Browse Topic: Superchargers
The combustion timing of auto-ignited combustion is determined by composition, temperature, and pressure of cylinder charge. Thus, for a successful auto-ignition, those key variables must be controlled within tight target ranges, which is challenging due to (i) nature of coupling between those variables, and (ii) complexity of managing multiple actuators in the engine. In this article, a control strategy that manages multiple actuators of a boosted homogeneous charge compression ignition (HCCI) engine is developed to maintain robust auto-ignited combustion. The HCCI engine being considered is equipped with multiple boosting devices including a supercharger and a turbocharger in addition to conventional actuators and sensors. Since each boosting device has its own pros and cons, harmonizing those boosting devices is crucial for successful transient operation. To address the multi-variable transient control problem, speed-gradient control methodology is applied to minimize coupling between boosting devices. Simulation results show that the control strategy overcomes turbo lag by utilizing the supercharger during transient. The controller developed is still appliable to manage multiple boosting devices with conventional engines as well as HCCI engine.
Waste Heat Recovery is one of the major opportunities to increase the engine efficiency in internal combustion engines (ICE) for the transportation sector and to meet the emissions targets. ORC-based units are widely investigated, in particular for heavy duty vehicles and light commercial ones. However, when a typical operation of the ICE on a vehicle is considered, working temperature and exhaust flow rates are not always suitable for recovery, being characterized by low-grade enthalpy. Volumetric expanders are among the most suitable technological solutions for small scale ORC-based power units, but they can suffer of low efficiency in real operation. A way to improve its performances is represented by a supercharging technique, which involves a further intake port. Indeed, keeping constant the mass flow rate provided by the pump, the dual-intake expander produces a reduction of the intake pressure with a mechanical power similar to the single intake machine, thanks to a higher permeability. This aspect can enhance the expander operability in off design conditions, which is particularly interesting when the hot source is represented by the exhaust gases of an ICE. In fact, the mass flow rate circulating inside the ORC-based recovery unit can increase, in order to recover more thermal power. In fact, keeping constant the intake pressure of the dual-port intake expander, a higher mass flow rate can be elaborated with respect to the single-intake port. In this paper, a combined theoretical and experimental activity has been done, reproducing real ICE operations in a small-scale ORC test bench fed by exhaust gases of a 3L turbocharged diesel engine and prototyping the supercharged expander. In this way, the benefits related to the additional port are assessed in real engine working points, compared to the single port one and introducing further developing paths.
The supercharged spark ignition engine (SI engine) has a problem of abnormal combustion. It is called Low Speed Pre-ignition (LSPI). The lubricating oil which has a tolerance for LSPI has been introduced already in automobile market nowadays. However, cause and mechanism of LSPI does not clear sufficiently. It has been reported that the peculiar behavior of LSPI corresponded with behavior of lubricating oil from piston crown [1, 2]. This paper focuses on effect of fuel ingredients on autoignition of a lubricating oil droplet about LSPI. On the ignition source point of view, it is important to clear the mechanism of a lubricating oil droplet autoignition in cylinder. This paper will be tried to clear its mechanism fundamentally by using of electric furnace which is heated an oil droplet. As a result, the activation energy E is found for quantitative evaluation of ignition sauce of LSPI. The experimental data which is heated a lubricating oil droplet by electric furnace show concentration of fuel in an oil droplet is strongly effect on autoignition compared with octane number. The effect of octane number with fuel is little for LSPI on the autoignition of a lubricating oil droplet. More than 30% concentration of fuel in lubricating oil occur autoignition remarkably. It is confirmed that carbon number of fuel ingredients effect strongly on autoignition. These experimental results are evaluated by the calculation with Livengood-Wu integral. The activation energy which is under 6200 [×10^4 J/mol] is dangerous region of autoignition of lubricating oil droplet for abnormal combustion as LSPI. The calculated results suggest that there is safety condition under low speed and high boost operation.
