Search Results

Water and diesel fuel emulsions containing 13% and 26% water by volume were investigated in a modern diesel engine with relatively early pilot injection, supercharging, and cooled EGR. The heat release from the pilot injection with water emulsions is retarded toward the top dead center due to the poor ignitability, which enables larger pilot and smaller main injection quantities. ...Heat transfer analysis with Woschni's equation did not show the decrease in cooling loss with the water emulsion fuels. Single spray combustions with the water emulsions and the regular unblended diesel fuel in a constant volume combustion vessel were analyzed with a high-speed video and a 2-D two-color method. ...Water and diesel fuel emulsions containing 13% and 26% water by volume were investigated in a modern diesel engine with relatively early pilot injection, supercharging, and cooled EGR.

It has been found that the water injection in the HCCI combustion retarded the combustion and increased its duration, preventing knock. ...Several methods to control the combustion had been investigated, between them, the injection of water may be useful to extend HCCI knock free operation and to enable combustion phasing control. ...The results indicated that the combustion without water injection tended to start considerably before TDC with a very fast combustion and abrupt heat release rates causing knock.

A maximum indicated thermal efficiency of 50.8% was achieved in the test at -5 °CA ATDC ignition time and 2ms per cycle water injection pulse width(15.83mg). However, excessive water injection rather deteriorates the combustion process with a loss of indicated thermal efficiency. ...In order to suppress the limitation of knock on the thermal efficiency, this paper adopts a combination of experimental and simulation methods to investigate the effects of port water injection on the knock suppression and combustion characteristics of an argon power cycle hydrogen engine. ...The results show that the port water injection can effectively reduce the knock intensity of the argon power cycle hydrogen engine and optimize the combustion process, thus achieving the improvement of the indicated thermal efficiency and the indicated mean effective pressure.

A steady-state, medium-speed, high-load engine operating point is investigated with focus on the effect of water injection on knock tendency and exhaust temperature. The impact of water injection on oxidation chemistry and auto-ignition is investigated using a detailed ethanol toluene reference fuel (ETRF) (ethanol, iso-octane, n-heptane, and toluene) reaction scheme. ...In the second step, the impact of water vaporization is analyzed for port and direct injection. For this purpose, the water mass flow and the injection pressure are varied. ...Water injection is a promising technology to improve the fuel efficiency of turbocharged gasoline engines due to the possibility to suppress engine knock.

With proper molding, machining or casting of the substrates a channel is created for an injection of gasketing material to follow, similar to the grove for a hand placed compression gasket. ...The material developed is flowable enough to fill the entire channel with small injection pressures. Once the channel is filled, the material cures in a very short time. This method allows for varying surface irregularities to be accounted for and sealed easily by the material. ...Materials have been design to seal oils, coolants, water and transmission fluid. Other materials can be designed to meet different and new seal needs.

This work focuses on the effects of cooled Low Pressure EGR and Water Injection observed by conducting experimental tests consisting mainly of Spark Advance sweeps at different cooled LP-EGR and WI rates. ...The implications on combustion and main engine performance indexes are then analysed and modelled with a control-oriented approach, showing that combustion duration and phase and exhaust gas temperature are the main affected parameters. ...The implications on combustion and main engine performance indexes are then analysed and modelled with a control-oriented approach, showing that combustion duration and phase and exhaust gas temperature are the main affected parameters. Results show that cooled LP-EGR and WI have similar effects, being the associated combustion speed decrease the main cause of exhaust gas temperature reduction.

In this paper, an experimental study was performed to investigate characteristics of flame propagation and knocking combustion of hydrous (10% water content) and anhydrous ethanol at different air/fuel ratios in comparison to RON95 gasoline. ...Heat release analysis reveals ethanol had the highest maximum cylinder pressure at the earliest crank angle, followed by E90W10 and then gasoline, because of their relative earlier combustion phasing (CA10 and CA50) and short combustion duration. This is confirmed by the faster developing flame fronts of ethanol fuels shown by the high speed combustion and OH* images. ...Experiments were conducted in a full bore overhead optical access single cylinder port-fuel injection spark-ignition engine. High speed images of total chemiluminescence and OH* emission was recorded together with the in-cylinder pressure, from which the heat release data were derived.

