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A variable compression ratio concept that can give a different expansion ratio to the compression ratio has been evaluated by means of a simulation of a turbocharged diesel engine. The VR/LE mechanism kinematics have been defined and described, and the compression ratio and expansion ratio have been presented as a function of the eccentric phase angle (αo). A zero-dimensional engine simulation that has been the subject of comprehensive validation, has been used as the basis of the VR/LE study. The effect of the compression ratio on the engine performance at fixed loads is presented. The principal benefits are a reduction in fuel consumption at part load of about 2%, and a reduction in ignition delay that leads to an estimated 6 dB reduction in combustion noise. The study has been conducted within the assumption of a maximum cylinder pressure of 160 bar.

An experimental investigation of the PJC (Pulsed Jet Combustion) system in a research engine is presented. The modus operandi is based on the introduction into the combustion chamber of a turbulent plume formed by a jet of rich combustion products issued from an orifice of a generator plug. This study is a continuation of previous investigations performed with the use of, sequentially, a constant volume vessel and a single compression machine. The PJC generator was supplied with a rich mixture via a Bosch injector. Methane was used as a fuel. Pressure records of a piezo-electric transducer were processed by a computer data acquisition system. The investigations were performed for lean combustible mixtures (ϕ=0.625, 1.0) over a wide range of spark advance angles. Direct comparison between the PJC system and conventional spark ignition was made for optimal ignition advance angle.

A new concept of an engine, called a Variable R/L Engine (VR/LE) is presented. The main feature of the engine is the continuous change of the crank-radius to connecting-rod-length ratio. (R/L) during the single engine cycle. The phase shift of the R/L=f(φ), function φ being the crank angle, can be adjusted from outside of the engine and it is a regulational parameter. The variations of the phase angle result in changes of all the engine stroke lengths and also-they are causing the changes of the thermodynamic cycle of the engine. Therefore the phase angle variations make it possible to regulate continuously the compression ratio and the displacement volume of the engine within the range which depends on the engine mechanism geometry. The presented concept can be applied to all the types of the IC piston engines, independently of their size and operation principle.