WO2013168112A1

WO2013168112A1 - A kit applicable to a vehicle with a hydraulic clutch to reduce fuel consumption

Info

Publication number: WO2013168112A1
Application number: PCT/IB2013/053726
Authority: WO
Inventors: Leonardo Grieco
Original assignee: Leonardo Grieco
Priority date: 2012-05-08
Filing date: 2013-05-08
Publication date: 2013-11-14
Also published as: CH706480A2

Abstract

Kit applicable to a motor-vehicle with manual gearbox and hydraulically operated clutch, comprising a hydraulic control unit which can be connected to the existing clutch operating system; control electronics; operating means comprising a flange (102) which can be directly associated with the accelerator pedal (101) of the vehicle; the accelerator can be operated by the driver by pressing or respectively releasing said flange; said electronics and said operating means cooperate so that the clutch is disengaged when said flange is in the rest condition, and the clutch is engaged as a result of pressing of said flange. A motor vehicle with a manual gearbox is also described, where the clutch is normally open when the accelerator is in the rest condition and the clutch is closed as a result of pressing of the accelerator pedal.

Description

A kit applicable to a vehicle with a hydraulic clutch to reduce fuel consumption

DESCRIPTION Field of application

The invention relates to a kit applicable to a motor vehicle which provides automated operation of the clutch and can reduce fuel consumption.

Prior Art

The fuel consumption of motor vehicles is nowadays a problem, due to the known issues of pollution, the high cost of the fuel and increasingly stringent limits imposed by the applicable regulations, for example with regard to carbon dioxide emissions.

The various efforts made by the automotive industry to reduce fuel consumption and emissions include, for example, the so-called "start-and stop" systems, which turn off the engine during the stops, or hybrid vehicles equipped with a thermal engine and one or more electric engines.

These solutions, on which leading motor-vehicle manufacturers appear to be concentrating their research efforts, are however not exempt from drawbacks: they are expensive and they are available only to those who can buy a new vehicle, being not applicable as a modification to existing vehicles (retrofit). Moreover the advantage in terms of fuel consumption does not always meet expectations.

For example the start-and-stop systems are efficient in bench simulation tests, but road tests reveal that they are much less efficient during the real use. First, they may reduce consumption only in conditions of use involving frequent stops; it must also be considered that turning off the engine during a stop is not always possible, for example in the summertime when the air conditioning system must be powered; another drawback is that the system tends to overload the electric components, which must be correspondingly adapted, thereby increasing costs.

Hybrid propulsion is expensive and, in the final analysis, is not always convenient: at present, the hybrid propulsion is employed almost exclusively in the medium to high vehicle range owing to the cost of the batteries, control electronics, etc., which would be too high for a small car; moreover, the known hybrid systems offer advantages mainly in the urban cycle, but offer little advantage during suburban or motorway travel where propulsion is substantially dependent on the thermal engine. Last but not least, hybrid systems result in a significant increase of the weight.

As regards the transmission system, automatic gearboxes with an increasing number of gears are becoming popular; for example six-speed gearboxes are now common, even in the case of medium-small motor vehicles, and gearboxes with seven or eight speeds are often employed for higher end vehicles. In this connection it should be noted that conventional automatic gearboxes with a torque converter penalize the efficiency and result in a certain increase in fuel consumption. The more recent gearboxes, for example automated manual transmissions, do not have this drawback although they do not provide the same smoothness of operation as a conventional automatic gearbox. In some cases an automatic gearbox may help reduce fuel consumption for example because it tends to engage the higher speed as soon as possible or because, owing to the large number of gears, it manages to keep the engine substantially always at the optimum speed range (for example the speed of maximum torque), but the advantage compared to a manual gearbox is generally limited, if not negligible. Moreover one may note the current tendency to reduce the size of the engine and to compensate by means of supercharging and/or an even more sophisticated management system, including variable-timing systems, modular engines, etc. On the other hand, the increasingly sophisticated design of engines inevitably increases not only the sell price but also maintenance costs. It should also be considered that the continuous search for new solutions, despite the undoubtedly positive aspects, also results in a negative consequence for users in that cars become rapidly out-of-date, and consequently used vehicles lose their value. Basically, despite the efforts made by the leading motor vehicle manufacturers, fuel consumption remains an open problem, also because a small advantage in terms of efficiency of the engine, achieved by means of expensive complex technical solutions, is often offset by the increase in weight and/or aerodynamic resistance, owing to the increasingly larger size and accessories or safety features provided on modern vehicles. Moreover, the market does not offer an effective retrofitting device applicable to existing vehicles, resulting in a disadvantage for those who cannot afford to buy a new car frequently.

