Charge Air Cooler Research Articles

Input impedance measurement of a narrow pipe with thermal gradient.

Input impedance measurement is commonly used in the design of internal combustion engines to improve their performance. The water-cooled charge-air cooler used in supercharged engines imposes a strong longitudinal thermal gradient on the air contained in its narrow channels. To isolate the resonances caused by the thermal gradient, the input impedance of a semi-infinite narrow pipe with multiple longitudinal temperature profiles is studied experimentally using the Two-Measurement Three-Calibration method. Three known non-resonant loads are used to calibrate the test bench. The importance of using a semi-infinite pipe as a calibration load in narrow pipes is further demonstrated. In the case of this paper, the acoustic propagation is highly influenced by the presence of microphones. The calibration process helps to take into account this influence. Measurements show that the presence of a non-uniform longitudinal temperature profile in the air inside a pipe modifies its input impedance.

Combustion System Design of a Genset Diesel Engine by Using DFSS Methodology

In this study, an optimum design for the combustion system of a genset diesel engine was conducted by using Design for Six Sigma (DFSS) methodology. As a result of this study, the best combination of design parameters to minimize the fuel consumption of the genset diesel engine was selected while meeting the requirements of NOx emission and peak firing pressure (PFP) limit. Compared to the initial design, the final design proposal has achieved 2.5 % and 1.6 % improvement in brake specific fuel consumption (BSFC) at switchable operating conditions, i.e., both 1500 and 1800 rpm. On the basis of this DFSS work, the design robustness was also enhanced. Hence, it is expected that the final design proposal would reduce the variability in fuel economy that could be caused by harsh environment and system aging. In this study, engine cycle simulation technique was employed to assess the effects of various design parameters on the performances of the genset diesel engine. The current optimum design work has considered four control factors such as turbocharger size, air temperature at charge air cooler (CAC) outlet, compression ratio, and fuel injection duration. Here, an L9 orthogonal array was used to efficiently choose the best design proposal among 81 design combinations (i.e., four independent control factors which individually have three different levels).

Simulation of combustion process in the forced transport diesel engine with the prescribed law of mixture formation

There was developed a new single-zone model of the fuel combustion process, based on the equations of chemical kinetics, which takes into account in more detail the features of the internal chamber processes of internal combustion engines. The combustion process is considered as a set of successive oxidation reactions to carbon dioxide and water of groups of active fuel molecules proceeding according to the Arrhenius law. The number of active molecules of fuel entering into the reaction depends on the total number of fuel molecules, the current mixture temperature and the conditional activation energy, varying depending on the fraction of burned fuel. The conditional duration of oxidation of this group of active molecules is assumed to depend not only on the total number of fuel molecules, but also on the volume of the combustion chamber, the number of oxygen molecules, the number of molecules of inert components and turbulence inside the combustion chamber. The heat released during the oxidation of each group of active fuel molecules is determined through the lower heat of combustion of the fuel and is expended to increase the temperature and pressure of the mixture in the combustion zone. At each step of the calculation, the number of molecules of all substances is corrected as a result of fuel burn-out. A special feature of the model is the introduction of a new parameter that takes into account the time factor at the molecular level, the conventional duration of the oxidation reaction of the active molecules of the fuel. A new mathematical model is used as the basis for the algorithm for the developed program for calculating the operating cycle of an accelerated diesel engine with a prescribed law of mixture formation. Calculations of the influence of the temperature of the fresh charge after the charge air cooler on the duty cycle of the forced diesel in the range from 360 to 430 K are performed. According to the results of the calculation, it is established that the best indicator characteristics of the working cycle are reached at a temperature of 360 K. Indicator diagrams of pressure in the cylinder and the laws of heat generation, obtained by calculation correspond with known experimental data.

Modeling and thermoeconomic optimization of marine diesel charge air cooler

This study presents a theoretical model for multi-objective optimization of marine diesel charge air cooler by firefly algorithm. By considering the overall cost and exergy destruction minimization as objective functions, energy and exergy analysis is carried out for multi-objective optimization design of a heat exchanger. Sensitivity analysis is performed to find out the effect of design parameters on the objective functions. Firefly algorithm is used to generate a set of Pareto optimum points and a normalized form of the Pareto front is applied as a decision-making approach to finding out optimum solutions. The theoretical model in the present study is verified by an experimental data and shows a good agreement between the current results and the experimental data. Also, the Pareto front shows that irreversible losses decrease while total cost increases and vice versa. Multi-objective optimization results reveal that overall cost and exergy destructions are reduced by 4.03% and 7.66%, respectively. Water pressure drop is decreased by 12.41% and air pressure drop is reduced by 2.95%.

