Experimental and computational analysis of the combustion evolution in direct-injection spark-controlled jet ignition engines fuelled with gaseous fuels
- Boretti, Alberto, Paudel, R., Tempia, A.
- Authors: Boretti, Alberto , Paudel, R. , Tempia, A.
- Date: 2010
- Type: Text , Journal article
- Relation: Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering Vol. 224, no. 9 (2010), p. 1241-1261
- Full Text:
- Reviewed:
- Description: Jet ignition and direct fuel injection are potential enablers of higher-efficiency, cleaner internal combustion engines (ICEs), where very lean mixtures of gaseous fuels could be burned with pollutants formation below Euro 6 levels, efficiencies approaching 50 per cent full load, and small efficiency penalties operating part load. The lean-burn direct-injection (DI) jet ignition ICE uses a fuel injection and mixture ignition system consisting of one main-chamber DI fuel injector and one small jet ignition pre-chamber per engine cylinder. The jet ignition pre-chamber is connected to the main chamber through calibrated orifices and accommodates a second DI fuel injector. In the spark plug version, the jet ignition pre-chamber includes a spark plug which ignites the slightly rich pre-chamber mixture which then, in turn, bulk ignites the ultra-lean stratified main-chamber mixture through the multiple jets of hot reacting gases entering the in-cylinder volume. The paper uses coupled computer-aided engineering and computational fluid dynamics (CFD) simulations to provide better details of the operation of the jet ignition pre-chamber (analysed so far with downstream experiments or stand-alone CFD simulations), thus resulting in a better understanding of the complex interactions between chemistry and turbulence that govern the pre-chamber flow and combustion.
- Authors: Boretti, Alberto , Paudel, R. , Tempia, A.
- Date: 2010
- Type: Text , Journal article
- Relation: Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering Vol. 224, no. 9 (2010), p. 1241-1261
- Full Text:
- Reviewed:
- Description: Jet ignition and direct fuel injection are potential enablers of higher-efficiency, cleaner internal combustion engines (ICEs), where very lean mixtures of gaseous fuels could be burned with pollutants formation below Euro 6 levels, efficiencies approaching 50 per cent full load, and small efficiency penalties operating part load. The lean-burn direct-injection (DI) jet ignition ICE uses a fuel injection and mixture ignition system consisting of one main-chamber DI fuel injector and one small jet ignition pre-chamber per engine cylinder. The jet ignition pre-chamber is connected to the main chamber through calibrated orifices and accommodates a second DI fuel injector. In the spark plug version, the jet ignition pre-chamber includes a spark plug which ignites the slightly rich pre-chamber mixture which then, in turn, bulk ignites the ultra-lean stratified main-chamber mixture through the multiple jets of hot reacting gases entering the in-cylinder volume. The paper uses coupled computer-aided engineering and computational fluid dynamics (CFD) simulations to provide better details of the operation of the jet ignition pre-chamber (analysed so far with downstream experiments or stand-alone CFD simulations), thus resulting in a better understanding of the complex interactions between chemistry and turbulence that govern the pre-chamber flow and combustion.
A novel in-vehicle real-time brake-monitoring system
- Fumi, Duncan, Sultan, Ibrahim
- Authors: Fumi, Duncan , Sultan, Ibrahim
- Date: 2009
- Type: Text , Journal article
- Relation: Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering Vol. 223, no. 6 (2009), p. 793-804
- Full Text:
- Reviewed:
- Description: The design of vehicle brake systems involves optimizing a large number of competing parameters. In order to find an appropriate balance of properties, it is important to have a good picture of the range of operating conditions that the system will operate under. Obtaining such information for a large range of driving conditions requires recording data over a long period of time from a number of vehicles under various driving conditions. In this paper, a proposed data acquisition system has been designed, constructed, and implemented to measure and to store in real time the performance-related parameters of brake systems. The system proposed here to monitor brake performance employs a small embedded personal computer together with a number of peripheral cards as its basis. As a part of the validation process, recordings have been made of some long-term test sequences during a brake development programme. The results, which would be considered representative of normal confident driving, are given and discussed at the end of the paper. These results are used to monitor brake performance and do offer valuable guidance for future brake design projects. © IMechE 2009.
