汽车专业英语.docx

宋有鹏SamSOMETHING FOR CAR THAT I NEED TO REMEMBERF SAE 美国汽车工程师学会（Society of Automotive Engineers）F ASTM 美国试验材料学会（American Society for Testing Material）F API 美国石油学会（American Petroleum Institute）F SI 国际单位制(System International) F ISO 国际标准化组织（International Standardization Organization）F IC SI Internal Combustion Spark IgnitionF IC CI Internal Combustion Compression IgnitionF SRP Seating reference point F AHP Accelerator heel point Q: What two systems of measurement are used in the auto industry? A: SI (ISO) & English Q: Why study the English system? A: Much of the world continues to use it, even in countries where SI system is universal. Q: What organization(s) write standards for the industry? A: SAE International, ASTM International, API Force (local)=mass acceleration (local) 5,280 ft = 1 mile (mi) = 1.60934 km Acceleration due to gravity = 32.174 fts2 If English system is being used F = ma ,must be replaced by F=1g0ma in order to properly express the units Units of Force = kgxms2=N If a force is applied to a body and it moves through some distance work occurs Unit of work in metric system is called a Joule - is defined as the amount of work done by a force of 1 N moving an object through a distance of 1 m Force times distance = Work Energy is a measure of how much fuel is contained within something, or used by something over a specific period of time. The kW-hr (kWh) is a unit of energy. Hp-hr Amount of work done by 1 Hp in 1 hr kW-hr (kWh) Amount of work done by 1 kW in 1 hr. Power is the rate at which energy is generated or used. Energy isnt actually generated or used, its converted from one form into another What units can we use to get Watt? W = N-ms = kgxms2 x ms W = Js (energy used per time) Power - Horsepower (hp) Horsepower is a very common term in the vehicle industry Power is a measure of the rate of work (energy used per time) Rate is always smth per time or smths Measure of the Work performed in some unit of Time 1hp=550ft-lbfs =33000ft-lbfmin =0.7067Btus=0.7457kW 1 W = 1kgms2m1s=Nm1s=Js=W Q: How do you calculate engine size in English units? A: Cross-section area of the Bore times the Stroke length V=(AStroke) in3 where A=r2=D24 Q: What is Power and how do we measure it (units)? A: Power is the rate (1/s) at which work is done or Power is the rate at which energy is transferred, used, or transformed Work performed in unit time It is a rate of doing work or expending mechanical energy In the SI system it is measured as a joule per second (J/s)=W In the English system it is called Horsepower (HP, hp)=ft-lb/s Body (Interior) Seats, carpets, floor board, toe-board抵趾板, fire-wall发动机档板, tunnel, transmission hump, dashboard, windshield (windscreen), door panel, window crank, door handle, mirror (rearview), headliner, upholstery垫衬物, footwell, rear center armrest, side armrest, escutcheon空罩, sunvisor, courtesy light, earmuffs, backlight (rear window), trim panel(s), kick pad, vent window Pistons ：/Rotary(Wankel)/Inline/ V/ Radial or Star /Opposed/ What is the purpose of the suspension? Control (springs and dampers) Prevent damage Ride comfort What parts make up the suspension Tires & wheels Linkage (connecting arms) to frame or chassis Dampers Springs Types Flat spring Bar spring Coil spring Pneumatic spring Hydraulic spring Steering also part of suspension Early tires where not made of rubber Roman times tires were made from iron Wooden wagon wheels were wrapped in iron or leather Early vehicle wheels were either spoke wood or bicycle wheels Wood followed wagon design Wood wheels could be made very strong though they were easily weakened from drying or other damage Wood wheels - high maintenance and required special skills Early metal spoke wheels were usually found on sport cars Metal spoke wheels were seen as sporty Lighter weight Stronger than wood more flexible Wood wheels were more flexible than later steel wheels resulting in lower noise from road surfaces Wood wheels supported a vehicle in compression while wire wheels supported a vehicle in tension Vehicle hung by the spokes when using wire wheels Flat springs Composed or made of tempered steel回火钢 Elliptical springs Early - in the shape of an ellipse came from carriages Advantage Used to support vehicle and locate the axle Disadvantage Designed for maximum carrying capacity high load rate Rough ride when not loaded Leaf spring materials Tempered spring steel Non-metals Aligned fiberglass fibers and resin树脂 Carbon fibers in resins Other composite materials kmpzt Front axles began with a beam and rear axles were enclosed with a differential and axle shafts Most vehicles adopted rear wheel drive with the live rear drive axle. With the engine in the front, power was delivered first by chains and then through a solid, then hollow shaft Independent front axles became the norm规范 Rear Wheel Drive (RWD) suspensions with a live rear axle were presented in previous slides Rear suspensions differ depending on whether the vehicle is rear wheel driven (RWD) or front wheel driven (FWD) Have to lock out the steering ability unless the rear allows for rear wheel steering All independent rear suspensions can be made to steer Active suspension design is a good example of remote rear wheel steering A torsion bar suspension, also known as a torsion spring suspension or torsion beam suspension, is a general term for any vehicle suspension that uses a torsion bar as its main weight bearing spring. Some suspensions have been designed to improve cornering while reducing body roll Tilting the wheels Some have been designed that allow roll into the turn rather than to the outside