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Exhaust gas recirculation, fuel injection strategy and boost pressure are among the key enablers to attain low NOx and soot emissions simultaneously on modern diesel engines. In this work, the individual influence of these parameters on the emissions are investigated independently for engine loads up to 8 bar IMEP. A single-shot fuel injection strategy has been deployed to push the diesel cycle into low temperature combustion with EGR. The results indicated that NOx was a stronger respondent to injection pressure levels than to boost when the EGR ratio is relatively low. However, when the EGR level was sufficiently high, the NOx was virtually grounded and the effect of boost or injection pressure becomes irrelevant. Further tests indicated that a higher injection pressure lowered soot emissions across the EGR sweeps while the effect of boost on the soot reduction appeared significant only at higher soot levels.

This study investigated neat n-butanol combustion, emissions and thermal efficiency characteristics in a compression ignition (CI) engine by using two fuelling techniques - port fuel injection (PFI) and direct injection (DI). Diesel fuel was used in this research for reference. The engine tests were conducted on a single-cylinder four-stroke DI diesel engine with a compression ratio of 18.2 : 1. An n-Butanol PFI system was installed to study the combustion characteristics of Homogeneous Charge Compression Ignition (HCCI). A common-rail fuel injection system was used to conduct the DI tests with n-butanol and diesel. 90 MPa injection pressure was used for the DI tests. The engine was run at 1500 rpm. The intake boost pressure, engine load, exhaust gas recirculation (EGR) ratio, and DI timing were independently controlled to investigate the engine performance.

This study describes a zero-dimensional algorithm for tracking the intake dilution in real-time. The inputs to the model are the oxygen concentration from the exhaust oxygen sensor, the manifold air pressure and temperature (MAP/MAT), the mass air flow (MAF) and the estimated fuel injected per cycle from the engine control module. The intake manifold, the exhaust manifold and EGR system are discretized into 3 volumes and the detailed concentrations of the gas species comprising the exhaust, EGR and intake streams are tracked at each time step (on a cycle-by-cycle basis). The model does not need the EGR ratio to be known in advance and is also applicable to oxygenated fuels such as ethanol. The model response is tuned to a multi-cylinder engine and the model output is empirically validated against a wide range of engine operations including load and EGR transients.

Engine performance and emission comparisons were made between the use of 100% soy, Canola and yellow grease derived biodiesel fuels and an ultra-low sulphur diesel fuel in the oxygen deficient regions, i.e. full or high load engine operations. Exhaust gas recirculation (EGR) was extensively applied to initiate low temperature combustion. An intake throttling valve was implemented to increase the differential pressure between the intake and exhaust in order to increase and enhance the EGR. The intake temperature, pressure, and EGR levels were modulated to improve the engine fuel efficiency and exhaust emissions. Furthermore, a preliminary ignition delay correlation under the influence of EGR was developed. Preliminary low temperature combustion modelling of the biodiesel and diesel fuels was also conducted. The research intends to achieve simultaneous reductions of nitrogen oxides and soot emissions in modern production diesel engines when biodiesel is applied.

Preliminary empirical and modeling analyses are conducted to evaluate the energy efficiency of in-cylinder and external fuel injection strategies and their impact on the energy required to enable diesel particulate filter (DPF) regeneration for instance. During the tests, a thermal wave that is generated from the engine propagates along the exhaust pipe to the DPF substrate. The thermal response of the exhaust system is recorded with the thermocouple arrays embedded in the exhaust system. To implement the external fuel injection, an array of thermocouples and pressure sensors in the DPF provide the necessary feedback to the control system. The external fuel injection is dynamically adjusted based on the thermal response of the DPF substrate to improve the thermal management and to reduce the supplemental energy. This research intends to quantify the effectiveness of the supplemental energy utilization on aftertreatment enabling.

A vehicle undergoing longitudinal or lateral accelerations experiences load transfer, dynamically changing the normal load carried by each tire. Conventional braking systems are designed only to work adequately over a large range of conditions, but often ignore the dynamic state of the tire's normal load. Fortunately, new developments in braking system hardware give designers more control over the application of braking pressures. By identifying the tires that carry increased normal load, and biasing the braking system toward those tires, total braking force can be increased. The purpose of this research is to investigate advantages of open-loop load transfer based active brake pressure distribution. By estimating the tractive ability of the tires as a function of measurable vehicle conditions, brake pressure can be applied in proportions appropriate for the current dynamic state of the vehicle, referred to as Active Brake Proportioning (ABP).

