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The acquisition of more authentic cylinder pressure data is the basis of engine combustion analysis. Due to the multiple advantages, quartz piezoelectric pressure transducers are generally applied to the measurement of the cylinder pressure. However, these transducers can only produce dynamic cylinder pressure data which may be significantly different from the actual values. Thus, the cylinder pressure data need to be corrected through a certain method, while different cylinder pressure correction methods will cause result divergences of the combustion analysis. This paper aims to acquire a proper cylinder pressure correction method by carrying out theoretical analysis based on the polytropic process in the compression stroke as well as the experimental research of the cylinder pressure of a turbocharged eight-cylinder diesel engine.

Hydrogen is a promising energy carrier because it is characterized by a fast combustion velocity, a wide range of sources, and clean combustion products. A hydrogen internal combustion engine (H2ICE) with a turbocharger has been used to solve the contradiction of power density and control NOx. However, the selection of a H2ICE compressor with a turbocharger is very different from traditional engines because of gas fuel. Hydrogen as a gas fuel has the same volume as its cylinder and thus increases pressure and reduces the mass flow rate of air in cylinder for a port fuel injection-H2ICE (PFI-H2ICE). In this study, a general method involving a H2ICE with a turbocharger is proposed by considering the effect of hydrogen on cylinders. Using this method, we can calculate the turbocharged pressure ratio and mass flow rate of air based on the target power and general parameters. This method also provides a series of intake temperatures of air before calculation to improve accuracy.

With the development of advanced ABE fermentation technology, the volumetric percentage of acetone, butanol and ethanol in the bio-solvents can be precisely controlled. To seek for an optimized volumetric ratio for ABE-diesel blends, the previous work in our team has experimentally investigated and analyzed the combustion features of ABE-diesel blends with different volumetric ratio (A: B: E: 6:3:1; 3:6:1; 0:10:0, vol. %) in a constant volume chamber. It was found that an increased amount of acetone would lead to a significant advancement of combustion phasing whereas butanol would compensate the advancing effect. Both spray dynamic and chemistry reaction dynamic are of great importance in explaining the unique combustion characteristic of ABE-diesel blend. In this study, a semi-detailed chemical mechanism is constructed and used to model ABE-diesel spray combustion in a constant volume chamber.

Nowadays, the world is facing severe energy crisis and environment problems. Development of hydrogen fuel vehicles is one of the best ways to solve these problems. Due to the difficulties of infrastructures, such as the hydrogen transport and storage, hydrogen fuel vehicles have not been widely used yet. As a result, Hydrogen-gasoline dual-fuel vehicle is a solution as a compromise. In this paper, three way catalytic converter (TWC) was used to reduce emissions of hydrogen-gasoline dual-fuel vehicles. On wide open throttle and load characteristics, the conversion efficiency of TWC in gasoline engine was measured. Then the TWC was connected to a hydrogen internal combustion engine. After switching the hydrogen and gasoline working mode, emission data was measured. Experiment results show that the efficiency of a traditional TWC can be maintained above 85%., while it works in a hydrogen-gasoline dual-fuel alternative working mode.

The low cycle fatigue experiment is extensively used to test the reliability and durability of turbocharger. Low cycle fatigue test is mainly the switching between high and low speed. As the result of the experiment, the fatigue life is shorter as the difference between high and low speed becomes greater. In the traditional low cycle fatigue test, a large air compressor is needed to drive the turbocharger under different operating conditions, which consume large amounts of electric power. This paper presents a new experiment device which has double chambers and double turbochargers. This device can be self-circulating, without the large air compressor, to realize high and low speed switching on the premise of not exceeding the limitation of turbine entry temperature. First, a detailed model is established in GT-Power and self-circulation test data has been used to validate the model.

When the EFI system is used in a specific engine, lots of experiments are needed to optimize the control data (MAP). This work is time and financial consuming. This paper aims to develop a computer-based simulation and test system, which can produce the initial control MAP with good accuracy, and calibrate the ECU on-line. So the experiments are reduced and calibration is accelerated. In order to improve the accuracy of the initial control data, the mathematical models are built not only based on theoretical equations, but also on the control data of typical operation points, which is obtained by the on- line calibration of specific engines. This system can also perform some special calibrations, like "constant pulse width" and "square wave modulation."