A 2-stroke boosted uniflow scavenged direct injection gasoline (BUSDIG) engine was researched and developed at Brunel University London to achieve higher power-to-mass ratio and thermal efficiency. In the BUSDIG engine concept, the intake scavenge ports are integrated to the cylinder liner and controlled by the movement of piston top while exhaust valves are placed in the cylinder head. Systematic studies on scavenging ports, intake plenum, piston design, valve opening profiles and fuel injection strategies have been performed to investigate and optimise the scavenging performance and in-cylinder fuel/air mixing process for optimised combustion process. In order to achieve superior power performance with higher thermal efficiency, the evaluation and optimisation of the boost system for a 1.0 L 2-cylinder 2-stroke BUSDIG engine were performed in this study using one dimensional (1D) engine simulations. The results show that the engine exhaust valve opening (EVO) timing and exhaust duration (ED) are key parameters affecting the engine performance with the single-stage turbocharging (T). By using an earlier EVO timing of 80 0CA and a longer ED of 140 0CA, a maximum brake power of 130.7 kW could be achieved at 3200 rpm and peak torque output of 488 N*m at 1600 rpm. Simulations were also performed to evaluate the engine performance with combined boost systems with a supercharger upstream the turbocharger (S-T) and a turbocharger upstream the supercharger (T-S). The results indicate that the combined boost systems increase both engine power and torque compared to the single-stage turbocharging system. In particular, the peak brake power and torque of the 1.0 L BUSDIG engine could reach 143.7 kW at 4000 rpm and 492 N*m at 800 rpm with the S-T setup.
To meet the requirements of sustainable development, car environmental impacts must be assessed at all stages of its life: from designing, through its manufacture and use, to its recycling after use. Life-cycle assessment (LCA) makes it possible. This approach to environmental assessment is necessary, particularly in assessment of new technologies of electric powertrain, where most environmental impacts are shifted from the use stage to production. Reliable and possibly the most recent data are required on materials and production processes to develop a valid flow model. Ecoinvent inventory database is a commonly used source of reliable data. However, Ecoinvent provides data about Golf 4 (1,240 kg), a compact class car. The ratio of glider and drivetrain is therefore optimized for that class. Using the dataset for other vehicle classes by simply considerably increasing or decreasing the total vehicle mass may lead to imprecise results. There is no mathematical relationship that would link parameters of body and powertrain when they change, when modelling a desired vehicle. The paper presents inventory results of production stage of cars substantially different from Golf 4 in terms of mass. For comparison purposes, we kept the modular character of material data, with division into body and powertrain. Significant differences were observed in the mass of materials, particularly for powertrains of vehicles with greater total mass. However, more research on a larger sample is necessary. We expect to find significant differences in data about materials particularly in the case of new powertrain systems working together with supercharged spark and diesel engines.
Although supercharged system has been widely employed in downsized engines, the effect of supercharging on the intake flow characteristics remains inadequately understood. Therefore, it is worthwhile to investigate intake flow characteristics under high intake pressure. In this study, the supercharged intake flow is studied by experiment using steady flow test bench with supercharged system and transient flow simulation. For the steady flow condition, gas compressibility effect is found to significantly affect the flow coefficient (Cf), as Cf decreases with increasing intake pressure drop, if the compressibility effect is neglected in calculation by the typical evaluation method; while Cf has no significant change if the compressibility effect is included. Compared with the two methods, the deviation of the theoretical intake velocity and the density of the intake flow is the reason for Cf calculation error. For the transient intake condition, such increase of intake flow velocity with increasing intake pressure was found to be valid only at low engine speeds (2000 rpm). At high engine speeds (4000 rpm), however, flow velocity remains almost unchanged regardless of the intake pressure. This implies that flow velocity is determined by the effective pressure difference across the intake ports, which is synergistically controlled by the initial intake pressure difference and the piston wall confinement, during early intake process, while the intake velocity is restricted by the piston motion speed in the middle and later intake stroke. As such, the increased intake mass in cylinder is mainly resulted from the larger intake gas density rather than the higher flow velocity in supercharged engines. Furthermore, the supercharging may cause a high Ma for high engine speed round the valve seats and valve stems at low valve lift; while the engine speed is the main reason for high Ma intake flow under intake process at high valve lift.
