5254 results about "Oil consumption" patented technology

The invention provides a vehicle formation driving control system and method, and belongs to the field of vehicle driving control. The vehicle formation driving control system comprises a head vehicle and at least one rear vehicle. The head vehicle and the rear vehicles are provided with fleet queue control terminals and whole-vehicle controllers. The whole-vehicle controllers control the driving states of the vehicles. The fleet queue control terminals are connected with the whole-vehicle controllers through CAN buses. Each fleet queue control terminal comprises a wireless communication module used for mutual communication among the head vehicle and the rear vehicles; a distance detecting module used for detecting the distance between the vehicle and a front vehicle; a positioning module used for obtaining the real-time information position of itself; and a lane information obtaining module used for obtaining lane information. The vehicle formation driving control system and method maintain the stability of a fleet, enhance the driving safety and help fleet members successfully and rapidly reach destinations respectively; in addition, the system and method are simple and effective, the scheme is mature, the oil consumption can be reduced by as much as 50%, and the frequency of traffic accidents is effectively lowered.

The invention discloses a stroke-increasing type electric automobile and a mode switching control method and system thereof. The stroke-increasing type electric automobile comprises a driving motor and a stroke increasing device, wherein the stroke increasing device is composed of a power generator and an engine. The mode switching control method comprises the following steps that an accelerator pedal signal and a brake pedal signal of the electric automobile are obtained; torque requirement analysis is conducted on the accelerator pedal signal and the brake pedal signal, so that the required torque of the driving motor is obtained, and the required power of the electric automobile is obtained according to the required torque of the driving motor; the power battery SOC of the electric automobile is detected, and the current speed of the electric automobile is obtained; and mode switching is conducted on the electric automobile according to the power battery SOC, the current speed of the electric automobile and the required power of the electric automobile. In this way, the oil consumption and NVH performance of the stroke-increasing type electric automobile are considered comprehensively, and the purposes of reducing oil consumption and improving the driving comfort are realized.

The invention relates to a hybrid driving system and a gear operating method thereof. The system comprises an internal-combustion engine, a first motor, a second motor, a planet coupling mechanism, a retarding mechanism and a differential mechanism, wherein an output shaft of the internal-combustion engine is connected with an input shaft of the first motor; an output shaft of the first motor is connected with an output shaft of the second motor by a first clutch; and the output shaft of the second motor is connected with one of a sun wheel and a gear ring of the planet coupling mechanism at the position of the axial direction of the output shaft, and output shaft of the second motor is connected with the other one of the sun wheel with a brake and the gear ring by a second clutch at the other position of the axial direction of the output shaft. In the hybrid driving system, two gear levels of forward gears of an automobile are formed by adjusting the planet coupling mechanism, so that operating modes and corresponding gears are selected flexibly according to different running work conditions of the automobile to achieve the effects of low emission and oil consumption, high kinetic energy and the like of the integral automobile.

The invention relates to the field of vehicles, the embedded field, the field of 3G / 4G wireless network communication and the technical field of data collection. Dynamic and static information of a vehicle is stored in a server end, and a series of services and managements with the vehicle as the center can be formed by data sharing. The technical scheme adopted in the invention is as follows: a vehicle service and management system based on an internet of vehicles comprises the following components: a vehicular terminal, which is used for collecting vehicle data in real time, sending the collected real-time vehicle data to a server and storing the same data in a corresponding database, wherein the vehicle data comprise data related to the operation of an engine,namely,a series of data comprising a vehicle speed, a water temperature, an oil volume, oil consumption and a tire pressure; and the server, which is provided with an application program based on data analysis, comprises a C / S structure and a B / S structure and can provide related services by a mobile phone client or a Web access server. The vehicle service and management system provided by the invention is mainly applied to vehicle communication and management occasions.

The invention provides a four-wheel driven hybrid vehicle driving system capable of meeting the needs of a motor vehicle for torque during running in an urban area and reducing oil consumption and tail gas emission and a driving management method thereof. The driving system comprises an engine driving front wheels, an ISG motor coaxially arranged with the engine and a driving motor driving rear wheels, wherein the engine is connected with an engine management unit; the ISG motor is connected with an ISG motor control unit; the driving motor is connected with the motor control unit; and the ISG motor and the driving motor are connected with a high voltage battery through an inversion unit. The key point is that the driving system also comprises a vehicle control unit and a high voltage management unit connected with the high voltage battery. The vehicle control unit, the high voltage management unit, the engine management unit, the ISG motor control unit and the motor control unit are connected through CAN buses; and the vehicle control unit is also connected with an accelerator pedal position sensor and a vehicle speed sensor.

