-- Scott Perl， Albuquerque， NM A: Auto racers have told us the main advantage in filling tires with nitrogen instead of ambient air is that nitrogen tends to maintain more consistent tire pressure over a wide range of As friction between the tire and pavement drives up the temperature， air with varying amounts of moisture content responds differently and can cause inconsistencies in tire While racing drivers are more likely to notice the advantages of nitrogen than everyday drivers， we haven't heard of any disadvantages to using Skeptics question the practice， noting that ambient air is about 80% nitrogen and that it expands and contracts at the same rate as pure A number of readers say there's no appreciable difference in how the tires will react if filled with nitrogen， especially in everyday Q: Is it safe to use cruise control in rain or on wet pavement? -- Scott Brake， Westminster， C A: Car makers often warn that cruise control should be used only in light traffic on open roads and in good There have been reports of accidents involving cruise control when the car lost traction -- or hydroplaned -- in slippery Some car makers warn that the steady throttle of cruise control -- like keeping one's foot on the gas -- could cause the wheels to spin when they hit a wet or icy patch of Car-company representatives say the cruise- control warnings reflect the fact that drivers should be particularly vigilant when conditions are less than ideal， and cruising along on what amounts to partial autopilot tends to lull some drivers into a false sense of Q: If an automobile manual suggests a certain weight oil (such as， 5W-30)， would adding a quart of a different weight oil (say， 10W-40) between complete oil changes damage the car's engine? -- Gil Ehrenkranz， Potomac， M A: Probably But today's engines generally are more precisely engineered than those of 20 or 30 years Many of us at some point have topped off our cars with whatever oil happened to be available without causing damage -- at least not that we know Auto makers， however， say modern engines can be more sensitive to a change in oil weight， and using the wrong oil， even in small amounts， can hurt an engine's performance and even cause Q: What is a sequential manual transmission? How does it differ from an automatic or a standard manual transmission? -- Harry J Jaffe， Germantown， T A: A sequential manual transmission is a gearbox that requires gear changes to be made in order (first to second to third)， instead of having a shift pattern with a lever that allows the driver to skip Motorcycles have used such transmissions for decades and racing cars began using them years ago because they allow quicker Shifting is usually done through levers， buttons or The sequential transmissions advertised today -- mainly in high- performance cars such as Ferraris， Aston Martins and some BMWs -- are technically manual transmissions， except that the clutch and the gear changes are controlled The advantage is that gear changes can be made more quickly and precisely than a human shifting the old-fashioned Traditionalists say the downside is that they simply aren't as much fun to drive and require less driver
Electronic brakeforce distribution or EBD or EBFD is an automobile brake technology that automatically varies the amount of force applied to each of a vehicle's brakes， based on road conditions， speed， loading， Always coupled with anti-lock braking systems， EBD can apply more or less braking pressure to each wheel in order to maximize stopping power whilst maintaining vehicular [1][2] Typically， the front end carries the most weight and EBD distributes less braking pressure to the rear brakes so the rear brakes do not lock up and cause a [3]How ABS worksUnder heavy braking， vehicle wheels may lock- The anti-lock braking system (ABS) monitors wheel speeds and releases pressure on individual wheel brake lines， rapidly pulsing individual brakes to prevent lock- During heavy braking， preventing wheel lock-up helps the driver maintain steering Modern ABS has four individual brake lines for each wheel， enabling different braking pressure on different road For example， less braking pressure is needed to lock a wheel on ice than a wheel which on bare If the left wheels are on asphalt and the right wheels are on ice， during an emergency stop， ABS detects the right wheels about to lock and reduces braking force on the right wheels， helping to avoid lock-up and loss of vehicle How EBD worksAs per SAE technical paper #920646 - Buschmann et "The job of the EBD as a subsystem of the ABS system is to control the effective adhesion utilization by the rear The pressure of the rear wheels is approximated to the ideal brake force distribution in a partial braking To do so， the conventional brake design is modified in the direction of rear axle overbraking， and the components of the ABS are EBD reduces the strain on the hydraulic brake force proportioning valve in the EBD optimizes the brake design with regard to: adhesion utilization; driving stability; wear; temperature stress; and pedal "EBD may work in conjunction with ABS and Electronic Stability Control ("ESC") to minimize yaw accelerations during ESC compares steering wheel angle to vehicle turning rate using a yaw rate "Yaw" is the vehicle's rotation around its vertical center of gravity (turning left or right) If the yaw sensor detects more/less yaw than the steering wheel angle should create， the car is understeering or oversteering and ESC activates one of the front or rear brakes to rotate the car back into its intended For example， if a car is making a left turn and begins to understeer (the car plows forward to the outside of the turn) ESC activates the left rear brake， which will help turn the car The sensors are so sensitive， and the actuation is so quick that the system may correct direction before the driver ABS helps prevent wheel lock-up and EBD helps apply appropriate brake force to make ESC work
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