Detection of combustion related phenomena such as misfire, knock and sporadic preignition is very important for the development of electronic controls needed for the gasoline direct injection engines to meet the production goals in power, fuel economy, and low emissions. This paper applies several types of combustion ionization sensors, and a pressure transducer that directly sense the in-cylinder combustion, and the knock sensor which is an accelerometer that detects the impact of combustion on engine structure vibration. Experimental investigations were conducted on a turbocharged four cylinders gasoline direct injection engine under operating conditions that produce the above phenomena. One of the cylinders is instrumented with a Piezo quartz pressure transducer, MSFI (Multi sensing fuel injector), a standalone ion current probe, and a spark plug applied to act as an ion current sensor. A comparison is made between the capabilities of the pressure transducer, ion current sensors, and the knock sensor in detecting the above phenomena. The signals from in-cylinder combustion sensors give more accurate information about combustion than the knock sensor. As far as the feasibility and cost of their application in production vehicles the spark plug sensor and MSFI appear to be the most favorable, followed by the Standalone mounted sensor which is an addition to the engine.

Engine-out NO x emissions from diesel engines continue to be a major topic of research interest. While substantial understanding has been obtained of engine-out (i.e. before any aftertreatment) NO x formation and reduction techniques, not least EGR which is now well established and fitted to production vehicles, much less data are available on cycle resolved NO x emissions. In this work, crank-angle resolved NO and NO x measurements have been taken from a high-speed light duty diesel engine at test conditions both with and without EGR. These have been combined with 1D data of exhaust flow and this used to form a mass average of NO and NO x emissions per cycle. These results have been compared with combustion data and other emissions. The results show that there is a very strong correlation (R 2 > 0.95) between the NO x emitted per cycle and the peak cylinder pressure of that cycle. In addition, the crank-angle resolved NO and NO x measurements also reveal that there is a difference in NO : NO 2 ratio (where NO 2 is assumed to be the difference between NO and NO x ) during the exhaust period, with proportionally more NO 2 being emitted during the blowdown period compared to the rest of the exhaust stroke.

There are many articles and papers published about the developments in engine downsizing as an effective means in reducing vehicle fuel consumption while improving engine performance. The increase in performance of gasoline turbo charged direct injected (GTDI) engines, in conjunction with diverse vehicle platform performance targets (i.e. towing capability) and higher gear transmissions pushes the engine to operate with higher torques at lower engine speeds. This operating condition has increased the propensity of an abnormal combustion event, known as Low Speed Pre-Ignition (LSPI) or Stochastic Pre-Ignition (SPI). The power cylinder unit (PCU) components exposed to this pre-ignition event can experience failure. The engine manufacturers, as well as MAHLE, continue to ensure engine and PCU component survivability against LSPI by performing life cycle robustness testing. MAHLE’s research of LSPI continues to focus on the robustness of PCU components in the presence of LSPI events, as well as investigating design developments that have the potential to minimize the propensity of LSPI to occur. The test procedure development for evaluating natural LSPI events will be presented. Various test results and parameter sensitivities that were documented during this procedure development, along with the many challenges associated with engine performance repeatability will be discussed. Parameters that were found to influence LSPI propensity, as well as parameters that were found not to influence LSPI propensity will be discussed.

Integrated Turbocompounding, Electrification and Supercharging (ITES) is a novel approach for integrated implementation of technologies aimed at reduction of fuel consumption in a single unit. The ITES system optimally manages the power flow between the turbocompound turbine, secondary compressor, 48V electric motor/generator and engine by employing a planetary gear set. The unified approach delivers a substantial reduction in both expense and space claim while improving the overall system efficiency in comparison to the independent implementation of each of these individual technologies. As part of a previous development effort the ITES system functionality was validated through engine drive cycle simulation primarily utilizing the 48V motor generator unit for power split turbocompounding, power split supercharging and engine torque assist. In this latest development phase, the functionality of ITES system has been evaluated on a vehicle level model through a vehicle drive cycle simulation. First, a supervisory control strategy was developed for the ITES system to facilitate start-stop, regenerative braking and engine torque assist functionality using the ITES motor/generator unit. Next, a GT-Suite engine model developed for a downsized engine with the ITES unit applied, along with an appropriate control strategy, was integrated in to a class 6/7 vocational vehicle 1D model. The model was then simulated over the GHG Phase 2 ARB cycle and the fuel economy was compared to that of vehicle model with only the baseline engine configuration. Finally, the battery capacity was optimized to maximize vehicle fuel economy and battery life.

