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Investigation of knocking combustion in a hydrogen spark-ignition engine is one of the major challenges for future vehicle development. The knock phenomenon in a Spark-Ignition (SI) engine is caused by autoignition of the unburned gas ahead of the flame. The explosive combustion of the end-gas creates a pressure wave that leads to damage of the cylinder wall and the piston head of the engine. We observed autoignition in the end-gas region due to compression by the propagating flame front using a high-speed colour video camera through the optically accessible cylindrical quartz window on the top of the cylinder head. Moreover, a high-speed monochrome video camera operating at a speed of 250, 000 frame/s was used to measure the pressure wave propagation. The goal of this research was to improve our ability to describe the effect of the autoignition process on the end-gas and propagating pressure wave during knocking combustion with the help of a high-speed video camera.

A turbulent gas jet impinging on a flat wall was visualized by a laser sheet method. Velocity fields were determined from the images with a high speed video system by processing them in terms of the cross correlation method for the jet and particle tracking method for the ambient air from the same images. The vortex flow near the transient jet tip impinging on the wall was visualized and analyzed successfully. The velocity field obtained from the above methods was compared to that determined with a laser Doppler anemometer. The path line of a certain period which was taken with a CCD camera with controlled shutter was analyzed and the mean rate of air entrainment was determined quantitatively. The spatial and temporal change of the entrainment rate was estimated and it was found that the entrainment rate near the upstream part of the jet tip region is larger because of the vortex.

The development of intelligent transportation improves road efficiency, reduces automobile energy consumption, and improves driving safety. The core of intelligent transportation is the two-way information interaction between vehicles and the road environment. At present, road environmental information can flow to the vehicle, while the vehicle’s information rarely flows to the outside world. The electronic throttle and electronic braking systems of some vehicles use sensors to get the state of the accelerator and brake pedal, which can be transmitted to the outside environment through technologies such as the Internet of Vehicles. But the Internet of Vehicles technology has not been widely used, and it relies on signal sources, which is a passive way of information acquisition. In this paper, an active identification method is proposed to get the vehicle pedal on-off state as well as the driver’s operation behavior through existing traffic facilities.

Using a 3 liter, 4 valves per cylinder, V6 Diesel engine model, this study investigates late intake valve closing (LIVC) time in an effort to reduce the fuel consumption of the engine. Two different intake cam duration technologies for diesel engines are evaluated using a 1-D engine simulation software code. The first method utilized for duration control delays the effective closing of the intake valve by moving one intake cam lobe with respect to the other baseline intake cam lobe. In the second method, the closing of both intake valves is delayed by the introduction of an adjustable dwell period during the closing portion of the valve motion. During this mid-lift dwell period, the lift is held at a constant value until it goes into the closing phase. The systems are evaluated and compared at 4 operating points of varying engine speed and load. At each operating point, while engine load is held constant, intake valve closing time is varied.

Prior work with the concept of dividing the exhaust process into an early and late phase has shown the potential of applying only the early stage (blow-down) of the exhaust period directly to a turbocharger or turbocharger system, and the later stage (scavenge) arranged to bypass the turbine. In this manner, the exhaust backpressure required to extract high turbine work from the engine can be isolated from the displacement phase of the exhaust stroke and thereby greatly reduce the exhaust pumping work and Residual Gas Fraction. In previously-published efforts, the challenges of valve-event control and high turbine inlet temperature have been revealed. The BorgWarner Engine Systems Group, in conjunction with Presta, has applied a cam-phaser controlled concentric camshaft system to the exhaust side of a divided exhaust port 4-valve per cylinder DOHC GDI engine, to enable variable phasing between the Blow-down and Scavenge cam profiles.

The structures of the turbulent premixed flame in the engine cylinder under lean burn conditions were investigated using ion probe method. The flow fields were measured with an LDA for two tumble ratios and two compression ratios. And ion-current signal was analyzed to discuss the interaction between the turbulence and the flame structure. The effects of turbulence and equivalence ratio on the characteristic values of the turbulent flame, that is to say number of ion-current peaks, thickness of flame front and thickness of burning zone of the flamelet, were investigated. In normal combustion, the structure of the turbulent flame front is almost the same as the laminar flame. In the lean limit, the flamelet is broken and stretched and then the structure may change.

Naturally aspirated HCCI operation is typically limited to medium load operation (∼ 5 bar net IMEP) by excessive pressure rise rate. Boosting can provide the means to extend the HCCI range to higher loads. Recently, it has been shown that HCCI can achieve loads of up to 16.3 bar of gross IMEP by boosting the intake pressure to more than 3 bar, using externally driven compressors. However, investigating HCCI performance over the entire speed-load range with real turbocharger systems still remains an open topic for research. A 1 - D simulation of a 4 - cylinder 2.0 liter engine model operated in HCCI mode was used to match it with off-the-shelf turbocharger systems. The engine and turbocharger system was simulated to identify maximum load limits over a range of engine speeds. Low exhaust enthalpy due to the low temperatures that are characteristic of HCCI combustion caused increased back-pressure and high pumping losses and demanded the use of a small and more efficient turbocharger.

