Method and apparatus of a "Computer controlled gearshift with automatic clutch actuator for vehicles with manual gearboxes", composed by servo mechanisms, electric sensors, magnectic sensors, resistive potentiometers' sensors, electric actuators, all of them connected to and controlled by a central microprocessor controller unit, that by its turn perform a special set of instructions in order to automate all gearshift and clutch actuation's in a manual gearbox equipped vehicle, in such a way to enable it to perform like an automatic transmission vehicle, without imposing any alterations in the vehicle manufacturer original motor-wheels transmission specifications. It is well known for several decades the use of automatic gearbox based on hydraulic pump and torque converter characteristics used on all kinds of vehicles to automate the gearshift and clutch actuation, being the gas pedal movement (position) and gearbox load conditions, the only parameters gathered to decide a gearshift action. It is also well known the disadvantages of this type of hydraulic automatic transmission, being the most important the lower transmission efficiency (increased power loss when compared to a manual gearshift) to perform vehicle departure from stop condition while transferring torque to the wheels and gearshift operations while moving in a road, the number of gearshifts performed that is normally limited to 5 gears ahead and one rear gear, the need to have it factory installed due to the required more powerful motor and the increased acquisition and operational costs if compared to a manual gearshift-motor couple and the further need to have additional braking devices to help assure stop the vehicle as well. It is also known the past use of gearshift devices, some electric, some hydraulic (British Leyland buses - 1960 decade, Chrysler vehicles -- 1970 decade) and more recently F-1 racing cars button actuated up-down gearshift. It is also known the market presence of electronically controlled hydraulic clutch actuators made by Luk GmbH and Sachs GmbH, both German manufacturers. It is also known heavy vehicles electronic driven gearboxes made by Eaton - an American manufacturer, ZF - a German manufacturer and Volvo - a Swedish manufacturer, that uses electronic gearshift engaging synchronizers and servo mechanism actuators in order to perform speedier gearshifts as compared to those made through mechanical synchronizing rings.

There are also some electronic controllers for the original hydraulic automatic transmission in order to tighter the gearshift point tolerance as to permit different behavior in gearshift point to simulated heavy traffic or a clear road condition (calm or sportive response).

The present invention, behaves like a perfect (human) driver actions, moving the gearshift lever and the clutch accordingly and controlling the fuel flow as well. The central microprocessor controller unit decides when a gearshift should take place and how (up or down), how and when the clutch is to be actuated and further controlling the fuel flow in order to adjust the engine (motor) speed (R.P.M. - rotations per minute) to permit a better gearshift engaging.

The gearshift lever and the clutch pedal are eliminated as both functions are to be actuated by the central microprocessor controller unit through servo mechanisms and are no longer available to the vehicle (human) driver.

The present invention permits the association of the low power transmission losses of a manual gearbox with a computer controlled precision gearshift timing decision, an action that very few vehicle drivers and some original hydraulic automatic gearboxes fail to perform correctly (plus or minus 10% tolerances), thereby allowing a better (higher) mileage per gallon (kilometer per liter of fuel) figure if compared to the original hydraulic automatic gearbox, an improvement in the power transmission component's life if compared to the manual gearbox, plus the safety and comfort of an automatic transmission vehicle, without the use of an additional braking device.

Moreover, it can be installed in a working vehicle, with any quantity of ahead and rear gears at a fraction of the cost of a factory installed automatic gearbox components with the added ability to take into account vehicle changing loads behavior. For a better understanding of the present invention operation and its component's association the following drawings are used to demonstrate it but should not be considered as a restriction to the invention functionality or usefulness. FIGURE 1 shows an example of a 5 gear ahead, one gear to rear and 3 neutral position gearshift lever template. At this example, there are two servo mechanisms, composed of a selection servo motor with a transversal movement (moves the gearshift lever towards one of the 3 neutral positions) and a engaging servo motor with a longitudinal movement (moves the gearshift lever towards one of the possible 6 gearshift engaging positions);

FIGURE 2 shows an example of a binary coded electric disc sensor (6) installed at the gearbox lever actuator servo motors axis whereas in this example sliding electric contacts transfers the coded information of the axis position;

FIGURE 3 shows an example of a view of the binary coded electric disc sensor (6) installation on a servo motor gear face plate (3) driven by a worm gear (2) that is an extension of the direct current motor axis (1); also a view of a lever attached to the face plate gear (3) axis provided with an arm (4) to enable a rotation movement to be converted to a translation movement (the classic solution);