Thermodynamic potential of twelve working fluids in Rankine and flash cycles for waste heat recovery in heavy duty diesel engines

A promising method to improve the efficiency of internal combustion engines is the use of thermodynamic cycles for waste heat recovery (WHR). In this study twelve working fluids are evaluated with regards to their thermodynamic potential for four cycles: the Rankine cycle (RC), the transcritical Rankine cycle (TRC), the trilateral flash cycle (TFC) and the single flash cycle (SFC). An energy and exergy analysis of a heavy duty Diesel engine revealed four sources with potential for WHR: the charge air cooler (CAC), the engine coolant, the exhaust gas recirculation cooler (EGRC) and the exhaust gas. Simulations performed for one engine operating mode, showed that the TFC performed best for the CAC with a power output of 2 kW. Owing to the thermal match between source and cycle, the RC outperformed all other cycles for the coolant with a power output of 5 kW. For the EGRC, the TRC with methanol gave the best output of 8 kW. As for the exhaust, all cycles had an output of around 6 kW with much variation between the fluids. A sensitivity analysis of the condensation temperature, source outlet temperature, degree of superheating, operating mode and expander efficiency showed significant impact on the output.

Improvement in high load ethanol-diesel dual-fuel combustion by Miller cycle and charge air cooling

At high load, dual-fuel compression ignition engines often rely on exhaust gas recirculation (EGR) to avoid excessive in-cylinder pressure rise rates caused by the autoignition of the premixed fuel. This can adversely affect the net indicated efficiency depending on the resulting fuel/air equivalence ratio and pressure differential across the cylinder used to drive the requested amounts of EGR. In this work, advanced combustion control strategies have been experimentally investigated to improve ethanol-diesel dual-fuel operation at a high engine load of 1.8 MPa net indicated mean effective pressure. Miller cycle and charge air cooling have been explored to reduce the in-cylinder gas temperature and help control the ethanol autoignition process, potentially minimising the EGR requirements and increasing net indicated efficiency. Experiments were carried out on a single-cylinder heavy-duty engine equipped with a high pressure common rail diesel injection, an ethanol port fuel injection, and a variable valve actuation system on the intake camshaft. Exhaust emissions and net indicated efficiency were measured and discussed for different ethanol energy fractions. Early autoignition of the premixed ethanol fuel at the baseline intake valve lift profile resulted in high levels of pressure rise rate, which limited the ethanol energy fraction to 0.26. The application of a Miller cycle strategy via late intake valve closing events effectively delayed the ethanol autoignition process. The reduction of the intake manifold air temperature via an air-to-water charge air cooler also suppressed the early ignition of ethanol. Both approaches allowed for a substantial improvement in terms of the maximum ethanol energy fraction, which was increased to 0.79 without EGR. Moreover, high load dual-fuel operations with Miller cycle and charge air cooling attained higher net indicated efficiency and lower nitrogen oxides emissions than conventional diesel combustion. These improvements can help generate a viable business case of dual-fuel combustion as a technology for future compression ignition engines.

Evaluation of Different Turbocharger Configurations for a Heavy-Duty Partially Premixed Combustion Engine

The engine concept partially premixed combustion (PPC) has proved higher gross indicated efficiency compared to conventional diesel combustion engines. The relatively simple implementation of the concept is an advantage, however, high gas exchange losses has made its use challenging in multi-cylinder heavy duty engines. With high rates of exhaust gas recirculation (EGR) to dilute the charge and hence limit the combustion rate, the resulting exhaust temperatures are low. The selected boost system must therefore be efficient which could lead to large, complex and costly solutions. In the presented work experiments and modelling were combined to evaluate different turbocharger configurations for the PPC concept. Experiments were performed on a multi-cylinder engine. The engine was modified to incorporate long route EGR and a single-stage turbocharger, however, with compressed air from the building being optionally supplied to the compressor. Experimental combustion heat release rates and boundary conditions were used to validate a simulation model. This model was then used to compare three different turbochargers: two single-stage turbochargers and one two-stage. The whole speed and load range was covered in the simulations to determine the engine performance. The influence of high EGR rates as well as the effect of charge air and EGR cooler gas outlet temperatures were also investigated. The simulation results showed that the two-stage turbocharger was able to give the highest load over the whole speed range with a brake mean effective pressure of 25.6 bar, whereas the two single-stage turbochargers reached 22.2 and 23.1 bar respectively. The average brake efficiency was 39.3, 39.7 and 40.2 %. It was found that decreasing the inlet temperature is critical for obtaining high loads and system efficiencies. Finally, it was shown that the optimal amount of EGR was dependent on the turbocharger efficiency and cooler temperatures.