A production V-8 engine was redesigned to run on low temperature combustion (LTC) with conventional Diesel fuel. Two fuel injection strategies were used to attain reduction in soot and NOx; a) early premixed injection strategy: fuel injected early during the compression stroke and b) late premixed injection strategy: fuel injected close to TDC with heavy EGR. The early premixed injection strategy yielded low NOx and soot but struggled to vaporize the fuel as noted in unburned hydrocarbons readings. The late premixed injection strategy introduced the fuel at higher in-cylinder temperatures and densities, improving the fuel's vaporization and limited the unburned hydrocarbon and carbon monoxide. The use of high EGR and high injection pressure for late premixed injection strategy provided sufficiently long ignition delay that resulted in partially premixed cylinder charge before combustion, and thereby prevented high soot, even in presence of high EGR.

A number of cylinder-pressure derived parameters including the crank angles of maximum pressure, maximum rate of pressure rise, and 50% heat released are considered as among the desired feedback for cycle-by-cycle adaptive control of diesel combustion. For real-time computation of these parameters, the heat release analyses based on the first law of thermodynamics are used. This paper intends to identify the operating regions where the simplified heat release approach provides sufficient accuracy for control applications and also highlights those regions where its use can lead to significant errors in the calculated parameters. The effects of the cylinder charge-to-wall heat transfer and the temperature dependence of the specific heat ratio on the model performance are reported. A new computationally efficient algorithm for estimating the crank angle of 50% heat released with adequate accuracy is proposed for computation in real-time.

Rally cars are among the most technologically advanced and complex race cars, with intercooled forced induction, adaptive all wheel drive and high-feature engine management being standard features for open class racers in all major North American Rally series. This high level of technology and complexity places additional burden on the service crews and mechanics charged with the task of preparing and repairing the vehicles during the competition. As such, it is of great importance that the brief service stops (thirty minutes per FIA regulation 17.2.2 [2008]) be executed as efficiently as possible. In the pursuit of valuable seconds, rally mechanics have shown a great deal of ingenuity, creating tools and procedures which are unique to the sport. One such innovation is the peg-style jack stand.

Highly accurate cylinder pressure data can be acquired using a wall-mounted and water-cooled quartz piezoelectric transducer. However, this type of transducer does not satisfy the cost and packaging constraints when used in a production engine application. A potential solution to these issues that has been the interest of many is the much smaller and less expensive optical fiber based pressure transducer. This research compares Kistler piezoelectric transducers to Optrand optical fiber transducers. The influence of the transducer type and mounting arrangement on the quality of cylinder pressure data was examined. The transducers were evaluated on a DaimlerChrysler 4.7L V-8 Compressed Natural Gas fuelled test engine. The analysis method is comprised of examining measured individual cycle and ensemble-averaged cylinder pressure records to assess the quality of the data and its usefulness for engine management.

This research work investigates the control strategies of fuel burn rate of neat n-butanol combustion to improve the engine load capability. Engine tests of homogeneous charge compression ignition (HCCI) and partially premixed combustion (PPC) with neat n-butanol show promising NOx and smoke emissions; however, the rapid burn rate of n-butanol results in excessive pressure rise rates and limits the engine load capability. A multi-event combustion strategy is developed to modulate the fuel burn rate of the combustion cycle and thus to reduce the otherwise high pressure rise rates at higher engine load levels. In the multi-event combustion strategy, the first combustion event is produced near TDC by the compression ignition of the port injected butanol that resembles the HCCI combustion; the second combustion event occurs near 7~12 degrees after TDC, which is produced by butanol direct injection (DI) after the first HCCI-like combustion event.

Thermal comfort in automotive seating has been studied and discussed for a long time. The available research, because it is focused on the components, has not produced a model that provides insight into the human-seat system interaction. This work, which represents the beginning of an extensive research program, aims to establish the foundation for such a model. This paper will discuss the key physiological, psychological, and biomechanical factors related to perceptions of thermal comfort in automotive seats. The methodology to establish perceived thermal comfort requirements will also be presented and discussed.

In this work, a pseudo three-dimensional coupled thermal-electrochemical model is established to estimate the heat generation and temperature profiles of a lithium ion battery as functions of the state of the discharge. Then, this model is used to investigate the effectiveness of active and passive thermal management systems. The active cooling system utilizes cooling plate and water as the working fluid while the passive cooling system incorporates a phase change material (PCM). The thermal effects of coolant flow rate examined using a computational fluid dynamics model. In the passive cooling system, Paraffin wax used as a heat dissipation source to control battery temperature rise. The effect of module size and battery spacing is studied to find the optimal weight of PCM required. The results show that although the active cooling system has the capability to reduce the peak temperatures, it leads to a large temperature difference over the battery module.