FIGURE 4 shows one of the gearshift lever movements servo mechanisms block diagram, where the central microprocessor controller unit (8) when detecting the right timing for a gearshift action drives a digital-to-analog converter (9) that feeds a power amplifier (11) that by its turn drives the direct current motor (1) that when turning its axis changes the binary coded electric disc sensor (6) position, and therefore the binary coded signal it supplies through the electric contacts (5) are feedback to the central microprocessor controller unit (8);

FIGURE 5 shows an example of a view of the clutch servo mechanism, where the resistive potentiometer sensor installation (7) at the face plate gear axis (3) driven by the worm gear (2) that is an extension of the direct current motor axis (1) can be identified and the remaining components as explained in FIGURE 3;

FIGURE 6 shows an example of the clutch actuator servo mechanism block diagram, where the central microprocessor controller unit (8), position feedback as detailed in FIGURE 7 ahead, feeds a digital- to-analog converter (9) which output is connected to a non- inverting input of a summing circuit (10) that has also connected to its other two inverted inputs feedback signals picked up one from the resistive potentiometer (7) axis position and the other one proportional to the angular speed of the axis rotation movement, then the summing result is fed to the power amplifier

(11) that drives the direct current motor (1) to rotate in one or other sense of rotation is a fast or slow motion;

FIGURE 7 shows the complete clutch actuator servo mechanism block diagram at the vehicle very departure moment from stop condition where the full block diagram described in FIGURE 6 is labeled here solely as block A, and the remaining components are the gas pedal that controls the engine (motor) labeled block B, that by its turn supplies a torque M (M as Motor) to a non- inverting input of a mechanical summing device (10') that when

idle, represents the motor axis rotation speed (RPM), which by its turn is further delayed by the motor inertia moment and when the axis rotation reaches, as a non limitating example, 1500 RPM, the electronic summing circuit (10) drives the clutch actuator servo motor (A) that starts to drive the clutch (14) to engage the gearbox where a torque C (C representing clutch) is produced and a feedback is provided to the inverting input of the mechanical summing device (10') thus reducing the motor axis speed (RPM) and its action can be understood as a brake effect on it, but the motor is further affected by its own inertia moment thereby a new motor axis angular speed ω is then set and measured by a RPM sensor (13) and depending upon its value compared to the threshold example of 1500 RPM at the electronic summing circuit (10) a signal (positive or negative) is then fed to the clutch actuator servo motor A thus increasing or decreasing the clutch engaging pressure, by changing its rotation direction.

On the basis of the previous drawings and the corresponding descriptions a detailed explanation of the invention operation and details are now presented, starting with the central microprocessor controller unit, that is a classic circuit comprising a microprocessor, random access memories, read only memories, I/O circuits, timers and interrupt controls plus digital-to-analog and analog-to-digital circuits, summing circuits and power amplifiers.

The gearshift servo mechanism as described in the example of FIGURE 1 with 5 gears ahead and one rear gear, shown generically and not restrictively only to demonstrate some of the invention concepts, shows two servo motors, each one with three stable positions that are set by the central microprocessor controller unit. In this example they work coordinately to establish 9 possible gearshift lever positions not restricting yet a third servo motor to engage/desengage an additional reduced gear as to double gear's figure.

Attached to each servo motor power axis there is a position sensor (6) and in the example given the position sensor is a binary coded electric disc sensor with 3 sliding contacts that divide the axis angular movement in 4 different binary coded areas.

The axis stable (stop) positions in the given example are the 3 boundaries of the 4 different binary coded areas. These positions are located at, e. g., +45°, 0° and -45° as shown in FIGURE 2. Each one of these 4 areas presents a unique binary coded signal to the central microprocessor

controller unit thereby allowing it to identify in which area the servo motor axis is in any moment thus enabling the central microprocessor controller unit to send the right polarity current to move the axis in the correct direction and to further stop it in one of the 3 possible boundaries as shown in FIGURE 3. The servo mechanism stabilization can be understood by examining FIGURE 4: lets suppose that the motor axis stands in the boundary located between the first and the second disc sensor (6) zones and a decision to move it to the boundary located between the second and the third disc zones is taken. The central microprocessor controller unit applies full power to the servo motor to rotate it in the direction of the third area till the boundary is crossed. Then the central microprocessor controller unit reverses the electric current, with reduced power to stop axis rotation and to return it again to the crossed boundary that when detected the drive current is shut-off. This process insures enough mechanical precision and the fastest possible settling time and these are basic characteristics of an ON-OFF servo mechanism. The gearshift servo motors is never actuated simultaneously, example: the gearbox is operating in the second gear and the central microprocessor controller unit is going to make a gearshift to the third gear, therefore the first servo motor is actuated to move the lever to the next neutral position, then the second servo motor is actuated to move the lever to the neutral position corresponding to the third gear, again the first servo motor is actuated to engage the third gear.