of the turn Tilting the wheels The first brakes were used on wagons A shoe forced against the rotating wheel or stationary wheel The shoe was attached to a lever arm and could be faced with leather to increase the braking efficiency Then came the band brake The band brake was simply a metal band loosely wrapped around a thick metal disc (disk) bolted to the inside of the wooden wheel The band was faced with different materials to improve friction Facing materials were woven编织 fibers and the one that became dominant was asbestos fiber石棉纤维 The band was actuated by rotating cams which tightened the band on the drum Actuation (making them work) Many cars, until the invention of hydraulic brake systems, used either cables or solid metal rods, with threaded connections, to actuate the band brake when the driver stepped on the brake pedal or pulled on the brake handle. The first caliper-type automobile disc brake was patented byFrederick William Lanchester in his Birmingham factory in 1902 and used successfully on Lanchester cars Friction pad material was copper and due to dirt and poor roads of the time, the copper material did not last long Material needed better friction materials Hydraulic brake system Fred Duesenberg originated hydraulic brakes on his 1914 Indianapolis racing cars. This braking system could have earned him a fortune if he had patented it. In 1918 Malcolm Lougheed (who later changed the spelling of his name to Lockheed) developed a hydraulic brake system. Developed special fluids that boiled at 500F (260C) ethylene glycol乙二醇 / glycol ether乙二醇醚 Compatible with rubber Non corrosive Non freezing Low water absorption High strength small diameter tubing Pressure resistant hoses Many cars used a drum with internal expanding brakes for the parking brake Mechanism was modified with hydraulic cylinder Two types developed Non servo Braking force develops solely due to hydraulic pressure forcing friction material against the inside of the drum Servo Utilizes the movement of the front friction surface to push against the rear friction surface increasing the braking force Action of the shoes increases the braking force provided by the hydraulic system and the driver Advantage Since most everyone used them they were easy and less expensive to manufacture than discs Disadvantage When drum got hot it would expand away from the brake shoes Drums warp from excessive heat build-up Become bell shaped Hard to cool even with fins on the surface When drums expand brakes begin to fade (stop working) When they get wet brake dust in the drum lubricates the friction surfaces Difficult to dry after soaking in rain or driving through puddles Discs require higher pressure to generate more force to stop the disc from turning and stop the car Q:How does a booster work and what is it supposed to do? Q:Why was it invented? A:Use atmospheric pressure to assist in pushing against the hydraulic fluid to increase pressure A:Makes stopping the car easier A:Not really needed if system is designed correctly A:Not needed even with disc brakes Brake boosters were developed to decrease the amount of pedal force necessary to stop the vehicle Came about because of the increasing number of women drivers Normal pedal force is 50 lbf. With a booster, this can be reduced to 20lbf or less Booster doesnt actually use a vacuum to boost pressure Uses atmospheric pressure to boost force on the master cylinder piston In America the first mass produced car to use a disc and caliper was the 1949 Crosley an economy car “First disc brakes on an American built car. Crosley did it in 1949, on his full line of cars and trucks. On all 4 wheels and on cars that sold for less than $1000.” Caliper was originally designed and used on small airplanes and corroded excessively when exposed to the salt used on winter roads in the Northeast US. Advantages Operate cooler Can be simple in design and execution Operate better in wet conditions Will still operate when red hot (depends upon friction material) Disadvantages Closer fit tolerances, especially non-floating Need more robust (stronger) mounting Tend to be heavy to absorb heat More sensitive to disc runout (non-parallel surfaces) More sensitive to friction pad characteristics and materials In an effort to reduce the weight of brake components there has been a move to ceramic materials for the disc and caliper Ceramics exhibit better heat dissipation (release, give off) characteristics than steel or iron discs Are as strong as metallic materials and weight much less Step 1 Define the concept or vision For a start, answer these questions What is my market? Who is it for? Where is the vehicle to be used? What am I trying to do that isnt being done now? How many seats? What is the competition, and what are they doing that I want to improve upon or do differently? How does the proposed market view personal transportation? What is needed (how can I convince the market that my solution is better than what they now have? What is my market? Market can includeWhoWhatWhyMarket is who you want to sell your product to. Who is also What and Why What do you want to do? Why do you want to do whatever it is? Step 2 Interior requirements This sets the size parameters required for the vehicle This can also help you determine the shape Exterior requirements Interior helps in setting physical size especially for the driver Items for exterior Crash worthiness Front, rear, and side Visibility requirements for driver Lighting based upon required standards Weather protection Fully enclosed or partly enclosed or not enclosed Interior Space required by