The flow field contained within ten planes inside a cylinder of a 3.5 liter, 24-valve, V-6 engine was mapped using a three-dimensional Laser Doppler Velocimetry (3-D LDV) system. A total of 1,548 LDV measurement locations were used to construct the time history of the in-cylinder flow fields during the intake and compression strokes. The measurements began during the intake stroke at a crank angle of 60° ATDC and continued until approximately 280° ATDC. The ensemble averaged LDV measurements allowed for a quantitative analysis of the dynamic in-cylinder flow process in terms of tumble and swirl motions. Both of these quantities were calculated at every 1.8 crank degrees during the described measurement interval. Tumble calculations were performed about axes in multiple planes in both the Cartesian directions perpendicular to the plane of the piston top. Swirl calculations were also accomplished in multiple planes that lie parallel to the plane of the piston top.

A heterodyne interferometry system with a fiber-optic sensor was developed to measure the temperature history of unburned gas in an engine cylinder. A polarization-preserving fiber and metal mirror were used as the fiber-optic sensor to deliver the test beam to and from the measurement region. This fiber-optic sensor can be assembled in the engine cylinder or the cylinder head without a lot of improvements of an actual engine. The feasibility of our system was sufficient to be applied to temperature history measurement of an unburned gas compressed by flame propagation in an engine cylinder. The resolution of the temperature measurement is approximately 0.7 K, and is dependent on both the sampling clock speed of the A/D converter and the length of the measurement region.

A fiber optical heterodyne interferometry system was developed to obtain high temporal resolution temperature histories of unburned and burned gases non-intrusively. The effective optical path length of the test beam changes with the gas density and corresponding changes of the refractive index. Therefore, the temperature history of the gas can be determined from the pressure and phase shift of the interference signal. The resolution of the temperature measurement is approximately 0.5 K, and is dependent upon both the sampling clock speed of the A/D converter and the length of the test section. A polarization-preserving fiber is used to deliver the test beam to and from the test section, to improve the feasibility of the system as a sensor probe. This optical heterodyne interferometry system may also be used for other applications that require gas density and pressure measurements with a fast response time, or a transient temperature record.

With the help of organic working medium absorbing the solar energy for steam electric power generation, green energy can be provided to automotive accessories so as to improve the vehicle energy efficiency. In the hot summer, the exhausted heat resulting from cars’ directly exposing to the sun can be used to cool and ventilate the passenger compartment. Considering the space occupied by the system in the combination of both practical features for solar heat source--low power and poor stability-- a compact evaporation structure was designed to enhance the solar utilization efficiency. In the research, the heat source of power and temperature variation range was determined by the available solar roof with photo-thermal conversion model. Then started from the ratio of exhausted heat utilization corresponding to evaporator’s characteristic parameter, the performance analysis was made in the different working conditions.

The hydraulic retarder, which is an auxiliary brake device for enhancing traffic safety, has been widely used in kinds of heavy commercial vehicles. When the vehicle equipped with the retarder is traveling in non-braking state, the transmission loss would be caused because of the stirring air between working wheels of the rotor and the stator no matter if the retarder connects in parallel or in series with the transmission [1]. This paper introduces an elaborate hydraulic retarder air-friction reduction system (AFRS) which consists of a vacuum generating module and pneumatic control module. AFRS works to reduce the air friction by decreasing the gas density between working wheels when the retarder is in non-braking state. The pneumatic control model of hydraulic retarder is built first. Then various driving conditions are considered to verify the performance of the AFRS. The stability of the AFRS is analyzed based on the complete driveline model.

The existence of the cyclic variation of the flow inside an cylinder affects the performance of the engine. Developing methods to understand and control in-cylinder flow has been a goal of engine designers for nearly 100 years. In this paper, passive control of the intake flow of a 3.5-liter DaimlerChrysler engine was examined using a unique optical diagnostic technique: Molecular Tagging Velocimetry (MTV), which has been developed at Michigan State University. Probability density functions (PDFs) of the normalized circulation are calculated from instantaneous planar velocity measurements to quantify gas motion within a cylinder. Emphasis of this work is examination of methods that quantify the cyclic variability of the flow. In addition, the turbulent kinetic energy (TKE) of the flow on the tumble and swirl plane is calculated and compared to the PDF circulation results.