The invention belongs to the field of traffic control and specifically relates to an efficient energy-saving speed guiding method based on the green wave control of urban trunk intersections. After the light color display situation of downstream intersections and the time needed by the dispersion of queuing vehicles behind stopping lines are synthetically considered, and the speed of traffic flows on urban trunks is guided from two aspects: when the condition that the vehicle can pass the downstream intersection at the current speed is detected, a stable driving speed is recommended to a driver, and if the vehicle is driven at the speed, the vehicle can pass the intersection controlled by downstream signals, without stopping; and when the condition that the vehicle can not pass the downstream intersection at the current speed is detected, an deceleration advice is given, the stopping and waiting time of the vehicle at the downstream intersection can be decreased as much as possible, and therefore, oil consumption is reduced. By using the method, the dispersion of vehicle queues can be avoided, the green light utilization ratio of the downstream intersection is increased, meanwhile, the purpose of umimpeded driving of the traffic flows on the trunk can be really achieved, and emission is decreased; and the speed guiding method has the advantages of simple control operation, good real-time performance and the like, and can efficiently guide the traffic flows on the urban trunks and improve the benefit of the green wave control.

The invention discloses an optimization method of an intersection dynamic comprehensive evaluation and signal control system based on a real-time simulation model. Statistical analysis is performed on an intersection vehicle arrival time distribution law and a saturation time headway distribution law, simulation control is performed on vehicles monitored in real time, analytical calculation of traffic flow parameters of an intersection such as mean queue length, queue time and travel vehicle speed, and characteristics such as vehicle exhaust, oil consumption and noise, and acquired information is shared and an optimized signal control scheme is implemented by a third party control platform. The method has the advantages that a real-time data acquisition function is realized by test coils embedded in interfaces at the near end and the far end of an intersection entrance road; the simulation model adopts vehicle arrival and green light termination as triggering conditions of starting a simulation system traffic flow parameter configuration; a saturation time headway is adopted as a time series distribution basis of vehicle leaving; simulation car following and lane changing behaviors are realized by a series of algorithms; and a traffic simulation function has timeliness, accuracy and rapid response.

There is provided a cylinder device having optimal arrangement of fine textures and optimal surface roughness capable of reducing wear of a cylinder bore side and a piston ring by processing fine textures in an optimal selection region of the cylinder bore side to improve lubrication characteristics between the piston ring and the cylinder bore side while reducing engine oil consumption by processing surface roughness of the cylinder bore side to an optimal status.

The invention discloses a driving behavior analyzing system. The driving behavior analyzing system comprises a driving information collecting module, a vehicle surrounding environment collecting module, a driver fatigue extent measuring module, a data recording and analyzing module, a judgment module, an alarming module and an evaluating module. The driving information collecting module, the vehicle surrounding environment collecting module and the driver fatigue extent measuring module are all connected with the data recording and analyzing module, the other end of the data recording and analyzing module is connected with the judgment module, and the other end of the judgment module is connected with the alarming module and the evaluating module. According to the driving behavior analyzing system, driving data are analyzed to measure the driving behavior of a driver, the driving behavior of the driver is evaluated accordingly, the driving behavior of the driver can be analyzed on thebasis of the driving environment, correct guiding is made for the driver, misguiding is avoided, meanwhile the driving behavior of the driver is improved, and the oil consumption of a vehicle is reduced.

The embodiment of the invention relates to a navigation path selecting method and a device. The navigation path selecting method comprises: obtaining an oil consumption coefficient corresponding to various oil consumption factors of each path between a staring position and a destination; according to the length of each path and the oil consumption coefficient, obtaining the oil consumption degreeof each path; according to the oil consumption degree of each path, selecting the path with lowest oil consumption. The embodiment of the invention can obtain the oil consumption degree of each path according to the oil consumption coefficient, the path length and the like of each path between the staring position and a destination and select a path which saves maximal oil for users, which not only saves fuel oil consumption of vehicle of the user and lowers energy consumption, but also reduces environment pollution and protects the environment.

