EP2327083A1

EP2327083A1 - Micro processor regulated timer and a method for preheating a motor of a vehicle

Info

Publication number: EP2327083A1
Application number: EP09816530A
Authority: EP
Inventors: Kjell-Åke HEDLUND
Original assignee: Global Innovation Trading Sweden AB
Current assignee: Global Innovation Trading Sweden AB
Priority date: 2008-09-23
Filing date: 2009-09-23
Publication date: 2011-06-01
Also published as: CA2738734A1; SE0802019A1; SE533990C2; WO2010036196A1; EP2327083A4

Abstract

The present invention relates to a microprocessor-controlled timer adapted to control mains power supply comprising a temperature sensor, wherein said temperature sensor is adapted to detect ambient temperature and that said timer comprises a control device, which is adapted to activate mains power supply in dependence upon temperature indicated by the temperature sensor. Furthermore, the invention includes a method for heating a motor of a motor vehicle and the use of such a timer for regulating withdrawal of electricity from a block heater post.

Description

MICRO PROCESSOR REGULATED TIMER AND A METHOD FOR PREHEATING A MOTOR OF A VEHICLE

TECHNICAL FIELD

The present invention relates to a microprocessor-controlled timer adapted to control a mains power supply comprising a control circuit and a temperature sensor. Furthermore, the invention relates to a method for heating a motor of a motor vehicle and to use of a timer for regulating electrical power from an electrical outlet.

STATE OF THE ART

In many countries, block heaters are an important comfort product in cars, and a number of patents exist within the field. The block heater brings about a possibility to obtain a comfortable temperature immediately in a car in spite of cold weather, and also results in that the working temperature of the motor is sufficiently high already at start-up to minimize emissions of polluting exhaust gases which otherwise are produced at cold start-up.

The patent US 6 218 643 discloses a heater for the battery of a passenger car, said heater comprising a control circuit and a temperature sensor which continuously senses the temperature of the battery. If the temperature falls below a predefined level, the electrical power is switched on and the battery heater is activated.

Another patent, US 6 390 047₅ relates to a device intended for controlling the temperature prevailing in a switched-off car. The system is primarily used to keep the temperature down inside the car. If it becomes too hot inside the passenger compartment of the car, the car motor is automatically started, and a fan system as well as AC are activated. However, the invention is also usable in the form of a passenger compartment heater, in that the motor instead will activate the heating system.

Due to their advantages, block heaters are frequently used in many countries, and block heater outlets are often provided for employees in parking lots in connection with the workplace. To provide block heater outlets is, however, not entirely unproblematic. On the one hand, it happens that individuals will use such an outlet without being authorized thereto, which depends on the fact that this is difficult, and often actually too expensive, to check. It is true that it is known to use lockable block heater outlets, but these often have locks of poor quality which are easy to break/pick open, and also adds a complication factor due to handling of keys. Accordingly, a cost effective solution to this problem is lacking.

An associated problem with block heaters is that outlets at workplaces, where the user does not pay the electricity himself/herself, often are used for connection times which are too long, i.e. connection times for the block heater which are longer than needed to achieve the desired temperature. The reason for this can have many different causes/explanations. One explanation is that a user simply lacks a time limiting means, implying that the block heater is active from being plugged in until being pulled out without regard to the actual need. It is known that many motorists plug in the block heater in connection with parking upon arrival, despite awareness of the resulting unnecessary consumption. One reason for this can, of course, be that the user has a long walking distance between the parking lot and the workplace, or that there is no time during the working day to leave to plug in the block heater.

This first mentioned cause can be eliminated substantially by having some form of time limitation for the connection, either arranged centrally or at the user's connecting device. Also in such circumstances, however, excessive withdrawals occur, for example due to the fact that the motorist, when parking the vehicle, makes an erroneous setting or an erroneous estimation of the time for activation of the block heater to achieve the desired temperature as close to the time of need as possible. One reason for misjudgement can be that a change in the weather takes place during the day, If it is very cold in the morning, but then gets warmer very quickly, it is obvious that the user will set an activation time which is too early if the user assumes the same cold weather to continue for the whole day. The same is the case if the user safeguards himself/herself against colder weather during the day, that is to say, an excessive withdrawal will occur if the temperature remains constant or increases instead, Accordingly, there are many explanations and causes for an excessive withdrawal of electrical energy occurring when using block heaters, which of course is undesirable from many aspects.

