Browse Topic: Water pumps
Cooling system for an IC engine, consisting of the Water pump (WP), Radiator and Fan, plays an important role in maintaining thermal efficiency of the engine and protects the engine from overheating. Based on the vehicle application requirement, Fan will be mounted directly either on Crankshaft or WP pulley. But wherever increase in Fan speed ratio are in demand, it is preferred to mount the Fan on WP pulley. So it important to understand the WP housing structural strength with respect to vibration loads contributed from Radiator Fan assembly. This paper presents investigation of Failure of WP Housing during engine validation at engine test bed with Electronic Viscous Fan, based on the different operating conditions of the engine and fan as per the validation cycle. While the accessories are loading and the corresponding stresses are high when the fan is engaged. But in the current case, the failure of WP housing happened only during Fan clutch disengaged condition. Experimental Frequency Response Function (FRF) were carried out to identify the mode shapes and resonant frequencies. Vibration on WP housing were compared with Fan engaged and disengaged condition to identify the critical frequency ranges that minimize vibrational impacts on the WP housing. The results indicate a significant correlation between Fan Blade Pass Frequency (FBPF) and vibrational amplitude on WP housing. By optimizing FBPF, it is successfully mitigated high vibration levels, thereby enhancing the structural integrity and operational reliability of the WP housing. In addition, the results of crack initiation points, strain gauge measurements, structural and modal analyses are examined to enhance the WP housing strength.
This document provides an overview on how and why EGR coolers are utilized, defines commonly used nomenclature, discusses design issues and trade-offs, and identifies common failure modes. The reintroduction of selectively cooled exhaust gas into the combustion chamber is just one component of the emission control strategy for internal combustion (IC) engines, both diesel and gasoline, and is useful in reducing exhaust port emission of nitrogen oxides (NOx). Other means of reducing NOx exhaust port emissions are briefly mentioned, but beyond the scope of this document.
Proton exchange membrane fuel cell has received extensive attention from different industries due to its advantages such as high efficiency, high energy density, and clean emissions. However, performance at low temperature is still one of the key factors that restricted its wide commercialization. To study the internal water state of the fuel cell at low temperature and verify different cold-start strategies, a fuel cell test platform that can simulate a low-temperature environment is needed. As the power of the stack grows, the impact of the size of a membrane and the impact of the number of single cells can’t be negligible. Meanwhile, the mutual influence between adjacent single cells at low temperatures is also worth studying. However, a test platform for high-power fuel cell stack with the ability to simulate a sub-freezing temperature is currently lacking. Thus, in this work, a 10kW-class fuel cell test platform is designed. This test platform includes a gas supply and exhaust module, a thermal management module, a control module, as well as an external humidification module, and an impedance measurement module. In addition to coolant circulation control in the thermal management module of the test platform, a refrigeration unit that can control the temperature of the gas and coolant is also specially designed to simulate a low-temperature environment. In the end, a set of verification experiments were carried out. The experimental results prove that this test platform can already meet the design requirements.
Power density (power/engine cubic capacity) of the latest passenger car Diesel and Gasoline engine keeps increasing with a focus to deliver best in class performance along with meeting CAFE and emission norms. This increase in power density increases the thermal load onto the coolant system. Coolant temperature sensor monitoring the coolant temperature, proper radiator sizing, optimum water pump flow capacity and thermostat tuned to the required coolant temperature range are the typical measures taken to ensure safe operation of the engine and avoid any over-heating. Typical cooling system failures are mostly due to low coolant level, a defective thermostat, non-operative water pump & fan and blockage in the coolant circuit, etc. Most of these failures can be detected with the help of a coolant temperature sensor and pre-emptive measures can be taken to avoid engine loss. However, in the event of complete loss of coolant in the engine, the coolant temperature sensor will become ineffective since there is no coolant in contact with the sensor probe. This paper presents an experiment that was conducted to see the effect of operating the IC engine without coolant. It is to be noted that the probability of a customer running a vehicle without having coolant at all is very less since he will be able to see overheating alarm in the cluster as soon as the coolant starts leaking. This experiment is conducted to assess the robustness of a system if it is run without coolant. There are several failures expected due to the running of an engine without coolant such as cylinder head gasket failure causing leakage of oil and gas, piston seizure, bearing seizure etc. It was noticed during the test that the coolant temperature sensor fails to detect the engine running in overheated condition and an eventual head gasket failure. The interesting part of this experiment is the consequential effects of this head gasket failure. Root cause analysis was performed to find the nature of the engine failure. Control measure to prevent catastrophic failure was designed and verified experimentally. Finally, a failsafe feature was suggested to prevent engine loss due to such failure.
