Showing papers on "Carbureted compression ignition model engine published in 2004"

Compression ignition internal combustion engine

Abstract: It is an object of the present invention to provide a compression ignition internal combustion engine capable of making compatible an increase in compression self-ignition operating area with an optimum output torque control in the operating area and also smoothly switching between a self-ignition combustion and a spark ignition combustion. The compression ignition internal combustion engine operates by switching between the spark ignition combustion using an ignition device and the compression ignition combustion which self-ignites a mixture by piston compression. Variable valve mechanisms vary at least one of the valve timings and valve lifts of an intake valve and an exhaust valve. Intake air is regulated to vary the amount of air intake into a combustion chamber on the upstream side of a combustion chamber inlet of the compression ignition internal combustion engine. The variable valve mechanisms and the intake air regulation are controlled during the compression ignition combustion so as to perform the compression ignition combustion.

Engine performance and emissions of a compression ignition engine operating on the diesel-methanol blends

Abstract: A stabilized diesel-methanol blend was realized and a study on the performance and emissions of the diesel-methanol blend was carried out in a compression ignition engine. The study showed that the engine thermal efficiency increases and the diesel equivalent b.s.f.c. decreases with increase in the oxygen mass fraction (or methanol mass fraction) of the diesel-methanol blends due to an increased fraction of premixed combustion phase, oxygen enrichment and improvement in the diffusive combustion phase. Further increase in the fuel delivery advance angle will achieve a better engine thermal efficiency when the diesel engine is operated using the diesel-methanol fuel blends. A marked reduction in the exhaust CO and smoke can be achieved when operating with the diesel-methanol blend. There is not a large variation in the exhaust hydrocarbon with the addition of methanol in diesel fuel. NOx increases with increase in the mass of methanol added; methanol addition to diesel fuel was found to have a strong influe...

Closed‐loop combustion control of homogeneous charge compression ignition (HCCI) engine dynamics

Abstract: Homogeneous charge compression ignition (HCCI) is a hybrid of the sparkignition and compression ignition engine concepts. As in a sparkignition engine, a homogeneous fuel-air mixture is created in theinlet system. During the compression stroke the temperature of themixture increases and reaches the point of auto ignition, just as in acompression ignition engine (or Diesel). One challenge with HCCI engines isthe need for good timing control of the combustion. Auto ignition of ahomogeneous mixture is very sensitive to operating condition. Evensmall variations of the load can change the timing from too early totoo late combustion. Thus a fast combustion timing control isnecessary since it sets the performance limitation of the loadcontrol. As measurement for combustion timing feedback, the crank angleof 50% burnt has been used. This paper performs a comparative studyof different cylinder-pressure based methods for estimating the crankangle of 50% burnt. The estimates are compared in terms of accuracy,robustness and feasibility for cycle-to-cycle real-time control.Dynamic models of CA50 are estimated using system identification asa means to find models relevant to engine control. (Less)

Effect of Premixed Gasoline Fuel on the Combustion Characteristics of Compression Ignition Engine

Abstract: The effect of the premixed ratio and supply condition of premixed fuel on the combustion and emission characteristics of a partial homogeneous charge compression ignition (HCCI) engine has been investigated experimentally and numerically. The fuel, which is supplied by an additional port fuel injector in the intake manifold, is premixed with air. The homogeneous charge is compressed and ignited by directly injected diesel fuel in the combustion chamber. In this work, the experimental investigation is made by varying the supply conditions of the premixed fuel, such as the injection pressure and the intake temperature. Results show that a partial HCCI engine with a premixed gasoline fuel shows single-stage ignition and the increase in premixed ratio of gasoline fuel results in the advance of ignition timing and the remarkable reduction of nitrogen oxide emission of the engine. Also, heating the intake air is useful for reducing the HC and CO emissions, which are regarded as one of the problems in the partia...

