Turbo Compound Research Articles

Energy recovery in automotive systems: A review of regenerative braking, flywheel, thermoelectric, rankin cycle and electric turbo compound

In the backdrop of escalating global vehicle proliferation and the consequent surge in carbon dioxide (CO2) emissions, there is a compelling urgency to innovate energy recovery methods during vehicular operations for heightened energy efficiency and substantial environmental emission reductions. This paper discussed a variety of vehicle technologies to address environmental emissions issues and critically evaluates contemporary energy recovery technologies across three core dimensions: automotive thermal energy conversion, electronic turbine systems (ETC), and kinetic energy recovery systems. By analyzing empirical data encompassing CO2 emission reduction, energy recovery efficiency enhancement, fuel economy improvement, and applicability diversity across vehicle models, the study aims to establish a scientific foundation for continuous vehicular energy efficiency enhancement and emission reduction. This entails a comprehensive investigation of internal combustion engine principles for potential heat energy recovery, juxtaposing conventional and advanced cycles like the Rankine cycle. Moreover, it involves assessing ETC effectiveness in utilizing exhaust energy while acknowledging system complexity and dynamic response challenges. Additionally, the performance disparities of kinetic energy recovery systems like regenerative braking and exhaust energy recovery in distinct operational contexts are examined. By meticulously comparing experimental data, the paper intends to provide a comprehensive assessment of each technologys merits and drawbacks in advancing energy efficiency and emission reduction, try to pick one or more combinations to minimise the impact, thereby guiding future research and application in automotive energy recovery, and contributing to sustainable automotive engineering technology advancement.

Feasibility Study of Exhaust Energy Recovery System for Mobile Carbon Capture Operations in Commercial Engines through 1D Simulation

The global proportion of eco-friendly vehicles continues to increase; however, regarding hybrid vehicles, the vehicle powertrains in most countries include internal combustion engines. Therefore, research on reducing the carbon emissions from internal combustion engines must be conducted. Carbon capture technology must be developed for e-fuel, which has recently attracted attention, to achieve carbon neutrality. In this study, a turbo compound system capable of recovering waste exhaust gas energy was selected as the most appropriate energy supply system to operate a mobile carbon capture system. The feasibility was reviewed by analyzing the turbo compound speed, pressure drop, power generation, etc., using a one-dimensional simulation method. The maximum power generation of the configured turbo compound system was approximately 9 kW, and approximately 1–3 kW of energy could be recovered under medium speed and load conditions, which are the optimal operating conditions for a test engine with the displacement of a 4 L.

Supervisory Control for NO$_\text{x}$ Emission Compliance of Heavy-Duty Vehicles

This article provides a detailed description of a supervisory control problem for a heavy-duty vehicle equipped with a diesel engine and an exhaust aftertreatment system (EATS). The control problem considers the coupling between the engine and EATS and assumes the availability of predictive driving information for a long horizon. The article also proposes a computationally efficient supervisory control algorithm, which is implemented in an existing engine electronic control unit. The algorithm is based on distributed economic nonlinear MPC. It minimizes total fuel consumption (by the diesel engine and EATS) and fulfils Euro VI real-driving and world harmonized transient cycle based NO <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$_\text{x}$</tex-math></inline-formula> emission legislation for the heavy-duty diesel vehicle. The performance of the algorithm is evaluated using a high-fidelity simulation platform, which includes a validated GT-POWER model of a 13 L turbo compound diesel engine and the first-principles model of an EATS. Simulation results show that the supervisory controller has 1.7% less total fuel consumption, and 88.4% less NH <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$_3$</tex-math></inline-formula> slip, compared to a baseline controller, to achieve the same real-driving NO <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$_\text{x}$</tex-math></inline-formula> emission.

