Gear stick

A selector lever, manual shift lever, shift knob, shift lever, pedal, gear lever, gear lever, gear selector lever or gear selector in the sense of automotive technology allows the selection of the translation stage of the vehicle transmission, possibly the separation of the power flow between the engine and driven wheels ( clutch control ) and when the transmission over a reversal of direction features ( reverse gear, rare in motorcycles ), and the control of the direction of travel.

In the art that the selector lever, to which, for example, the levers and the switching gate are valid, as a circuit system, and together with the connection to the transmission ( for example consists of rods, cable ) classified as the " external control element", " external circuit " or " shift operation ". In the conceptual contrast, there are the " internal switching elements ", such as shift sleeves, synchronizer rings. Functional controls the driver via the selector lever, the transmission.

• 3.1 parking position
• 3.2 shiftlock
• 3.3 Monostable and stable multi selector lever
• 3.4 Other Functions
• 3.5 operating 3.5.1 A key circuit
• 3.5.2 Rotary Switch

• 4.1 Central and cockpit circuit
• 4.2 Lenkradschaltung 4.2.1 Vehicles with steering wheel gearshift
• 4.2.2 Miscellaneous

History

The first gear selector lever on cars were simple rods protruding from the gearbox and allowed the election of the Ganges. The transmission was located near the driver's seat and could be switched directly. In early cars, the lever was mounted laterally outside of the body where the handbrake lever was sitting.

In the course of vehicle development, different concepts led ( front wheel drive with transverse mounting of the gearbox, rear engine, transaxle ) means that the gearbox was wegverlegt the driver's seat, which required a spatial separation of service from the actual transmission.

First, for purely mechanical solutions have been developed. Alternatively, mixed electrical / mechanical and purely electrically tethered selector lever (shift - by-wire) developed. In commercial vehicles is also hydraulically connected with the driver on the shift lever operates a master cylinder that acts on the cylinder or on the gearbox. Because of the compressed air supply for the brake system also offer electric / pneumatic circuits, see electro-pneumatic circuit EPS.

Technology

Differentiator for circuit systems in current car is the type of connection to the transmission:

• Purely mechanical connections
• Electrical connection (shift -by-wire ) via a special interface or via the vehicle (usually CAN)

In addition, there are mixing shapes in which some functions take place mechanical fasteners, and other means of electrical connections. The selection in a particular case depends on the interface offered by the transmission the selector lever.

In automatic transmissions from the selector lever several functions are required:

• Recognition of the driver-selected gear and transmission to the transmission
• Lighting the speed level indicator ( partial)
• Highlighting the selected gear by the lighting (partly)
• Turn the selector lever lock (if present, partly through the transmission )
• Detecting whether the P key is pressed
• Mutual blocking of ignition and P position (depending on national regulations )

Especially with manual transmissions and the reversing light is switched via the selector lever.

Mechanical connection

Since the mechanism was much earlier than the electronics to control, most vehicles have more a mechanical bond. Rocker can be coupled, for example via a linkage, a multi-joint kinematic chain or via cables to the transmission.

Today is the mechanical connection is still common, even if the transmission has an internal electronic controls. Reason is usually that with proven and reliable gear changes for purely electronically controlled transmission with electronic gear selector is postponing cost reasons as possible and it changes across different vehicle platforms and generations as little as possible.

Advantages:

• Low-cost, simple and robust construction.
• Most repair by simple means, beneficial for maintenance in emerging and developing countries.
• Current -free switching possible, especially to open in the transmission when the vehicle needs to be pushed in case of failure the positive connection.
• Even in an emergency individual control in purely mechanical transmissions ( eg motor brake with over-revving the engine in brake failure or downhill), where electronic controls would prevent the operation.

The mechanical connection between the selector lever and transmission has over other circuit systems from today's perspective, various disadvantages, as the relocation must consider several points that restrict the free positioning in the interior.

