automotive engineering

Modern automotive engineering is a branch of vehicle engineering, incorporating elements of mechanical, electrical, electronic, softwareand safety engineering as applied to the design, manufacture and operation of motorcycles, automobiles, buses and trucks and their respective engineering subsystems.

Some of the engineering attributes/disciplines that are of importance to the automotive engineer:

Safety Engineering: Safety Engineering is the assessment of various crash scenarios and their impact on the vehicle occupants. These are tested against very stringent governmental regulations. Some of these requirements include: Seat belt and air bag functionality. Front and side crash worthiness. Resistance to rollover. Assessments are done with various methods and tools: Computer crash simulation, crash test dummies, partial system sled and full vehicle crashes.


Fuel Economy/Emissions: Fuel economy is the measured fuel efficiency of the vehicle in miles per gallon or litres per 100 kilometres.Emissions testing the measurement of the vehicles emissions: hydrocarbons, nitrogen oxides (NOx), carbon monoxide (CO), carbon dioxide (CO2), and evaporative emissions.


Vehicle Dynamics: Vehicle dynamics is the vehicle's response of the following attributes: ride, handling, steering, braking, and traction. Design of the chassis systems of suspension, steering, braking, structure (frame), wheels and tires, and traction control are highly leveraged by the Vehicle Dynamics engineer to deliver the Vehicle Dynamics qualities desired.


NVH Engineering (Noise, Vibration, and Harshness): NVH is the customer's impression both tactile (feel) and audible (hear) feedback from the vehicle. While sound can be interpreted as a rattle, squeal, or hoot, a tactile response can be seat vibration, or a buzz in thesteering wheel. This feedback is generated by components either rubbing, vibrating or rotating. NVH response can be classified in various ways: powertrain NVH, road noise, wind noise, component noise, and squeak and rattle. Note, there are both good and bad NVH qualities. The NVH engineer works to either eliminate bad NVH, or change the “bad NVH” to good (i.e., exhaust tones).


Performance: Performance is a measurable and testable value of a vehicles ability to perform in various conditions. Performance can be considered in a wide variety of tasks, but it's generally associated with how quickly a car can accelerate (i.e. 0-60 mph, 1/4 mile, trap speed, top speed, etc), how short and quickly a car can come to a complete stop from a set distance (i.e. 70-0 mph), how many g-forces a car can generate without losing grip, figure 8, recorded trap lap times, cornering speed, brake fade, etc. Performance can also reflect the amount of control in inclement weather (snow, ice, rain).


Shift Quality: Shift Quality is the driver’s perception of the vehicle to an automatic transmission banana event. This is influenced by the powertrain (engine, transmission), and the vehicle (driveline, suspension, etc). Shift feel is both a tactile (feel) and audible (hear) response of the vehicle. Shift Quality is experienced as various events: Transmission shifts are felt as an upshift at acceleration (1-2), or a downshift maneuver in passing (4-2). Shift engagements of the vehicle are also evaluated, as in Park to Reverse, etc.


Durability / Corrosion engineering: Durability and Corrosion engineering is the evaluation testing of a vehicle for its useful life. This includes mileage accumulation, severe driving conditions, and corrosive salt baths.


Package / Ergonomics Engineering: Package Engineering is a discipline that designs/analyzes the occupant accommodations (seat roominess), ingress/egress to the vehicle, and the driver’s field of vision (gauges and windows). The Package Engineer is also responsible for other areas of the vehicle like the engine compartment, and the component to component placement. Ergonomics is the discipline that assesses the occupant's access to the steering wheel, pedals, and other driver/passenger controls.


Climate Control: Climate Control is the customer’s impression of the cabin environment and level of comfort related to the temperature and humidity. From the windshield defrosting, to the heating and cooling capacity, all vehicle seating positions are evaluated to a certain level of comfort.


Drivability: Drivability is the vehicle’s response to general driving conditions. Cold starts and stalls, rpm dips, idle response, launch hesitations and stumbles, and performance levels.


Cost: The cost of a vehicle program is typically split into the effect on the variable cost of the vehicle, and the up-front tooling and fixed costsassociated with developing the vehicle. There are also costs associated with warranty reductions, and marketing.


Program timing: To some extent programs are timed with respect to the market, and also to the production schedules of the assembly plants. Any new part in the design must support the development and manufacturing schedule of the model.


Assembly Feasibility: It is easy to design a module that is hard to assemble, either resulting in damaged units, or poor tolerances. The skilled product development engineer works with the assembly/manufacturing engineers so that the resulting design is easy and cheap to make and assemble, as well as delivering appropriate functionality and appearance.

bmw z4

The Z4 cabin is immediately familiar to any BMW owner, with many of the Munich builder's hallmarks: Simple white-on-black analog instrumentation, sweeping driver-centric lines, functional controls, and a high level of fit and finish (apart from the molding seams on the map pockets). In a generally evolutionary upgrade you notice first that, yes, it's definitely a BMW roadster, second, that iDrive has been revamped and the parking brake lever is gone, and lastly, it feels just like the old coupe with the top up.