The clutch servo mechanism can be examined at the FIGURE 5 and one can spot that this is a more elaborated servo mechanism thereby allowing it to stop its axis in any point of its angular course. The FIGURE 6 block diagram shows its concepts.

Attached (ganged) to the servo motor axis there is a variable resistive potentiometer (7) that feedback to the central microprocessor controller unit a signal (DC voltage) proportional to instantaneous angle exhibited by the servo motor axis. This signal is compared to the desired wheels torque value allowing the central microprocessor controller unit to invert it and/or reducing its driving current until the final value is reached when a current shut-off occurs. For increased stability reasons, a signal which value is proportional to the axis angular speed is also feedback to the servo mechanism circuits. The central microprocessor controller unit controls the clutch servo motor axis final positioning through a digital-to-analog converter that is power amplified to drive the servo motor. All power amplifiers are pulse width modulated to reduced power dissipation.

Regarding other sensors, the present invention has one position sensor (variable resistive potentiometer) attached to the gas pedal as to supply an analog signal that reflects the pressure applied to it, and two speed sensors, one attached to the gearbox speedometer cable connector that reflects vehicle speed and the second to the motor in order to reflect rotation-per- minute figures, both pulse output devices.

In the given example, the position sensor (variable resistive potentiometer) attached to the gas pedal furnishes an analog signal to the analog-to-digital converter located at the central microprocessor controller unit, that reflects the driver intention to accelerate, reduce or to keep the present speed as it also reflects the supplied fuel to the motor.

The speed sensors actually measures wheels and motor rotation periods. The angular speed is derived from its inverse by the central microprocessor controller unit computing algorithm as speed = 1 /period. In order to compute the motor rotation period, two pulses' time interval from e. G. the spark plug pulses are doubled in a 4 stroke 4 cylinder gasoline motor as there is only two explosions per motor axis turn and in a diesel motor a suitable sensor that can supply proportional results to the axis rotation is to be used. In order to measure wheel rotation a shaft extension in the speedometer cable that has a magnetic sensor inside furnishes pulses proportionally to the cable rotation that by its turn is also proportional to the wheel period. The central microprocessor controller unit computes it by multiplying these pulses by a constant value (the vehicle power transmission constant). The present invention has only one actuator that is a fuel blocking device attached to the fuel distributing device (carburetor, electronic fuel injection, diesel fuel injector, etc.). When actuated the fuel supply is interrupted. This actuator has a motor rotation-per-minute limit action without load in order to reduce its value to a point below the corresponding value of a given gas pedal pressure point, when the motor is suddenly load freed. This situation normally occurs while in a gearshift operation: the gas pedal has is pressure sustained by the driver while the central microprocessor controller unit disengages the clutch. Without load the motor RPM will start to climb but the central microprocessor controller unit controls it by switching the actuator to adjust it to the rotation of the next gear. When the gearshift is completed the actuator is set out to allow the motor to develop torque. The start-rolling process in order to have a soft one without bumping and oscillations is a servo mechanism that try to keep constant the motor rotation- per-minute (RPM) at the chosen threshold value, shown at the FIGURE 7.

The central microprocessor controller unit (8) measures RPM continuously and when the threshold value is reached, 1500 RPM in the example, it starts to engage the clutch, the more the RPM increases the more it engages. The vehicle load applied to the motor has a brake effect on it and forces the RPM value to be reduced while sustaining it a little bit above the threshold value (1500 RPM).

Meanwhile, supposing the driver keeps the gas pedal with the same pressure, a skid effect on the clutch sustain the overall system equilibrium with a constant torque and constant motor rotation-per-minute under the clutch servo mechanism supervisory action.

But as torque is being applied to the wheels the vehicle accelerates and more and more speed is achieved till the gearbox axis speed equals motor axis speed. At this very point the motor axis speed starts to climb freely as there is no more clutch skid and there is no more need of clutch control by the central microprocessor controller unit and the vehicle starts to roll fully clutch engaged.