SUMMARY OF THE INVENTION

It is an object of the present invention to eliminate or at least minimize the above- mentioned problem, something which is achieved by means of a microprocessor- controlled timer, adapted to control mains power supply comprising a temperature sensor, which is characterized in that said temperature sensor is adapted to detect ambient temperature and that said timer comprises a control device, which is adapted to activate mains power supply in dependence upon temperature indicated by the temperature sensor.

Owing to the invention, it is possible, when heating a motor of a motor vehicle, to limit the withdrawal of electricity to an amount corresponding to that required for obtaining a desired temperature. In this way, energy and costs are saved without having to forgo the comfort of having a warmed-up motor and passenger compartment, respectively, at start-up.

In the description, the invention is exemplified by the use for heating a motor of a passenger car by means of a block heater, but it should be understood that the invention can be used for all types of vehicles being equipped with block heaters driven by electricity. Furthermore, also passenger compartment heaters are encompassed by the word.

According to another aspect of the invention, said control device comprises a time control means which can be set to disconnect the electricity supply at a predetermined stopping time. Thereby, no electricity is consumed when the motor is completely warmed up. Because said time control means is adapted to calculate a time window, based on said time control means, wherein said time window comprises the time immediately before the predetermined stopping time, it is ensured that the motor is completely warmed up at the set stopping time. Because said calculation takes place continuously and because the timer activates mains power supply at a point in time corresponding to the beginning of said calculated time window, the advantage is achieved that the timer can continuously adjust for temperature changes and thereby regulate the withdrawal of electricity so that a minimum consumption of electricity is obtained with a maintained result, i.e. a completely warmed-up car.

According to another aspect of the invention, the timer is to be placed on a suspension device in close vicinity of an electrical outlet, whereby undesired load on the electrical outlet can be avoided. Furthermore, the advantage is achieved that owners of conventional posts with electrical outlets for connection of a block heater, hereinafter referred to as block heater posts, can achieve the advantages of a controlled withdrawal of electricity, at the same time as the user of the timer achieves the same comfort as before, i.e. a warmed-up car on departure. Preferably, the suspension device is provided with a unit generating a magnetic field and the timer comprises a magnetic field sensor which senses the magnetic field in the suspension device. Because the magnetic field sensor sends a signal to the microprocessor which, via a relay, regulates the current supply to a female connector of said timer to which the block heatei cable is connected, it is ensured that the timer is positioned correctly for enabling the female connector to become current-carrying. A correct positioning of the timer on the suspension device is 5 important from an electrical safety point of view.

According to still another aspect of the invention, said timer comprises a position sensor which senses whether the female connector of the timer is directed substantially vertically downward. Because the position sensor sends a signal to the microprocessor l o which, via a relay, controls the current supply to the female connector of the timer to which the block heater cable is connected, it is ensured that the female connector is not current-carrying unless the female connector is directed substantially vertically downward. This means, inter alia, that the risk of the timer being current-carrying, if it is positioned so that there is a risk of penetration of moisture, is eliminated.

15 Furthermore, it is ensured that the female connector is not current-carrying if e.g. a child is tempted to try to insert something else into the timer while it is connected to an electrical outlet, since the handling probably results in the timer being turned upwards, so that the female connector will not be substantially directed vertically downward. 0 According to another aspect of the invention, it is an advantage, inter alia, from an anti- theft point of view, that utilization of said timer requires some kind of identification, preferably in the form of a personal pin code. Thereby, the employer or the owner of the timer can make sure that no other individuals than those authorized can use the timer. 5 Furthermore, it is an object of the invention to provide a method for heating a motor of a motor vehicle. Because of the fact that said method comprises the steps of:

a) detecting a point in time (Si), i.e. stopping time, when said motor is desired to be warmed up, 0 b) detecting a temperature (T) in the environment where the vehicle is located, c) calculating a time window (W_v), i.e. the time required to warm up the motor, from the prevailing temperature, d) calculating a starting time for switching on electricity (So) to a block5 heater in said motor vehicle, based on said stopping time and said time window, e) supplying a block heater in said vehicle with electricity at said point in time for switching on electricity,

an efficient method of regulating the withdrawal of electricity when using block heaters is obtained, and unnecessary withdrawal of electricity can be avoided or at least minimized.