Cons:

• Transmission of structure-borne noise in the interior, including, for example vibration absorbers are used.
• Necessity of decoupling the movement of the transmission in its storage, for example during load changes, so that the selector lever can be seen no effect
• Friction of the mechanical ( shifting comfort )
• Heat radiation in the vicinity of the exhaust system
• Sealing and noise problems ( NVH) in the required through-holes to the interior of
• Crash behavior of the entire outer circuit
• Hazard to other vehicle components by abuse and misuse, eg Overrevving When connecting or damage to the synchronizer rings by incompletely separate coupling ( " Greetings from the gear unit")
• Limited relocation, for example, by minimum bending radii of the cables or straight sections in the guide rod.

These may increase in some vehicles, the wear in the gear, if for example the driver can permanently resting his hand on the shift knob.

Although in private transport demand will rise to the robust and cheap manual transmissions through the entry of emerging economies, will probably be used, so that the electronic circuit systems are more widespread in new developments in the higher vehicle segments increasingly rare mechanical circuits.

Shift -by-wire

Shift-by- wire systems (short SbW, as part of Drive -by-wire ) only have an electrical connection to the transmission. To this end, the transmission is in any case must have an actuator, the electrical signals can implement in gear changes.

As a port on the side of the selector special electrical interfaces are used that control the gear selection and the lighting in the selector lever. Such systems can do without software and without a microcontroller when the transmission control unit takes over the corresponding tasks.

Technical effort

In practice it has been shown that the vehicle bus ( usually CAN) is for the interior design and the vehicle production is a simple yet flexible way to connect the selector lever to the transmission. Another possibility is the communication via pulse width modulation with fixed duty cycles.

Advantages of shift-by -wire:

• When connecting via the CAN bus ranging from two lines for the bus plus power supply (especially terminal 15, 30, ground) to replace all information with the gears and other control devices (eg, instrument cluster ).
• The selector lever can be placed anywhere in the work area of the driver, the connection is made via free deployable electrical connections.
• With a suitable design of the selector lever can easily be taken over unchanged for installation in multiple platforms and series or adjusted by configuring the software.
• Quick installation in vehicle production, while mechanical connections additional relocation and adjustment work may require during installation.
• Free choice of the type of actuation, actuation forces and paths, operating locks
• Additional functions such as force feedback, automatic extension and retraction of the selector lever

Disadvantages of SbW:

• No forced combination of running and the selector lever position, so that the transmission has a delay compared to the selector lever position.
• If the tasks are not taken by the control unit of the transmission, the shift lever requires a separate control unit ( embedded system ) with their own software and a microcontroller.

In general SbW circuits are offered because of the decoupling of gear position and selector lever position is considered a hint circuits so that the selector lever position itself allows no conclusion on the gear. Chosen by the transmission gear is shown to the driver by displaying on the instrument panel or on the selector lever itself, but these ads are then synchronized with the gearbox and not with the selector lever position.

Distribution of tasks

In shift-by- wire systems, the control unit of the selector lever takes mainly the acquisition of lever position, the mechanical locks improper positions, lighting the driving position, if provided, and the implementation of the selector lever position on the control bus.

The decision on whether and at what speed a particular gear may be connected (eg reverse at high speed) is usually taken by the gearbox control unit.

Operation

The type of operation depends on the transmission. Manual transmissions usually have a design as H circuit ( 4-speed ) or corresponding extensions.

In automated and automatic transmissions, four names have become established internationally in line with legal requirements, departing from which only rarely:

In addition, there are legal requirements that a higher braking effect must be present below 40 km / hr. This allows the engine braking effect can be better utilized in slope and the danger that the brakes overheat is lower.

This feature is from the gearbox implemented if the higher gears are locked and available on the selector lever in several ways:

• Newer gearboxes have a manual jog lane (see also Tiptronic ), for example, with "M" as a stable intermediate position between " " ( upshift ), and - is ( downshift ) " ".
• Older gear ( eg Mercedes ) have the steps " S" and " L" (highest engine brake torque ), or "3 ", "2 " and "1 " if no tip gate is available.

These speed levels usually lined up one behind D, known schemes are PRNDSL or PRND -3-2 -1.