The invention aims to provide an extended range hybrid electric vehicle power system with modes switched by a synchronizer. The system comprises a first motor and a second motor, an engine, a planetary gear train, the synchronizer, a fixed canine tooth ring which is fixedly connected with a box, a shaft gear canine tooth ring which is fixedly connected with a gear of an output shaft of the first motor, and a battery and an inverter; the engine is connected with a planet carrier of the planetary gear train; the second motor is connected with a sun gear of the planetary gear train through a sleeve; annular internal gears of the planetary gear train can be fixed on the box through the synchronizer and can also be connected with the output shaft of the first motor through the synchronizer, and the output shaft of the first motor is connected with a main change gear; the synchronizer is positioned between the fixed canine tooth ring and the shaft gear canine tooth ring; the annular internal gears of the planetary gear train are connected with a shaft sleeve spline of the synchronizer; the extended range hybrid electric vehicle power system can run in a pure motor-driven way to realize zero oil consumption and emission, and if the extended range hybrid electric vehicle power system needs to run for a long distance, the extended range hybrid electric vehicle system can run in an extended range mode, and the motor controls the position of the synchronizer to realize mode switching.

The invention provides a hybrid power drive system, which comprises an engine, a motor, a planetary gear mechanism and a wheel drive shaft, wherein the planetary gear mechanism comprises a first rotting element, a second rotating element and a third rotating element; the first rotating element is connected to an output shaft of the engine; the second rotating element is connected to the wheel drive shaft; and the third rotating element is connected to the output shaft of the motor. The system also comprises a first clutch and a second clutch, wherein the first clutch is arranged between the output shaft of the engine and the first rotating element of the planetary gear mechanism; and the second clutch is arranged between the wheel drive shaft and the second rotating element of the planetary gear mechanism. The invention also provides a method for driving the hybrid power drive system. Under various drive modes, according to the rotating speed relation of the three rotating elements of the planetary gear mechanism, through control of the rotating speed of the motor, the rotating speed of the engine can be controlled, and the engine always runs in an oil consumption economical area, thereby reducing the oil consumption of the engine to the maximum.

The invention discloses an automobile fuel saving reminding method and system. The method comprises the steps of obtaining the rotating speed of an engine, the speed of an automobile, the gear of a gearbox, the opening degree of an accelerator pedal and the opening degree of a brake pedal at intervals of a set sampling period; judging whether the automobile is in a starting period or an accelerating period or a constant speed period or a decelerating period; according to each driving period, judging whether the automobile is in the non-fuel-saving state or not, and if the automobile is in the non-fuel-saving state, sending out a reminding signal corresponding to the driving period. According to the automobile fuel saving reminding method and system, the driving behavior of a driver is monitored in real time, whether the automobile is in the non-fuel-saving state or not currently is judged according to the specific driving state, and the reminding signal corresponding to the driving state is sent out under the situation that the automobile is in the non-fuel-saving state, the driving behavior which can increase fuel consumption can be warned, driving suggestions can be given to the driver, oil consumption of the automobile is reduced, and meanwhile safety of driving is improved; in addition, the bad driving behavior of the driver can be corrected, and good driving habit can be developed.

The present invention has provided a welding forged steel single piece piston and its manufacturing methods. A semi-finished head and a semi-finished skirt are forged respectively; the semi-finished head and semi-finished skirt are heat-treated respectively; rough machining is carried out respectively to the semi-finished head and the semi-finished skirt, and a face of weld between the two adjacent ring grooves is higher than the one under the combustion chamber; the head and the skirt are welded together through friction welding; an annular groove, a combustion chamber, a ring groove, a pinhole, an outer annulus and oil inlet / outlet holes are manufactured respectively; and the surface of the piston is phosphorized and graphitized. Compared with one-piece forged piston, it has better processing technology, because the head and skirt are forged respectively and then welded together. Over-all structural rigidity of the piston has been increased, and distortion of the ring groove in high temperature is slight because the cooling oil recess is sealed through welding. As the annular groove is located on the upper part of skirt, the weight of body of the piston is lowered and this kind of structure can accelerate engine oil returning on, decrease the clearance between the piston and the cylinder and reduce the engine oil consumption.

