engines with single fuel HSD oil but were injected with superheated steam in 1 atm (abs) 130 0C by utilizing Heat Recovery Generating System (HRSG) using heat of exhaust gas for a flowrate of 1.5-4.5 kg/hour. It is capable of delivering the performance improvement of Specific Fuel Consumption (SFC), which is reduced by 8.92% compared to diesel engines without steam injection. Recent research combines the above two modification methods so that diesel will adopt two types of fuel- oil-LPG with additional superheated steam injection resulting from exhaust gas heat cogeneration system. Experimental results of the diesel engine with LPG injection maintained at 0.4 kg/h and 3.5 kg/h superheated steam with an engine variation loading of 0.3-0.7 kWh provide an average AFR of 30.09 and SFC improvement up to 37.2% lower than SFC engine standard with a single fuel HSD oil.