Exhaust system typically experiences vibration during engine operating conditions due to periodic disturbing forces (firing force and inertia force) which are generated from the engine. Natural frequency of the exhaust system gets excited due to the periodic forces causing resonance which often leads to high cycle fatigue (HCF) failure. Turbocharger is a part of exhaust system and it is mounted on the exhaust manifold. The periodic forces are transferred from engine base (Cylinder head and Block) and these forces gets amplified to overhanging components like exhaust system turbocharger. It is an industrywide practice to perform modal analysis to determine the natural frequencies of the system. However, modal analysis cannot predict the intensity with which the system would vibrate. Thus, we need to make some assumptions about the system vibration ‘g’ levels. Based on accuracy of this assumption, we may end up under-designing or over-designing the system. Harmonic analysis enables us to accurately predict the ‘g’ level at turbocharger using experimental cylinder head base excitations. After recording the correlation with experimental data in many cases it was found that this approach further aided in establishing damping constant factor of the exhaust manifold at elevated temperature. This analysis process has been validated with multiple cases as it has turned out to be a potential approach while doing design risk assessments and optimizing the engine vibration validation efforts. The benefit of prediction of exhaust system vibration level allows us to avoid iterative design process in the early stage of product development thus optimizing the design by taking advantage of shifting the natural frequency of exhaust system to lower source excitation (cylinder head). This saves vast amount of simulation lead time. Another benefit of this process is that the prediction of resonance condition of exhaust system through simulation helps us to estimate the fatigue life against the predicted ‘g’ level.

Engine valvetrain is one of the complex mechanisms in internal combustion engine as it involves many components namely, cam, pushrod, rocker lever, crosshead, intake and exhaust valves etc. Due to many components, their interactions with each other and presence of valve lash makes the system complicated to simulate. Typically, engine system level valvetrain dynamic simulation is performed in 1D software. Aim of this study is to understand the physics governing interactions and motion of the components in the valvetrain. This is done by simulating an inline 6-cylinder engine valvetrain mechanism through transient dynamic analysis in Ansys. This paper describes an approach used to simulate the valvetrain mechanism in Ansys and associated learnings. Finite Element Analysis model considers actual stiffnesses of all components. Appropriate joints/contacts are used to model the interactions. The comparative assessment of the valvetrain forces between Ansys results and 1D simulation results shows a good match. Further, 3D simulation in Ansys captures the key characteristics of valvetrain like crosshead tilting, uneven valve actuations and closing. It is also able to predict uneven contact and polishing observed on valve tip face. Overall, this study helped to ascertain the validity of 3D FEA method. This method also enhances the understanding of the valvetrain dynamics which can be helpful in further design improvements. This paper also includes a discussion on further steps to improve analysis model to make it more realistic e.g. including hot valve lash, valve seat wear etc. These improvements will help to understand effects of valve lash on valve velocities, sudden impact loads on valves, valve stresses/fatigue, pushrod buckling etc.

In transport applications, reciprocating internal combustion engines still have important advantages in terms of endurance and refueling time and available infrastructure when compared against fuel cell or battery-based powertrains. Although conventional internal combustion engine configurations produce important amounts of greenhouse gases and pollutant emissions, oxyfuel combustion can be used to mitigate to a great extent such emissions, mainly producing NO x -free, CO 2 and H 2 O exhaust gases. However, the oxygen needed for the combustion, which is mixed with flue gases before entering the cylinder, has to be stored in an additional tank, which hinders the adoption of this technology. Fortunately, the latest developments in gas separation membranes are starting to produce extremely-high selectivity and high permeability oxygen-separation membranes. Using the waste heat of the exhaust gases to heat up a mixed ionic-electronic conducting membrane, and feeding it with pressurized air, it is possible to produce all the oxygen needed by the combustion process while keeping the whole system compact. This works presents a design of an oxy-fuel combustion engine with in-situ oxygen production. The numerical simulations show also that this concept keeps a competitive brake specific fuel consumption, while the high concentration of CO 2 in the exhaust gases facilitates the introduction of carbon sequestration technologies, leading to potentially carbon-neutral internal combustion engines.