Emissions reduction by using e-components in 48 V mild hybrid trucks under dual-mode dual-fuel combustion

The European community foresees a 15% CO2 tailpipe emissions restriction in 2025 and 30% in 2030 for the trucks. While battery electric vehicles would help to reach these levels, their low ranges make them unfeasible for the good transport sector. By this reason, hybrid vehicles are considered the bridge between the current technology and the battery electric vehicles. The 48 V mild hybrid technology is an effective solution due to its low cost and changes needed with respect to the current technology. It also allows the use of electrical components that help to improve the brake thermal efficiency, reduce the emissions and recover energy. This works explores the potential of an electric turbo compound (e-TC) and an electric exhaust gas recirculation pump (e-EGR pump) in a mild hybrid truck platform working under dual-mode dual-fuel (DMDF) combustion with diesel and gasoline. The e-components are simulated by means of 0D-Engine modeling. Finally, a general overview of the potential in real applications is done by means of a vehicle model considering different driving cycles and truck payloads for two truck platforms (18-ton and 25-ton maximum payload). The results show that to achieve the large EGR rates required by the DMDF combustion and meet the air requirements, it necessary the use of both e-components together. The evaluation at vehicle conditions allows to conclude that the mild hybrid platform allows to reduce the CO2 emissions around 6% in homologation conditions and 10% in urban cycles. Moreover, it was found that the use of e-components only improves the vehicle efficiency in the cases with low truck payloads.

Hybrid Turbo Compound Fan Engine an Eco-Efficient Propulsion System for Aviation

The path to electric propulsion systems depends on the development of powerful, compact and very light energy storage system with a high storage density. In order to create an environment-friendly intermediate solution in the medium term, especially for aircraft engines of medium power classes, it makes sense to use an innovative, electrically parallel hybrid unit based on rotary engines and electric boosters for start and climb phases as a propulsion system. An aero-engine application, based on the HSD concept (HSD = hybrid super-drive – hybrid Wankel rotary engine) for different hybrid-parallel propulsion systems is presented. In this article, the introduced technology is based on a currently produced family of multi-component Wankel rotary engines. The proposed HSD concept uses a chamber volume of 650ccm per rotor. The projected power range (0.8 to 1.36 MW) is covered by an innovative hybrid electric parallel turbo compound concept together with 2x4 rotary engine units. A novel, air-bearing turbo engine with integrated electric drive is used as a turbocharger for charging the rotary engine. For the aero-engine technology, the counter-rotating fan (CRF) concept shown as an example for an aircraft technology carrier (light jet) leads to a further increase in the efficiency of a complete system.

Improving the Engine Efficiency by Installing the Turbo Compound System

Improving the Engine Efficiency by Installing the Turbo Compound System

Matching method of electric turbo compound for two-stroke low-speed marine diesel engine

Two-stroke low-speed diesel engine is widely employed in marine industry thanks to its evident advantages on fuel economy and reliability. Normally, turbocharger together with an auxiliary air blower are employed in the two-stroke engine to ensure the smooth scavenging over whole propeller characteristics, but fuel economy and layout compactness of the engine are scarified due to the employment of the auxiliary device. This paper investigates influences of electric turbo compound, which integrates a conventional turbocharger with electric motor/generator (EMG) and capable of replacing the auxiliary blower, on the performance of a two-stroke low-speed marine engine as well as the matching method of the turbocharging system. Firstly, influences of EMG power and compressor/turbine matching on the engine nominal efficiency are discussed in details. The analytical model together with simulation results show that the efficiency of the turbocharger is the most important factor influencing variation behaviors of engine nominal efficiency. In particular, the peak engine nominal efficiency can be achieved when the operational points of the compressor and turbine are pushed to their peak efficiency islands by either the control of EMG power or compressor/turbine matching. Therefore, a matching guideline of the electric turbo compound is proposed based on the study and then applied on a two-stroke low-speed marine engine. Compared with the conventional turbocharger, a smaller compressor is matched at high loads while a smaller turbine is matched at low loads for the optimal electric turbo compound turbocharger. Specifically, brake specific fuel consumption (BSFC) of the engine is reduced by about 2–3% at three load profiles by the new technology.