Another object of the invention is to enable a cost effective solution for regulating the withdrawal of electricity from existing block heater posts, at the same time as the car owner using the block heater post is ensured a.completely warmed-up car on departure. This is enabled by the use of an inventive timer for regulating withdrawal of electricity from a block heater post.

The solution further implies that owners of conventional block heater posts can provide time and temperature controlled withdrawal of electricity in a very simple and cost effective way, since it is only a very limited adaptation or no adaptation at all which has to be done in order to enable the use of an inventive timer at such a block heater post.

Furthermore, it is an object to provide a possibility of upgrading existing block heater posts with an earth fault breaker placed in a cabinet, which also provides a reliable suspension of the timer in connection with an existing block heater post.

BRIEF DESCRIPTION OF FIGURES

In the following, the invention will be described in greater detail with reference to the attached figures in the drawings, in which:

Fig. 1 shows a perspective view of a timer according to a preferred embodiment of the invention,

Fig. 2 shows the inside of a timer according to the invention,

Fig. 3 shows a parked passenger car connected to a timer according to the invention, Fig. 4 shows a timer suspended on a holder.

DETAILED DESCRIPTION OF FIGURES

Fig. 1 shows a timer 1 according to a preferred embodiment of the invention, in a view obliquely from the front. In its upper part, the timer comprises a display 2, control buttons 3-6, and in its lower part, a downwardly directed female connector 8 for connection of a block heater via a block heater cable. The timer is further enclosed by an external protective casing 7, adapted for a single-handed grip around a central portion^ making it user friendly and easy to handle for both right and left handed persons. The timer further comprises a mains cable 9 with a male connector 10 for connection of the timer to an electrical outlet. The mains cable runs out through a hole on the back side of the casing in the lower part of the timer, and also here it is an advantage if the hole in the casing through which the mains cable runs is directed downward, suitably also sealed, in order to prevent penetration of moisture and dirt. In the upper part of the timer, there is arranged a lug 11 adapted for suspending the timer on a suspension device. The display and the control buttons are, in a way known to the skilled person, placed underneath a sealing window, a so-called overlay 12, which protects against dirt, moisture and wear,

The above-mentioned display 2 is preferably a LED display with a number of light segments which makes it easy to read even in difficult light conditions. In close proximity of said display, there are control buttons 3-6 by means of which the user controls the selection of preset stopping time, selection of hours/minutes, ON/OFF function. Furthermore, the function (stopping time, real-time clock or temperature indication) which is to be shown on the display can be selected by means of the control buttons.

Fig. 2 shows a timer 1 according to the invention, where the front side of the casing is removed and the inside components are exposed. The female connector 8 into which a male connector is intended to be plugged is situated in the lower part of the timer. It can be seen that said female connector is positioned so that it will be turned substantially vertically downward when the timer is suspended by its lug 11, which protects the female connector from dirt and descending dampness. The female connector is suitably provided with a foldable cover and is finger-safe.

The display 2, the control buttons 3-6 and a battery 19 are mounted on a first circuit board 13 attached inside the casing 7 of the timer 1. The casing further comprises a second circuit board 14 on which a transformer 15, a position sensor 17 and an AC/DC converter for the electronics 18 are mounted, here schematically shown as a box. Furthermore, the casing comprises a relay 16, a temperature sensor 20 for sensing the temperature of the environment, a magnetic field sensor 21, and a microprocessor 22 placed on the bottom side of the first circuit board 13. The above-mentioned microprocessor comprises a battery-supported real-time clock, which is used for the microprocessor programmer and receives its current from said battery 19. The microprocessor also controls the display 2, the relay 16, and decodes button strokes and sensors.

A user sets said timer by means of the control buttons 3-6. The timer must be connected to an electricity source to enable settings to be made, Real-time and desired stopping time are settable, whereas temperature can only be observed on the display. Stopping time refers to the point in real-time when the car will be taken in use and is desired to be warmed up, Several stopping times, preferably at least three, can be preset in the timer, so that one of these times easily can be selected on arrival at the parking lot.