The exhaust manifold is one of the key components of an engine exhaust system. Exhaust manifold simulations are time-consuming as they require modeling of complex thermal loading and multiple non-linearities like friction and plasticity. This proves to be a big constraint for using Multidisciplinary Design Optimization (MDO) for exhaust manifolds as it involves running a large number of models specified by a Design of Experiments (DOE). Also, during the initial phase of design development, it seems reasonable to compromise the accuracy of simulations at the cost of speed for getting correct feedback on design direction. Hence, the main objective of the current work was to a develop simplified analysis process for Thermomechanical Fatigue (TMF) and modal analysis of exhaust manifold. At the concept stage, due to the lack of availability of accurate thermal Boundary Conditions (BCs) and the goal to simplify modeling, thermal BCs are assumed with the help of thermal data history instead of accurate thermal BCs from test cells. Similarly, other aspects such as ‘level of component assembly required’, ‘mechanical loading’, and ‘outputs to be monitored for making design decisions were also investigated to come up with a simplified approach. The proposed approach was quick compared to the conventional one. This approach was implemented on a few heavy-duty and mid-range engine programs to check repeatability. It was observed that the proposed analysis approach provides correct design direction with a significantly reduced computational time of up to 80%. Incorporating the simplified approach for the MDO process has made it more practical and feasible for implementation during the concept design cycle in the early stage of an engine development program.

Rubber torsional vibration dampers are often used on mid-range engines. Usually, the geometry of a rubber torsional vibration damper is such that the rubber element in it undergoes shear. However, in the work presented, a compression rubber damper is being proposed, in which the rubber element undergoes compression rather than shear. The proposed compression rubber damper, just like the shear rubber damper, is a tuned damper. An analytical tool is being used to evaluate the stiffness of compression rubber design and thus evaluate its performance. The rubber geometry, material and plate design are selected through simulations. The analytical tool demonstrates the functionality of the compression rubber damper paper and focuses on simulation-based product development using ANSYS for FEA and an in-house tool for torsional vibration analysis.

Improving internal combustion engine performance is a significant concern over the past few decades for engine researchers and automobile manufacturers. One of the promising methods for improving the engine performance is variable valve actuation system with camless technology. In the camless system, the conventional spring-operated valve actuation mechanism is removed, and an actuator is used to independently control the valve events (lift, timing, and duration). Among different camless systems, electromagnetic variable valve actuation (EMVA) becomes more viable because of its faster valve operation. However, the major challenge is to control the valve seating velocity (velocity at which valve comes to rest during seating on the cylinder head) due to the absence of the cam mechanism. A sophisticated control system must be developed to achieve an acceptable valve seating velocity. In this study, a proportional-integral-derivative (PID) controller was used to control the EMVA system. A machine learning tool, i.e., genetic algorithm, and an iterative method, i.e., Ziegler-Nichols, were used to optimize the PID controller’s gain values. The valve lift profiles obtained using the Ziegler-Nichols method and the genetic algorithm were compared. It was found that the developed algorithm for the EMVA system can achieve faster rise time compared to the experimental results [25] utilized inverse square method. A parametric investigation was performed to verify the robustness of the PID controller with a change in temperature. It is concluded that the temperature rise may increase the resistance and inductance, but the controller with the updated gain values can control the EMVA system without affecting the performance parameter. The simulation was performed for both forward and backward strokes to investigate the valve seating velocity. It was found that the controller can achieve an acceptable valve seating velocity. Hence, the machine learning tool helps in optimizing the PID controller’s gain values to achieve faster valve operation with an acceptable valve seating velocity.