With the increasing focus on reducing emissions and making fuel efficient vehicles within the automotive industry over the past few years, new methods are constantly being investigated to improve the efficiency of the powertrain. One such method is recovering waste heat from the exhaust gases as well as the coolant using a thermodynamic cycle such as a Rankine cycle. However, most studies looking into low temperature or coolant heat recovery investigate the use of a separate secondary cycle for the recovery of waste heat itself. This has the disadvantage of having the working fluid at a lower temperature than the coolant which reduces the recovery efficiency. This paper investigates the potential of an integrated Rankine cycle waste heat recovery system where the coolant also acts as the refrigerant and is integrated with the exhaust gas recirculation waste heat recovery. The refrigerant/coolant used for this study is ethanol, while being used in two modes for low temperature/coolant recovery: using the engine as the preheater and using it as an evaporator. Using a combination of GT Power and Matlab, a Scania D13 engine was simulated in partially premixed combustion operation with a waste heat recovery system. For the engine load-speed range, the coolant flow rate, pressure ratio and superheat were swept for determining the optimal values for maximizing output power. It was seen that while using the engine both as a preheater and as an evaporator the recoverable power increased in comparison to using only the exhaust gas recirculation heat for recovery. When using the engine for preheating, the recoverable power increased marginally with an indicated efficiency gain of less than 0.5 percentage points whereas when using the engine for the evaporation of the coolant, the indicated efficiency showed gains of up to 1.7 percentage points in comparison to using EGR-only heat recovery with a total gain in indicated efficiency of up to 5.5 percentage points. This larger gain in recoverable power while using the engine as an evaporator in comparison to as a preheater is due to the location of the pinch point in analyzing the heat exchange process. The system behavior was also studied with regards to the pressure ratio, the mass flow rate of coolant and the superheat. It was generally observed that at higher loads and speeds these parameters increased as more waste heat was available for recovery for the system.

Due to the direct connection between the engine and the compound power split hybrid transmission (CPSHT) in hybrid electric vehicle (HEV), engine ripple torque (ERT) can result in obvious jerks in engine starting process (ESP). In order to improve the riding comfort, two wet clutches are mounted in this novel CPSHT. This research developed a new coordinated control strategy and its effectiveness was verified in simulation. Firstly, the mechanical and hydraulic parts of the CPSHT were introduced, and the riding comfort problem during ESP in primary design was illustrated. Secondly, the dynamic plant model including ERT, driveline model and clutch torque was deduced. Thirdly, a coordinated control strategy was designed to determine the target engine torque, motor torque, clutch torque and the moment of fuel injection. A Kalman filter based clutch torque estimator was applied with the help of electric motors information. The simulation result indicates that proposed coordinated control strategy can indeed suppress vehicle jerk and improve the riding comfort in ESP.

According to current worldwide trends for homologation vehicles in real driving conditions, is forced to test the engines in altitude and in highly dynamic driving cycles in order to approach nowadays and next future emissions standard. Up to now, there were two main options to perform this type of tests: round-robin tests of the whole vehicle or hypobaric chambers, both with high costs and low repeatability. In this paper a new device is described, which can emulate ambient conditions at whatever altitude between sea level and 5000m high. Even it can be used to emulate ambient conditions at sea level when test bench is placed up to 2000 m high. The main advantages of the altitude simulation equipment are: dynamic emulation of all the psychrometric variables affecting the vehicles during round-robin tests; lower space usage and low energy consumption. The altitude simulator has been validated comparing with results from a hypobaric chamber at different altitudes. Previously a research about the dispersion in the measurements of both testing devices has been done for assessing the results of the comparison experiment. Final conclusion resulted in the same operating performance and emissions of the studied engine with both types of testing equipments for altitude simulation.