Extensive experimental investigations done over a decade in different engine types demonstrated the capability of achieving high efficiency along with low levels of oxides of nitrogen (NOx) and soot emissions with low temperature combustion (LTC) modes. However, the commercial application of LTC strategies requires several challenges to be addressed, including precise ignition timing control, reducing higher unburned hydrocarbon (UHC) and carbon monoxide (CO) emissions. The lower exhaust gas temperatures with LTC operation pose severe challenges for after-treatment control systems. Among the available LTC strategies, Reactivity Controlled Compression Ignition (RCCI) has emerged as the most promising strategy due to better ignition timing control with higher thermal efficiency. Nevertheless, the complexity of engine system hardware due to the dual fuel injection system and associated controls, high HC and CO emissions are the major limiting factors in RCCI. Homogeneous Charge with Direct Injection (HCDI) strategy is recently proposed to address the above limitations of RCCI. Unlike RCCI, HCDI is a single fuel LTC strategy with port and direct injection of diesel fuel, and thus, there is no reactivity stratification. However, the equivalence ratio and thermal stratification with direct-injected (DI) diesel fuel result in better combustion control lower HC and CO emissions in HCDI. The HCDI strategy is investigated with multiple injections of direct-injected (DI) fuel to examine the benefits in the present work. A production light-duty diesel engine used for agricultural water pumping applications is modified to run in HCDI mode through suitable changes in the intake manifold and fuel injection system. Experiments are conducted at the rated engine speed under varying load conditions in conventional diesel combustion (CDC), HCDI with single and double pulse DI modes. The results obtained show that at 4.6 bar imep, the indicated thermal efficiency is increased by 3.9% compared to CDC. However, NOx emissions are increased from 2.7 g/kW-hr to 13.41 g/kW-hr, CO increased from 2.8 g/kW-hr to 10.49 g/kW-hr, but UHC decreases drastically from 4.18 g/kW-hr to 0.10 g/kW-hr in single DI pulse HCDI. In the case of double-pulse HCDI at 3.5 bar imep, indicated thermal efficiency increases by 5.5%, CO decreases by 13%, UHC increase by 48%, smoke increase by three times, and NOx increase by 49.7% in comparison of single pulse HCDI.
BYD recently introduced its new DM-i (Dual Mode-Intelligent) plug-in hybrid architecture with a new dedicated 1.5NA (Naturally Aspirated) high-efficiency engine, which can reach a peak of 43% brake thermal efficiency. With this architecture, the vehicle is mainly driven by motors and engine only starts when required. This requires that once started, the engine can reach its best working temperature as quick as possible. To achieve this target, a new intelligent thermal management system was designed. This system adopted an advanced split cooling strategy to control the flow ratio between cylinder block and head, which was realized by the combination of one electronic thermostat and one wax thermostat. An electronic water pump was used to actively control the coolant flow rate. Together with the intelligent control of thermal needs under all working conditions, the new thermal management system realized the following benefits: faster engine warm-up, better fuel economy and lower pollutant emissions. 1D (One Dimensional) simulation was used to optimize the flow ratio between cylinder block and head. By analyzing the flow distribution, temperature level and pressure drop of each component in the HT (High Temperature) loop and LT (Low Temperature) loop, the cooling performance of this new thermal management system was evaluated and optimized. 3D (Three Dimensional) simulation was used to optimize the flow channel design. Finally, the performance of the thermal management cooling system was validated on the engine test bench and the coolant temperature was calibrated for the whole engine map.