In order to rise to global challenges such as climate change, environmental pollution and conservation of resources, internal combustion engine manufacturers must meet the requirements of substantially reduced emissions of CO 2 and other greenhouse gases, zero pollutant emissions and increased durability. This publication addresses approaches that can help improve engine efficiency and durability through the engine crankshaft bearing and lubricant system. An understanding of the operating behavior of key engine components such as crankshaft main bearings in fired engine operation allows the development of appropriate tools for bearing condition monitoring and condition-based maintenance so as to avoid critical engine operation and engine failure as well as unnecessary engine downtime. Such tools are especially important when newly developed low viscosity oils are employed. Though these oils have the potential to reduce friction and to increase engine efficiency, their use comes with a higher risk of accelerated bearing wear and ultimately bearing failure. The specific target of this paper is therefore to obtain detailed knowledge of the influence of engine operating parameters and oil parameters on crankshaft main bearing temperature behavior and engine friction behavior in fired operation as a starting point for condition monitoring and condition-based maintenance approaches and as a basis for improving the bearing and lubricant system as a whole. To achieve this target, experimental investigations were carried out on an engine test bed employing an in-line six-cylinder heavy-duty diesel engine with a displacement of approximately 12.4 dm 3 . Defined and accurately reproducible engine operating conditions were ensured by comprehensive external conditioning systems for the coolant, lubricating oil, fuel, charge air and ambient air. Since the focus was on investigating the bearing and friction behavior by means of the base engine, several auxiliary systems were removed; these included the lubricating oil and coolant pumps, the front-end accessory drive and the generator. Each crankshaft main bearing was instrumented with a thermocouple on the back of its bottom bearing shell to measure the bearing temperature. Piezoelectric pressure transducers were applied to all six cylinders in order to facilitate the accurate determination of the friction mean effective pressure (FMEP) based on indicated and brake mean effective pressures. The variations in engine operating parameters (engine speed and torque) mainly serve as a reference for the variations in oil parameters. They confirm the existing knowledge that engine speed has a significant impact on FMEP and bearing temperature while the impact of engine torque is comparatively low. The variations in oil parameters reveal that lowering the viscosity grade from SAE 10W-40 to 5W-20 leads to a decrease in both bearing temperature and FMEP, which can be explained by the lower fluid friction in the bearing system and the increased mass flow and convective heat transport with the lower viscosity oil. An increase in the lubricating oil temperature at the engine inlet leads to a significant increase in bearing temperature and a decrease in FMEP; the former is explained by the increased heat influx from the lubricant oil, and the latter is caused mainly by the temperature dependency of the lubricant oil viscosity and its impact on fluid friction. The impact of engine oil inlet pressure on bearing temperature and FMEP is generally found to be low. The results will serve as the basis for future research that includes approaches to condition monitoring and evaluating improved engine operating strategies with regard to oil parameters.

As part of an initiative to explore additive manufacturing technologies and their application to internal combustion engines, Wabtec Corporation invested in the development of a new turbocharger for high speed engines. This program had a primary goal of utilizing additive manufacturing methods to enable improvements in product performance, cost and development time. This paper will provide an overview of the Additive Content Turbocharger design and additive processes used for production of functional prototypes.

The thermal efficiency of an Otto cycle engine is directly related to the compression ratio (CR). However, in a spark-ignited engine, the CR is often restricted by full load knock, thus limiting part load efficiency. A proof of concept design and experimental study has been conducted on a 4-cylinder naturally aspirated spark-ignited (SI) engine whereby a four-bar linkage mechanism has been implemented to vary the CR. The base engine selected was a production 2.0L GM-LNF SI 4-cylinder engine with a stock CR of 9.2:1 and with a bore and stroke of 86mm and 86mm, respectively. The engine was modified to allow the centerline axis of rotation of the crankshaft to translate in an arc about a fixed point. With the use of the four-bar mechanism, and larger dome volume pistons, a range of 8:1 to 11.5:1 CR was achieved. The prototype VCR engine was tested and analyzed at three different CR’s at a fixed load of 600 kPa net indicated mean effective pressure gross (IMEP GROSS ) at an engine speed of 1000 revolutions per minute (RPM). At this condition, a sweep of combustion phasing was conducted. with a stoichiometric air to fuel mixture for each case. The CR’s selected for engine testing were 8.7:1, 10.2:1, and 11.1:1. The processed data includes averaged cycle analysis of each of the test conditions including combustion phasing, combustion duration, and cycle variation. The combustion data was also analyzed to determine overall heat release, indicated gross, net, pumping mean effective pressures, and indicated fuel conversion efficiency for each of the CR’s. The studies show an indicated fuel conversion efficiency of 31.2% for the 8.7:1 CR. As the CR was increased to 10.2:1 and 11.1:1 the relative increase in efficiency was 7.1% and 9.7% respectively at MBT combustion phasing.