- Authors: Fumi, Duncan , Sultan, Ibrahim
- Date: 2009
- Type: Text , Journal article
- Relation: Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering Vol. 223, no. 6 (2009), p. 793-804
- Full Text:
- Reviewed:
- Description: The design of vehicle brake systems involves optimizing a large number of competing parameters. In order to find an appropriate balance of properties, it is important to have a good picture of the range of operating conditions that the system will operate under. Obtaining such information for a large range of driving conditions requires recording data over a long period of time from a number of vehicles under various driving conditions. In this paper, a proposed data acquisition system has been designed, constructed, and implemented to measure and to store in real time the performance-related parameters of brake systems. The system proposed here to monitor brake performance employs a small embedded personal computer together with a number of peripheral cards as its basis. As a part of the validation process, recordings have been made of some long-term test sequences during a brake development programme. The results, which would be considered representative of normal confident driving, are given and discussed at the end of the paper. These results are used to monitor brake performance and do offer valuable guidance for future brake design projects. © IMechE 2009.
Vehicles with cooperative redundant multiple steering systems: Alternative driver interfaces
- Authors: Spark, Ian , Percy, Andrew
- Date: 2015
- Type: Text , Journal article
- Relation: Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering Vol. 229, no. 3 (2015), p. 311-329
- Full Text:
- Reviewed:
- Description: This paper presents the results of calculations of the wheel angles and the drive wheel speeds to ensure that the steering effect of the wheel angles and the steering effect of the speeds of the drive wheels are identical. These calculations are general insofar as the centre of curvature of the path of the centre of the vehicle can lie anywhere in the 'horizontal' plane, including within the plan view of the vehicle. These minimal turning circles at times require large wheel angles and large differences in the drive wheel speeds. When the driver selects a centre of curvature inside the rectangle defined by the wheelbase and the track, problems arise owing to the multiple solutions of the arctan function. This problem is solved so that flipping of the wheels through 180° is avoided. Similar problems can arise in the calculation of the correct wheel speed because of the ambiguity of the square root function, which has both positive and negative roots. This problem is also solved. Alternative driver interfaces are described in detail. Vehicles with cooperative redundant multiple steering systems promise safety benefits relative to vehicles with a single non-redundant steering system and environmental benefits relative to vehicles with conflicting redundant multiple steering systems. The safety benefits result from increased traction, stability and manoeuvrability (especially on hills). The environmental benefits include reduced ground damage, tyre wear and fuel wastage on turning. These vehicles would be used to best advantage as extreme off-road vehicles. The general case of vehicles described is capable of both pure rotation and pure translation in any direction, and all motion in between. This maximized manoeuvrability also makes the system ideal for vehicles operating in confined spaces, such as forklift trucks.
- Authors: Spark, Ian , Percy, Andrew
- Date: 2015
- Type: Text , Journal article
- Relation: Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering Vol. 229, no. 3 (2015), p. 311-329
- Full Text:
- Reviewed:
- Description: This paper presents the results of calculations of the wheel angles and the drive wheel speeds to ensure that the steering effect of the wheel angles and the steering effect of the speeds of the drive wheels are identical. These calculations are general insofar as the centre of curvature of the path of the centre of the vehicle can lie anywhere in the 'horizontal' plane, including within the plan view of the vehicle. These minimal turning circles at times require large wheel angles and large differences in the drive wheel speeds. When the driver selects a centre of curvature inside the rectangle defined by the wheelbase and the track, problems arise owing to the multiple solutions of the arctan function. This problem is solved so that flipping of the wheels through 180° is avoided. Similar problems can arise in the calculation of the correct wheel speed because of the ambiguity of the square root function, which has both positive and negative roots. This problem is also solved. Alternative driver interfaces are described in detail. Vehicles with cooperative redundant multiple steering systems promise safety benefits relative to vehicles with a single non-redundant steering system and environmental benefits relative to vehicles with conflicting redundant multiple steering systems. The safety benefits result from increased traction, stability and manoeuvrability (especially on hills). The environmental benefits include reduced ground damage, tyre wear and fuel wastage on turning. These vehicles would be used to best advantage as extreme off-road vehicles. The general case of vehicles described is capable of both pure rotation and pure translation in any direction, and all motion in between. This maximized manoeuvrability also makes the system ideal for vehicles operating in confined spaces, such as forklift trucks.