During hot ambient, the cabin temperature of vehicle undergoing soaking may rise up to 70oC. Warm temperature and seats often turn uncomfortable to the passenger. The high temperature may result in thermal degradation of various plastic components, which in turn may release hazardous gases [2]. Usual practice to improve air quality inside the cabin includes switching on the air conditioning while keeping the window panes open. Such a practice minimizes the stabilization time to achieve comfortable cabin temperature. However, significant power requirement by the air-conditioning system during cool down cycle results in excess fuel consumption [7]. To eliminate these problems, the SOLAR POWERED INCABIN EVAPORATIVE COOLING SYSTEM can be installed in the car. This system uses a solar panel which converts the Solar energy into the Electrical energy. This energy can be used to recharge small battery or can be directly used to give necessary power for the cooling system. System includes compact intelligent water cooler with low wattage fan motor & water pump and honeycomb cooling pad with extra water retention capacity. Cool air is circulated in the car which reduces the temperature in the car cabin, to a level which is comfortable to the occupant. System works on very low Power consumption. It is different from system that includes high power consuming parts like Electrical Compressor or Thermo-electric cooling module. This helps in saving time in getting cooling effect, even when the car is left parked in the open sunny environment at high ambient temperature.
The dynamic effects of a coolant flow rate variation on knock tendency are experimentally investigated on a small S.I. engine. The analysis concerns the transient response of the unburned gas temperature and the knock onset to a step variation in load and coolant flow rate. This phenomenological investigation aims at preventing knock through a proper thermal management as an efficient alternative to the currently adopted strategies. Moreover, the proposed approach may result particularly useful for hybrid-electric powertrain, where the engine is expected to operate in the highest efficiency region by adopting high compression ratios and full stoichiometric map. The analysis is carried out through an experimental campaign, where the control of cylinder wall temperature is achieved by means of an electrically driven water pump. The spark advance and the air/fuel ratio have been properly varied in order to operate with advanced spark timing and stoichiometric mixture at full load. A comparison with the standard conditions involving the adoption of the belt-driven pump and the production ECU combustion parameters is included. Results demonstrate that, under transient conditions, an increase in coolant flow rate retards the knock onset, thus allowing the adoption of higher spark advance and the use of stoichiometric mixture at full load. Under these conditions, an increase in engine efficiency of about 3%, without penalizing engine performance, is achieved.
Fuel consumption reduction and CO2 emissions saving are the present drivers of the technological innovation in Internal Combustion Engines for the transportation sector. Among the numerous technologies which ensure such benefits, the role of the cooling pump has been recognized, mainly referred to the possibility to improve engine performances during warm up. During engine homologation, an additional benefit on the fuel consumption can be also reached reducing the energy demand of the pump. In fact, during the cycle, propulsion power requested by the vehicle is low and the importance of the energy absorbed by the pump became significant, since the pump operates far from its maximum efficiency. Indeed, the pump is usually designed at high load working point (Best Efficiency Point, BEP), where the cooling request is maximum: starting from these design conditions, when the pump operates at lower engine coolant requests (as it happens very frequently and more specifically during the homologation cycle of the engine), its efficiency can be very low. This aspect invites pump designer to take care about the choosing of the design point, privileging engine operating points which are more frequent during real operation. In this paper, a dynamic test bench for engine coolant pumps has been developed and engineered. It has been linked to a software procedure which evaluates, according to a vehicle’s mission profile, the propulsion power of the vehicle, the engine speed and, definitively, the pump speed. The knowledge of the cooling circuit and, specifically, the pressure-flow rate relationship of the circuit, allows the calculation of flow rate and pressure delivered in each point of the mission. From the pump efficiency, the instantaneous mechanical power requested by the pump can be calculated, i.e. that subtracted from the engine. The integral of this instantaneous power allows the calculation of the energy requested by the engine over the sequence of operation. The dynamic pump test bench allows to reproduce the real working condition of the pump for a specific sequence of engine operating conditions, and in particular, when this sequence is represented by a homologation WLTP, the one on which emissions and CO2 are measured and referred to an unit of distance (passenger or light duty vehicles). When a Real Driving is specified (as it happens to evaluate the emissions in real driving, RDE), the test bench is able to reproduce the real sequence of operation of the pump as, consequently, the measurement of all relevant quantities. An electrical water pump was designed following the new design concept over a WLTC cycle. Thanks to the comparison between electric and the hydraulic cumulated energy, efficiency of the pump was identified during dynamic working conditions. These experimental results claimed the necessity of a novel design of the pump having resulted an average propulsion power of the pump over the WLTP 10 % lower than the value which would be associated to a pump designed at its BEP when the engine power is maximum.