A fuel and engine management system have been successively applied to a 4.5L spark-ignition gaseous-fueled engine used for stationary power generation applications up to 80 kW. The system operates on low-pressure commercial grade natural gas or liquid propane gas and governs engine speed at either 1500 or 1800 rpm, for generator frequencies of 50 Hz and 60 Hz respectively. The fuel and engine management system consist of an engine control module, an electronically controlled fuel mixer, a fuel pressure sensor, and other supporting sensors/actuators. This new system replaces a legacy of fixed-orifice metering or vacuum-actuated-valve mechanical mixer designs. This new system allows for closed-loop control of stoichiometric combustion that meets both performance and emissions requirements without the need for a fuel pressure regulator within the genset frame. It also allows a single fuel system assembly to be used on all 4.5L engines regardless of fuel type (LP/NG) or nominal speed (50/60Hz), as these are now selected with standard J1939 CAN protocol messages from the genset controller. This paper reviews the development aspects for the new fuel system on the 4.5L engine. The electronic-actuated fuel mixer system offers a wider range of fuel flow control compared to mechanical-actuated mixers, this results in better air-fuel control due to variations in fuel quality, low fuel supply pressure and changing ambient conditions. The range of fuel control is result of the different mixer valve construction and control. The fuel metering valve is a butterfly type and is controlled from a stepper motor. The valve controls the fuel flow rate just before the fuel mixes with the combustion air passing thought a venturi. Lag in fuel flow, typical of low supply pressure and low restriction / signal venturi, is corrected for using a feedforward control strategy based on genset electrical load. The mixer sizing and flow bench measurements for calibration, will be reviewed. The ECM uses a speed-density air flow model, along with fuel supply and air filter pressure, to determine the best mixer valve position. The engine air flow model is used for determining venturi flow and the resulting mixer vacuum signal, but a final calibration correction was created with hot wire-anemometer-flow meters on a running engine. A long-term fuel trim is also applied to the mixer position, but unlike a fuel-injection system which corrects volumetric efficiency based on known fuel flow rate and HEGO sensor feedback, this mixer control strategy learns a steady-state mixer correction or offset. The entire control strategy was developed within a Simulink model and auto code generation tools were used to create final ECM C and machine code. The development of the mixer and ECM control strategy will be detailed herein.

Lube oil emission is thought to have a negative influence on hydrocarbon and particle emissions, autoignition and the life-cycle cost of internal combustion engines. Thus, one of the major goals of combustion engine research and development is to optimize lube oil consumption, for example by optimizing the tribological behavior of the piston group (interaction between piston rings and cylinder liner). This requires the application of a fast and accurate lube oil consumption measurement method. Methods such as gravimetric and volumetric measurement are outdated for R&D applications because of measurement time, absolute accuracy as well as repeatability, however some OEMs are still applying this method. At present, the use of tracer methods for measuring lube oil consumption is considered the most promising in terms of decreasing measurement time and increasing accuracy. For example, sulfur as a tracer is one of the most established methods for measuring lube oil consumption, but previous publications have revealed downsides and future challenges of its use. This publication, however, highlights the challenges of using the stable hydrogen isotope deuterium as a tracer which are still to overcome, in order to become a viable and reliable method for measuring lube oil consumption on internal combustion engines. In the introduction, a novel concept of measuring lube oil consumption with deuterated engine oil and the test bench setup are explained. Following laboratory experiments, test bench runs on a heavy-duty diesel engine and long-term studies on a field engine, three major challenges facing the new approach are identified and potential solutions are proposed. First, the long-term stability of the tracer in the lube oil and potential changes in the physical and chemical properties of the oil due to deuteration are discussed in light of the results of tests on a field engine that uses deuterated engine oil. Second, the hydrogen-deuterium exchange process to mark the oil with the tracer is examined and potential approaches for reducing cost and duration are highlighted. The universal applicability of the deuteration process to several base oil groups is also explained. Finally, the detection of deuterium in the gas of the engine exhaust and potential cross-sensitivities to trace gases as well as other crucial limitations of the detector in analyzing engine exhaust are addressed. The summary presents the requirements for converting the experiments with a deuterium tracer into a reliable method for lube oil consumption measurement providing crucial properties such as high accuracy, short measurement time, effort and ease of use.