To meet the demand for greater fuel efficiency in passenger vehicles, various strategies are employed to increase the power density of light-duty SI engines, with attendant thermal or system efficiency increases. One approach is to incorporate higher-performance alloys for critical engine components. These alloys can have advantageous thermal or mechanical properties at higher temperatures, allowing for components constructed from these materials to meet more severe pressure and temperature demands, while maintaining durability. Advanced alloys could reduce the need for charge enrichment to protect certain gas-path components at high speed and load conditions, permit more selective cooling to reduce heat-transfer losses, and allow engine downsizing, while maintaining performance, by achieving higher cylinder temperatures and pressures. As a first step in investigating downsizing strategies made possible through high-performance alloys, a GT-Power model of a 4-cylinder 1.6L turbocharged direct-injection SI engine was developed. The model was tuned and validated against experimental dynamometer data collected from a corresponding engine. The model was then used to investigate various operating strategies for increasing power density. Results from these investigations will provide valuable insight into how new materials might be utilized to meet the needs of future light-duty engines and will serve as the basis for a more comprehensive investigation using more-detailed thermo-mechanical modeling.

The purpose of this study is evaluate emission characteristics, such as nitrogen oxides (NO x ), hydrocarbon, carbon monoxide, and particulate matter (PM), of excavator with Tier-4f level diesel engine in the real work conditions. The test excavator has an engine power of 124 kW at an engine speed of 1800rpm, and it has various after-treatment devices, such as exhaust gas recirculation (EGR), selective catalytic reduction (SCR), and diesel oxidation catalyst (DOC), to reduce the engine-out emissions. The emissions including carbon monoxide (CO), carbon dioxides (CO 2 ), and NO x , were measured by portable emission measurement system (PEMS). The PEMS device conducted a correlation analysis with the emission bench on the engine dynamometer before being used to measure the real-work to confirm the reliability of the equipment. The tests were carried out in four categories: idling, driving, excavations and flattening. It revealed that the average power output for each operation mode was higher in the order of flattening, excavation, and drive. On average, those are higher than that for the non-road transient cycle (NRTC) certification mode as 1.5 to 1.9 times. It may be determined that the power output is higher in conditions where there are more boom and bucket movements than the movement of the vehicle itself. In emission analysis, NOx and HC emission in driving mode are higher than other two modes: excavation and flattening. The real time NO x have been low in most test conditions, but large quantities of NO x have been released due to the deactivation of the SCR catalyst during cold start period or immediately after the non-working.

Recent particulate regulations for gasoline passenger cars have prompted the utilization of Gasoline Particulate Filters (GPF’s) to mitigate particulate emissions. This study overviews a comprehensive experimental methodology for examination of essential GPF parameters: spatial exothermic temperature rise, particulate trapping efficiency, and the pressure rise versus particulate loading. A GDI vehicle equipped with a subfloor catalytically washcoated GPF downstream of the three-way catalyst was operated on a chassis dynamometer for data collection. Accelerated soot accumulation procedures were developed to expedite the testing while avoiding passive particulate regeneration based on both particulate concentration and size distributions. Soot concentrations pre and post GPF were used to measure the soot trapping efficiency and total soot accumulation. Fuel-cut coast events, common in real-world driving, were utilized to initiate worst case GPF regenerations, namely regenerations which produce maximum temperature rise due to the limited exhaust flow through the GPF. CO 2 measurements simultaneously measured before and after the GPF were examined to calculate the quantity of soot burned during each regeneration event. Thermocouples located inside the GPF were implemented to obtain the spatially disparate, transient temperature traces and analyzed to obtain insights on the soot distribution inside the GPF. The maximum exothermic temperature rise within the GPF was tracked for different soot loadings and regeneration temperatures to ensure GPF substrate and catalytic washcoat health. Most initial soot loadings required multiple ‘fuel-cut coast’ regenerations for complete soot oxidation of all trapped particulate mass. Additionally, externally supplied oxygen was utilized to obtain complete GPF regeneration in a single event. This purpose built system created O 2 availability while maintaining constant GPF temperatures, similar to actively commanding lean A/F ratios during vehicle operation. Emissions measurements indicated that this system successfully regenerated all GPF soot. However, due to magnitude disparity between exhaust flow and total exothermic heat released, the thermocouples inside the GPF recorded only minimal exothermic temperature rises, providing confidence that lean active regeneration strategies pose little threat to GPF health.