There's the old saw about a something being better than the sum of its parts. That phrase applies to the 2020 Ford Mustang Shelby GT500 - despite most of its parts being categorically bombastic. Its performance far exceeds any old-school ponycar yardstick, but those expecting a straight-line brute will be surprised. The Shelby GT500's sublime chassis stands it more in the company of powered-up Porsches than howling Hellcats. The supercharged “Predator” 5.2-L V8's stun-grenade numbers - SAE-rated 760 hp and 625 lb-ft (847 Nm) - might logically be blamed for perpetuating any perceptions of the Shelby GT500 as one-trick musclecar. It's the “most power-dense V8 in America,” boasts Mustang chief engineer Carl Widman. The backstory is nearly as good as the raw performance: it was long assumed that the Predator would be a supercharged variant of the heralded and high-revving 5.2-L “Voodoo” flat-plane-crankshaft V8 that debuted in 2015's Mustang Shelby GT350. Instead, engineers fitted a conventional cross-plane crank and changed nearly every internal component, retaining only the basic architecture from the Voodoo.
You don't get a second chance to make a first impression. That's why Polestar, Volvo's new electric performance subsidiary, used its first vehicle as a rolling showcase of the brand's technology. We took the $156,500, 600-plus-horse-power plug-in hybrid (PHEV) Polestar 1 coupe on a 110-mi (177-km) drive in California, where Axle Stenberg, technical concept leader, summarized the Polestar 1's extraordinary recipe. “First you take an SPA car,” he said, referring to Volvo's Scalable Product Architecture (SPA), the platform underpinning the XC90, XC60 and S90. “Now you add the biggest combustion engine we had.” That means a supercharged/turbocharged 2.0L 4-cylinder mill that produces 326 hp (243 kW) and 384 lb-ft (521 Nm). The internal-combustion power is distributed strictly to the front axle via an 8-speed automatic gearbox. “Then we added as much battery as we could fit.”
Aiming at the high altitude operation problems for piston-type aero-engines and to improve the practical ceiling and high altitude dynamic performance, this thesis analyzes a controllable three-stage composite supercharging system, using a two-stage turbocharger coupled supercharger method. The GT-Power simulation model of a four-cylinder boxer engine was established, and the control strategy of variable flight height was obtained. The simulation research of engine performance from 0 to 20,000 meters above sea level has been carried out, which shows that the engine power is at the same level as the plain condition, and it could still maintain 85.28 percent of power even at the height of 20,000 meters, which meets the flight requirements of the aircraft.
Valeo is an industry leader in technologies essential to vehicle electrification and connected/automated driving. The French Tier 1 pioneered 48V mild-hybrid systems and is a major producer of e-hardware and software including belt-starter generators, power electronics, electric superchargers and traction motors. Valeo recently entered a collaboration with Dana Inc. to develop and supply electrified AWD systems featuring 48-V hybrid power. The first of these is scheduled to launch in volume in early 2020 with a major European OEM. One of the architects of Valeo Group's steady evolution as a mobility-tech supplier is Guillaume Devauchelle, vice president of Innovation & Scientific Development. He joined Valeo in 2000 after the acquisition of Italy-based wiring harness maker Sylea where he served as VP of R&D. Monsieur Devauchelle recently spoke by phone with editor-in-chief Lindsay Brooke.
The demanding CO2 emission targets are fostering the development of downsized, turbocharged and electrified engines. In this context, the need for high boost level at low engine speed requires the exploration of dual stage boosting systems. At the same time, the increased electrification level of the vehicles enables the usage of electrified boosting systems aiming to exploit the opportunities of high levels of electric power and energy available on-board. The aim of this work is therefore to evaluate, through numerical simulation, the impact of a 48 V electric supercharger (eSC) on vehicle performance and fuel consumption over different transients. The virtual test rig employed for the analysis integrates a 1D CFD fast running engine model representative of a 1.5 L state-of-the-art gasoline engine featuring an eSC in series with the main turbocharger, a dual voltage electric network (12 V + 48 V), a six-speed manual transmission and a vehicle representative of a B-SUV segment car. The evaluation tests chosen for the case study were, on the one hand, vehicle elasticity manoeuvres for the performance assessment and, on the other hand, type approval and RDE driving cycles, for the fuel economy assessment. An evaluation of possible engine and vehicle hardware modifications was also carried out. In particular, the effects of a variation of the final drive ratio, of the increase of the turbine size and of the usage of a high efficiency engine concept (featuring an increased compression ratio from 10 to 12 and a late intake valve closing, exploiting the advantages of a Miller cycle) were investigated. The introduction of a 48 V electric supercharger on a gasoline passenger car was shown in the selected test cases to lead to up to 16% reduction of the elasticity time and up to 9% improvement in fuel consumption when the high efficiency engine concept was considered.
