DE3627718A1 - Automated mechanical manual shift transmission - Google Patents

Abstract

Arrangement of an engine (especially an internal combustion engine in the motor vehicle) with a conventional mechanical manual shift transmission, characterised in that the transmission is shifted automatically by a programmable control. This control (computer) is programmed so that it always selects the most appropriate transmission shift stage at any time, thereby to some extent simulating a conventional automatic transmission. Engine and transmission are equipped with corresponding sensors, in order to detect important characteristic variables. The transmission shifting criteria derived from these are programmed according to the performance characteristics of the engine so that a certain performance (for example lowest possible fuel consumption or greatest possible acceleration), which in turn is automatically adjusted to the respective driving situation. An accelerator pedal determines the acceleration according to which the speed of travel and engine speed are calculated and held constant relative to the fuel. The pedal has a non-linear characteristic curve with brake, constant and acceleration range. The arrangement is equipped so that it is possible to intervene in the control process (for example, in order to change down) or so that it can also be shifted manually in the conventional way in the event of a malfunction. <IMAGE>

Description

1. State of the art

An automatic transmission in the motor vehicle is intended to be used facilitate, especially for inexperienced drivers. But it is also increasingly preferred by experienced drivers so that they can better deal with today's heavy traffic can concentrate.

1.1 It has been in automotive history for this "automatic Gearbox "have given many solutions. Have prevailed especially multi-stage gearbox with a so-called hydraulic Torque converter. These automatic transmissions have achieved great perfection today. That's how they will be already provided with programmed controls internally - which are hydraulic or electronic - to be precise to achieve the desired switching behavior. Be too the switching levels included often without interrupting the Power flow switched.

1.2 Such an "automatic transmission" with hydraulic Torque converter comes because of its size, the inner one Performance losses and the price only for larger ones Motors in question.

1.3 The so-called "Variomatic" gearbox has for smaller motors (Fa. Saab) achieved a certain importance. It consists of a rubber V-belt that can be adjusted in two Bevel gear pairs running.

For a long time, experiments on other automatic Gearboxes made for smaller motors, e.g. i.a. from FIAT with a working similar to the "Variomatic" Gearbox, however, that is a metallic push chain used. It is for a market launch of this transmission but haven't come yet.  

1.4 All of these more or less mechanical solutions for have a gearbox with a variable gear ratio several major disadvantages in common: they are relative complicated and expensive, have poor efficiency (often over 10% losses) are relatively large and heavy generally also prone to failure.

1.5 With different designs - especially with the mentioned automatic transmissions with hydraulic torque converters - there are other disadvantages: so can not braked by the engine, towed over long distances or be pushed.

2. Advantages of the arrangement according to the invention

The arrangement according to the invention also results in an effect automatic transmission that in use and operation roughly similar to conventional automatic Transmission. The disadvantage of this is that it is not switched without interrupting the flow of power, but apart from that a wide range of advantages.

2.1 It is much smaller and lighter. Manually operated, simple mechanical gearboxes are much smaller and lighter than an automatic transmission. Compared to the simple one Mechanical gears come in size and weight the arrangement according to the invention only the actuating Device for clutch and transmission added.

2.2 The mechanical structure is much less complicated and therefore less prone to failure. To the usual, many times tried and tested mechanical manual transmissions only come few, simple and non-susceptible mechanical parts added. The electronic one still required Control today can be much more reliable than the corresponding one  mechanical components are built.

2.3 For the option "automated switching" largely the same standard parts are used, as for the manually switched variant. As a matter of fact all used parts correspond completely to the manually switched Basic version, provided the attachment points are already attached to it the one required for automated operation Sensors and actuators are provided.

2.4 It has a much better efficiency. The mechanical Efficiency completely corresponds to that of a normal manual gearbox. It can also be in the same Way with a higher gear ratio (economy gear) be equipped.

2.5 The arrangement according to the invention can equally well for larger as well as small motors can be used. Because of the small size and high efficiency this arrangement is particularly suitable for the smallest vehicles and motors suitable.

2.6 The arrangement enables an unrivaled economic Driving style, but nevertheless, if necessary, reaching the highest possible acceleration; both even better than with conventional manual gearboxes because the electronic control always the optimal operating point in the characteristic field of the motor.

2.7 There is a high level of ease of use, so by the inherent constant speed control, the few Controls and automatic starting.

2.8 Because important operating data is already recorded by the computer with little additional effort  Calculate data and continuously display it on a display.