A numerical control algorithm for a B-double truck-trailer with steerable trailer wheels and active hitch angles
- Authors: Percy, Andrew , Spark, Ian
- Date: 2012
- Type: Text , Journal article
- Relation: Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering Vol. 226, no. 3 (2012), p. 289-300
- Full Text:
- Reviewed:
- Description: This paper presents a new algorithm for the control of a B-double truck–trailer with steerable trailer wheels and active hitch angles, designed to minimize both off-tracking and scuffing. Each trailer has six autonomously steered double wheels, although each double wheel is modelled by a centrally placed single wheel. Each hitch point, joining truck to first trailer and first trailer to second trailer, as well as a nominated point central to the axles of the second trailer, traverses the same path which is determined by an operator controlling the path curvature and truck speed. The algorithm approximates the ideal solution in which all wheels on each trailer have the same centre of curvature. The actively controlled hitch angles, satisfying the path-following constraints, provide a further level of cooperative redundancy of steering systems. Simulations are carried out to show the effects of changing curvature and front hitch speed on hitch path, wheel angles, and hitch angles as well as the accuracy of the algorithm. Further simulation is carried out to show the improvement in off-tracking of the new control system over current B-double fixed-wheel systems.
- Authors: Percy, Andrew , Spark, Ian
- Date: 2012
- Type: Text , Journal article
- Relation: Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering Vol. 226, no. 3 (2012), p. 289-300
- Full Text:
- Reviewed:
- Description: This paper presents a new algorithm for the control of a B-double truck–trailer with steerable trailer wheels and active hitch angles, designed to minimize both off-tracking and scuffing. Each trailer has six autonomously steered double wheels, although each double wheel is modelled by a centrally placed single wheel. Each hitch point, joining truck to first trailer and first trailer to second trailer, as well as a nominated point central to the axles of the second trailer, traverses the same path which is determined by an operator controlling the path curvature and truck speed. The algorithm approximates the ideal solution in which all wheels on each trailer have the same centre of curvature. The actively controlled hitch angles, satisfying the path-following constraints, provide a further level of cooperative redundancy of steering systems. Simulations are carried out to show the effects of changing curvature and front hitch speed on hitch path, wheel angles, and hitch angles as well as the accuracy of the algorithm. Further simulation is carried out to show the improvement in off-tracking of the new control system over current B-double fixed-wheel systems.
A numerical control algorithm for a B-double truck-trailer with steerable trailer wheels and active hitch angles. Part 2: reversing
- Authors: Percy, Andrew , Spark, Ian
- Date: 2013
- Type: Text , Journal article
- Relation: Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering Vol. 227, no. 6 (2013), p. 899-904
- Full Text:
- Reviewed:
- Description: The authors have previously proposed a solution to the twin problems of wheel scuffing and off-tracking of B-double truck–trailer vehicles thereby reducing tyre wear and environmental damage as well as improving maneuverability. The solution to the scuffing problem requires that trailer axles in excess of one per trailer must have steerable wheels. However, if all trailer wheels are steerable, then the off-tracking problem can also be solved. The previous work devised an algorithm for a B-double in forward motion, whereby an on-board computer would be used to calculate the correct wheel and hitch angles and a control system would implement these angles. The purpose of the present technical note is to complete the study of a numerical algorithm for navigating a B-double truck–trailer vehicle by considering travel in the reverse direction. In this case the angle of the front wheels of the truck must also be controlled by the on-board computer. The algorithm for determining the effective angle of the truck’s steerable wheels is derived using an innovative combination of vector geometry and calculus and completes the total control system for these B-double vehicles. The paper concludes with a simulation study of the control algorithm demonstrating its versatility for reversing along twisting paths and effectiveness in reducing off-tracking.
- Authors: Percy, Andrew , Spark, Ian
- Date: 2013
- Type: Text , Journal article
- Relation: Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering Vol. 227, no. 6 (2013), p. 899-904
- Full Text:
- Reviewed:
- Description: The authors have previously proposed a solution to the twin problems of wheel scuffing and off-tracking of B-double truck–trailer vehicles thereby reducing tyre wear and environmental damage as well as improving maneuverability. The solution to the scuffing problem requires that trailer axles in excess of one per trailer must have steerable wheels. However, if all trailer wheels are steerable, then the off-tracking problem can also be solved. The previous work devised an algorithm for a B-double in forward motion, whereby an on-board computer would be used to calculate the correct wheel and hitch angles and a control system would implement these angles. The purpose of the present technical note is to complete the study of a numerical algorithm for navigating a B-double truck–trailer vehicle by considering travel in the reverse direction. In this case the angle of the front wheels of the truck must also be controlled by the on-board computer. The algorithm for determining the effective angle of the truck’s steerable wheels is derived using an innovative combination of vector geometry and calculus and completes the total control system for these B-double vehicles. The paper concludes with a simulation study of the control algorithm demonstrating its versatility for reversing along twisting paths and effectiveness in reducing off-tracking.
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