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HCNG is short for hydrogen enriched natural gas. Compared to traditional gasoline, diesel or even natural gas engines HCNG fuelled engines have several advantages on environment protection and energy security and in order to make full extent of the new fuel, several modifications have to be made in the corresponding engine and the control strategy. So there is a need to develop a predictive model to simulate the engine's performance without really running the engine, which could speed up the development of HCNG engines. This paper dose such a job. At first the paper presents the fundamentals of the quasi-dimensional model. The equations of the two-zone thermodynamic model and turbulent entrainment combustion model are both introduced. The methods of calculating the related parameters such as theoretical adiabatic flame temperature, laminar burning velocity of HCNG mixture under various hydrogen blending ratios are also given.

Hydrogen enriched compressed natural gas (HCNG) is thought to be a potential alternative to common hydrocarbon fuels for SI engine applications. Experimental researches focusing on how to use this kind of fuel to its full extent have been conducted for over ten years and are still on their way. From a review of these researches it is found that one of the biggest obstacles of efficiently and economically conducting such experiments is how to mix desired amount of hydrogen with natural gas. Most of the previous experiments use pre-bottled hydrogen/ NG mixtures (by mixing and storing desired amount of hydrogen and NG in high pressure steel cylinders before the tests) which are quite costly and unsafe, due to high pressure operation. More importantly, the blending ratio cannot be varied by that approach. By comparison, this paper presents an on-line hydrogen-natural gas mixing system through which the hydrogen/ NG blending ratio can be easily varied during the tests.

With the development of the automobile industry, the requirements of quick response and high performance are put forward for the brake system. Since the traditional brake system cannot achieve these, the international brake parts manufacturers put forward an integrated electro-hydraulic brake system -the 1-Box. It can realize active brake through the servo motor. In addition, by controlling the pressure of the servo cylinder and working with solenoid valves, the wheel cylinder pressure can be controlled. However, it has some problems, such as hydraulic hysteresis disturbance and complex friction obstruction, which cause obstacles to the accurate control of wheel cylinder pressure. In this paper, the active braking pressure control strategy of wheel cylinders is designed based on 1-Box.

The application of oxygen-enriched or oxy-fuel combustion coupled with carbon capture and storage technology has zero carbon dioxide emission potential in the boiler and gas turbine of the power plant. However, the oxygen-enriched combustion with high oxygen level has few studies in internal combustion engines. The fundamental issues and challenges of high oxygen level are the great differences in the physical properties and chemical effects compared with the combustion in air condition. As a consequence, the diesel spray combustion characteristics at high oxygen level were investigated in an optical constant volume vessel. The oxygen volume fraction of tested gas was from 21% to 70%, buffered with argon. The high-speed color camera was used to record the natural flame luminosity.

In order to achieve high-efficiency and clean combustion in HCCI engines, combustion must be controlled reasonably. A great variety of species with various reactivities can be produced through low temperature oxidation of fuels, which offers possible solutions to the problem of controlling in-cylinder mixture reactivity to accommodate changes in the operating conditions. In this work, in-cylinder combustion characteristics with low temperature reforming (LTR) were investigated in an optical engine fueled with low octane number fuel. LTR was achieved through low temperature oxidation of fuels in a reformer (flow reactor), and then LTR products (oxidation products) were fed into the engine to alter the charge reactivity. Primary Reference Fuels (blended fuel of n-heptane and iso-octane, PRFs) are often used to investigate the effects of octane number on combustion characteristics in engines.

OH, soot and temperature distributions of wall-impinging diesel fuel spray were investigated in a high-temperature high-pressure constant volume combustion vessel. The ambient temperature (Ta) was set as 773 K, and the wall temperature (Tw) was set as 523 K, 673 K, 773 K, respectively. Three different injection pressures (Pi) of 60 MPa, 100 MPa, 160 MPa, and the ambient pressures (Pa) of 4 MPa were applied. The OH spatial distributions of wall-impinging spray were measured by the method of OH chemiluminescence imaging. Two-color pyrometry was applied to evaluate the spatial distributions of KL factor and flame temperature of wall-impinging spray. The results reveal that, OH chemiluminescence is observed in the region near the impingement point firstly. The regions of high OH chemiluminescence intensity and high KL factor appear in the location near the wall surface along the whole combustion process.

Pumping Mean Effective Pressure (PMEP) is the main factor limiting the improvement of thermal efficiency in a spark-ignition (SI) engine under low load. One of the ways to reduce the pumping loss under low load is to use Cylinder DeActivation (CDA). The CDA aims at reducing the firing density (FD) of the SI engine under low load operation and increasing the mass of air-fuel mixture within one cycle in one cylinder to reduce the throttling effect and further reducing the PMEP. The multi-stroke cycles can also reduce the firing density of the SI engine after some certain reasonable design, which is feasible to improve the thermal efficiency of the engine under low load in theory. The research was carried out on a calibrated four-cylinder SI engine simulation platform. The thermal efficiency improvements of the 6-stroke cycle and 8-stroke cycle to the engine performance were studied compared with the traditional 4-stroke cycle under low load conditions.

Bio-derived butanol is a potential CO2 neutral alternative fuel to be applied in internal combustion engines. However, the physical and combustion characteristics have to be fully understood before it can be used efficiently in engines. This work investigates the viscosity and the combustion characteristics of n-butanol/diesel fuel blends, with a particular focus on the combustion property at low load performance. N-butanol was mixed with diesel from 20 vol% up to 80 vol% blend ratio. Tests were performed in a combustion research unit (constant volume) at fixed chamber pressure that mimic a low load condition. The effects of various chamber temperatures and ambient oxygen concentrations (21%, 13%, and 11%) are evaluated. As expected, the viscosity of n-butanol/diesel fuel blends decreases at high temperature. The decrease is non-linear with the blend ratio.

The tripod constant velocity joint (CVJ) has been widely used in mechanical systems due to its strong load-bearing capacity, high efficiency, and reliability. It has become the most commonly used plunging-type CVJ in automotive drive-shaft. A generated axial force (GAF) with a third-order characteristic of driven shaft speed is caused by the internal friction and motion characteristics in a tripod joint. The large GAF has a negative impact on the NVH (Noise, Vibration, and Harshness) characteristics of automobiles, and this issue is particularly prominent in new energy vehicles. A multi-body dynamic model of the Adjustable Angular Roller (AAR) tripod CVJ is developed to calculate and analyze the GAF. To describe the internal motion of the AAR tripod CVJ, the contact interactions between the roller and the track or the trunnion were modeled using non-linear equivalent spring-damping models for contact collision forces and modified Coulomb friction model for friction.