The purpose of this study is to develop an artificial neural network (ANN) model for performance prediction of a variable compression ratio gasoline port fuel injection spark ignition engine. For ANN modeling, a large experimental data set was generated in which at random 85% was assigned for training the network, and 15% that are not included during the training process was used for testing the network. A multilayer perception feed forward neural network was used to predict the correlation between input and output layer. The input layer consists of engine speed, throttle position, spark timing, and compression ratio. Whereas, the output layer consists of torque, brake power and indicated mean effective pressure (IMEP). Neurons in the hidden layer were varied and optimized based on a specified goal error. A standard supervised back propagation learning algorithm was used in which the error between the target and network output was calculated and minimized. In the hidden and output layers, a non-linear tan-sigmoid and a linear transfer function were used, respectively, for input-output mapping. The performance of the network was evaluated by statistical parameters like correlation coefficient (R), mean relative error (MRE) and root mean square error (RMSE). It was found from the test data that the R and MRE values are lies in between 0.99853 to 0.99875 and 0.42% to 0.58%, respectively. Whereas, RMSE value for all performance parameters was found to be very low. Hence, this study reveals that the application of ANN modeling has the ability to predict the performance of a variable compression ratio gasoline engine and is the best alternative tool over all classical modeling techniques.

The innovative Common Feeding (CF) fuel injection system has been designed for a light duty commercial vehicle diesel engine in order to reduce production costs and allow easy installation on the engine, compared to a traditional Common Rail system. In the CF apparatus, a delivery chamber with a volume around 10 cm 3 is integrated in the high-pressure pump. The chamber at one side is connected to the pump, and at the other side is linked to the solenoid injectors by means of pipes (the rail is removed from the hydraulic circuit). Experimental tests have been carried out on a hydraulic test rig at the Politecnico di Torino in order to compare the general performance of the prototypal CF system with that of a Common Rail (CR) system equipped with different rail volume sizes (realized by manufacturing rails of the same length but with different internal diameter). The injected mass flow-rates of single injections as well as of pilot-main injections have been captured by instantaneous flow-rate meters. In the case of the double injection schedules, the dependence of the injected mass pertaining to the second injection shot has been investigated during dwell time sweeps and design solutions have been provided to minimize the oscillations of such injected mass with respect to dwell time for the CF system. Furthermore, the injector inlet pressure time histories, the static and dynamic injector leakages, the nozzle opening and closure delays and the injected volume cycle-to-cycle dispersion have been evaluated for both CR and CF systems. In general, the injection performance of the injection systems with different hydraulic capacitances or shapes of the accumulator is similar. One significant difference is that the injection rate feature slightly different slopes during the rising phases. Furthermore, cycle-to-cycle dispersion in the injected mass increase to some extent when the accumulation volume of the high-pressure circuit is dramatically decreased. Finally, the frequencies of the free pressure waves that are originated by the water hammer, which occurs at the end of a hydraulic injection, are different when the shape of the accumulation volume change, whereas these frequencies are basically independent of the accumulation volume size.