Other regularly encountered on the selector lever designations are:

• "S " (Sport) for a sport mode, which automatically switches such as D, but a " sportier " shift strategy pursued. Because such transmissions have a tip gate, with the engine braking effect can be controlled in the gradient, the confusion with "S" as low translation for overspeeding on gradients.
• "E" ( Economy ) for particularly economical switching strategies
• "B" in hybrid vehicles to increase the braking effect by recuperation in addition to the motor brake and downshift, for example because when driving downhill, the braking effect is insufficient recuperation

Sometimes these options for additional switch for the driving program at the selector lever can be realized. All-wheel vehicles also controls the four-wheel drive can be placed near the gear selector lever, if differential locks can be switched.

Park position

The position of P must generate an extra safeguard against rolling of the vehicle, this function is often implemented by a mechanical lock in the transmission.

After numerous accidents with " self-perpetuating " it was customary for the position P can only be exited if the driver is applying the service brake. In the self-perpetuating the driver had indicated that their vehicle had accelerated, even though they have stepped on the brake. Many of these accidents were attributed to a confusion of accelerator and brake pedals, because of the public attention suffered by the affected vehicle manufacturers still in sales. The principle that when the brake the motor controller ignores the accelerator, has become widespread and is used after the 2009 report on alleged self-perpetuating Toyota increasingly used in manual transmissions.

In some countries, moreover, is a lock of the ignition lock required ( parking lock, key lock, interlock ), so that the ignition key can only be removed when gear selector lever and gear are available on P. Conversely, the selector lever can not be move from P when the ignition is not switched on the ignition key. This regulation globally slightly different operating concepts arise with regard to the locks in the selector lever:

Due to the different concepts that will ensure that the driver can also with a technical problem interrupting the power transmission in the drive train in any case, either by turning off the ignition ( Concept 1 ), or by switching to N ( Concept 2 ).

Some operating concepts have an auto-P function in conjunction with shift-by -wire. Here P is the transmission automatically inserted when a ( depending on the manufacturer took into account different ) combination of the following circumstances occurs: vehicle is not the driver's seat (more ) proves Ignition key or door is opened.

In contrast to some national laws, there are certain near-series special vehicles a motor overrun circuit in which the engine in P can continue despite the ignition key removed.

Shiftlock

For all transmissions a barrier for the reverse gear is provided. There are also automatic transmissions further locks that allow you to freely move the selector lever only under certain conditions. This usually relates to R and D, which can be operated only after pressing the brake and possibly other conditions (only when engine is running, for example ). To provide these functions, electrically controlled magnets or latches are used.

Monostable and multistable selector lever

The first selector lever for the automatic transmission were multi -stable, ie the selector lever is arranged every possible position to a stable position of the selector lever. This characteristic arose from the purely mechanical connection between the selector lever and the transmission.

Since the first manual shift gates ( Tiptronic gate ) is no longer stable each position. If the selector lever in the manual gate (M), then you can and - are connected only with typing. After the driver lets go of the lever returns to the M position.

Newer concepts are completely mono -stable, ie all positions can be switched by touching it. In this approach, similar to the sequential circuit of a motorcycle, of course no longer be detected in the selector lever position, but the driver need an additional gear display.

Other Features

Occasionally, a " swing function" for low speeds is provided in which a rapid change (within 1 to 2 seconds) between R - N - D and back without applying the brakes is possible since with stuck vehicles this method to " rock free " has proven. This is generally not a function of the selector lever, but the gearbox ECU, since usually this monitors the operation of the brake pedal.

Operation

While most controls are a further development of the mechanical lever, allow shift-by -wire circuits completely different operating concepts, such as the outsourcing of functions from the selector lever in the steering wheel switch.

Key circuit

In principle, allows the switching function for automatic transmissions not only by lever, but also by switches realize.

An example of a push-button circuit can be found at Chrysler in connection with the TorqueFlite automatic transmission that was advertised from about 1956 as a "push button Drive". The N- position actuated simultaneously the starter with the ignition on. First, even lacking the P position with the gear lock, which was installed in later models. From a legal perspective, the time was not a problem because the first U.S. law ( FMVSS ), provided the specific requirements of the selector lever, were not adopted until the late 1960s.

The most common vehicle with the "push button Drive" is likely the Chrysler Plymouth be, which was used as the lead in the horror film Christine, but he is incorrectly described in the original novel.

Ford - Edsel models keys circuits have been incorporated in the middle of the steering wheel, and referred to as tele- touch. The Touch Button Ultramatic transmission of Packard were also operated via a button control.