The object of the invention is to provide a system which allows reducing fuel consumption by means of a modification applicable to any vehicle, new or used, having a low cost and simple to fit.

Summary of the invention

The invention arises from the observation that motor vehicles continuously operate in "stop-start" fashion, with slowdowns or brakings immediately followed by accelerations, as a result of heavy traffic and queues, crossroads, traffic lights, etc. Each slowdown results in a waste of the kinetic energy accumulated by the vehicle and the subsequent acceleration is quite expensive in terms of fuel consumption. During acceleration, in fact, the instant fuel consumption is very high, reaching as much as 20 litres per 100 km, for example. Another observation from the inventor, underlying the present invention, is that roads are not always perfectly flat; sometimes a slight downward slope (e.g. a 2% slope) would be sufficient to maintain a constant or nearly constant speed, but the driver is often unaware of this, and unnecessarily uses fuel also when travelling downhill.

Recovery of the kinetic energy at present is possible only in electrically powered or hybrid vehicles, while in conventional vehicles the kinetic energy accumulated at each acceleration is inevitably dissipated as soon as slowdown or braking occurs.

On the basis of these considerations, the underlying idea of the invention is to provide a system which allows to use propulsion only when strictly needed, disengaging the clutch (neutral) whenever possible, so as to make optimum use of the kinetic energy accumulated by the vehicle. The objects of the invention are achieved with a kit applicable to a motor vehicle with a manual gearbox and a clutch with a hydraulic control, comprising at least:

- a hydraulic control unit which can be connected to the existing hydraulic control so as to automate operation of the clutch itself; - control electronics which in particular perform opening and closing of the clutch by means of said control unit;

- operating means which can be associated with the accelerator pedal of the motor-vehicle;

- wherein said electronics and said operating means cooperate in such a way that the clutch is kept open, that is disengaged, when the accelerator pedal is released, and the clutch is closed, that is partially or totally engaged, as a result of pressing of the accelerator pedal.

The operating means which can be associated with the accelerator pedal advantageously comprise a block which carries the sensors and a flange which can be superimposed on the accelerator pedal. Said flange may be for example hinged or pivotably mounted on the pedal or formed with a flexible member acting substantially as a spring. A flexible flange for example has an end which is fixed to the accelerator pedal and an opposite end which is free to bend. The position of said flange activates at least one sensor adapted to send a clutch engaging/disengaging signal to the control unit. Basically the flange mounted on the accelerator pedal acts like a second pedal which controls the clutch in manner coordinated with the accelerator. The flange is deformable or movable relative to the accelerator, as a result of a pressure exerted by the driver's foot, from a rest position into a contact position where the flange makes contact with the accelerator. From said contact position, a further pressure on the flange results in the pressing of the accelerator similarly to what occurs in a conventional vehicle.

Consequently, a pressing of the flange, starting from the rest position, causes:

- engagement of the clutch, as a result of activation of the sensor; - then, the pressing of the accelerator and therefore an increase in the speed of the engine.

On the contrary, a release of the flange causes:

- release also of the accelerator pedal, to which the flange itself is connected, and therefore engine at minimum speed; - opening / disengagement of the clutch as a result of deactivation of the sensor.

The described sensor may be activated for example by means of direct contact with a part of the flange, advantageously one end of the same. It should be noted that the accelerator is not modified by the application of the kit. In practice, the accelerator is operated every time the driver presses the flange until the flange reaches the aforementioned contact position.

The kit comprises advantageously other accessories which can be mounted on the aforementioned support block, including, for example, a mechanical end-of-travel stop, screw for adjusting the position of the flange, indicator lamp for mounting on the dashboard, etc. The kit also advantageously comprises electric cables and hydraulic pipes for the pressurised oil, which are required during installation on the motor vehicle.