Electrically-assisted engine boosting systems lend themselves to better throttle response, wider effective operating ranges, and can provide the ability to extract excess energy during deceleration and high-load events (and store it in a vehicle’s onboard batteries). This can lead to better overall vehicle performance, emissions, and efficiency while allowing for further engine downsizing and increased power density. In this research effort, a hybrid-electric turbocharger, variable-frequency drive (VFD), and novel sensorless control algorithm were developed. An 11kW permanent-magnet machine was coupled to a commercial turbocharger via an in-line, bolt-on housing attached to the compressor inlet. A high-efficiency, high-temperature variable-frequency drive, consisting of custom control and power electronics, was also developed. The variable-frequency drive uses SiC MOSFETS to achieve high-switching frequency and can be cooled using an existing engine coolant loop operating at up to 105 °C at an efficiency greater than 98%. A digital sliding mode-observer (DSMO) sensorless speed control algorithm was created to command and regulate speed and achieved ramp rates of over 68,000 rpm/sec. A two-machine benchtop motor/generator test stand was constructed for initial testing and tuning of the VFD and sensorless control algorithm. A gas blow-down test stand was constructed to test the mechanical operation of the hybrid-electric turbocharger and speed control using the VFD. In addition, a liquid-pump cart was assembled for high-temperature testing of the VFD. Initial on-engine testing is planned for later this year. This paper intends to present a design overview of the in-line, hybrid-electric device, VFD, and performance characterization of the electronics and sensorless control algorithm.

This research study focuses on determining optimal points of operation for the engine-generator system and regenerative braking at the wheels in a plug-in series hybrid electric Chevrolet Camaro. The goal is to improve overall fuel economy of the vehicle as well as reducing overall tail-pipe emissions. An abstract mathematical model of the series hybrid electric Chevrolet Camaro is being used to simulate the overall energy consumption of the vehicle. Previously tested and published control algorithms and strategies are studied, discussed and a viable scheme is chosen for optimization. The results from the optimal strategy considered are compared against the unoptimized results. An improvement of ∼ 8.9% in fuel economy and ∼ 8.2% reduction in tail-pipe emissions is estimated.

The prospect of analysis-driven pre-calibration of a modern diesel engine is extremely valuable in order to significantly reduce hardware investments and accelerate engine designs compliant with stricter EPA fuel economy regulations. Advanced modeling tools, such as CFD, are often used with the goal of streamlining significant portions of the calibration process. The success of the methodology largely relies on the accuracy of analytical predictions, especially engine-out emissions. However, the effectiveness of CFD simulation tools for in-cylinder engine combustion is often compromised by the complexity, accuracy, and computational overhead of detailed chemical kinetics necessary for combustion calculations. The standard approach has been to use skeletal kinetic mechanisms (∼50 species) which consume acceptable computational time but with degraded accuracy. In this work, a comprehensive demonstration and validation of the analytical pre-calibration process is presented for a passenger car diesel engine using CFD simulations with CONVERGE™ and a GPU-based chemical kinetics solver (Zero-RK, developed at Lawrence Livermore National Laboratory) on high performance computing resources to enable the use of detailed kinetic mechanisms. Diesel engine combustion computations have been conducted over 600 operating points spanning in-vehicle speed-load map, using massively parallel ensemble simulation sets on the Titan supercomputer located at the Oak Ridge Leadership Computing Facility. The results with different mesh resolutions have been analyzed to compare differences in combustion and emissions (NOx, Carbon Monoxide CO, Unburned Hydrocarbons UHC, and Smoke) with actual engine measurements. The results show improved agreement in combustion and NOx predictions with a large n-heptane mechanism consisting of 144 species and 900 reactions with refined mesh resolution; however; agreement in CO, UHC and Smoke remain a challenge.