Holistic Diesel Engine and Exhaust After-Treatment Model Predictive Control

Abstract Today’s and future more stringent Diesel on-road emission regulations requires low emissions during normal operation with fewer exceptions. This together with the demand for low fuel consumption resulting that the control strategy must be able to fulfill both objectives simultaneously. In this work we present a holistic engine and Exhaust After-Treatment System (EATS) control which robustly fulfill the emission legislation together with optimal fuel consumption. With traditional PID control schemes it is typically non intuitive how to create a holistic controller that obtain both these objectives. The proposed holistic scheme is based on Model Predictive Control (MPC) framework in an intuitive straight forward way. The EATS system used in this paper does not include any external heating device and the SCR system was setup to always target NH3 storage levels to secure high NOx conversion efficiency. The holistic MPC controller is therefore setup to control the engine out NOx and temperature to meet the EATS demands. The holistic MPC controls the gas exchange actuators, while the injection strategy is controlled with a traditional map-based structure. The designed controller is integrated in a production Engine Electrical Control Unit (EECU) and tests are performed in engine test bench. The engine used in this work is a Heavy Duty 13L Diesel engine with turbo compound as a waste heat recovery device. The results show that using the proposed holistic MPC scheme the controller can be on a high level intuitively tuned to fulfill the emissions robustness while maintaining low fuel consumption in on-road cycles.

Performance evaluation of low-pressure turbine, turbo-compounding and air-Brayton cycle as engine waste heat recovery method

This paper presents an equivalent comparison of waste heat recovery method on an internal combustion engine using low-pressure turbine (LPT), turbo compound (TC) & air-Brayton cycle (ABC). A 5.9 L, six cylinders turbocharged diesel engine is used for this case study. All recovery methods are simulated on AVL BOOST where the engine model, turbocharger and heat exchanger are validated with experimental data. It is found that all three methods cannot work effectively without at least reducing the turbocharger turbine size to amplify the compressor surplus power. It is done by using a commercially available turbocharger turbine with smaller area over radius (A/R) volute, hence ensuring the least possible engine hardware change. In all the cases, the engine is ensured to deliver its baseline brake power. It is shown that LPT can recover the most exhaust waste heat (up to 5.40 kW), followed by TC (up to 1.75 kW) and ABC (up to 0.64 kW).

Performance evaluation of a medium size diesel vehicle equipped with different electric‐turbo compound layouts

One of the key strategies to reduce fuel consumption and emissions is given by engine downsizing, together with turbocharging. Under this aspect, the possibility to couple an electric drive to the turbocharger to recover the residual energy of the exhaust gases is becoming more and more attractive. However, additional energy coming from an electric turbo compound (ETC) application has to be managed by the vehicle powertrain through a proper energy management strategy. This study shows the numerical results of a research programme under way focused on the comparison of the benefits resulting from the application of two ETC configurations to a medium size vehicle equipped with a small four cylinders turbocharged diesel engine (1561 cm3). Starting from the experimental maps of the turbine and compressor, the complete engine model was created using a commercial one-dimension code. The numerical activity then moved to the whole vehicle modelling. Engine results have been used to properly define a powertrain architecture and energy management strategy in order to maximise the benefits coming from the single-ETC or the dual-ETC solution. Finally, vehicle performance and energy flows have been analysed in different real driving conditions and compared to the original vehicle without ETC.

Model Predictive Control of a Diesel Engine with Turbo Compound and Exhaust After-Treatment Constraints

In this work we consider air path control of a Volvo Heavy Duty 13L Diesel engine equipped with three air path actuators Exhaust Gas Recirculation Valve (EGV), Intake Throttle Valve (ITV), turbocharger Wastegate (WG), and a Turbo Compound (TC). The purpose of the TC device is to recover the waste heat energy to improve fuel efficiency. Thus, the motivation is to control the air path system and in particular the exhaust energy to achieve satisfaction of the Exhaust After-Treatment System (EATS) requirements and assess the fuel economy. For this purpose a commercially available industrial tool for Model Predictive Control (MPC) has been applied. The designed controller is integrated in a production Engine Electrical Control Unit (EECU) and tests are performed both in engine test bench and on-road. The results show that by coordination of the air path actuators utilizing advanced MPC framework it leads to improvements in the exhaust energy conversion which was measured by fuel reduction of 0.3% with maintained NOx levels in a World-Harmonized Transient Cycle (WHTC) compared to a Proportional Integral Derivative (PID) control scheme. The designed MPC controller reached mass production maturity level and had a similar margin to the EU6 emission regulation as the compared PID control scheme.