Fuel consumption reduction and emission reductions in internal combustion engines (ICE) is a hot topic nowadays. An adaption of cylinder de-activation technique called ECONAMIQ over-expansion can be applied to engines to improve fuel efficiency. Using the pressure from the exhaust gas from the active cylinders, the ‘idle’ cylinders could be expanded to extract more work out of the engine during partial load operation. Using the virtual simulation environment GT-Power, this cycle is applied to a 4-cylinder SI engine. This engine model is simulated for a part load operation point and compared with a standard 4-cylinder engine model and 4-cylinder engine model equipped with cylinder de-activation. From these simulations various variables for engine operation (valve timing etc.) are optimized to further reduce fuel consumption of the engine. A final brake specific fuel consumption reduction of over 10% is achieved using the overexpansion cycle, while improving engine performance on two burning cylinders over 10% as well. With this improvement it is shown that the over-expansion cycle has a significant benefit compared to a standard ICE and cylinder de-activation techniques. These simulations are being validated on an engine test dyno using a natural aspirated ICE.

This study demonstrates the effects of technologies applied for the development of a gasoline direct injection (GDI) engine for improving the brake thermal efficiency (BTE) over 44%. The GDI engine for the current study is an in-line four-cylinder engine with a displacement of 2156cm 3 , which has relatively high stroke to bore ratio of 1.4 (110mm stroke and 79mm bore). All experiments have been conducted using a gasoline having RON 92 for stoichiometric operation at 2000RPM. First, since compression ratio is directly related to the thermal efficiency, four compression ratios (14.3, 15.2, 15.8 and 17.2) were explored for operation without exhaust gas recirculation (EGR). Then, for the same four compression ratios, EGR was used to suppress the knock occurrence at high loads with high compression ratio (CR), and its effect on initial and main combustion duration was compared. Second, the shape of intake port was revised to increase tumble flow of in-cylinder charge for reducing combustion duration at low and high load, and extending EGR-stability limit further eventually. Then, as an effective method to ensure stable, complete and fast combustion for EGR-diluted stoichiometric operation, the use of twin spark ignition system is examined by modifying both valve diameter of intake and exhaust, and its effect is compared against that of single spark ignition. In addition, the layout of twin spark ignition was also examined for the location of Front-Rear and Intake-Exhaust. To get the maximum BTE at high load, 12V electronic super charger (eSC) was applied. Under the condition of using 12V eSC, the effect of intake cam duration was identified by increasing from 260deg to 280deg. Finally, 48V eSC was applied with the longer intake camshaft duration of 280deg. As a result, the maximum BTE of 44% can be achieved for stoichiometric operation with EGR.

Oil traveling upward through the sliding surface of a piston ring causes oil consumption of an engine. Piston rings are designed considering conformability to deformed cylinder bore. However, cylinder deformation sometimes affects strongly oil consumption. It suggests that a piston ring cannot conform dynamically to the cylinder bore. In this study, distribution of oil film thickness of an oil ring was measured for investigating the dynamic conformability. An optical fiber has embedded in the sliding surface of the lower rail of the oil ring, and oil film thickness was measured by laser induced fluorescence method. The measuring point was rotated in the circumferential direction, so the distribution in both the circumferential and the axial direction could be measured. Thick oil films partially were found and it was found that the oil ring did not conformed to the deformed cylinder bore dynamically. Furthermore, such oil film showed thicker value than those expected theoretically. It was showed that dynamic conformability must be considered for piston ring design for reducing oil consumption.

Oil consumption of an engine causes particulate matter, poisoning catalysts and sometimes abnormal combustion like pre-ignition. One of the factors of oil consumption is oil transport via a piston ring-gap. Coincident of ring-gaps at a same position may cause an increase in oil consumption. In this research, the effect of coincident the ring gaps on oil consumption was measured using with/without the a stopper pin for the ring rotation by sulfur tracer method. A lot of spikes was found in the wave form of sulfur concentrate for the rings without the stopper pin, and higher value of oil consumption was simultaneously measured. Then the force which caused ring rotation (hereafter ‘rotational force’) was measured by a newly developed method. A cantilever was installed in the ring gap, and the strain gauges were pasted on the cantilever. Therefore, the rotational force was measured as the bending stress of the cantilever. It was found that the rotational force showed a periodic wave form against the crank angle. Furthermore, it was also found that the amplitude of the rotational force was strong affected by the engine operating conditions. The rotational force was also affected by the gap position. It was assumed that not only the piston lateral motion but also the cylinder bore shape affected the rotational force. The mechanism of generating the rotational force is the future subject.