Experimental Investigation to Specify the Effect of Oxygenated Additive Content and Type on DI Diesel Engine Performance and Emissions

Abstract: The reduction of brake specific consumption and pollutant emissions are issued as future challenges to diesel engine designers due to the depletion of fossil fuel reserves and to the continuous suppression of emission regulations. These mandates have prompted the automotive industry to couple the development of combustion systems in modern diesel engines with an adequate reformulation of diesel fuels and have stirred interest in the development of clean diesel fuels. The use of oxygenated fuels seems to be a promising solution towards reducing particulate emissions in existing and future diesel motor vehicles. The prospective of minimizing particulate emissions with small fuel consumption penalties seems to be quite attractive in the case of biodiesel fuels, which are considered as an alternative power source. Studies conducted in diffusion flames and compression ignition engines have shown a reduction of soot with increasing oxygen percentage. However, the effects of the type of oxygenated additive and oxygen content on gaseous and particulate emissions obtained from modern DI diesel engines have not been fully investigated. An experimental investigation is conducted to determine the effect of oxygen content and oxygenate type on DI diesel engine performance and emissions. One conventional and three oxygenated fuels are examined having an oxygen content ranging from 0% to 9%. The fuels are prepared by blending a biodiesel compound (RME), Diglyme and Butyl-Diglyme with a low sulfur diesel fuel in various proportions. An experimental installation is prepared and engine tests are conducted on a naturally aspirated single-cylinder Ricardo Hydra research engine. The measurements are carried out at various operating conditions. The experimental findings reveal an increase of in-cylinder pressure due to the increase of cetane number. In addition, a slight increase of bsfc is observed due to the small decrease of fuel heating value with the increase of the oxygen content. A decrease of ignition delay is observed with increasing oxygen content following thus, the increase of cetane number. A considerable reduction of soot, carbon monoxide and unburned hydrocarbon emissions is witnessed while; nitric monoxide emissions are increased when the oxygen content is increased from 3% to 9%. Similar effects are observed when replacing the rapeseed methyl ester with a mixture of diglyme and butyl-diglyme and the oxygen percentage remains unaltered. As revealed, a reduction of tailpipe soot without overall considerable penalties in bsfc and NO x emissions can be achieved in modem DI diesel engines using oxygenated additives at elevated percentages (30% by mass).

An Investigation into Bioethanol Homogeneous Charge Compression Ignition (HCCI) Engine Operation with Residual Gas Trapping

Abstract: Given the increasing interest in renewable fuels, bioethanol has been successfully used in conventional internal combustion engines. However, its application in homogeneous charge compression ignition (HCCI) engines requires various approaches, such as high compression ratios and/or intake charge heating, to achieve auto ignition. The approach documented here utilizes the trapping of internal residual gas (as used previously in gasoline-fueled controlled auto ignition engines) to lower the thermal requirements for the auto ignition process. In the present work, the achievable engine load range is controlled by the degree of internal trapping of exhaust gas, supplemented by moderate intake charge heating. Moderate intake heating extends the narrow auto ignition load window while varying the inlet valve timing extends the upper load range. Nitrogen oxide (NO x ) emissions are characteristically low, because of the nature of homogeneous combustion.

Method and Apparatus for Controlling Exhaust Gas Recirculation and Start of Combustion in Reciprocating Compression Ignition Engines With An Ignition System With Ionization Measurement

Abstract: An apparatus and method to detect combustion conditions using ion signals for use in a feedback control of a reciprocation engine is presented. The ion signals are used as a feedback signal to control EGR and diesel injection timing. The apparatus is an ignition system with a spark plug type of sensor. The ignition system is used to provide a cold start mechanism for diesel engines and start of combustion for spark ignition engines. The ignition is combined with ion sensing feedback that can control the engine.

High compression ratio, high power density homogeneous charge compression ignition engines using hydrogen and carbon monoxide to enhance auto-ignition resistance

Abstract: High compression ratio, homogeneous charge compression ignition engines. In one aspect the engine is dual mode utilizing spark ignition at high load levels including the addition of hydrogen or a hydrogen/carbon monoxide mixture. In another aspect, the engine operates on a high cetane fuel with the addition of hydrogen or a hydrogen/carbon monoxide mixture at low-to-mid-load levels.