One can note that the applied torque to the wheels depends solely on the gas pedal pressure. If the driver wishes a fast departure all he has to do is to apply more pressure with his foot to the gas pedal: the central microprocessor controller unit will engage more deeply the clutch in order to try to keep the motor RPM within the selected threshold value tolerances, therefore more torque will be applied to the wheels and a greater acceleration will take place. The overall clutch servo mechanism gain is purposely set low to insure system stability and also another effect is achieved: for bigger torques, the stabilized rotation is also higher which led to a better motor horsepower handling in fast departures. The comparator block which establishes the comparison between the motor rotation and the rotation threshold is a electronic summing circuit and it is included in the central microprocessor controller unit while the other comparator block is purely mechanical (a summing torque device). Actually it is a summing circuit of the positive motor torque imposed by the accelerator and the negative torque (vehicle load) applied by the clutch engaging action resulting in a positive angular acceleration when the former is higher than the later and vice-versa.

Furthermore, as the feedback parameter is speed one can consider the motor block as an mathematical integrator.

During departure condition and while clutch skid occurs, the valid model is a classic second order servo mechanism that obeys the following equations: Torque = A (1500 RPM - ω) and ω •= k ({motor • torque - clutch • torque)δt

This servo mechanism equilibrium keeps the ω speed constant for each motor torque level (gas pedal position):

Torque C (Clutch) = Torque M (Motor) = B x gas pedal There are other parameters that might affect this type of servo mechanism stability like clutch delays and associated non-linearities, but with a open-loop low gain set-up this problem do not occur.

The final result aside a soft vehicle departure driver controlled, the overall system is self-adjusted without transmission behavior changing due to mechanical components lasting or road pavement conditions. To define gearshift decision, the toque x motor rotation, the torque x fuel consumption curves and the transmission reduction factors (motor axis rotation speed x wheels rotation speed) for each gear as well, are included in the central microprocessor controller unit operational software table, which one depending of the vehicle characteristics establishes the right gearshift instant.

The gearshift move from a short gear (more torque) to a longer gear (less torque) is determined solely by the motor rotation-per-minute level, it is independent from the gear in use but directly dependent from the gas pedal position (vehicle speed and acceleration). The central microprocessor controller unit reads the higher pressure on the gas pedal position as a driver intention to increase speed faster thereby holding the gear in use to achieve higher motor rotations till a gearshift is mandatory. The gearshift move from a longer gear (less torque) to a short gear (higher torque) is solely determined by the vehicle speed: when the vehicle loses speed, e. g. 30% below the point the present gear was selected (see last paragraph), the central microprocessor controller unit makes the gearshift to a higher torque gear. One can note that the gearshift decision may be accelerated by the gas pedal position if the foot pressure on it increases as compared to the cruise pressure evaluated on it.

Smooth gearshifts without sudden vehicle accelerations or large RPM changes are achieved with the following gearshift synchronization: the motor

RPM is adjusted to a value very close to that of a disengaged clutch for the present gear. The clutch is then deactivated (disengaged) and the gearshift lever is moved to its corresponding neutral position. While the clutch is not disengaged from the gearbox nothing happens. When the motor RPM starts to climb due to clutch disengaging (the gas pedal pressure is maintained constant by the driver) the central microprocessor controller unit activates the actuator device that controls fuel flow and sustains the previous motor RPM with the clutch engaged (the motor inertia moment is taken into account). When the gearshift lever reaches the new neutral position, the motor RPM is then set to a new motor RPM compatible with the next gear and vehicle speed, and when reached the gearshift lever is advanced to engage it. When the new gear is engaged the clutch starts to be smoothly engaged with the gearbox. When the clutch engaging is finished the motor RPM has already reached its correct value. The central microprocessor controller unit deactivates the actuator device and the gearshift procedure is final. The gearshift driver control is accomplished according to the acceleration range and the gearshift speed depends upon the gas pedal position. The driver has some control regarding the gearshift instant: if the vehicle moves in a speed close to a gearshift action to a lesser torque gear and the gas pedal has a momentarily reduction on its foot pressure then the lower torque range is enabled for this new speed and the gearshift is performed. Similarly, if the gas pedal is further pressed close to a condition of gearshift to a higher torque gear, then the gearshift is also anticipated (an operation known as kick-down) and performed.

This type of gearshift control when performed by a skilled driver can optimize the vehicle performance and further reduce fuel consumption, as the central microprocessor controller unit cannot sense road conditions and traffic, closed traffic lights, coming uphill, etc.. The central microprocessor controller unit operational software, based on the related descriptions and techniques, using specially developed algorithms can be ported to any microprocessor that the state-of-the-art at any time indicates its adaptability to it. It was duly registered in Brazil at the Instituto Nacional de Propriedade Industrial under n ^Q 93006208 in July 12, 1993 and is protected worldwide by international treaties and agreements.