Small single & two cylinder diesel engines, still have primitive technical design features and extensively used in India and various Asian countries to power small and light motor vehicles viz., three wheelers, light duty four wheelers. These vehicles have become inevitable for the transport for both urban and rural areas. Vehicles with small single & two cylinder engines have high market demand in commercial transport due to restrictions on entry of Heavy Commercial Vehicles (HCV) in congested cities roads. Due to ever rising market demand for higher power and torque requirement along with better fuel economy, vehicle manufacturer are developing high Brake Mean Effective Pressure (BMEP) engines or replacing single cylinder engine by two cylinder engine, similarly two cylinder engine by three cylinder engines. Further, these engines should meet the present and forthcoming stringent emission limits. Single cylinder and two cylinder small diesel engines are widely used in various applications like Light Commercial Vehicle (LCV), power generation, three wheelers, agricultural machines and small house-hold applications in India as well as other Asian countries. Therefore simple mechanically controlled components are used for these engines which make them simple in operation with low maintenance and cost effective. Several studies & research work so far conducted on these small single engine have revealed that, successful & economically acceptable turbocharging of single cylinder diesel engine is not yet achieved. This is due to its phase mismatch between intake and exhaust stroke timings, long gap between two exhaust stroke and continuous flow of exhaust gas to drive the turbine wheel efficiently. This paper addresses the problems through mechanical supercharging. For this research work, a small 0.4 liter, three wheeler (3W), naturally aspirated, air-cooled, single cylinder DI diesel engine, equipped with mechanical fuel injection system, is used. A roots type supercharger, driven mechanically from a drive pulley directly mounted on crankshaft, is used for boosting the engine. Experiments were conducted with various engine parameters, settings and step-up ratios of the drive pulley. The results show an observed increase in engine power more than 20 % throughout the full load curve and favorable emission levels with respect to the base BS III compliant single cylinder engine. The experimental outcomes and reviews which are required to arrive at adequate boosting to enhance the performance & emissions of the engine are reported.
This document discusses formulae considered applicable to aircraft engines having integral supercharging without aftercooling, and using gasoline introduced at the entrance to the supercharger or directly into the cylinders. Such engines are normally designated as single and two speed engines. Correction formulae for engines having two stage or exhaust turbo supercharging will not be discussed. Corrections for engines having a high degree of integral supercharging will be discussed in general terms only and no specific formulae will be presented. The correction formulae and methods listed are empirical and subject to error due to conditions beyond the scope of known corrections. Usage has indicated, however, that the correction formulae listed will provide a satisfactory approximation of power output under standard conditions.
This document lists definitions that are commonly used in describing aircraft reciprocating engine performance.
This paper provides insight into the tradeoffs between exhaust energy recovery and increased pumping losses from the flow restriction of the electric turbo-generator (eTG) assessed using thermodynamic principles and with a detailed GT-Power engine model. The GT-Power engine model with a positive displacement expander model was used to predict the influence of back pressure on in-cylinder residuals and combustion. The eTG is assessed for two boosting arrangements: a conventional turbocharger (TC) and an electrically assisted variable speed (EAVS) supercharger (SC). Both a low pressure (post-turbine) and high pressure (pre-turbine) eTG are considered for the turbocharged configuration. The reduction in fuel consumption (FC) possible over various drive cycles is estimated based on the steady-state efficiency of frequently visited operating points assuming all recovered energy can be reused at an engine efficiency of 30% with 10% losses in the electrical path. On the city FTP and US06 cycles, the EAVS SC engine benefits more than the turbocharged from adding the eTG. The opposite is observed for the highway cycle where adding the eTG causes greater fuel consumption reductions for the turbocharged engine. Boost reserve in the TC case at low load, however, makes the EAVS SC with eTG (boost-by-wire) a better boosting and energy recovery system overall with reductions in FC up to 1.4%, 2.4% and 4.6% relative to the TC engine over the FTP, highway and US06 cycles respectively.
Items per page:
50
1 – 50 of 304