2.9 Engine braking is possible.

2.10 It can be towed and pushed as usual.

2.11 If the automatic system malfunctions, a simple change can be made can be switched manually in a conventional manner.

2.12 If desired, the automated mode of operation can also can be easily retrofitted.

2.13 The arrangement according to the invention is much cheaper than conventional automatic transmissions. The additional effort consists only of the sensors, the actuators and the Computer; everything in the series today increasingly cheaper to manufacture.

3. Detailed description of the mode of operation

The following is an example of the structure and operation a possible embodiment of the invention Arrangement described.

3.1 Structure

3.11 A largely standard is assumed Motor vehicle internal combustion engine with clutch and usual mechanical manual transmission. The engine is arbitrary as Carburetor, injector or diesel engine equipped.

3.12 The motor is additionally equipped - as on the attached Function diagram shown - with mechanical electrical sensors for the most important operating parameters, especially engine speed, engine torque and Driving speed. It is also equipped with a electrically controllable fuel metering and electric controllable actuators (actuators) for the Clutch and shifting the transmission.  

3.13 These operations can be done in a manner known per se effected electrically, pneumatically or electro-hydraulically will. Another idea according to the invention is one hydraulic actuation with pressure oil from the existing one anyway To operate the lubricating oil circuit.

With pneumatic or hydraulic actuation would have a pressure accumulator, an electric auxiliary pump or the like. be present so that they start when the engine is started is able to work.

3.14 It would be useful for the operations (in the functional Position feedback not shown) to the computer to provide precise control to ensure clutch and gear shift.

3.15 Except for the usual (not shown) ignition / starter Key switches and a foot brake are e.g. the following Operating elements available: a driving mode switch, a driving pedal and a "downshift button", as well a (digital) display panel for operating values).

The driving (mode) switch has a function similar to the pre-selection lever for automatic transmissions. But he only owns 3 positions: R = reverse, = neutral, D = drive forward. In particular, it does not require a special parking position and no further forward gears.

The accelerator pedal corresponds roughly to the function the conventional accelerator pedal and the (down) Switch button has about the function of "kickdown" in usual Automatic gearboxes.

3.16 The sensors and actuators listed above are interconnected with a programmed electronic Control (hereinafter referred to as computer), which e.g. digital works and i.a. from a central processor unit  (CPU), a working memory (RAM) and a program memory exists, as well as inputs for the sensors and Has outputs for the actuators.

3.2 basic mode of operation)

3.21 As is well known, an internal combustion engine can operate at medium Output the highest torque and works most economical here too. However, the highest output usually given at the highest speed. These connections can be made for a specific Represent motor type in so-called characteristic curve fields.

3.22 The arrangement according to the invention is now e.g. designed so that the computer has a specific target Driving speed specifies. This target speed will gained from operating the accelerator pedal. The accelerator pedal specifies accelerations; positive in the upper area - the Target speed increases - negative in the lower area - there is braking. Mathematically speaking, the internal one Target speed the time integral with the Accelerator pedal given accelerations. According to the just switched gear stage results in a certain target engine speed. This in turn is from a subordinate control loop about fuel metering kept constant. With changing loads (e.g. Road gradient), the driving speed remains constant. The accelerator pedal is not - as usual - direct the amount of fuel in front, but a target acceleration.

3.23 The accelerator pedal is expediently designed in such a way that there is a non-linear relationship between the applied pedal force Fp and the desired acceleration aw caused (see diagram aw = f (Fp) in the function diagram). This can be achieved in a simple manner by means of stepped counter springs.

With no or little pedal force, negative acceleration values specified, (motor) braking range. In a certain subsequent area of increasing pedal force (a kind of detent) no acceleration is output (Constant range). If the pedal force continues to increase then an increasingly positive value is given (acceleration Area).

3.24 An important aspect of the arrangement according to the invention is now that the computer according to the upcoming actual operating values (e.g. engine speed and torque) constantly checks, in which area of the characteristic field the motor works. At the same time, a check is also made as to whether not in each case the working conditions of an adjacent gear stage would be better. If this is the case, (with a short Deceleration) automatically into the more advantageous gear stage switched up or down.

3.25 The evaluation criteria for this switch are changing. When a constant driving speed is required the consumption optimum is sought. But when accelerating with the pedal is required Gear increasingly switched so that at the output (Wheel drive) a higher torque available if possible stands. So the higher the required acceleration, the more the switchover criteria in the direction of high cycling Torque changed. That means practically if with that The pedal is required to accelerate faster Engine increasingly in the map area of higher speed,  i.e. higher performance (and poorer economy) hazards.