By the year 2020, EU legislation limits CO2 emissions for new passenger cars to a maximum of 95 g/km, and further reductions to 68 g/km are expected. An electric motor (e-motor) with high power density often requires shaft cooling in combination with increased rotational speeds to boost efficiency. Especially, low friction and durability of sealing faces are essential to overcome severe friction under high-speed rotation. This challenge can be resolved by using the revolutionary GlideXTM sealing technologies, featuring advanced surface-texturing that enables microscopic flow control in dynamic sealing faces. The surface-textured mechanical seal can reduce leakage to the level of insignificance and up to 90% less friction, compared to a non-textured seal. The advanced texturing produces a thin liquid-sealing film between sealing faces, and liquid-lubrication becomes dominant at low speeds; at high speeds, gas-lubrication becomes dominant by manipulating liquid ingress into sliding surfaces. As a result, the textured seal can maintain low friction even at very high-speed rotations, taking advantage of air as less viscous lubricant. Low friction promotes less wear, more service life, and less power/fuel consumption. Less power consumption helps higher battery range; lower friction leads to a reduction in CO2 emissions compared to ICE (Internal Combustion Engine) and hybrid vehicles. The proposed sealing technologies can be used for applications like ORC (Organic Rankine Cycle) compressors, water pumps, e-motor shaft cooling, reduction gear sealing, fuel cell compressors, and more. Herein, development of ultra-low-friction and zero-leakage mechanical seal for high-speed e-motor shaft is explained. Both numerical calculations and experiments are performed to confirm fluid film thickness, friction coefficient, and amount of leakage. Furthermore, application examples for e-motor shaft cooling system, reduction gearbox, and electric water pumps are introduced.
This paper explains the methodology to design a high power-density diesel engine capable of 180 bar peak firing pressure yet achieving the lowest level of mechanical friction. The base engine architecture consists of an 8 mm crank-offset which is an optimized value to have the lowest piston side forces. The honing specification is changed from a standard plateau honing to an improved torque plate slide honing with optimized surface finish values. The cumulative tangential force of the piston rings is reduced to an extreme value of 28.5 N. A rectangular special coated top ring and a low-friction architecture oil ring are used to reduce the friction without increasing the blow-by and oil consumption. A special low-friction coating is applied on the piston skirt in addition to the optimized skirt profile to have reduced contact pressure. The piston pin is coated with diamond-like carbon (DLC) coating to have the lowest friction. The main bearing and crankpin diameter and width are optimized to have the lowest friction yet meeting the bearing unit-load and oil film thickness requirements. A unique oil supply concept is introduced to reduce the oil flow through the main bearings by 24%. The oil pump is driven by a chain to reduce the operating speed and rotor diameter and inertia. Water pump efficiency is improved by adopting a closed-vane curved impeller and low-friction bearing. Chain guides are designed with polyamide 46 (PA46) material to reduce the friction; low friction coating on the chain links is used for further friction reduction. A low-friction single-plunger fuel injection pump (FIP) is used in place of a 3-plunger pump. Engine oil with special additives is used to reduce the cold-friction yet maintaining the required dynamic viscosity at high temperatures. Overall, the final measurement results confirm that the overall engine friction is measured to be about 0.806 bar at a motoring speed of 2000 rpm at 90 deg.C. coolant and oil temperature. The authors give further insight into the future friction reduction potentials which include further reduction of oil ring tension (5N), belt system tension reduction by using an over-running alternator decoupler (OAD), the introduction of variable oil pump, switchable piston cooling jets and switchable water pump. With these measures, it is estimated that the engine friction can be further brought down to an ultra-low value of about 0.680 bar.