Experiments are carried out with the diesel particulate filter and oxidation catalyst embedded in the active-flow configurations on a single cylinder diesel engine. The combined use of various active flow control schemes are identified to be capable of shifting the exhaust gas temperature, flow rate, and oxygen concentration to favorable windows for filtration, conversion, and regeneration processes. Empirical and theoretical investigations are performed with a transient one-dimensional single channel aftertreatment model developed in FORTRAN and MATLAB. The influence of the supplemental energy distribution along the length of aftertreatment device is evaluated. The theoretical analysis indicates that the active-flow control schemes have fundamental advantages in optimizing the converter thermal management including reduction in supplemental heating, increase in thermal recuperation, and improving overheating protection.

Research regarding higher efficiency engines and renewable energy has lead to HCCI engine technology as a viable option with the ability to utilize a variety of fuels. With a larger focus on environmental effects the ability of HCCI engines to produce low levels of NOx and potentially other combustion products is another attractive feature of the technology. Biomass gas as a renewable primary fuel is becoming more predominant regarding internal combustion engine research. The simulated fuel in this study replicates compositions derived from real-world gasification processes; the focus in this work corresponds to fuel composition variations and their effects regarding combustion phasing and performance. There are three biomass gas fuel compositions investigated in this study. All compositions consisted of combustibles of CH₄, CO, and H₂ accompanied by CO₂ then balanced with N₂. The CH₄ and CO₂ constituents of each fuel mixture are held constant at 2% and 5% respectively.

This empirical work investigates the impacts of thermodynamic parameters, such as pressure and temperature, and fuel properties, such as fuel Cetane number and aromatic contents on ignition delay in diesel engines. Systematic tests are conducted on a single-cylinder research engine to evaluate the ignition delay changes due to the fuel property differences at low, medium and high engine loads under different EGR dilution ratios. The test fuels offer a range of Cetane numbers from 28 to 54.2 and aromatic contents volume ratios from 19.4% to 46.6%. The experimental results of ignition delays are used to derive an ignition delay model modified from Arrhenius’ expression. Following the same format of Arrhenius’ equation, the model incorporates the pressure and temperature effects, and further includes the impacts of intake oxygen concentration, fuel Cetane number and aromatic contents volume ratio on the ignition delay.

Due to considerable efforts of automobile manufacturers to attenuate various noise sources within the passenger compartment, other sources, including induction noise have become more noticeable. The present study investigates the feasibility of using a non-conventional noise cancellation technique to improve the acoustic performance of an automotive induction system by using acoustic energy derived from the exhaust manifold as the dynamic noise source to cancel intake noise. The validity of this technique was first investigated analytically using a computational engine simulation software program. Using these results, a physical model of the bridge was installed and tested on a motored engine. The realized attenuation of the intake noise was evaluated using conventional FFT analysis techniques as well as psychoacoustic metrics including loudness, sharpness, roughness and fluctuation strength.

Empirical and theoretical studies are made between active-flow control and passive-flow control schemes in investigating the influences of gas flow, heat transfer, chemical reaction, oxygen concentration, and substrate properties. The exhaust active-flow control includes the parallel alternating flow, partial restricting flow, periodic flow reversal, and extended flow stagnation that are found to be especially effective to treat engine exhausts that are difficult to cope with conventional passive-flow converters [1, 2]. The tests are set up on a single cylinder Yanmar engine. Theoretical studies are performed with the one-dimensional transient modeling techniques to analyze the thermal behavior of the diesel after-treatment systems when active flow control schemes are applied.

Diesel Particulate Filters (DPF) are viable to reduce smoke from diesel engines. An oxidation process is usually required to remove the Particulate Matter (PM) loading from the DPF substrates. In cases when the engine exhaust temperature is insufficient to initiate a thermal regeneration, supplemental energy is commonly applied to raise the exhaust gas and/or the DPF substrate temperatures. A flow reversal (FR) mechanism that traps a high temperature region in the DPF substrate by periodically altering the gas flow directions has been identified to be capable of reducing the supplemental energy and thus to improve the overall thermal efficiency of the engine. However, extended operations with low exhaust temperature lowers the DPF boundary temperatures that defers the regeneration processes. Furthermore, the temperature fluctuations caused by the periodic FR operation also increase the thermal stress in the DPF.

One-dimensional transient modeling techniques are adapted to analyze the thermal behavior of lean-burn after-treatment systems when active flow control schemes are applied. The active control schemes include parallel alternating flow, partial restricting flow, and periodic flow reversal (FR) that are found to be especially effective to treat engine exhausts that are difficult to cope with conventional passive flow converters. To diesel particulate filters (DPF), lean NOx traps (LNT), and oxidation converters (OC), the combined use of active flow control schemes are identified to be capable of shifting the exhaust gas temperature, flow rate, and oxygen concentration to more favorable windows for the filtration, conversion, and regeneration processes. Comparison analyses are made between active flow control and passive flow control schemes in investigating the influences of gas flow, heat transfer, chemical reaction, oxygen concentration, and converter properties.