3.26 It should therefore be emphasized that - without any switching the mode of operation - with "little pedal" with optimal Profitability (e.g. economy gear) driven can be or - e.g. when overtaking - with "full stepping" the highest possible acceleration is achieved. No matter how good a driver, this Optima cannot be achieved with the security of a properly programmed computer.

3.3 Detailed functional description 3.31 Parking, starting the engine

Switching off the engine (parking the car) is effected by moving the drive switch to the position (neutral) brings and then turns off the ignition. Here is then automatically removed from the computer - before the engine actually is shut down - the first gear is engaged and then (when the engine is stopped) the clutch (parked state).

When starting the engine (as usual, e.g. with a key switch) the computer disengages the clutch first and then started the engine. This is what the Computer also immediately idle speed. The first course is still inserted and the accelerator pedal at the lower stop. So the engine will start automatically and it will no separate parking position of the driving switch required.

3.32 Starting

Starting is at least with the arrangement according to the invention as simple as with conventional automatic transmissions. First the driving switch is in a driving position (D or R). As long as the accelerator pedal in the brake or Is constant range, nothing happens. Then if with that  Pedal is given a higher acceleration, increased the computer first (the electrical set point for) the Motor speed accordingly. The engine speed will So increased in advance so that for the given acceleration Experience has shown that the engine torque is sufficient is available; at high acceleration to medium Speed, where the engine give the greatest torque can. At the same time (due to the integration of the acceleration specification in the computer) the target driving speed. Then the computer engages in a controlled manner, i.e. so slow that at the respective engine speed available torque is not exceeded. The subordinate The control loop doses the fuel supply after that initially the engine speed does not drop. If then the driving speed of the (integrated) If the target speed approaches, the computer Target speed reduced (it is now only less torque needed to accelerate). If then the engine speed finally with the gearbox input speed matches, is fully engaged.

If you accelerate further after starting the computer drives the engine speed again and further up. If switching criteria are met, the computer switches - as described below - automatically switches to the next higher gear.

3.33 Automatic gear change

The up and down shift of the gear stages is from Computer with a fixed subroutine, as soon as it fulfills the criteria mentioned in 3.24 and 3.25 are. In addition, there are precautions  which is too frequent an automatic and prevent switching. The criteria areas overlap something (hysteresis). The downshift - important when accelerating quickly - is practical right away. Upshifting to a faster (more economical) Aisle - e.g. when a constant speed is reached is - is only executed with a certain delay.

The upshifting will take place in such a way that the computer first reduces the gas, then (without load) opens the clutch. Then the new gear is engaged and the engine decelerates in a controlled manner until the engine speed n coincides with the new transmission input speed (which is continuously calculated from v and i ). The computer then engages in a controlled manner and, if necessary, continues to accelerate.

The downshift is done in a similar way Subroutine. It is obvious that even savvy Don't always switch drivers so quickly and in a controlled manner can, like a properly programmed computer.

3.34 Normal driving

If after accelerating (accelerator pedal positive area) the desired driving speed has been reached Accelerator pedal in the constant range (detent) withdrawn will. The current driving speed is then was complied with - regardless of changing loads - because the lower-level control loop Dosing so that the internally specified motor Speed remains constant.

As described in 3.24 and 3.25, the computer continuously checks whether the engine is operating under optimal conditions and will change gear if necessary. If e.g. If a steep slope occurs, the computer will continue to move in shift into lower gears until they are still the same Driving speed with the now high engine speed the maximum available power is also pending. If this performance is no longer sufficient on steep inclines, engine speed and driving speed decrease - the subordinate regulation comes out of engagement.

Since the map optimization from the actual driving speed depends on - if the speed drops even further - if necessary, switched to a lower gear again. It is now no longer the desired driving speed adhered to, but the arrangement works but in the most favorable condition under the given circumstances.

If the driving resistance (incline) again become smaller without further action the old target driving speed is sought again.

3.35 Engine braking and downshifting before accelerating

There is a possibility in the automatic gear shift intervene manually, e.g. through a so-called (down) Switch button. It is conveniently in the grip area the steering wheel attached. If you press this, the Computer (after checking certain criteria) the transmission automatically switched to the next lower gear.

This button is primarily intended for two driving situations: the so-called engine braking and downshifting before Overtaking. Both driving modes are also each one special subroutine of the computer operated, but by causes the same control button.