Preferably the hydraulic control unit and the electronics are housed inside a closed container which may be mounted in the luggage compartment. Consequently an electric power supply line is provided, so as to power the control unit from the engine compartment, together with a hydraulic line which conveys the pressurised oil from the control unit to the clutch, so as to perform opening or closing thereof.

Other preferred features are now described. The kit advantageously comprises a pushbutton to be mounted in a suitable position, for example on the shift lever, on the dashboard or on the steering wheel, so as to engage the clutch when the engine braking effect is desired. This function may be used for example on mountain downhill roads. Preferably, said control device is a pushbutton to be mounted on the existing shift lever or, according to another preferred embodiment, said control device is a pushbutton/pedal to be housed on the support for the driver's left foot, normally provided on the left of the clutch pedal. The existing clutch pedal is no longer used, after installation of the kit, since the clutch is operated automatically. The clutch pedal may be physically removed or, more advantageously, may be locked in its end-of-travel position so that the modification is reversible. Another preferred feature consists in a switch with at least two positions governing the system operating logic and in particular the behaviour of the control unit. Preferably, said switch has at least a first position for normal operation and a second position for travel in a queue. In greater detail, said switch may modify the settings and/or mode of operation of the hydraulic control unit or respective accessories and, consequently, may adjust the speed of engagement and disengagement of the clutch. This may be obtained for example by enabling or disabling means for slow delivery or fast delivery, respectively, of the oil. For example, the hydraulic control unit comprises a fast delivery valve and a slow delivery valve and the selector switch may disable or not the slow valve, so as to influence the response of the clutch.

A further optional feature is a system which allows delaying engagement of the clutch, so as to provide engagement at a predetermined engine speed higher than the idling speed. The inventor has in fact noted that in the known motor-vehicles, including those with an automatic gearbox, the clutch engages immediately at a speed which is substantially equal to the idling speed (typically less than 1000 rpm). The applicant has noted that, in order to reduce fuel consumption when starting from standstill, it is preferable to engage the clutch at a higher speed, for example 1400 rpm. Engagement may be controlled at the predetermined engine speed by means of a delay timer or by means of an engine speed sensor. This regulating feature is advantageous in particular when moving in confined spaces, for example when performing manoeuvres; when travelling in a queue with frequent starts and stops; on slippery roads or snow; in general so as to favour the starting manoeuvre.

It should also be noted that the clutch of a conventional vehicle may be defined as being normally closed. The term of normal is understood as meaning the condition of the device when there is no external operation, i.e. in the rest condition. Pressing of the clutch pedal in fact causes disengagement, while when the pedal is released into the rest position, the clutch remains closed and engaged. On the other hand, the invention provides a clutch which is normally open and which closes (engages) when pressure is applied on the flange and the accelerator pedal, the two together forming a combined pedal.

The invention has the advantage that the vehicle is brought to neutral as soon as the accelerator is released, using the kinetic energy of the vehicle to move forwards. The engine is used only where strictly necessary. The inventor has verified that, on extra-urban roads, with ups and downs, or during conditions of ordinary use, there is a considerable saving in the amount of fuel. It should be noted that the invention does not require the driver to modify substantially his/her driving style, this constituting a further advantage.

The invention is particularly advantageous while travelling in low gears, i.e. typically during the urban cycle. In motor vehicles with a manual gearbox, or also with a mechanical gearbox, in fact, each release of the accelerator corresponds to a sudden deceleration (with waste of kinetic energy) and this occurs in particular when using the low gears where the engine braking effect is most evident. The invention disengages simultaneously the engine and the clutch so as to make full use of the kinetic energy of the vehicle.

Further advantages are achieved with the aforementioned devices including the switch for managing the engaging speed and/or regulator for controlling the delay of clutch engagement, which reduce the fuel consumption levels during various operating conditions, including travel in queue, starting from standstill, etc.

The invention also has the advantage of simplifying driving and reducing the stress in traffic similarly to automatic gearboxes. Compared to automatic gearboxes, however, the invention offers the considerable advantage that it can be applied to practically all vehicles with a hydraulic clutch. Other advantages are the low cost and the compact size.