Electric turbochargers offer an additional degree of freedom in engine design to meet the conflicting needs of emissions, fuel consumption and performance targets. This paper presents a simulation study of the application of a mechanically decoupled electric turbocharger to a 2.0L Gasoline engine. The aim of this work is to investigate and quantify how the sizing of the turbine influences performance and efficiency both in steady state and over homologation and on-road duty cycles. Steady state simulations are performed in a GT Power 1D gas dynamics model that includes a simplified model of the electric turbocharger. The 1D model was used to create a mean value engine model for the drive cycle simulations. The turbine diameter was varied from 58mm to 78mm (representing 50%–150% of the baseline turbine size). In steady state conditions, the electric turbocharger achieved a maximum of 1.5% improvement in system efficiency. Larger turbines can improve efficiency by reducing the engine pumping loss, however, they compromise the amount of electrical energy that can be harvested in the low engine speed region. This is problematic as this represents a key area of engine operation in a passenger vehicle. A series of mean value engine models were created for different sized turbines to predict BMEP, turbine power generation and overall system efficiency — these were used to evaluate performance over key duty cycles. The mechanically-decoupled electric turbocharger can generate up to 0.38kW average power in the real road driving simulation which can greatly increase the engine fuel economy. In NEDC and WLTP cycles, the e-turbo system can always generate energy and store it into battery (0.21kW and 0.23kW average power in the whole cycle respectively). In several real road driving tests, the energy consumption of the compressor exceeds that of the turbine due to significant running in the low speed/high torque region (A 0.04kW in specific on-road cycle simulation). The sensitivity of these results to vehicle gear ratios and electrical system efficiency is also presented.

This paper is one of the first publications documenting the performance optimization of a port fuel injected, spark ignited, internal combustion engine for an unmanned aerial vehicle hybrid powertrain. An optimized hybrid powertrain enables long-duration quadcopter flight and provides vertical takeoff and landing capability for fixed-wing aircraft. This technology can improve flight times and lessen runway requirements, helping to solve two of the biggest problems faced by the booming UAV industry. The main activities contributing to this hybrid powertrain effort are the development of a small engine test facility, design of powertrain vehicle integration hardware, and the testing and characterization of both electric motor-generators and fuel-injected two-stroke engines. This paper investigates engine testing completed to date including experimental setup, testing procedures, data post processing, and results.

In 2027, the fully phased-in EPA/NHTSA Phase-2 greenhouse gas (GHG) emission legislation for heavy-duty (HD) diesel engines will mandate a 5.1% reduction in fuel consumption for MY2017 tractor engines and a 4.2% reduction in fuel consumption for MY2017 vocational engines. Along with improvements in engine efficiency, manufacturers are likely to face a simultaneous challenge to achieve a significant reduction in tailpipe NOx emissions, as the ARB is expected to implement an ultra-low NOx emission standard in the 2024–27 timeframe. With this consideration, technology solutions for Phase-2 GHG will have to be NOx neutral or provide additional reduction in NOx emissions which is typically contrary to a reduction in fuel consumption. In this study, various advanced engine technologies — such as engine downsizing and downspeeding, variable compression ratio, cylinder deactivation and turbocompounding — have been evaluated to improve engine efficiency with a goal to reach Phase-2 GHG engine requirements. Simultaneously, the impact of these technologies on engine-out NOx emission and aftertreatment inlet temperature has also been evaluated. The technologies were evaluated with a GT-Power model of a 7.7 liter medium HD diesel engine applied in vocational vehicles at steady-state operating conditions as well as over transient operating profiles. Significant fuel consumption reductions were observed with engine downsizing and engine downspeeding at the same engine-out NOx emissions as the baseline engine. Cylinder deactivation showed a moderate impact on fuel consumption while variable compression ratio and turbocompounding had a much lower impact on fuel consumption. In general, exhaust gas temperatures decreased with a reduction in fuel consumption, except in the case of cylinder deactivation where significant increase in exhaust gas temperatures was observed. The results of the study show that engine efficiency improvements beyond what has been mandated by the Phase-2 GHG regulations are possible without increasing the engine-out NOx emissions of a Phase-1 GHG compliant engine. However, if an ultra-low NOx emission standard is implemented as expected, some of the efficiency gains demonstrated in this study will need to be offset to achieve higher exhaust gas temperatures and lower engine-out NOx emissions.