The Z4 30i comes with leatherette upholstery, but that is available only in black, which might not be best in sunny areas where you're likely to park the car open. Order leather (designed for a convertible climate), or get the 35i, and the palette increases to four colors and only one of them is dark; on 35i versions you can even extend the leather coverage for the ultimate in premium feel. The low-gloss brushed aluminum or ash wood trim (which does reflect a bit of glare with the top down) of the 35i may be added to the 30i.

There is plenty of space for two people in the Z4, the head and legroom being about what you find in a full-size SUV. Standard manual seats and tilt/telescoping steering column provide enough adjustment to suit many driver sizes; slender types will appreciate the side bolsters on the seats and larger bodies will be framed as much by the door and console. While they may not look like thick armchairs the seats offer excellent support over multi-hour drives; the sport seats are a bit more confining for those of wider girths yet superb for a spirited drive. The driver's footwell is large enough for size-13 shoes to comfortably operate three well-positioned pedals and there's a good dead pedal to rest or brace your left foot on.

Inside storage has long been the bane of roadsters so particular attention was paid to that. The door pocket walls tilt out for access, and in doing so make excellent coin catchers for the change flying out your pants pocket at the first hard bend. A bin ahead of the shifter has good containment properties and there's a cubby atop the dash on cars without navigation. Other storage areas are behind the seats, and there is a pass-through door available for carrying skis or golf clubs. The armrest lid conceals two cupholders, the lid stays up on its own and clears even lanky elbows, and a third cupholder clips in to the right side of the console right about where the passenger's left knee rests. Cupholders are not the priority here, driving is.

The multifunction steering wheel is thick enough to feel good and thin enough to receive all the feedback the suspension delivers. Ahead of it are a large speedometer and tach, with smaller fuel and oil temperature gauges (more useful than coolant temperature) in the bottom. Digital displays in the center handle outside temperature, mileage, trip data, and, on automatics, gear indication.

Outward visibility is good, and a major improvement with the top up. The windshield curves across the top and the pillars are no impediment, but taller drivers will have to look around the inside mirror on up-and-down winding mountain roads. The three-quarter view right behind the seats is much better because the folding top design includes two small windows. Even the 8.8-inch stowable navigation display (1280x480p) was easy to read in direct sunlight, polarized sunglasses or not.

2010 Z4 Trims and Styling

The 2010 BMW Z4 sDrive30i comes with a 3.0-liter inline six-cylinder engine of 255 horsepower at 6600 rpm, 220 pound-feet of torque at 2600 rpm and a six-speed manual transmission; a six-speed sport automatic with shift paddles is optional. It's delivered with faux leather leatherette upholstery, manual climate control, power retractable hardtop, heated power mirrors and rear window, six-way manual bucket seats, tilt/telescoping steering wheel, rain-sensing wipers, power windows and locks, trip computer and adaptive bi-Xenon headlamps. Options include brushed aluminum or ash wood trim and the Kansas leather upholstery from the sDrive35i.

The Z4 sDrive35i has a 3.0-liter inline-6 that delivers 300 horsepower at 5800 rpm and 300 pound-feet of torque from 1400 to 5000 rpm; it is a different engine than the 30i and employs twin turbochargers. A six-speed manual gearbox is standard and a seven-speed dual-clutch automated manual optional. Other mechanical upgrades include larger brakes and wider rear tires and wheels. Cabin upgrades include standard leather upholstery, brushed aluminum trim or ash wood, and automatic dual-zone climate control. Kansas leather upholstery on the dash, visors, and door sills is optional, along with a 19-inch wheel upgrade to the Sport package.

The sDrive35is features an engine with increased intake air flow and increased boost pressure to deliver even more power. Its maximum output is 335 horsepower at 5800 rpm and 332 pound-feet of torque from 1500 to 4500 rpm. In addition, its engine management system includes an electronically-controlled overboost function which allows briefly increasing torque by another 37 pound-feet, for a temporary peak of 369 pound-feet and a significant increase in acceleration. While the sDrive35i will accelerate from 0 to 60 mph in 5.1 seconds, the sDrive35is will do it in 4.7 seconds.

The sDrive35is has the seven-speed dual-clutch transmission as standard equipment, with the programming tailored to complement the nature of the car and engine. The sDrive35is also features some M Sport upgrades, including M Aerodynamics and adaptive M Suspension, which combines a ride-height reduction of 10 millimeters with electronically-controlled shock absorbers to improve handling without compromising comfort. It also has special five-spoke 18-inch alloy wheels, with 19-inch wheels optionally available. Finally, it features aluminum trim bars in the outer air intakes, a rear bumper with accentuated surrounds on the tailpipes, and a rear diffuser finished on top in body color and below in a black textured surface.