An intelligent automatic-transmission matching method on the basis of working conditions and driving intention includes the following steps of acquiring data of driving habits and working conditions; analyzing data, modeling and emulating; integrating the recognition algorithm and the data models with the gear shifting schedules; and finally testing on vehicles. By the intelligent automatic-transmission matching method on the basis of working conditions and driving intention, vehicles can be adaptable to different driving habits and working conditions automatically and have high drivability and low combined oil consumption on different working conditions. The intelligent automatic-transmission matching method can accord with the gear shifting schedules having requirements to drivability, economy and dynamic property simultaneously, and thereby corresponding gear shifting schedules can be provided according to different driving habits and driving conditions on the basis of researching technologies of engines and transmissions.

The invention discloses a bad driving behavior analysis evaluation system. The system comprises a vehicle CAN bus, a vehicle-mounted intelligent terminal and a service platform; the vehicle-mounted intelligent terminal comprises a bus interface controller, a driving behavior acquisition module, a first communication module and an information display module; and the service platform comprises a standard driving behavior model database, a second communication module, a user individual driving behavior model database and a driving behavior analysis evaluation module. The driver driving behavior is acquired and accumulated in real time and is analyzed through the service platform to form an individual driver driving behavior habit model, the driver driving behavior habit model and the standard driving behavior model database are compared and analyzed to obtain the standard evaluation of the driver driving habit, and a corresponding driving habit improvement suggest is provided against the bad driving habit alarm of a driver. The purposes of traffic accident hidden trouble elimination, vehicle use efficiency increase and driving oil consumption reduction are realized.

The invention discloses a hybrid electric vehicle working mode switching process dynamic coordination control method. Accelerator pedal depth is acquired by an EMS (engine management system) to obtain required vehicle torque, and an HCU (vehicle control unit) can select a work mode under a current working condition to work according to the required vehicle torque or the actual working condition; by controlling change rate from engine throttle percentage to target throttle percentage, the engaging speed of a clutch is reasonably controlled according to speed differences of an engine and a motor, insufficient dynamic output torque of the engine is offset by the quick response ability and the characteristic of accuracy torque control of the motor, and output torques of the motor and the engine are coordinated and allocated in the mode switching process. According to the technical scheme, the torque output of a hybrid power system is controlled, so as to reduce the dynamic process of the engine; oil consumption is reduced, so as to improve the economical efficiency; great fluctuation of the required vehicle torque is not generated in the mode switching process, so as to improve vehicle riding comfort; wear of the clutch is reduced, so as to ensure power transmission smoothness.

The invention relates to a construction method for a gas storage reservoir in a rock salt cavity, belongs to the salt mine mining and the rock salt cavity utilization fields, and mainly used for the dissolution construction of an underground gas storage reservoir in a eutectic salt deposit. The construction method is characterized in that a method for down-flow type gas storage reservoir construction comprises the following steps: fresh water is infused into a salt deposit by a water injection pump and through a water injection pipe, the rock salt is dissolved from up to down, and at the same time, the natural gas is infused; the expenses for oil consumption of the original oil cushion method and the cost for brine purification treatment can be saved by using the method; and the method is more economical and more environment-friendly. The gas storage reservoir can be used from the beginning of construction; the single well oil cushion method with three to five years of construction cycle is not required for constructing the gas storage reservoir; the construction of the gas storage reservoir needs no cycle basically; the reservoir storage capacity is small in the beginning period; the gas storage reservoir can be used as a large gas storage reservoir in the middle and the late periods; the problems of long period for the construction of the gas storage reservoir by using the oil cushion method, difficult detection of the oil water interface, as well as other relative technical problems are thoroughly solved; and the construction method is an ideal method for rapid dissolution construction of the gas storage reservoir in the rock salt deposit.

A shell low-pressure rotary compressor and a control type and application for refrigerant and oil return of the compressor comprise a compression component and a motor component arranged in the shell. The compression component comprises one and more cylinders, pistons arranged in the cylinders, sliding pieces arranged in sliding piece trough of the cylinder, an eccentric crankshaft driving the piston and an upper bearing and a lower bearing supporting the eccentric crankshaft; the motor component comprises a motor rotor, and a motor stator; the shell is provided with a refrigerant diffluence device which is arranged on top or side surface of the shell; the refrigerant diffluence device comprises a diffluence pipe which is internally provided with a spring pipe which adjusts the diffluence rate. An air suction muffler is arranged between the motor component and the compression component; a radial spacing is arranged between the air suction muffler and a main bearing, and / or the motor rotor or the eccentric crankshaft or the upper bearing which is provided with a round plate. The invention has the advantages of high safety degree, low manufacture cost, smart operation, good lubrication performance, little oil consumption, high compression efficiency, and long service life.