Investigation of spray characteristics from a low-pressure common rail injector for use in a homogeneous charge compression ignition engine

Abstract: Homogeneous charge compression ignition (HCCI) combustion provides extremely low levels of pollutant emissions, and thus is an attractive alternative for future IC engines. In order to achieve a uniform mixture distribution within the engine cylinder, the characteristics of the fuel spray play an important role in the HCCI engine concept. It is well known that high-pressure common rail injection systems, mainly used in diesel engines, achieve poor mixture formation because of the possibility of direct fuel impingement on the combustion chamber surfaces. This paper describes spray characteristics of a low-pressure common rail injector which is intended for use in an HCCI engine. Optical diagnostics including laser diffraction and phase Doppler methods, and high-speed camera photography, were applied to measure the spray drop diameter and to investigate the spray development process. The drop sizing results of the laser diffraction method were compared with those of a phase Doppler particle analyser (PDPA) to validate the accuracy of the experiments. In addition, the effect of fuel properties on the spray characteristics was investigated using n-heptane, Stoddard solvent (gasoline surrogate) and diesel fuel because HCCI combustion is sensitive to the fuel composition. The results show that the injector forms a hollow-cone sheet spray rather than a liquid jet, and the atomization efficiency is high (small droplets are produced). The droplet SMD ranged from 15 to 30 µm. The spray break-up characteristics were found to depend on the fuel properties. The break-up time for n-heptane is shorter and the drop SMD is smaller than that of Stoddard solvent and diesel fuel.

Combustion and emission characteristics of partial homogeneous charge compression ignition engine

Abstract: To investigate the effect of premixed fuel on the combustion and exhaust emission characteristics in a partial homogeneous charge compression ignition (HCCI) engine, an experimental study was performed. The premixed fuels are supplied by the additional fuel injection system in the intake manifold of a direct-injection diesel engine and the injection nozzle for directly injected fuel is equipped in the center of the combustion chamber. The results show that, in the case of gasoline as a premixed fuel, single-stage ignition is found, but premixing the diesel fuel is accompanied by a cool flame prior to the combustion of the directly injected diesel fuel. NOx emissions in the partial HCCI engine with premixed gasoline fuel decrease linearly with increase in premixed ratio. But, for diesel premixed fuel, NOx emission increases at high intake temperature and high premixed ratio conditions.

Method and system for detecting ignition failure in a gas turbine engine

Abstract: A method of operating a gas turbine engine is provided. The method includes introducing a fuel into a combustor, detecting a failure of ignition of the fuel, and preventing ignition until the introduced fuel is substantially removed from the gas turbine engine.

Effect of Injection Pressure and Engine Speed on Air/Fuel Mixing and Emissions in a Pre-Mixed Compression Ignited (PCI) Engine Using Diesel Fuel

Abstract: PCI combustion of diesel fuel was accomplished in a direct-injected heavy-duty single-cylinder research engine. An impinging spray nozzle combined with a shallow bowl piston design offered a shor ...

Study on Auto-Ignition and Combustion Mechanism of HCCI Engine

Abstract: In the HCCI (Homogeneous Charge Compression Ignition) engine, a mixture of fuel and air is supplied to the cylinder and auto-ignition occurs resulting from compression. This method can expand the lean flammability limit, realizing smokeless combustion and also having the potential for realizing low NOx and high efficiency. The optimal ignition timing is necessary in order to keep high thermal efficiency. The Ignition in the HCCI engine largely depends on the chemical reaction between the fuel and the oxidizer. Physical methods in conventional engines cannot control it, so a chemical method is demanded. Combustion duration is maintained properly to avoid knocking. In addition, the amount of HC and CO emissions must be reduced. The objective of this study is to clarify the following through calculations with detailed chemical reactions and through experiment with the 2-stroke HCCI engine: the chemical reaction mechanism, and HC and CO emission mechanisms. Ignition and combustion mechanisms and the effect of pre-mixture heterogeneity on ignition and combustion are also clarified. This is done by using an optically accessible engine and measuring the luminescence at auto-ignition and during the combustion process.