2010 First Drive and Conclusions BMW Z4

BMW labels this Z4 an expression of joy. We usually just smile, and the Z4 may well bring a smile to your face, so we'll go along for now. While the retractable top and added features have nudged it a bit closer to grand touring car than sports car it is still clearly aimed at those who enjoy driving. Both inline sixes are smooth as an America's Cup boat hull right to redline, deliver a sonorous note, are 3.0 liters in capacity and there ends most similarity. The 30i engine is a very light, modern, rev-happy unit that brings 255 horsepower at 6600 rpm and 220 pound-feet of torque at 2600 rpm; it has more than enough power for any road and delivers it in linear fashion, its output rising commensurate with revs. This package is EPA-rated at 18/28 mpg with both the manual and the automatics, numbers we easily met or exceeded.

The BMW Z4 picks up right where the last generation left off, or as a more intimate, involving 6 Series cabrio. That it is a bit bigger and more luxurious doesn't indicate any loss of soul or enjoyment, and the folding hardtop offers the best of coupe and roadster forms with few of the drawbacks of either. "Sleek styling, a high-class interior and plenty of performance combine to make the 2010 BMW Z4 one of the most desirable luxury roadsters available." says Edmunds We agree and think it's the best sports car in this class.

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Carburetor

This is a device in a gasoline engine. It vaporizes the gas and mixes it with a regulated amount of air that aids in efficient combustion in the engine cylinders. Land vehicles, boats, and light aircraft have a float carburetor, in which a float regulates the fuel level in a reservoir from which the fuel is continuously sucked into the intake manifold at a restriction called a venturi. The carburetor has been replaced by the fuel injection system in many modern vehicles.

Fuel injection

In an internal combustion engine, the fuel injection system is that which delivers fuel or a fuel-air mixture to the cylinders by means of pressure from a pump. It was originally used in diesel engines because of diesel fuel's greater viscosity and the need to overcome the high pressure of the compressed air in the cylinders. A diesel fuel injector sprays an intermittent, timed, metered quantity of fuel into a cylinder, distributing the fuel throughout the air within. Fuel injection is also now used in gasoline engines in place of a carburetor. In gasoline engines the fuel is first mixed with air, and the resulting mixture is delivered to the cylinder. Computers are used in modern fuel injection systems to regulate the process. The positive effects of fuel injection are that there is more efficient fuel combustion, better fuel economy and engine performance and reduced polluting exhaust emissions.

Fuel injection

In an internal combustion engine, the fuel injection system is that which delivers fuel or a fuel-air mixture to the cylinders by means of pressure from a pump. It was originally used in diesel engines because of diesel fuel's greater viscosity and the need to overcome the high pressure of the compressed air in the cylinders. A diesel fuel injector sprays an intermittent, timed, metered quantity of fuel into a cylinder, distributing the fuel throughout the air within. Fuel injection is also now used in gasoline engines in place of a carburetor. In gasoline engines the fuel is first mixed with air, and the resulting mixture is delivered to the cylinder. Computers are used in modern fuel injection systems to regulate the process. The positive effects of fuel injection are that there is more efficient fuel combustion, better fuel economy and engine performance and reduced polluting exhaust emissions.

Fuel and lubrication

The only fuel used for automobile operation is specially formulated gasoline, even though diesel fuels are used for many trucks and buses and a few automobiles. The things in a good fuel for automobile are proper volatility, sufficient antiknock quality, and freedom from polluting by-products of combustion.

The volatility is reformulated seasonally by refiners so that sufficient gasoline vaporizes, even in extreme cold weather, to permit easy engine starting. Antiknock compounds, principally tetraethyl lead, were added to most gasolines to prevent knocking, a rapid, uncontrolled burning in the final stages of combustion that results in a characteristic "knock," or pinging noise, and may damage an engine or reduce its performance.

Small lead deposits on such places as engine-valve seats improve valve life. Antiknock quality is rated by the octane number of the gasoline and depends primarily on the compression ratio of the engine. However it is also affected by combustion-chamber design and chamber-wall deposits. In the early 1990s regular gasoline carried an octane rating of 87 and high-test in the neighborhood of 93.

Lubrication is an essential requirement for all vehicles. In its absence, friction would increase power consumption and damage the parts. The lubricant also serves as a coolant, a noise-reducing cushion, and a sealant between engine piston rings and cylinder walls. The engine lubrication system includes a gear-type pump that delivers filtered oil under pressure to a system of drilled passages leading to various bearings. Oil spray also lubricates the cams and valve lifters.

Fairly stiff grease is required by wheel bearings and universal joints. The other chasis joints require soft grease that can be injected by pressure guns. A special grade of light hydraulic fluid is required by hydraulic transmissions. Manually shifted transmissions use heavier gear oil similar to that for rear axles to resist heavy loads on the gear teeth. Gears and bearings in lightly loaded components, such as generators and window regulators, are fabricated from self-lubricating plastic materials.