Dual-fuel combustion combining a premixed charge of compressed natural gas (CNG) and a pilot injection of diesel fuel offer the potential to reduce diesel fuel consumption and drastically reduce soot emissions. In this study, dual-fuel combustion using methane ignited with a pilot injection of No. 2 diesel fuel, was studied in a single cylinder diesel engine with optical access. Experiments were performed at a CNG substitution rate of 70% CNG (based on energy) over a wide range of equivalence ratios of the premixed charge, as well as different diesel injection strategies (single and double injection). A color high-speed camera was used in order to identify and distinguish between lean-premixed methane combustion and diffusion combustion in dual-fuel combustion. The effect of multiple diesel injections is also investigated optically as a means to enhance flame propagation towards the center of the combustion chamber.

The combustion characteristics of gasoline-diesel dual-fuel in an electronic-controlled high pressure common rail optical engine were investigated under different diesel injection timings and gasoline/diesel ratios by a high-speed photography method. The experimental results show that the dual-fuel combustion process is influenced by diesel combustion and gasoline homogenous combustion, respectively, with bright yellow flames and blue flames observed in the combustion chamber. At a gasoline/diesel ratio of 0.91, the injection timing affects the ignition timing and combustion modes significantly. When the diesel injection timing is before −25° after top dead center (ATDC), advancing the injection timing tends to prolong the ignition delay and the gasoline-diesel dual-fuel combustion is similar to the pre-mixed charge compression ignition (PCCI) combustion with a rapid single-stage heat release.

A single-cylinder Gasoline Direct Injection Engine (GDI) engine with a centrally mounted spray-guided injection system (150 bar fuel pressure) has been operated with stoichiometric and rich mixtures. The base fuel was 65% iso-octane and 35% toluene; hydrogen was aspirated into a plenum in the induction system, and its equivalence ratios were set to 0, 0.02, 0.05 and 0.1. Ignition timing sweeps were conducted for each operating point. Combustion was speeded up by adding hydrogen as expected. In consequence the MBT ignition advance was reduced, as were cycle-by-cycle variations in combustion. Adding hydrogen led to the expected reduction in IMEP as the engine was operated at a fixed manifold absolute pressure (MAP). An engine model has also been set up using WAVE. Particulate Matter (PM) emissions were measured with a Cambustion DMS500 particle sizer.

A boost system with an auxiliary gas turbine used to recover diesel engine power at plateau conditions is proposed. System matching calculation, preliminary design, and performance simulation of the compressor with double parameter output are presented, as well as the preliminary design, flow simulation, and combustion process of the combustion chamber. Results show that the new system has better recovery performance and higher fuel economy potential than the simple charging scheme. For future research work, possible improvements and development direction are recommended.

The effect of temporally-splitting high pressure injection on Diesel spray combustion and soot formation processes was studied by using the high-speed video camera. The spray was injected by the single-hole nozzle with a hole diameter of 0.11mm into the high-pressure and high-temperature constant volume vessel. The free spray and the spray impingement on the two dimensional (2D) piston cavity wall were examined. Injection pressures of 100 and 160 MPa for the single injection and 160 MPa for the split injection were selected. The flame structure and soot formation process were examined by using the two-color pyrometry. The soot generated in the flame under the split injection under 160 MPa becomes higher than that of the single injection under 160 MPa.

Compressed natural gas (CNG) is widely used as an alternative option in spark ignition engines because of its better fuel economy and in part cleaner emissions. To cope with the haze weather in Beijing, about 2000 gasoline/CNG dual-fuel taxis are servicing on-road. According to the government's plan, the volume of alternative fuel and pure electric vehicle will be further increased in the future. Thus, it is necessary to conduct an evaluation on the effectiveness of alternative fuel on curbing vehicular emissions. This research examined the regulated emissions and particulate matter of gasoline/CNG dual-fuel taxi over New European Driving Cycle (NEDC). Emission tests in gasoline- and CNG-fuelled, cold- and warm-start modes were done for all five taxies. Test vehicles, Hyundai Elantra, are powered by 1.6L spark-ignited engines incorporated with 5-gear manual gearboxes.

The electronic control of direct injection fuel system, which could improve engine fuel efficiency, dynamics and engine emission performance through good atomization, precise control of fuel injection time and improvement of fuel-gas mixture, is the key technology to achieve the stratified combustion and lean combustion. In this paper, a direct injection injector that based on voice coil motor was designed aiming at the technical characteristics of one 800cc two-stroke cam-less engine. Prior to a one - dimensional simulation model of injector was established by AMEsim and the maximal fuel injection demand was met via the optimization of the main parameters of the injector, the structure of the voice coil motor was optimized by magnetic equivalent circuit method. After that, the maximal flow rate of the injector was verified by the injector bench test while the atomization characteristic of the injector was verified by using a high-speed camera.