Diesel engine is the main source of power for many agricultural applications such as water pump sets, compressors and tractors. At the same time it is also the main source of vibrations. Mechanical vibrations have instantaneous and long term effects on human body. Kinds of effects depend upon duration of exposure and frequency of vibrations. The increasing demands of improved comfort levels of operators are putting pressures on tractor manufacturers on reducing the vibration levels which thereby resulting in improving diesel engine vibrations. Vibration is the movement or mechanical oscillations about an equilibrium position of a machine or component. A Vibration analysis is about the art of looking for changes in the vibration pattern and then relating those changes. Vibration always occurs when there is unbalanced body in reciprocating or rotary motion. In an internal combustion engine there are many parts in reciprocating and rotary motion such as pistons, connecting rod, crankshaft, flywheel etc. This paper explains the study carried out to evaluate combined effect of location of unbalance in individual components when they are assembled and work as a system. This study was carried out to assess the impact of change in of vibration pattern from Lateral to Vertical, Change of location of an eccentric mass, changes in acceleration/displacement pattern with different percentage of balancing
Reactivity-controlled compression ignition (RCCI) is a dual fuel low temperature combustion (LTC) strategy which results in a wider operating load range, near-zero oxides of nitrogen (NOx) and particulate matter (PM) emissions, and higher thermal efficiency. One of the major shortcomings in RCCI is a higher unburned hydrocarbon (HC) and carbon monoxide (CO) emissions. Unlike conventional combustion, aftertreatment control of HC and CO emissions is difficult to achieve in RCCI owing to lower exhaust gas temperatures. In conventional RCCI, an early direct injection (DI) of low volatile diesel fuel into the premixed gasoline-air mixture in the combustion chamber results in charge stratification and fuel spray wall wetting leading to higher HC and CO emissions. To address this limitation, a homogeneous charge reactivity-controlled compression ignition (HCRCCI) strategy is proposed in the present work, wherein the DI of diesel fuel is eliminated. HCRCCI strategy is achieved by inducting diesel and gasoline vapor along with inlet air in the intake manifold during the suction stroke, and the premixed diesel-gasoline-air mixture is autoignited during the compression stroke. Unlike RCCI, the charge stratification is eliminated in HCRCCI owing to the induction of gasoline and diesel fuel vapor and a longer time available for fuel-air mixing which in turn results in higher degree of homogeneity. A production light-duty diesel engine used for agricultural water pumping applications is modified to run in RCCI and HCRCCI through suitable changes in the cylinder head and intake and exhaust systems. The unmodified test engine is initially run under conventional combustion with diesel fuel to generate the baseline reference data for comparison. The DI diesel fuel timings, gasoline-to-diesel energy ratio, and exhaust gas recirculation (EGR) are optimized in RCCI, while gasoline-to-diesel energy ratio and EGR percent are optimized in HCRCCI at each load condition to achieve higher brake thermal efficiency. After parametric optimization, the engine combustion, performance, and emissions are compared among RCCI, HCRCCI, and conventional combustion. The comparison shows that the engine could be operated in both RCCI and HCRCCI over the entire operating regime with near-zero NOx and smoke emissions along with higher brake thermal efficiency compared to the conventional combustion. As compared to RCCI, HCRCCI result in higher brake thermal efficiency at part load conditions along with ~87% and ~37% lower CO and HC emissions, respectively. Thus, HCRCCI could be a promising LTC strategy for diesel engines to reduce all the regulated pollutants with higher brake thermal efficiency without any compromise on achievable load range.
The horizontal water cooled diesel engine has a structure including all component parts such as a fuel tank that are necessary to drive engine, and is often a single cylinder engine. It is mounted on many applications such as power tiller and water pump because of high general versatility of installing owing to belt drive. It has a simple structure because of single cylinder, and is active mainly in Southeast Asia. At the same time, the market requires this type of engine higher power while a compact structure is also required from the viewpoint of easy to supply and use. In other words, “High power density” that is improving the output per body size has been required. We have responded to the demand of “High power density” by increasing output without changing the engine size. In order to keep the engine size, we have been enlarging displacement by using our peculiar stroke-up expertise and original bore-up contrivance. In addition to those techniques, we introduced analytic technology for early approach to optimal solution. While we had used deep bowl combustion chamber for emphasizing medium and low speed torque, we adopted shallow dish combustion chamber because we shortened the compression height of piston for stroke-up. We utilized combustion analysis so as to approach optimal solution early because we have no base data of shallow dish combustion chamber. In addition, we used stress analysis to optimize the hardening of crankshaft. As written above, by incorporating analytic technology in addition to conventional development methods, we have been supplying correct size engines speedily in response to requirement of market. In this paper, we introduce the techniques that we adopted in order to realize the high power density.