This key can also be used several times in succession if you e.g. from 5th to 2nd gear. The computer  then checks in advance whether the next one Driving speed of the engine after downshifting would not assume a too high speed. - The termination these special modes happen automatically through the Computers according to special criteria.

The computer detects engine braking when in the Brake position of the accelerator pedal pressed the switch button becomes. The computer carries out a resolution of this mode e.g. through if for a certain time, e.g. 5 seconds, again acceleration is required and in terms of torque the low gear is no longer needed.

A preventive downshift before accelerating detected when the switch button is in positive or constant Area of the accelerator pedal is operated. The computer keeps this driving mode until, e.g. the accelerator pedal a certain Time was in the braking area and then a certain one Time in positive or constant range; without losing torque ago the lower gear would still be needed.

3.36 Normal braking

The accelerator pedal is released for normal braking (Braking area). The speed slows down the natural driving resistance of the vehicle and engine. By pressing the switch button, as previously described, (increased) engine braking. Around to brake even harder, the foot is released from the pedal and braked in the usual way with the foot brake.

4.37 Display of the operating values

Since many important operating values are already available on the computer ( n, M, v, fuel flow), further characteristic data can be calculated without any significant additional effort and all can be shown on a display, e.g. motor cable, route, time and absolute, relative and average consumption, etc .

3.38 towing and pushing

With the arrangement according to the invention, one can without problems Vehicle towed or the engine started by pushing if it doesn't start as usual. Therefor are two other special subroutines in the computer intended. Criterion for their activation could e.g. be a certain driving speed with the engine stopped; the ignition is off when towing and on when pushing on.

With battery voltage on - like when starting the engine - disengaged. When towing (without ignition) turns on then the transmission automatically idles. - When pushing (with ignition) the computer places the second one Gear and then - if there is enough travel - he couples automatically and carefully. - Both functions can but of course also (p.3.39) can be carried out manually.

3.39 Manual switching in the event of a fault

Another great advantage of the arrangement according to the invention is that in the event of a fault (e.g. computer or actuators) easy to switch to conventional manual operation is. To do this, only the accelerator pedal is electrical from the computer input directly on the fuel metering of the carburetor etc. switched. In addition, a carried Clutch pedal and a gear lever on the designated Places attached. The vehicle can then be conventional Be operated in a way.

Claims (12)

1. Arrangement of an engine (especially internal combustion engine in a motor vehicle) with a conventional mechanical gearbox and clutch, characterized in that the switching of the transmission is done automatically with a programmable controller known per se. This can be hydraulic, pneumatic, electronic or mixed. 2. Arrangement according to claim 1, characterized in that the controller (computer) is programmed that they always automatically for the respective operating state cheapest transmission gear selects, so to speak a conventional automatic transmission is simulated. 3. Arrangement according to claim 1-2, characterized in that the engine and transmission are equipped with appropriate mechanical electrical or other sensors (sensors) in order to record the most important parameters. 4. Arrangement according to claim 3, characterized in that the determination of the engine torque arithmetically from the counter torque of the entire engine gearbox Combination and the gear stage selected in each case takes place. 5. Arrangement according to claim 1-4, characterized in that the criteria for switching the transmission according to the specified characteristic field of the motor are programmed that a certain driving behavior results (e.g. lowest fuel consumption or largest possible Acceleration). 6. Arrangement according to claim 1-5, characterized in that the criteria for switching the transmission are continuously varied according to the respective Driving situation - especially depending on the respective required acceleration - and thus driving behavior is adjusted accordingly.   7. Arrangement according to claim 1-2, characterized in that the main operating element (e.g. pedal) is not as usual, directly the fuel and thus the torque controls, but specifies an acceleration, from which then a target driving speed and a target engine speed can be calculated, which in turn is based on the fuel supply are constantly regulated. 8. Arrangement according to claim 7, characterized in that the control element (e.g. pedal) with a non-linear Characteristic is carried out in such a way that on A negative value is output at the beginning (braking range), no acceleration in the next stage (constant range), and then with a further increase in the operating force increasing acceleration is specified. 9. Arrangement according to claim 1-8, characterized in that the input and Output signals can also be used at the same time, further Calculate characteristic values and show them on a display. 10. Arrangement according to claim 1-8, characterized in that additional controls are provided to specifically intervene in the control in certain driving situations to be able to, e.g. a downshift button. 11. Arrangement according to claim 1, characterized in that it is equipped so that in the event of a fault the control also operates the transmission manually in the conventional way can be. 12. Arrangement according to claim 1, characterized in that the switching operation with pressure oil from the Lubricating oil circuit takes place.