Thermodynamic potential of Rankine and flash cycles for waste heat recovery in a heavy duty Diesel engine

In heavy duty Diesel engines more than 50% of the fuel energy is not converted to brake power, but is lost as heat. One promising way to recapture a portion of this heat and convert it to power is by using thermodynamic power cycles. Using the heavy duty Diesel engine as the waste heat source, this paper evaluates and compares the thermodynamic potential of different working fluids in four power cycles: the Rankine cycle (RC), the transcritical Rankine cycle (TRC), the trilateral flash cycle (TFC) and the single flash cycle (SFC). To establish the heat input into the cycle, operating conditions from an actual heavy duty Diesel engine are used as boundary conditions for the cycle heat source. A GT-Power model of the engine was previously developed and experimentally validated for the stationary points in the European Stationary Cycle (ESC). An energy analysis of this engine revealed that it has four heat sources with the potential for waste heat recovery: the charge air cooler (CAC), the coolant flow, the exhaust gas recirculation cooler (EGRC), and the exhaust flow. Using fixed heat input conditions determined by the selected engine operating mode, the TFC performed best for the CAC with a net power increase of around 2 kW, while the RC performed best for the coolant flow, with a net power increase of 5 kW. For the EGRC, ethanol performed especially well with both the RC and TRC, leading to an 8 kW net power increase. When using the exhaust as heat source, all four cycles provided a power output of around 5 kW with some variation depending on the working fluid. This study shows that for most cases, considering the different heat sources, the choice of cycle has a larger impact on the cycle performance than the choice of working fluid.

Study and Comparison of Charge Air Cooling Techniques their Effects on Efficiency of Automobile Engine

Study and Comparison of Charge Air Cooling Techniques their Effects on Efficiency of Automobile Engine

Performance Estimation of Charge Air Cooler for Passenger Car

This charge air cooler is extensively used in diesel engine mostly for marine applications. The main purpose of a charge air cooler is to cool the engine air, ensuring efficient performance. The main objective of the charge air cooler is to increase the heat dissipation capacity and to reduce the outlet temperature. In this paper, the charge air cooler was designed, simulated and developed in MAHLE Behr India Private Limited, Pune. Based on the simulation results it is observed that heat rejection and outlet temperature were matched with the requirement and tested values.

Application of Moldflow Simulation in Injection Molding of Plastic Tank

Abstract This article presents an application of moldflow simulation to optimize the injection molding process of charge air cooler plastic tank. The work shows the advantages of this kind of simulation software and information that it can provide. It also explains how big role today play simulation softwares and how they can improve product and reduce development cost.

Acoustic Modeling of Charge Air Coolers

The necessity of reducing CO2 emissions has lead to an increased number of passenger cars that utilize turbocharging to maintain performance when the internal combustion (IC) engines are downsized. Charge air coolers (CACs) are used on turbocharged engines to enhance the overall gas exchange efficiency. Cooling of charged air increases the air density and thus the volumetric efficiency and also increases the knock margin (for petrol engines). The acoustic properties of charge coolers have so far not been extensively treated in the literature. Since it is a large component with narrow flow passages, it includes major resistive as well as reactive properties. Therefore, it has the potential to largely affect the sound transmission in air intake systems and should be accurately considered in the gas exchange optimization process. In this paper, a frequency domain acoustic model of a CAC for a passenger car is presented. The cooler consists of two conical volumes connected by a matrix of narrow ducts where the cooling of the air takes place. A recently developed model for sound propagation in narrow ducts that takes into account the attenuation due to thermoviscous boundary layers and interaction with turbulence is combined with a multiport representation of the tanks to obtain an acoustic two-port representation where flow is considered. The predictions are compared with experimental data taken at room temperature and show good agreement. Sound transmission loss increasing from 5 to over 10 dB in the range 50–1600 Hz is demonstrated implying good noise control potential.