Fuel economy is a crucial parameter in long-haulage heavy-duty vehicles. Researchers tended to focus initially on engine combustion efficiency, while modern researchers turn their attention to the energy consumption of engine accessories in an attempt to enhance fuel economy. The accessories investigated in this study include the cooling fan, water pump, air compressor, power steering pump, air-conditioning (AC) compressor, and generator. Normally, accessory energy consumption analysis is based on rig data and simulation results. Here, we focus on the disparate test environments between the rig and vehicle to establish a novel constant power test method; the proposed method provides accurate accessory power data under different working conditions. A typical highway driving cycle is selected to collect accessory duty-cycle. The heavy-duty vehicle accessories’ energy consumption distribution under highway road conditions is obtained through the repeated road tests. Accessories comprise energy consumption proportions of 4.7%-6.4% of the engine in winter and 10.3%-12.6% in summer; they show different characteristics under different temperature or road conditions. The two influence factors of accessory energy consumption, constant power and duty-cycle, are analyzed to evaluate possible energy-saving schemes. Applying the clutch or electrical accessories, especially for the cooling fan and air compressor, is recommended.
The dynamic performances of the cooling circuit have a great impact on ICE efficiency and CO2 emissions. Engine thermal management is among the most promising technologies able to offer a sensible reduction in terms of engine fuel consumption and CO2 emission. These aspects are widely treated in literature and many technologies are already on the market or ready to be used. A reduced attention in literature, has been done on the pump performances during the real operating conditions. Homologation cycles try to reproduce these conditions. In light duty vehicles these cycles consist in accelerating and decelerating the engine following a specified velocity-time sequence. According to this procedure, the propulsion power requested by the vehicle is low, and the power absorbed by the auxiliaries became significant. The pump of the cooling fluid is the most important component among the auxiliaries. In this paper, the performance of a cooling pump has been studied according to its operating points when a homologation cycle is run: the variability of the engine RPM drives, in fact, the pump at different speeds whose values are in a fixed ratio with engine RPM. Being the hydraulic load of the circuit known, the pump produces a sequence of flow rates variable during time. A procedure to evaluate the variation of the pump speed during the homologation cycle has been developed. This time-pump speed variations have been used as set point in a dynamic pump test bench which reproduces closely the cooling circuit of the engine. Thanks to the wide applicability of the test bench, the limits of the usual centrifugal pumps have been discussed; the energy required to drive the pump has been measured and compared with that requested to drive the vehicle. Moreover, the coolant pump has been re-designed having as target the NEDC working points.
The thermal management system of the water medium retarder using engine coolant (water and ethylene glycol) as transmission medium, omits oil-water heat exchanger in the structure. When the hydraulic retarder is operated, the valve is connected with the retarder and water pump, and then the engine coolant enters the working chamber. The kinetic energy of the vehicle is converted into internal energy of the coolant, and the heat is discharged to the external environment through the engine thermal management system. The braking torque of the water medium hydraulic retarder is determined by the water medium flow rate in the working chamber. The smaller the valve opening degree, the greater the braking torque and the faster the heating transmission fluid. Small valve opening is not conducive to the loss of heat. It will affect the normal working of the engine and hydraulic retarder. In this paper, the thermal management system of the water medium hydraulic retarder is independent of the engine. Hydraulic retarder can be controlled individually so that to improve the auxiliary braking performance. Firstly, the independent thermal management system is designed according to the heat dissipation requirement of the hydraulic retarder. Secondly, the heat transfer of the hydraulic retarder thermal management system is analyzed. Finally, compare to the thermal management system of the traditional water medium retarder and the paper. The results show that the thermal management system of parallel water medium hydraulic retarder can effectively use the radiator cooling capacity, and reduce the working temperature of the water hydraulic retarder.
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