In recent years, many engine manufacturers have turned to downsizing and boosting of gasoline engines in order to meet the ever more stringent fuel economy and emissions regulations. With an increase in the number of turbocharged gasoline engines, solutions are required to manage knock under a range of operating conditions. The charge air cooler has been introduced to mitigate knock. Moreover, the engine is required to operate with spark retard and/or boost reduction to provide knock reduction leading to reduced fuel economy. Under some operating conditions water can condense in the charge air cooler (CAC). Corrugated plate separators have been widely used in gas-water separation and oil-water separation in many industries including marine diesel engines. However, this sort of separator has not been applied to gasoline engines in vehicles to separate the condensation in the charged air. In this paper, a 1-D condensation model to estimate the potential amount of water condensation and entrainment from the charge air coolers is presented. An approach to designing a unit to separate condensation in the flow from the charge air cooler while maintaining a low pressure drop is described. The design approach provides correlations of separator geometries versus separation and pressure drop performance. The study is developed using a 3-D computational model for analyzing charge air and condensation flow. The model results of the 1-D condensation model and the 3-D computational model have been validated by experiments on an engine-dynamometer based test cell. The set-up incorporates a 4 cylinder gasoline direct injection (GDI) turbocharged engine. An air-to-air charge air cooler is mounted under the engine. The intake air for the engine is supplied using a combustion air unit which enables the operators to control the temperature and humidity. Test conditions have been identified to demonstrate the phenomenon of CAC water condensation. Measurements of water condensation and motion through the system confirm the results of models. A separator has been designed that achieves high separation efficiency and low pressure drop.

In previous publications, the model development and simulation of a vacuum-insulated catalytic converter was presented. GT-Suite model simulations demonstrated the heat retention capacity of the converter, and corresponding emissions reductions. This paper provides an update of the converter model development and analysis of real-world benefits of the converter. The vehicle-aftertreatment model of the vacuum-insulated converter (VICC) was improved significantly, and detailed explanations of all theoretical modeling considerations are presented. In absence of experimental data, a flow-test experiment was conducted to measure the flow rate in exhaust tailpipe during vehicle soak due to thermosiphon. These results were used as inputs in the GT-Suite model simulations of conventional and hybrid electric vehicles (HEVs). New model simulations demonstrated the ability of the VICC to achieve significant emissions reductions following vehicle soaks of up to 18 hours. To examine the real-world benefits of the converter, driving data was obtained from the National Renewable Energy Laboratory (NREL), and a MATLAB code was developed to statistically analyze 23,156 drive cycles. The VICC was simulated on standard drive cycles to develop a correlation between melt time of the phase-change material (PCM) and average drive cycle speed and acceleration. This correlation was used to predict the probability that the PCM will melt in a given real-world driving cycle. The MATLAB code was also used to calculate soak time and re-solidification time probability. Finally, FTP emission results were weighted with the soak time probabilities. This analysis showed that in real-world driving conditions, the VICC is expected reduce cold-start CO and HC emissions by 26% and 48% respectively.

Spark ignition engine in-cylinder air charge estimation is important for air-to-fuel ratio control, maintaining high after-treatment efficiency, and determination of current engine torque. Current cylinder air charge estimation methodologies generally depend upon either a mass air flow (MAF) sensor or a manifold absolute pressure (MAP) sensor individually. Methods based on either sensor have their own advantages and disadvantages. Some production vehicles are equipped with both MAF and MAP sensors to offer air charge estimation and other benefits. This research proposes several observer based cylinder air charge estimation methods that take advantage of both MAF and MAP sensors to potentially reduce calibration work while providing acceptable transient and steady-state accuracy with low computational load. This research also compares several common air estimation methods with the proposed observer based algorithms using steady-state and transient dynamometer tests and a rapid-prototype engine controller. With appropriate tuning the proposed observer based methods are able to estimate cylinder air charge mass under different engine operating conditions based on the manifold model and available sensors. Methods are validated and compared based on a continuous tip-in tip-out operating condition.

In order to ensure that every portion of the emission control software in a vehicle works, all fault conditions must be tested. Simply simulating faults in the software of the engine controller and reporting it to the OBD II scanner is inadequate; the fault condition must be injected externally to the Engine Control Unit (ECU). In the case of hard-to-reproduce mechanical failures, this is a challenging task. This paper discusses the development of a system capable of emulating various faults that a fuel injector can have while operating as part of a complete working vehicle. For the ECU to operate properly, all fuel injectors must be present in the vehicle, be fully functional, and must represent an accurate electrical load to the ECU. Then, the induced faults must be seamlessly inserted into the running system in less than 10μs and removed before the subsequent injection event. This was accomplished with a variety of COTS hardware, a simple custom circuit, and the use of a large, flexible FPGA platform.