While the Chrysler Push Button Drive was purely mechanically connected to the transmission, the transmission at Packard and the Edsel was electrically controlled, which succeeded initially less reliable than Chrysler in both cases.

In current commercial vehicles key circuits are found.

Rotary switch

As a further alternative for automatic rotary switches have been known for a long time. However, they are only found in a few vehicles:

• Range Rover Evoque
• When Jaguar XF, the rotary switch moves out only when you press the start button

Since rotary switch for the manual transmission (M ) of the transmission does not correspond to the normal operating habits, manual transmission is provided by the steering wheel buttons or paddles.

Installation position

With some gear selection levers depend on structure, direction of operation and the order of automatic positions on whether the vehicle was built as a RHD or LHD.

Medium and cockpit circuit

Usually they are found, the switching device in cars in the middle, a little before the front seats (middle circuit or center console circuit ). For automatic transmissions, a worm or labyrinth lane is used occasionally. This reduces the risk of accidental operation because the gear selector must be moved successively in two directions to load a different gear.

In the structure is a little different from the cockpit circuit ( also dashboard circuit dashboard ) circuit, wherein the switching means is located on the dashboard. This place is chosen, for example, to allow a free cross-cab between the driver and passenger seat.

As a control element and a rotary switch is at this position usually a stick shift, rarely used.

Lenkradschaltung

The column shifter was from the 1940s to the late 1970s, a common type of transmission operation. In contrast to the floor shift the gear lever does not sit between the front seats, but he is right, installed on the left of the steering column at cars with right-hand drive.

The colloquial term " wheel gearshift " had prevailed, although the shift lever is not mounted on the steering wheel, but the steering column. Chance is the technically accurate term " pitman circuit " or " steering column circuit " used.

In the U.S., the automatic transmission selector lever often sits still on the steering column.

In the 2010s the shift lever on the steering column is experiencing a renaissance, first of luxury vehicles. Both Mercedes -Benz and BMW arrange the selector lever back to its automatic transmission on the steering column. The advantage here is the shift-by -wire design which requires minimal restrictions regarding adjustability and crash behavior of the steering column.

As a control element a steering column lever or shift paddles is used at this position usually. When Ford Edsel here was the key circuit.

Vehicles with steering wheel gearshift

In the 1960s and 70s, most mid-sized cars were delivered with either medium or steering wheel gearshift. Some models gave it exclusively with steering wheel gearshift, such as DKW, Saab and Renault 16

Others

• The Tatra 603 was produced with a rear engine, but with column shift, ie the shift linkage had to be performed in a complicated way from the steering column to the trailing gear.
• The DKW models of the 1950s, which were equipped with four-speed gearbox, the gears were reversed to normal shift pattern: The first and third gear were down, second and fourth gear above.
• The Opel Rekord C had a button that had to be pressed so that the reverse could be inserted at the end of the shift lever.
• The Trabant has indeed built the gear lever together with the steering column, but not the usual circuits for steering wheel mechanism, in which the gear lever is moved to the steering column, but mechanics and circuit diagram of a Krückstockschaltung.
• While the usual position of the reverse gear in the H circuit is back, it is most Volkswagen cars in front.

In right-hand drive vehicles, the arrangement of gears in the steering circuit is a mirror image.

Revolver and Krückstockschaltung

The revolver circuit is a further variant of the mechanical connection. It got its name from the shape of the shift lever, which is reminiscent of a ( inverted ) revolver. It is very similar to the Krückstockschaltung. The main difference is that the shift gates are longitudinally positioned in the transverse Krückstockschaltung in the turret indexing.

The shift lever is located at the turret circuitry in the dashboard, the gears are shifted by pulling, pushing and turning the lever. The most popular cars with revolver circuit Citroën 2CV and Renault 4 The Lloyd Alexander is next to the Trabant car with a known Krückstockschaltung.

Advantages of the arrangement of the gear lever on the dashboard are the better floorboard between the front seats and the ability to move the transmission from the engine and it can still accurately operate without failure-prone joints.

A disadvantage of the known constructions is that the shift stick penetrate in a traffic accident between the passengers inside the car and can cause injury.