Another advantage consists in the fact that it facilitates starting from standstill. The invention reduces slipping during the starting manoeuvre which is* the cause of unnecessary fuel consumption. This effect is also noticeable in particular in the urban cycle and in situations which are characterized by frequent stops and starts, for example in heavy traffic.

Compared to a vehicle with an automatic gearbox, which tends to frequently change the spees, the invention allows travel using the same speed (e.g. third speed at about 30-60 km/h), making use of the engine only for short periods and making use of the kinetic energy during the remaining periods.

The invention is applicable to various motor vehicles including cars, light commercial vehicles, etc. The kit may be produced in various versions specifically designed for given vehicles, as will be clear to the person skilled in the art.

One aspect of the invention consists also in a motor vehicle initially provided with a gearbox based on the principles of the invention. Accordingly, one aspect of the invention consists in a motor vehicle with manual gearbox comprising an accelerator pedal and control electronics for performing opening and closing of the clutch, which operates so that the clutch is kept normally open, i.e. disengaged when the accelerator pedal is in the rest condition (i.e. is not pressed), and the clutch is closed, i.e. is engaged partially or totally following pressing of the accelerator pedal. Preferably, the clutch is hydraulically operated and said control electronics perform opening and closing of the clutch by means of said hydraulic operating system.

The invention is now described with reference to preferred examples of embodiment.

Description of the figures

Fig. 1 shows schematically the accelerator pedal of a vehicle modified with a kit according to one of the various modes of implementing the invention.

Fig. 2 shows, by way of example, another possible embodiment which is an alternative to that shown in Fig. 1 .

Fig. 3 shows a block diagram illustrating by way of example a mode of implementing a hydraulic control unit forming part of the kit.

Detailed description

Fig. 1 shows an accelerator pedal 101 after application of the kit. A spring- type induction flange 102 is fitted to the pedal 101 using suitable fixing means which, in this example, consist of a screw 109 which secures one end of the flange to the pedal 101 . The opposite end of the flange is free to flex and therefore may move towards or away from the underlying pedal 101. A block 105 supported by screws 106 carries a sensor 103 able to sense the position of the flange 102. Advantageously the sensor 103 is an induction sensor. The flange 102 may be made for example of tempered sheet metal.

Also shown are the following: a spacing screw 104; an extension spring 107 with a fixing screw 108; an end-of-travel stop 1 1 1 for the flange 102; a switch 1 10 which can be used as an acceleration signalling device able to sense pressing of the accelerator. Advantageously, one or more of these components may be part of the kit.

The spring 107 has substantially the function of damping release of the accelerator 101 so as to give the clutch (now operated by release of the accelerator) time to open. The screw 108 provides an anchoring point and may be fixed, for example, to the floor of the vehicle. The related advantage is that sudden movements during release, which negatively affect the comfort as well as fuel consumption, are avoided.

It should be noted that this embodiment is provided by way of example and that variants are possible as shown for example in Fig. 2 where the flange ( 102 is not fixed to the end of the accelerator with the screw 109, but is fastened on the block 105. The embodiment shown in Fig. 1 is preferred because it ensures a broad deflection of the free end of the flange 102.

Some options (not shown) are as follows. The kit may comprise a luminous or acoustic signalling device, to be mounted in the passenger compartment, for indicating that a predetermined optimum engine speed has been reached. Said engine speed advantageously corresponds to the speed set for engagement of the clutch, as mentioned above.

Another option consists in an electromechanical stop which increases the resistance of the accelerator beyond a threshold position, so as to indicate to the driver a threshold not to be exceeded, for reduction of the fuel consumption.

Fig. 3 shows a diagram of an example of the hydraulic control unit. The following main components are shown in said figure:

1 - electric motor and oil pump 2 - oil flow control and distribution head - oil storage tank

, 6 - flow regulators

- fast delivery electrovalve

- slow delivery electrovalve

, 8B - pressure switches

- oil pressure compensation and diffuser valve0 - purnp oil pressure stabilizer electrovalve1 - clutch pump

- pump actuating cylinder

- slider support flange and extension springs , 17 - sliders for operating selector switches , 19B - pump travel regulating bushes

, 20B - bush fixing and regulating nuts

- extension springs

, 22B - support and cylinder-pump joining screws - cylinder bleed

- oil tank plug

- relay board

- timer for opening valve 10 27 - timer for opening valves 5, 7 with variable delay 28, 29 - oil connection lines

