Compared to widening usage of CNG in commercial gasoline engines, insufficient but increasing number of studies have appeared in the open literature during last decades, while engine characteristic...

Effects of equivalence ratio and CNG addition on engine performance and emissions in a dual sequential ignition engine

This article presents an investigation of air–fuel ratio (AFR) controllers applied to liquefied petroleum gas (LPG) fuelled vehicles with second-generation LPG kits. When a vehicle is running on a down-way, fuel consumption tends to be rich because of the increased vacuum in the intake manifold. Therefore, an AFR controller was developed that can work based on a vehicle’s tilt sensor combined with an oxygen sensor. AFR controllers are employed to regulate injectors to form leaner mixtures. We tested the performance of AFR controller at a typical down-way of 10°, 15°, and 20°. As a result, the AFR controller was able to increase AFR value from an average of 14.5 (without controller) to 15.5–16.2, depending on the gear position and down-way angle. Furthermore, a greater of road slope was observed to have produced greater AFR. This AFR controller is very promising to be applied to vehicles operating in mountainous areas.

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Design and application of air to fuel ratio controller for LPG fueled vehicles at typical down-way

Influence of high compression ratio and hydrogen addition on the performance and emissions of a lean burn spark ignition engine fueled by ethanol-gasoline

Liquefied petroleum gas (LPG), like many other alternative fuels, has witnessed increased adoption in the last decade, and its use is projected to rise as stricter emissions regulations continue to be applied. However, much of its use is limited to dual fuel applications, gaseous phase injection, light-duty passenger vehicle applications, or scenarios that require conversion from gasoline engines. Therefore, to address these limitations and discover the most efficient means of harnessing its full potential, more research is required in the development of optimized fuel injection equipment for liquid port and direct injection, along with the implementation of advanced combustion strategies that will improve its thermal efficiency to the levels of conventional fuels. This paper focuses on the development of a liquid phase port-injection system for LPG, the design of a reference piston, and the baseline evaluation of the performance, combustion, and emissions characteristics of a single cylinder research engine to establish a benchmark comparable to existing LPG engines. A sweep of start of injection (SOI) timing is performed by injecting liquid LPG at several closed and open intake valve timings, which demonstrates no significant variation in engine performance, but accounts for a 10% reduction in bsCO with the optimal SOI timing. Spark timing sweep demonstrates the 50% burn crank angle location related to maximum brake torque (MBT) point with a brake thermal efficiency (BTE) of ~34% for the tested load case. The effect of equivalence ratio is also presented with optimal SOI timing at MBT condition. The engine starts exhibiting knocking combustion at 140kPa intake manifold air pressure (IMAP) with a peak torque of 253Nm and a 5% reduction in brake specific fuel consumption compared to the naturally aspirated scenario.

Performance, Combustion and Emissions Evaluation of Liquid Phase Port-Injected LPG on a Single Cylinder Heavy-Duty Spark Ignited Engine

This paper reports the results of studying the electronic control system designed for a gas internal combustion engine with spark ignition operated on liquefied petroleum gas. A new feature in the control system is the possibility to provide the most effective sequential type of gas fuel injection, in which fuel is injected in a sequence corresponding to the order of operation of the cylinders. The special feature of the designed control system is that a movable voltage distributor (ignition distributor) of the ignition system was modified to ensure sequential injection. The ignition distributor modification involves installing an additional setting disc with one integrated permanent magnet on its drive shaft and an additional Hall sensor on the body of the ignition distributor. This makes it possible to ensure that the electronic control unit receives a signal about the angular position of the camshaft, thereby enabling consistent fuel injection. The principle of operation of the gas engine control system provided by the electronic control unit has been described. The structure of the modified ignition distributor is shown. Tests of the gas engine with a new control system involving the designed electronic control unit Avenir Gaz 37 "B" and the software module "B2" were carried out. The tests confirmed the feasibility of the designed electronic control system, which implies consistent injection of gas fuel. In addition, idling tests have shown that the carbon monoxide and hydrocarbon content in exhaust engine gases is significantly lower than the maximum allowable for motors without catalysts. The control system designed could be used for converting the diesel vehicles in operation into gas engines. The use of this control system ensures their safe operation.

/pdf/design-of-control-system-for-the-gas-engine-with-an-177a7qa3.pdf

Design of control system for the gas engine with an electronic control unit and sequential fuel injection

Gaseous fuels have always been established as an assuring way to lessen emissions in Spark Ignition engines. In particular, LPG resolved to be an affirmative fuel for SI engines because of their efficient combustion properties, lower emissions and higher knock resistance. This paper investigates performance, emission and combustion characteristics of a microcontroller based electronic LPG gaseous phase port injection system. Experiments were carried out in a single cylinder diesel engine altered to behave as SI engine with LPG as fuel at a compression ratio of 10.5:1. The engine was regulated at 1500 rpm at a throttle position of 20% at diverse equivalence ratios. The test results were compared with that of the carburetion system. The results showed that there was an increase in brake power output and brake thermal efficiency with LPG gas phase injection. There was an appreciable extension in the lean limit of operation and maximum brake power output under lean conditions. LPG injection technique significantly reduces hydrocarbon and carbon monoxide emissions. Also, it extremely enhances the rate of combustion and helps in extending the lean limit of LPG. There was a minimal increase of NOx emissions over the lean operating range due to higher temperature. On the whole it is concluded that port injection of LPG is best suitable in terms of performance and emission for LPG fuelled lean burn SI engine.

https://iopscience.iop.org/article/10.1088/1755-1315/40/1/012069/pdf

Porpatham E

Papers

LPG gaseous phase electronic port injection on performance, emission and combustion characteristics of Lean Burn SI Engine