The cooling system with two fans is generally driven by electrical motors in the small cars. Compared with the traditional cars, heavy duty trucks have the larger heat dissipation power of cooling system. The motors power consumption of dual fans will be larger and the two electrical motors will occupy a large space in the engine cabin. Hydrostatic drive refers to the cooling fan is driven by hydraulic motor, but it has the low transmission efficiency. According to the engine water temperature value and the actual working status of the hydraulic system, the actual speed of cooling fan can be controlled by the computer, which guarantees the normal working water temperature of the engine. Hydrostatic drive is generally applied to heavy vehicles, engineering machinery and excavators as driving source of cooling fan which contains the advantages of large output power, overload protection, continuous speed regulation and flexible space arrangements.

A turbulent entrainment model is considered to be reasonable for the combustion in a spark-ignition engine. For this kind of model, it is important to estimate the turbulence characteristics, turbulent burning velocity, flame surface area and several empirical constants. Nevertheless, the examination of these values have not been examined sufficiently. In this study, a combustion model was proposed, and initiation of flame propagation, burning process of an eddy, scale of turbulence and turbulent burning velocity were discussed in detail. This model was examined under various conditions of engine speed (600-1200rpm), compression ratio (3.2-4.8) and ignition timing. The calculation results of mass fraction burned, burn rate and burn duration were in good agreement with the experimental ones. It was found that the concept of such a turbulent entrainment model was valid for predicting the combustion in a spark-ignition engine.

Natural gas has been considered to be one of the most promising alternative fuels due to its lower NOx and soot emissions, less carbon footprint as well as attractive price. Furthermore, higher octane number makes it suitable for high compression ratio application compared with other gaseous fuels. For better economical and lower emissions, a turbocharged, four strokes, direct injection, high pressure common rail diesel engine has been converted into a diesel/natural gas dual-fuel engine. For dual-fuel engine operation, natural gas as the main fuel is sequentially injected into intake manifold, and a very small amount of diesel is directly injected into cylinder as the ignition source. In this paper, a dual-fuel electronic control unit (ECU) based on the PowerPC 32-bit microprocessor was developed. It cooperates with the original diesel ECU to control the fuel injection of the diesel/natural gas dual-fuel engine.

The behavior of the compression system in turbochargers is studied with a one-dimensional engine simulation code. The system consists of an upstream compressor duct open to ambient, a centrifugal compressor, a downstream compressor duct, a plenum, and a throttle valve exhausting to ambient. The compression system is designed such that surge is the low mass flow rate instability mode, as opposed to stall. The compressor performance is represented through an extrapolated steady-state map. Instead of incorporating a turbine into the model, a drive torque is applied to the turbocharger shaft for simplification. Unsteady compression system mild surge physics is then examined computationally by reducing the throttle valve diameter from a stable operating point. Such an increasing resistance decreases the mass flow rate through the compression system and promotes surge.

With increasing interest to reduce the dependency on gasoline and diesel, alternative energy source like compressed natural gas (CNG) is a viable option for internal combustion engines. Spark-ignited (SI) CNG engine is the simplest way to utilize CNG in engines, but direct injection (DI) Diesel-CNG dual-fuel engine is known to offer improvement in combustion efficiency and reduction in exhaust gases. Dual-fuel engine has characteristics similar to both SI engine and diesel engine which makes the combustion process more complex. This paper reports the computational fluid dynamics simulation of both DI dual-fuel compression ignition (CI) and SI CNG engines. In diesel-CNG dual-fuel engine simulations and comparison to experiments, attention was on ignition delay, transition from auto-ignition to flame propagation and heat released from the combustion of diesel and gaseous fuel, as well as relevant pollutants emissions.

The Organic Rankine Cycle System (ORC) is an effective means to use the solar energy. The system adopts the solar energy on the car roof as the heat source to make the ORC work and drive the thermoelectric air-conditioner. It can improve the entering comfort on the parking condition and the vehicle energy utilization efficiency. In this research, the system comprehensively applied the principle of sunshine concentration, heat collection and photo electricity. Then considering the working condition and performance features of ORC system, the car roof was designed to have a compact structure, through which the efficiency of the solar vehicle system could be improved. Firstly, the research analyzed the heat source temperature and the heat flux impact on the output power of the ORC system. After that, the performance of heat collection was identified according to the given thermoelectric air-condition’s power requirements.

In this study, residual gas fraction measurements in a spark-ignition engine were carried out using an optical sensor installed in the spark plug with infrared absorption method. The residual gas fraction inside engine cylinder is proportional to the CO2 concentration. Infrared absorption method was applied and an infrared lamp and optical filter (center wavelength: around 4.3 μm) that coincides with the absorption lines of CO2 was used as a light source.The molar absorption coefficient of CO2 is discussed and compared to results in the HITRAN database. The effect of water vapor absorption doesn't affect the absorption of CO2. The absorption characteristics of CO2 were determined in advance using a constant volume vessel. Molar absorption coefficient depends on the CO2 concentration and ambient pressure and temperature, and wavelength of absorption line.