30 - cross-type flow deviator

31 - clutch connection line During use, the delivery of the oil pump 1 1 is connected via a suitable line to the existing hydraulic clutch, such that the system is able to control the clutch of the vehicle. It should be noted that there is a set of regulating bushes 19, 19B and associated nuts which allow adjustment of the pump so as to ensure correct engagement and disengagement of the clutch. The motor-pump assembly 1 supplies oil via the flow distribution head 2; in particular the oil delivery can be controlled by the electrovalves 5, 7 (slow delivery valve and fast delivery valve, respectively), the action of which is dependent on the position of a selector switch / flow regulator for example with two positions (normal conditions / travel in heavy traffic) which preferably forms part of the kit and is installed in the passenger compartment. For example, the selector switch in the position for travel in heavy traffic disables the slow delivery valve 7. The motor 1 advantageously consists of a 12, 24 or 48 volt DC motor.

Other particular features and details are not described in that they are not essential for implementing the invention and are within the sphere of competence of the person skilled in the art. It is understood, obviously, that Figs. 1 -3 are provided by way of example and the invention may be subject to variations.

Claims

1 . Kit applicable to a motor vehicle with a manual gearbox and clutch with a hydraulic control, comprising at least:

- a hydraulic control unit which can be connected to the existing hydraulic control so as to automate operation of the clutch itself;

- control electronics which in particular controls the opening and closing of the clutch by means of said control unit;

- operating means comprising a flange (102) which can be directly associated with the accelerator pedal (101 ) of the motor vehicle, said flange being able to be superimposed on the accelerator pedal, after assembly of the kit, so that the accelerator can be operated by the driver by pressing or respectively releasing said flange,

- and wherein said electronics and said operating means cooperate in such a way that the clutch is kept normally open that is disengaged when said flange is in the rest condition, and the clutch is closed that is partially or totally engaged as a result of pressing of said flange.

2. Kit according to claim 1 , said flange being deformable or movable with respect to the accelerator, once mounted, from a rest position in which

^' the flange or at least a part thereof is at a distance from the accelerator, to a contact position where the flange makes contact with the accelerator, and wherein from said contact position a further pressure exerted on the flange results in pressing of the accelerator.

3. Kit according to claim 1 or 2, wherein said operating means which can be associated with the accelerator pedal comprise a block (105) which carries at least one sensor (103) able to sense a displacement or deformation of said flange.

Kit according to any one of the preceding claims, also comprising a control device to be mounted in a suitable position inside the passenger compartment, which allows to force the closing of the, to use the braking effect of the engine.

Kit according to claim 4, said control device being a pushbutton to be mounted on the existing shift lever or a pushbutton/pedal to be housed on the support for the driver's left foot, on the left of the clutch pedal.

Kit according to any one of the preceding claims, also comprising a switch with at least two positions, which can be installed inside the passenger compartment, the positions of said selector switch corresponding to respective settings of said hydraulic control unit which in turn correspond to different speeds of engagement and disengagement of the clutch.

Kit according to claim 6, wherein the positions of said switch correspond to the enabling or disabling of means (5, 7) for slow delivery or fast delivery, respectively, of the oil, which are associated with said hydraulic control unit, such as to obtain different speeds of engagement or disengagement of the clutch.

Kit according to claim 6 or 7, wherein said selector switch has at least a first position for normal operation and a second position for travel in a queue.

Kit according to any one of the preceding claims, comprising a regulator which allows engagement of the clutch to be delayed, so as to cause engagement at a predetermined engine speed higher than the idling speed.

10. Kit according to claim 9, wherein engagement of the clutch at the predetermined engine speed is controlled by means of delay timer or by means of an engine speed sensor.

1 1. Motor vehicle with manual gearbox comprising an accelerator pedal and control electronics for control of the opening and closing of the clutch, which operates so that the clutch is kept normally open, that is disengaged when the accelerator pedal is in the rest condition, and the clutch is closed, that is partially or totally engaged, following pressing of the accelerator pedal.

12. Motor vehicle according to claim 1 1 , wherein the clutch has a hydraulic control and wherein said control electronics commands the opening and closing of the clutch by means of said hydraulic control.