Water injection (WI) can improve gasoline engine performance and efficiency, and on-board water recovery technology could eliminate the need for customers to refill an on-board water reservoir. ...From the appearance of the condensate samples, MEM-collected water had better quality than the CS and AS collected water. Water collected after the CAC showed better quality and lower pH than that collected downstream of the EGR cooler. ...Water injection (WI) can improve gasoline engine performance and efficiency, and on-board water recovery technology could eliminate the need for customers to refill an on-board water reservoir. In this regard, the technical feasibility of exhaust water recovery (EWR) is described in this paper.

Optimum total engine cooling by direct water injection was accomplished over a wide range of water injection timings (from 450-720 CA deg after TDC power stroke) at water/fuel ratios of 2.9-3.7 with output power and brake specific fuel consumption improved to 5-20%, respectively, over that with the standard jacket-cooled CLR engine. 2. ...Difficulty was experienced in corrosive damage to bearings, cam, and cam follower of the water injection pump caused by water leakage into the lower end of the pump. Injection of water contributed very little to combustion chamber deposits as observed upon disassembly of the engine. ...The feasibility of total cooling a single-cylinder diesel engine by various methods of introducing water into the combustion chamber was investigated, including direct injection, manifold injection, and manifold induction.

The objective of this research work was to assess the potential of an electrostatic fluid atomization method for application in direct injection systems for combustion engines. The most important finding of this study was that it is possible to detect the influence of electrostatic atomization at injection pressures up to 300 bar using diesel fuel. ...The most important finding of this study was that it is possible to detect the influence of electrostatic atomization at injection pressures up to 300 bar using diesel fuel. The electrostatic force affects the liquid core of the fuel spray from typical diesel nozzles in such a way that additional surface waves are produced which in turn cause the spray to breakup earlier, i.e. the spray breakup length is reduced significantly.

Modern water injection systems typically deliver water separately from the primary fuel system using a discrete injector either through the intake port or directly to the cylinder. ...Removing water from naturally hydrous fuels such as ethanol requires large amounts of energy; consequently, it is possible to combine water injection with more economical production by leaving some amount of water in the fuel. This paper compares experimentally the water dilution effects on the combustion and emissions characteristics and overall engine performance when delivering the water through either a hydrous fuel blend or discrete port water injection. ...This paper compares experimentally the water dilution effects on the combustion and emissions characteristics and overall engine performance when delivering the water through either a hydrous fuel blend or discrete port water injection. A 2.4L 4-cylinder NA GDI engine was used in experimental testing.

Several injection strategies, such as varying start of injection, injection pressure, and water to fuel ratio, are tested at the single-cylinder engine test bench. ...Among others, water injection is a promising technology to improve engine combustion efficiency, by mainly reducing knock sensitivity and to keep high conversion rates of the TWC over the whole engine map. ...Measurements are performed with different injectors for indirect/direct water injection in the single-cylinder engine in order to assess water break-up, wall wetting, spray interaction and penetration.

Many control strategies have been reported in literature, in spite of that even today no HCCI combustion engine is available on commercial basis. Pilot and main fuel injection strategy is used as a control strategy in this work. ...Pilot injection timing was fixed at 270 degrees bTDC allowing sufficient time for homogeneous mixture preparation and main injection was fixed at 26 degrees bTDC to trigger the combustion. Split ratio was varied from zero to 95% at various operating load (2 bar Net IMEP to 6.5 bar Net IMEP) conditions. ...It was evident from the results that with increasing split ratio, all combustion parameters start advancing. Similarly, at any constant split ratio all combustion parameters started advancing with increasing load.

Two different technologies are examined for the addition of water into the combustion chamber: use of a water-fuel emulsion or injection of water into the intake manifold. ...A promising technology for NOx reduction especially for heavy-duty diesel engines and mainly large scale ones is the addition of water to the combustion chamber to reduce peak combustion temperature that obviously affects NOx formation. ...The reduction is higher when using water-fuel emulsion compared to water injection in the intake manifold for the same water percentage. Information is derived concerning the penalty on fuel consumption, which is a dominating parameter especially in large diesel engines.