The present invention relates to automobile technology, and is especially one series-parallel mixed power system. The present invention features the mixed connection structure of double motor and double clutch, the secondary motor for fast start of the engine, and the motor mode or the generator mode of both the main motor and the secondary motor. The secondary motor is connected to the output of the engine, the secondary clutch is set between the secondary motor and the main motor, and the main clutch is set between the gear box and the main motor. The mixed power system is similar to available internal combustion engine automobile in structure and has simple structure, compact arrangement, low manufacture cost, optimized running, braking energy feedback, low oil consumption, less harmful exhaust, excellent power performance and high running flexibility.

A high-content environmental-protecting alcohol ether fuel for vehicle consists of additives and methanol or alcohol 75-87 proportion. The additives contain methanol, alcohol, isopropyl alcohol, isobutanol, dimethylcuprate, n-amyl alkyl, dipropyl, cyclopentane, nitro-methane, dimethyl benzene, pinecone oil, cyclopentadienyl, poly-isobutylene, propane diamine, carbomethoxy formate, dimethoxyester carbonate, natural gasoline, hydrocarbon solvent oil, diisopropyl ester, dimethoxy-methane, petroleum ether, methyl tert-amyl ether, tert-amyl tert-butyl ether, lauryl phenol poly-ethenoxy ether, anti-static agent, metal-corrosive inhibitor, rubber plastic swelling inhibitor and anti-oxidant. It's clean and universal; it has excellent burning stability, shock resistance and dynamic character and less oil consumption.

When honing working cylinders for reciprocating piston-type machines or engines, e.g. internal combustion engines, unlike in conventional honing methods working takes place with a much higher axial speed than circumferential speed. This gives a mark pattern, which admittedly differs significantly from the axial direction, but runs more in the axial direction than in the circumferential direction. On the dominant mark pattern can be superimposed in a finishing operation a honing mark pattern, which has much finer honing marks and creates a plateau surface with diamond-shaped islands pointing in the working direction of the piston. A thus treated working cylinder, in the case of limited wear, leads to much lower oil consumption on the part of the engines.

The invention provides an engine tail gas after-treatment control system and control method. The engine tail gas after-treatment control system and control method are applied to after-treatment of tail gas. The control system comprises a tail gas post-processor, an engine electric control unit, a diesel injection device, a urea spraying device and a post-treatment electric control single element.The control method is based on the measured values of different sensors and the working condition parameters of an engine, and is based on a pre-calibrated data model to complete the four functions ofDPF active regeneration controlling, DPF accumulated dust cleaning, SCR urea injection controlling and system fault diagnosing. The system is composed of a software system and a hardware system, wherein a transient segmented linear interpolation algorithm is adopted for MAP data, and the calculation precision and the execution efficiency are improved to a great extent. A DPF differential pressuresensor adopts a differential pressure dynamic integral and time-sharing comparison method, so that the condition that the differential pressure value is unstable and the fluctuation is large due to the fact that the differential pressure sensor is influenced by various factors is solved, the robustness of a control strategy of the tail gas after-treatment system is enhanced, and the misjudgment of regeneration is reduced to a great extent, so that the improper active regeneration operation is reduced, and the oil consumption is reduced.

The present invention is welded integral forged steel piston and its manufacturing process. The manufacturing process includes the following steps: forging the head blank and the skirt blank; separate heat treatment of the head blank and the skirt blank; coarse machining the head blank and the skirt blank; friction welding the head and the skirt together; machining the ring slot, combustor, pin hole, excircle and oil outlet in the piston; and final surface phosphorizing or graphitizing treatment of the piston. The present invention has raised manufacturability, high integral structural rigidity, lowered weight and low machine oil consumption compared with available integrally cast piston.