Experimental study on homogeneous charge compression ignition engine operation with exhaust gas recirculation

Abstract: This paper is concerned with the Homogeneous Charge Compression Ignition (HCCI) engine as a new concept in engines and a power source for future automotive applications. Essentially a combination of spark ignition and compression ignition engines, the HCCI engine exhibits low NOx and Particulate Matter (PM) emissions as well as high efficiency under part load. The objective of this research is to determine the effects of Exhaust Gas Recirculation (EGR) rate on the c°l!'bustion processes of HCCI. For this purpose, a 4-cylinder, compression ignition engine was converted into a HCCI engine. and a heating device was installed to raise the temperature of the intake air and also to make it more consistent. In addition. a pressure sensor was inserted into each of the cylinders to investigate the differences in characteristics among the cylinders.

Combustion control method for compression ignition internal combustion engine

Abstract: PROBLEM TO BE SOLVED: To suppress increase of combustion noise even when resuming fuel injection for acceleration after speed reduction by fuel cut. SOLUTION: In this combustion control method for the compression ignition internal combustion engine performing premixed combustion when engine load of the compression ignition internal combustion engine is low or middle load, ignition time is controlled without relying on EGR gas amount (S103 to S105) during a predetermined period of time after resuming fuel injection when the compression ignition internal combustion engine is accelerated (S102) by resuming fuel injection after speedreduction (S101) by fuel cut during premixed combustion. COPYRIGHT: (C)2006,JPO&NCIPI

Internal combustion engine of compression ignition type

Abstract: The present invention aims at expanding an operation range for allowing a compression ignition combustion operation. The present invention provides an internal combustion engine of a compression ignition type that is capable of operating with a compression ignition combustion scheme in a given operation range. The ECU of the internal combustion engine detects an operating condition of the internal combustion engine and determines, according to the detected operating condition, which mode is to be used operate the internal combustion engine, a 4-cycle compression ignition mode or a 2-cycle compression ignition mode. The ECU controls the internal compression engine to perform the compression ignition mode determined. According to the present invention, the compression ignition combustion operation is switched from 4-cycle to 2-cycle when the operating condition of the internal combustion engine is in such state that the 4-cycle compression ignition mode cannot be performed, fro example, when the exhaust temperature is low.

A Study on Combustion Structure of Premixed Compression Ignition Diesel Engines

Abstract: The author et al. propose a new system named UNIBUS (Uniform Bulky combustion System) which falls in the category of systems for diesel engine combustion with the premixed compression ignition

An investigation of using various diesel-type fuels in homogeneous charge compression ignition engines and their effects on operational and controlling issues

Abstract: Homogeneous charge compression ignition (HCCI) engines appear to be a future alternative to diesel and spark-ignited engines. The HCCI engine has the potential to deliver high efficiency and very low NOx and particulate matter emissions. There are, however, problems with the control of ignition and heat release range over the entire load and speed range which limits the practical application of this technology. The aim of this paper is to analyse the use of different types of diesel fuels in an HCCI engine and hence to find the most suitable with respect to operational and control issues. The single-zone combustion model with convective heat transfer loss is used to simulate the HCCI engine environment. n-Heptane, dimethyl ether and bio-diesel (methyl butanoate and methyl formate) fuels are investigated. Methyl butanoate and methyl formate represent surrogates of heavy and light bio-diesel fuel respectively. The effects of different engine parameters such as equivalence ratio and engine speed on the ignition timing are investigated. The use of internal exhaust gas recirculation is investigated as a potential strategy for controlling the ignition timing. The results indicate that the use of bio-diesel fuels will result in lower sensitivity of ignition timing to changes in operational parameters and in a better control of the ignition process when compared with the use of n-heptane and dimethyl ether.