In this paper, a new-type balanced opposed-piston folded-cranktrain (OPFC) two-stroke diesel engine is developed by Beijing Institute of Technology. OPFC has some potential advantages such as simple structure, good balance, compact, high power density and thermal efficiency. The structural feature of OPFC engine leads to the performance is different with the conventional engine. In order to study and verify the characteristics of this kind of engine, the folded-crank train dynamics, cylinders scavenging process and combustion process are investigated. The influence of parameters on the engine performance is investigated, includes the fuel injection timing, intake/exhaust port timing. In addition, the nozzle diameter is investigated as a main factor to affect the mixture and combustion process in the cylinder.

A multi-task control template has been established for diesel engine control system in this paper. By analyzing the function requirements and control strategies of electronic diesel engine control system, the data flow diagram has been obtained. Based on the mechanisms and characteristics of the RTOS as well as the design methods of real-time system software, modules in data flow graph has been divided further. So that the multi-tasks of the control system have been drawn. Then each task's properties have been designed. Afterwards, every task and the embedded RTOS have been transplanted into Freescale MPC5554 microcontroller. After that the multi-tasks have been tested and optimized in a Hardware-in-the-Loop Simulation (HILS) system of dSPACE AUTOBOX. The results show good reusability and real-time performance and it can increase the efficiency of the diesel engine control software development.

Methanol has been regarded as a potential transportation fuel due to its advanced combustion characteristics and flexible source. However, it is suffering from misfire and high HC emissions problems under cold start and low load conditions either on methanol SI engine or on methanol/diesel dual fuel engine. Hydrogen is a potential addition that can enhance the combustion of methanol due to its high flammability and combustion stability. In the current work, the effect of hydrogen fraction on the laminar flame characteristics of methanol- hydrogen-air mixture under varied equivalence ratio was investigated on a constant volume combustion chamber system coupled with a schlieren setup. Experiments were performed over a wide range of equivalence ratio of the premixed charge, varied from 0.8 to 1.4, as well as different hydrogen fraction, 0%, 5%, 10%, 15% and 20% (n/n). All tests were carried out at fixed temperature and pressure of 400K and 0.1MPa.

An opposed-piston two-stroke folded-cranktrain diesel engine was studied in this paper. In order to achieve asymmetric scavenging, asymmetric angle between two crank throws were designed. However asymmetric crank-throw angle has direct effect on the piston dynamic, which affects engine performance. This paper investigated the characteristics of the piston dynamic on an opposed-piston two-stroke folded-cranktrain diesel engine; effects of the asymmetric angle on the piston displacement, velocity and acceleration were analyzed; further researches were done to studied the effect of piston dynamic on the gas exchange performance and in-cylinder performance. The results show that, larger asymmetric angle is positive for the scavenging efficiency but negative for combustion.

As known, the constant injection mass is a criterion for measuring the thermal efficiency of diesel engines. In this study, the effects of nozzle hole diameter on diesel free-spray characteristics were investigated in constant injection mass condition. The experiment was performed in a constant volume combustion chamber equipped with a high pressure common-rail injector that can change nozzles. Three single-hole axis nozzles with different hole diameters were used. High speed camera and Schlieren visualization set-up were used to capture the spray behaviors of liquid phase and vapor phase respectively. For liquid phase spray, the higher nozzle hole diameter, the higher were the liquid phase spray penetration rate and the saturated liquid phase spray penetration length. The saturated liquid phase spray penetration length wound not grow but oscillate around different mean values at the steady stage.

In this paper the experiments of hydraulic free piston diesel engine is described. The experimental data were obtained from measurement instruments on the free piston diesel engine that has been developed by Beijing Institute of Technology [ 1 ]. This article discusses the influences of compression pressure, injection timing, and combustion process to the free piston diesel engine principle. The compression process experiment shows that the piston velocity, the compression ratio can be controlled by adjusting the compression pressure. With the increasing of the compression pressure, there is a growing a compression ratio and piston velocity. The study on injection timing shows that the injection timing impacts the cylinder pressure peak value and the pressure peak arrival time. The combustion process is quite different from the crankshaft engine because of the unique piston movement characteristics of the hydraulic free piston engine.

Self recirculation casing treatment has been showed to be an effective technique to extend the flow range of the compressor. However, the mechanism of its surge extension on turbocharger compressor is less understood. Investigation and comparison of internal flow filed will help to understand its impact on the compressor performance. In present study, experimentally validated CFD analysis was employed to study the mechanism of surge extension on the turbocharger compressor. Firstly a turbocharger compressor with replaceable inserts near the shroud of the impeller inlet was designed so that the overall performance of the compressor with and without self recirculation casing treatment could be tested and compared. Two different self recirculation casing treatments had been tested: one is conventional self recirculation casing treatment and the other one has deswirl vanes inside the casing treatment passage.