Supervisory Control for Real-Driving Emission Compliance of Heavy-Duty Vehicles

This paper presents an economic nonlinear MPC based strategy for integrated control of the engine and the exhaust aftertreatment system (EATS) of a heavy-duty powertrain. The objectives of this control strategy are to improve the fuel economy while fulfilling real-driving emission legislation based on work-based-window, as stipulated in the Euro VI emission legislation for heavy-duty vehicles. The strategy is evaluated using a high-fidelity simulation platform including a validated GT-POWER model of a 13 L turbo compound diesel engine and a first principles model of an EATS. Simulation results show that the strategy always fulfills the real-driving emission legislation.

New Turbo Compound Systems in Automotive Industry for Internal Combustion Engine to Recover Energy

The large amount of heat is scattered in the internal combustion engine through exhaust gas, coolant, convective and radiant heat transfer. Of all these residual heat sources, exhaust gases have the potential to recover using various modern heat recovery techniques. Waste heat recovery from an engine could directly reduce fuel consumption, increase available electrical power and improve overall system efficiency and if it would be used a turbochargers that can also produce energy. This solution is called turbo aggregation and has other ways to develop it in other areas of research like the electrical field. [1-3]

Evaluation of an electric turbo compound system for SI engines: A numerical approach

In a medium term scenario hybrid powertrain and Internal Combustion Engine (ICE) downsizing represent the actual trend in vehicle technology to reduce fuel consumption and CO2 emission. Concerning downsizing concept, to maintain a reasonable power level in small engines, the application of turbocharging is mandatory both for spark ignited (SI) and compression ignited (CI) engines. Following this aspect, the possibility to couple an electric drive to the turbocharger (electric turbo compound) to recover the residual energy of the exhaust gases is becoming more and more attractive, as demonstrated by several studies around the world and by the current application in the F1 Championship.The present paper shows the first numerical results of a research program in collaboration between the Universities of Pisa and Genoa. This first study is focused on the evaluation of the benefits resulting from the application of an ETC (Electric Turbo Compound) to a small twin-cylinder SI engine (900cm3). Starting from the experimental maps of two turbines and one compressor, the complete model of a turbocharged engine was created using the AVL BOOST one-dimension code. The numerical activity then moves to the whole vehicle/powertrain modelling, considering three driving cycles and two different vehicle configurations, in order to verify the effectiveness of the proposed ETC solution.Results show that the adoption of ETC is not advantageous if used for a conventional turbocharger turbine, if the target is to optimize the overall efficiency in one specific operating point of the ICE, like in the case of range-extended electric vehicles. Besides, ETC can slightly improve the average overall efficiency when the ICE must provide variable power output, as in the case of conventional or hybrid vehicles. However, the major benefits coming from ETC are the boost range extension in the lowest engine rotational speed region and a possible reduction of turbo lag, which are key points in parallel-hybrid and especially in conventional vehicles.Concerning the whole vehicle/powertrain simulation, first results show that the ETC does not improve fuel economy of the smaller vehicle, especially when employed in urban cycles. The ETC is much more advantageous in the case of the larger vehicle, particularly when extra-urban roads or motorways are considered.

三井‐ＭＡＮ Ｂ＆Ｗ電子制御機関とＴＥＳについて

This paper deals with a new electronically controlled marine two-stroke diesel engine and TES (Thermal Efficiency System) tuning applicable to future marine carriers. Demand for prime movers for marine applications centers on the following four points:1. Compliance with future more-stringent emission regulations;2. Increase of Engine Output for large, high-speed vessels;3. High thermal efficiency;4. High reliability and safety.As the best way of meeting this market demand, we propose application of the Mitsui-MAN B&W Electronically Controlled Diesel Engine with TES tuning. The Thermal Efficiency System is a diesel engine combined with a Turbo Generator and Turbo Compound System to increase the total thermal efficiency of the ship. The Thermal Efficiency System is an essential technique for reducing CO2 emission levels of ships.

Technical Literature Digest

Technical Literature Digest