The objective of current research on internal combustion engines is to further reduce exhaust emissions while simultaneously reducing fuel consumption. The resulting measures often mean an increase in complexity of internal combustion engines, which on one hand increases production cost and on the other hand increases the susceptibility of the overall system to defects. It is therefore necessary to develop technologies which can generate an advantage for the consumer despite increasing complexity. Within the scope of the project “High Efficiency Diesel Engine Concept” (“Hocheffizientes Diesel-Motoren-Konzept” HDMK), funded by the Federal Ministry of Economic Affairs and Energy with TÜV Rheinland as project management organization (funding code: 19U15003A), two engine concepts were investigated and combined on a John Deere four-cylinder inline engine. On the one hand, a new cylinder activation concept (“3/4-cylinder concept”) was implemented with the aim of reducing fuel consumption. On the other hand, a fully variable valve train was developed for this engine, which both improves the functionality of the 3/4-cylinder concept and can have a positive influence on exhaust emissions through internal exhaust gas recirculation. A comparison of this engine concept with its series reference based on measurement data showed a fuel economy advantage of up to 5.2% in the low load field cycles of the DLG PowerMix. The maximum fuel consumption benefit in the low load engine regime exceeded 15% in some of the operating points. As a final step, the engine was modified for the integration into an existing and working tractor, maintaining the available installation space of the powertrain.

In addition to a further reduction in fuel consumption and emissions, the current focus of internal combustion engine development is on system integration of the engine and its components to ensure perfect engine operation and high engine performance over the entire service life of the engine. Extensive sensor application allows acquisition, storage and intelligent processing of numerous engine parameters in digital engine control systems. Intelligent software platforms are increasingly being used to fully exploit the data generated by sensor systems and ensure optimal engine operation. This paper deals with new concepts for measuring physical quantities that are characteristic of sliding bearings. It describes the development of a flexible and multifunctional sensor technology for real-time measuring of temperature and pressure as well as the signal transfer and data acquisition from moving parts to outside the engine. The sensor technology required for such a system must meet the challenges of defining a quickly responding method that captures the measured variable as close to the bearing surface as possible in order to detect bearing failures in advance. The system must be able to withstand the high temperatures and mechanical loads inside the engine. In addition, fast wireless data transfer of signals acquired from moving components such as conrod bearings is necessary. A highly flexible sensor package based on thin-film technology was developed to meet these requirements. The sensor is integrated into the bearing shell and has the potential to be employed in series application. A robust telemetry unit able to withstand harsh environmental conditions such as high temperature and extremely high centrifugal forces was developed that transfers the measured data to engine ECU or other external devices. At the same time, transmission rate, distances and power demand are subject to stringent requirements. To create a comparative basis for further verification of bearings with thin film sensor technology and to gain insight into the temperature distribution in the bearing gap, measurements with conventional sensor technology that assesses temperatures directly inside the lubrication gap were undertaken on a bearing test rig as well as on a multicylinder heavy duty diesel truck engine. The results of these investigations also provide a fundamental understanding of the temperature distribution in the bearing gap for crankshaft as well as for conrod bearings. The results of ongoing investigations will include a validation of the new temperature measurement method based on thin film technology under real engine conditions.

A 5-stroke engine was analyzed using an improved 2-zone combustion model utilizing an equilibrium combustion model to calculate the gas properties in each zone. The flows of inlet, exhaust, and transfer port are handled using quasi-steady 1-D flow models. Heat transfer in the transfer port is also considered. The results are reported as indicated thermal efficiency and power output over a range of operating points and design characteristics, including engine RPM, compression ratio, overall expansion ratio, expansion cylinder clearance volume, and transfer port volume. It was found that the transfer port volume had a significant effect on the overall indicated thermal efficiency. The results were compared with those of a baseline 4-stroke engine. The 5-stroke engine with a compression ratio of 9:1, and an overall expansion ratio of 27:1 achieves a peak indicated thermal efficiency of 47%, representing a 6% increase over the baseline 4-stroke engine with the same compression ratio.