The invention discloses a method for real-timely monitoring automobile fuel quantity and processing statistic on automobile fuel consumption via wireless network, comprising: using calibration method to obtain the corresponding relation between the fuel quantity of an automobile oil tank and the output value of a fuel level sensor; using an automobile terminal to obtain actual measured value via real-time data collection and data filter algorithm, to real-timely, accurately and reliably report prior fuel quantity to an automobile management center; based on the corresponding calibration relation between the fuel quantity of the oil tank and the output value of the fuel level sensor, using the management center to convert prior fuel quantity reported by the automobile terminal to actual fuel quantity, and display various application fuel quantity relative statistic reports according to the history data. The method has low cost, and automobile managers can real-timely and effectively monitor the real-time operation state and fuel consumption of automobiles, and find out the effect on fuel consumption via fuel consumption statistic, thereby realizing real-time management and effective distribution on the fuel consumption of automobiles.

The invention discloses a wing with a self-adaptive variable camber trailing edge. The wing comprises a main wing, a rear beam and a variable camber trailing edge section, wherein the variable camber trailing edge section is connected with the main wing through the rear beam; the variable camber trailing edge section comprises an upper surface skin and a lower surface skin; the first end of the upper surface skin and the first end of the lower surface skin are respectively connected with the rear beam; the other end of the upper surface skin and the other end of the lower surface skin are connected through a rigid trailing edge; the parts, close to the rigid trailing edge, of the upper surface skin and the other end of the lower surface skin, are connected through a sliding mechanism; the sliding mechanism is connected with the rear beam through a shape memory driving part. By adopting the technical scheme, compared with a conventional similar wing, the wing with the self-adaptive variable camber trailing edge has the advantages of simple structure, light weight, low research and manufacturing cost, high flying performance and the like, the aerodynamic performance of an aircraft is greatly improved, the aerodynamic efficiency of the aircraft is improved, the oil consumption is reduced, and the use cost of the aircraft in the whole service life is lowered.

The invention relates to a power management system and a control method for an automobile body controller thereof. In the invention, refine control for the load of automobile electrical equipment and management for a starter and a generator are realized; a controller area network (CAN) / local interconnect network (LIN) bus is utilized to monitor the power utilization states of the generator, storage batteries and an whole automobile; the voltage of the generator is regulated to realize dynamic charge and discharge for the electric quantity of the storage batteries; and large current loading iscut off in accordance with the dynamic states of the automobile, thus effectively reducing the oil consumption of the automobile, and decreasing the volumes of the storage batteries. A body control module (BCM) is integrated with the functions, thus not only avoiding increasing electronic modules, but also being simple in switching and strengthening the practicability of the power management system.

The invention discloses an electronic-controlled engine, an energy-saving method of the electronic-controlled engine, an energy-saving device of the electronic-controlled engine and an engineering machine. The energy-saving method of the electronic-controlled engine comprises the steps of obtaining output power of the electronic-controlled engine according to actual operation working conditions of the engineering machine, determining the current operation mode of the electronic-controlled engine according to the output power, determining an universal characteristic curve corresponding to the current operation mode according to the current operation mode, according to the universal characteristic curve, determining the optimal rotation speed of the electronic-controlled engine, adjusting the current actual rotation speed of the electronic-controlled engine into the optimal rotation speed, and enabling the electronic-controlled engine to operate in an optimal oil consumption area corresponding to the current working condition. Therefore, the optimal oil consumption area can be correspondingly set according to loads, and the purpose of effectively reducing energy consumption of the whole engine can be achieved according to the working condition with different loads.

The invention relates to a electronic car queuing system and method based on a position, can prevent frequent starting and moving of a car when drivers wait for passengers and queue up, and can also realize the human-based management of queuing taxies. The electronic car queuing system is at least formed by a vehicle-mounted terminal, a number calling terminal and a background dispatching center, wherein the vehicle-mounted terminal and the background dispatching center are communicated in a bidirectional manner in a wireless manner; the vehicle-mounted terminal sends position information to the background dispatching center and receives queuing information sent by the background dispatching center; the number calling terminal is used for sending a number calling instruction to the background dispatching center and receiving dispatching information sent by the background dispatching center. The electronic car queuing system and method based on the position have the advantages that a queuing lane does not need to be specially arranged for the taxies during passenger waiting, and the drivers can easily and effectively queue up; the loss and the oil consumption of the cars are reduced and management manpower resources of a passenger waiting region can also be reduced; and therefore, the environmental pollution caused by frequency starting the queuing taxies is avoided.