Fuel Consumption Benefits of Indirect Charge Air Cooling in Commercial Vehicles

Fuel Consumption Benefits of Indirect Charge Air Cooling in Commercial Vehicles

Accelerating the Product Development of a Commercial Vehicle Radiator using Finite Element Analysis

Emissions such as Nox and CO resulting from the combustion of the diesel engines in the commercial vehicles leads to environmental degradation and ozone layer depletion. Alarming environment trend forces the government institutions to develop and enforce strict emission laws for the next generation transportation vehicles. Stricter emission laws mean higher operating pressure, temperature, reduced weight, tight packaging space, engine downsizing etc. Engine cooling systems are the critical components in the managing the engine cooling requirement of the commercial vehicle. Generally engine cooling system includes radiator, charge air cooler, engine oil cooler etc. Product development of thermal management system using the traditional design process takes more time, resource and money. To solve the complex design problem, numerical technique such as finite element analysis is performed upfront in the product development of the radiator to evaluate the structure behaviour under mechanical loading. In this paper, internal static pressure analysis of a radiator is presented to showcase the benefits of using the finite element technique earlier in the product design phase. Pressure cycle life at a critical joint of the radiator is calculated using strain-life approach. Finite element analysis aids in visualization of the hot spots in the design, comparing different design options with less turnaround time. Experimental testing and prototypes can be reduced. Risk of a product being failed is greatly minimized by performing the numerical simulation.

Numerical investigation on various heat exchanger performances to determine an optimum configuration for charge air cooler, oil and water radiators in F1 sidepods

Abstract The present work focuses on a three-dimensional CFD approach to predict the performance of various heat exchangers in conjunction with non-isothermal transitional flows for motorsport applications. The objective of this study is to determine the heat transfer, pressure drop and inhomogeneous flow behaviour for distinct heat exchangers to identify an optimum configuration for the charge air cooler, water and oil radiators placed in the sidepods of a formula one (F1) car. Therefore, a comprehensive analysis of various heat exchanger configurations has been carried out in this work. In order to assess the reliability of the obtained results, a mesh sensitivity study along with additional parametric investigations have been performed to provide numerical parameters predicting accurately (a) the heat transfer rate at the fluid-solid interface and (b) the sporadic separation. As a result of the performed validation procedure in this study, the aerodynamic- and thermal boundary layer development along with the convective characteristics of the air flow have been captured accurately near to the heated surface. The characterization of a heat exchanger core and a core configuration in a closed domain is also possible with this procedure. The presented three-dimensional CFD approach could overcome the difficulties of macroscopic heat exchanger and porous media methods for F1 applications, because it can be used to predict the heat transfer and pressure drop related to the mass flow rate correlation curves. The contribution of fins to the total heat transfer rate has been predicted theoretically, and application benchmark test cases have been presented to analyze five different heat exchanger configurations in accordance with the 2014 formula one technical regulations. The numerical data extracted directly from three-dimensional CFD simulations can be used in the sidepod design process of the external cooling system of F1 engines.

Linear acoustic multi-port modeling of automotive charge air coolers

1D linear acoustic or gas-dynamics modeling of intake and exhaust systems is typically done during the early development stages of a vehicle in order to do quick sound design assessments. One of the components in the intake system of a turbocharged IC engine is the automotive charge air cooler. The charge air cooler is positioned at the outlet of the compressor in order to cool the charged air before it enters the engine. Charge air coolers are typically modeled as a 1D system comprised of an intake tank/duct, cooling tubes and an outlet tank/duct. A problem arises when the position of the inlet/outlet ducts is not axially symmetrical, which introduces three-dimensional acoustic effects. This behavior is not included in typical 1D modeling. Finite element modeling could be used to describe this 3D effect but would need much longer time and a detailed geometrical model that could be unavailable during the early development stage. In this study an acoustic multi-port description of the charge air cooler model is presented. Such a description includes the influence of the asymmetric position of the inlet/outlet ducts on the acoustics. The multi-port description is then reduced to an equivalent acoustic two-port model for the entire charge air cooler between its inlet/outlet ports. The frequency dependent transmission loss (TL) is calculated and compared to experimental results with good agreement.