rear axle or suspension Location and shape of fuel tank Height of SRP Rear seating room or space Headroom Longitudinal dimensions are influenced by the height of the SRP over the AHP When this increases, the space required for the legs decreases Seating space between front and rear can decrease Clearance between driver and interior objects can be increased Interior - seating reference point (SRP) Developed from ergonomic considerations This is based upon standards that have developed over years Standards have become legal requirements in EU, US, & Canada SRP is used Define the positions of the eye ellipse and the eye points as a basis for determining the drivers direct field of view To define hand reach envelopes in order to correctly position controls and actuators To determine the accelerator heel point (AHP) as a reference point for positioning the pedals Exterior Space required for front suspension including track (width) Space required by rear axle or suspension and track Location and shape of fuel tank Roof height from interior dimensions (seating) Wheelbase (length between front and rear suspensions) Powertrain Passenger cell width Shape of sides and space for door mechanisms, passive restraint, crush zones, and other assemblies (exhaust system, propshaft, etc.) Trunk space, if one. Some vehicles may include space for battery packs between inside and outside Step 3 Drive train have to make a choice Electric vehicle ICE vehicle Hybrid Series, Parallel Other Parallel hybrid not using an IC engine but an EC engine Number of wheels and arrangement Four wheels (but not necessarily at the corners) Four laid out like three Three wheels 2F1R 1F2R Two wheels Side-by-side or end-to-end (stability control will be needed for some) Lets do an example for this discussion Concept Vehicle that meets needs for personal urban transport How are cars used in China? Mostly in urban areas where there are low regulated speeds, traffic, stop and go driving, etc. How many drivers drive by themselves? More than 80% How many share rides? Maybe 10% If it is primarily urban then it doesnt need to have Continuous speed capability over 65 mph (104 kph) Majority of time driven 37.5 mph (60 kph) For example, vehicle will be enclosed with comfort features, communication features, economical, fuel efficient Concept Define interior requirements first How many seats? At least one, more likely 2 at least Maybe 3 - lets look at three (third could be jump or temporary seat) What are the seating requirements? Size of person this alone helps to determine seating requirements Seat spacing if any side to side Front to back spacing of seats if any Seat arrangements Do all seats need to be adjustable? How are they arranged inside the car? Today, many things can be optimized using computer generated images Seating height to get roof height from ground 240mm (height of butt from the floor) Seat back at 25 from vertical Maximum height to upper eye ellipse 665mm I exceed the 95% male. Back height from SRP is 610mm. Guess head clearance of 5in (125mm) Minimum inside roof height from floor 240+665=905mm Plus head clearance 905+125=1030mm Vehicle ground clearance 125mm Total roof height from ground datum 1030+125=1155mm Body length Engine compartment in the front Length changes depending on longitudinal or transverse engine/drive train layout Dependent on FWD or RWD Assume FWD Can we fit either proposed engine/drive train in the space including the suspension components What is height requirement Model engine and transmission as boxes with maximum outside dimensions some of this can change depending on where you put the accessories This is an approximation but will get you very close Can use this with roof height to determine windshield angle Shape can be arrived at with sketches, clay models, computer generated models (2D and 3D) Can use all if it is preferred. Chassis components Include suspensions front and rear Consideration needs to be given to drive train selection as this can influence the size and configuration of the suspension as well as the cost Another thought should be given to safety Do any of the drive train components affect the shape of the interior? If drive train has a transverse layout this impacts the interior space the least Steering is part of the drive train Can we layout the steering in the interior so it has little impact on the driver in an accident? Steering system within the interior Steering system within the passenger space does not need to line up with the driver the wheel should be in front of the driver but connecting part can be offset This will prevent wheel from impacting the driver Can use jointed shafts Can also use a flexible shaft will have no impact on the steering wheel in the event of an accident Can use steering by wire need some type of feedback What could we use to provide steering feedback if use steer-by-wire? Any of you play games with a joystick? Can use hydraulic steering this will give feedback to the steering Steering system within the interior Could you use something other than a steering wheel? If you use something other than a steering wheel what could it be? Should be easy to use intuitive Vehicles started with tiller or control stick steering could use with power systems today The braking system needed in our car is very much dependent upon the mass of the proposed car Some decisions needed: Do we mount them outboard at the wheels or inboard? This may also depend on the room available for mounting ABS or not? Are we going to include any active suspension/steering controls as an option? Are we going to use accident