A new combustion process has been developed based on the patented concept of injection-ignition known as Transonic Combustion or TSCi™; this combustion process is based on the direct injection of fuel into the cylinder as a supercritical fluid. ...Spark ignition gasoline engine efficiency is limited by a number of factors; these include the pumping losses that result from throttling for load control, spark ignition and the slow burn rates that result in poor combustion phasing and a compression ratio limited by detonation of fuel. A new combustion process has been developed based on the patented concept of injection-ignition known as Transonic Combustion or TSCi™; this combustion process is based on the direct injection of fuel into the cylinder as a supercritical fluid. ...The short combustion delay angles allow for the injection timing to be such that the ignition and combustion events take place after TDC.

Other emissions were almost unchanged or slightly decreased with water injection. Water injection reduced the flame temperature at the center of the swirl chamber, while the mean gas temperature in the cylinder and the rate of heat release changed little. ...The effect of direct water injection into the combustion chamber on NOx reduction in an IDI diesel engine was investigated. ...Direct water injection into a swirl chamber prior to fuel injection reduced NOx emission significantly over a wide output range without sacrifice of BSFC.

The control of fuel ignition timing and suppression of rapid combustion in a premixed charge compression ignition (PCCI) engine was attempted with direct in-cylinder injection of water as a reaction suppressor. The water injection significantly reduced the heat release at low temperature oxidation, which suppressed the increase in charge temperature after the low temperature oxidation and the rapid combustion caused by the high temperature oxidation. ...The possible engine operating range with ultra low NOx and smokeless combustion was extended to a higher load range with the water injection. Rapid combustion was suppressed by reductions in the maximum in-cylinder gas temperature due to water injection while the combustion efficiency suffered. ...Rapid combustion was suppressed by reductions in the maximum in-cylinder gas temperature due to water injection while the combustion efficiency suffered. Therefore, the maximum charge temperature needs to be controlled within an extremely limited range to maintain a satisfactory compromise between mild combustion and high combustion efficiency.

Experimental results obtained through modification of a CFR test engine confirm the predicted effectiveness of water injection on nitric oxide control. For a water injection rate 1-1/4 times the engine fuel consumption rate, nitric oxide reductions of over 90%were achieved. ...Theoretical analysis based on chemical equilibrium calculations indicates that the reduction of combustion temperature due to water injection at rates comparable to the engine fuel consumption rate is sufficient to yield significant reductions in nitric oxide emissions. ...Parallel theoretical and experimental studies of the influence of inlet manifold water injection on nitric oxide emission from spark ignition engines have been performed. Theoretical analysis based on chemical equilibrium calculations indicates that the reduction of combustion temperature due to water injection at rates comparable to the engine fuel consumption rate is sufficient to yield significant reductions in nitric oxide emissions.

In this paper a combustion concept is presented that may be well suited to these applications. The novel combustion concept operates in two distinct operation modes: lean operation at light engine loads and stoichiometric operation at intermediate and high engine loads. ...The two-mode diesel combustion concept was implemented on a 6.8L medium duty diesel engine and several iterations of the combustion system were evaluated for smoke response and combustion efficiency. The engine was then evaluated over the Non Road Transient Cycle (NRTC) to evaluate performance, emissions and fuel consumption. ...Results show that this novel combustion concept can meet the Tier 4 final emissions regulations without the use of selective catalytic reduction (SCR).

The influence of water injection on the combustion process and raw emissions was analyzed experimentally on a single-cylinder research engine with direct and indirect water injection. Even though water injection initially slows down the combustion process, both injection concepts allow a clear shift in the knock limit and a reduction in the exhaust gas temperature. ...A promising technology to solve these conflicting objectives is the injection of water. Both the indirect and the direct water injection achieve a significant reduction in the load temperature. ...Experimental investigations on particle size distribution in connection with different water injection concepts are not yet known. Water injection strategies are worked out with a variation of the injection parameters.