Thermal design of liquid cooled charge air cooler: A computational approach

Successive advent of vehicle emissions norms & strong emphasis on fuel efficiency have enforced vehicle manufactures to deploy turbo charging of intake air prior to intake manifold. However introduction of turbochargers also signify need of a heat exchanger called charge air cooler or intercooler to reduce the temperature of turbocharged air to optimum limit prior to intake manifold of engine. The major limitation of conventional air to air charge air coolers is that they yield low heat transfer rate to weight ratio & low heat transfer rate to frontal area ratio characteristics. Beside this at higher boost pressure and higher temperature conditions there are metallurgical challenges for conventional air to air charge air coolers. Therefore; design optimization aimed at improved heat transfer from charge air is the need of strict environmental norms (Euro V onward). Rapid growth of automobile sector coupled with cutting edge technology development is also leading demand for highly efficient as well as compact solutions for charge air cooler. This provide motivation and challenge to design highly optimized new technology based system, which can provide increased rate of heat transfer with lesser pressure drop & overall compact size. To overcome discussed limitations of conventional air to air charge air cooler; the present research explores thermal design of liquid cooled charge air cooling device with unique charge air flow mechanism. The new design of liquid cooled charge air cooler provides multiple flow passes in order to achieve advantages of both cross flow as well as counter flow type heat exchangers. Multiple flow passes basically ensure maximum interaction of two heat exchanging fluids; hence heat exchanger effectiveness gets improved. Charge air is introduced to the heat exchanger with the help of an inlet tank header. The flow of charge air around the heat exchanger is precisely controlled by a casing, which ensures a uniform guided flow to successive passes of heat exchanger. An outlet tank header serves the purpose of supplying charge air to the engine intake manifold. A Computational Fluid Dynamics (CFD) methodology is used to optimize flow dynamics of two working fluids, namely liquid water and charged air coming out of turbocharger.

THE METHODOLOGY FOR DETERMINING THE INSTALLED REFRIGERATION COOLING BY WASTE HEAT RECOVERY POWER CHARGING AIR MAIN ENGINE TRANSPORT SHIP

Discusses some aspects of the methodology to determine the rational installed (design) of the refrigeration cooling by waste heat recovery power charging air main engine for maximum fuel economy for the climatic conditions of operation of a vessel for a specific voyage line. While charging the air cools down to a lower temperature compared to the traditional system of cooling seawater, and waste heat the refrigeration machine recycles the warmth of charge air cooler after the turbocharger. The peculiarity of the methodology is that the installed cooling by waste heat recovery power charging air cooling installation choose based on the high rate of increment of fuel savings per flight.

The influence of fuel type on the cooling system heat exchanger parameters in heavy-duty engines

The paper discuses the problem of selection of cooling systems for heavy-duty engines fitted in city buses. Aside from diesel engines, engine manufacturers also have in their portfolio engines fueled with natural gas, whose design is based on that of a conventional diesel engine. Based on the parameters of the engines from this type-series (the same displacement and rated power) an analysis has been performed of the influence of the applied fuel on the heat flows directed to the radiators and charge air coolers, hence, their size and space necessary for their proper installation. A replacement of a diesel engine with a natural gas fueled engine of the same operating parameters results in an increased amount of heat released to the coolant and a reduced heat from the engine charging system. This forces a selection of different heat exchangers that require more space for installation. A universal cooling module for different engines is not an optimal solution.

THERMAL ANALYSIS OF WATER COOLED CHARGE AIR COOLER IN TURBO CHARGED DIESEL ENGINE

Air-cooled and water-cooled charge air coolers are used as applications in automobiles. The cooling media include engine’s coolant, ambient air or any other external coolant source. Charge air cooler with offset strip fin geometry is chosen on both hot and cold sides with fin thickness 0.15 mm, length 3.2 mm, height 5.2 mm and frequency of 18 fins per inch. The flow rate on hot side is taken as 0.3 kg/s and cold side as 2 kg/s for air-cooled charge air cooler and for water-cooled charge air cooler on hot side it is 0.3 kg/s and cold side is 0.265 kg/s with inlet temperature on hot side 160 C and cold side 40 C. With the above conditions, performance evaluation is done on both charge air coolers. Having found water-cooled charge air cooler is having higher effectiveness than air-cooled type, performance evaluation is carried out on water-cooled charge air cooler with varying mass flow rates on hot side from 0.1 to 0.6 kg/s and keeping cold fluid rate constant at 0.265 kg/s and the outputs obtained are Colburn-j factor, Fanning friction factor, heat transfer coefficient, overall heat transfer coefficient and effectiveness of heat exchanger. From the obtained results, graphs are drawn to assess the performance of the water charge air cooler.