Upon arrival at the parking lot, the timer 1 is connected to an electrical outlet, e.g. an electrical outlet on a block heater post, via the mains cable 9, The user connects the timer to the electrical outlet of the block heater post, whereby the timer is switched on. Preferably, a log-in is then required in order to be able to activate the timer and to make actual settings, for example in the form of a personal code which is input via the control buttons. It is of course conceivable to use some other kind of identification, e.g. an electronic transponder RFID, Thereafter, the operator can select a preset stopping time or set a new one and then select the new stopping time. The timer also comprises a function for temporarily moving the preset stopping time, e.g. with intervals of fifteen minutes, to up to ±2 hours,

The block heater cable 17 (see Fig. 3) to the parked car is connected to the timer via the female connector 8. Thereafter, the timer is suspended by its lug 11 on a suspension device intended for this purpose, most easily placed below the electrical cabinet on the post itself. It is advantageous that the female connector 8 is directed substantially vertically downward when it is used. Thereby, the advantage is achieved that the connector is protected from descending rain and moisture in case the car is parked in the open. This advantage is achieved because the timer is intended to be freely suspended via its lug 11. The block heater cable 17 is hanging directed downward, which also contributes to maintaining said timer in a vertical position during use.

In a conceivable embodiment of the timer, the suspension device comprises a unit generating a magnetic field, and the timer a corresponding magnetic field sensor 21. The magnetic field sensor, which can be of a magneto-resistive type, senses the magnetic field when the timer is positioned on the suspension device and sends a signal to the microprocessor 22 which, in its turn, switches a relay 16 to a closed position, which is a prerequisite to enable the female connector 8 to become current-carrying. It is appreciated that this is an advantage from a safety point of view, since all handling of the timer, i.e. setting of stopping time etc. and connection of the block heater cable, can take place without the female connector being current-carrying.

Because the timer is placed on a suspension device, an additional advantage is obtained in that the female connector in the block heater post is not subjected to any appreciable load. There are regulations which regulate how high a turning torque such connectors can be subjected to. In Sweden, the regulations from Elsakerhetsverket stipulate that turning torque cannot exceed 0.25 Nm. Another advantage is that the cover over the electrical outlets in the block heater post can be closed and locked, as is stipulated. Still an advantage with this arrangement is that the timer becomes unusable without the suspension device, which makes it less liable to be stolen. As soon as the timer has been suspended correctly on the suspension device, the timer enters an active state. The active state will be described in the following.

In another conceivable embodiment, the timer comprises a safety function in the form of a position sensor 17, which senses whether the female connector 8 of the timer is directed substantially vertically downward. The position sensor (tilt sensor) can e.g. be of the type marketed by the company Signal Quest, www. signalquest. com under the designation SQ-SEN-660. This position sensor is mechanical and operates without electricity, which is advantageous. The position sensor can be set to sense the angle of inclination of the timer, e.g. an imaginary vertical line through the timer or an imaginary centre axis of the female connector, and to temporarily disconnect the current to the female connector if it exceeds a preset angle α to the plumb line L (see Figure 4). If this occurs, the position sensor will temporarily disconnect the current to the female connector by sending a signal to that effect to the microprocessor which switches the relay to an open position. Because this type of sensor has a spherical range of control, i.e. scans over 360°, and wherein the area outside the preset acceptable angle α is classified as a so-called dead zone which generates a sλvitch-off signal, it also senses if the timer should end up upside down. When the timer reassumes its correct position, the position sensor senses this, and the current to the female connector is switched on again- This function primarily aims at preventing that children, playing with a suspended timer and trying to insert something into the female connector, come to harm. Together with the design of the timer, this function ensures that the timer is not usable if, for some reason, it should end up hanging in its mains cable, i.e. be hanging upside down. From a handling point of view, it is an advantage if the current to the female connector is not disconnected by too small deviations from the plumb-line, It is appreciated that the timer may be oscillating like a pendulum motion about its attachment due to wind, that someone might unconsciously get in contact with the mains cable from the timer to the block heater receptacle on the vehicle and that the timer thereby may end up hanging slightly diagonally. This should of course not result in the current being switched off, and the applicant therefore estimates that a suitable angle α for when the current is to be switched off is somewhere between 30-60° from the plumb line. In this embodiment, the angle α has been selected to be 60° from the plumb line, i.e, the total angle where the current to the female connector is switched on is 120° between the end positions. This angle can of course both decrease and be increased if this is found to be suitable. However, as pointed out previously, the current to the female connector should be disconnected if it ends up in a position where there is a risk that moisture penetrates into it. In such a case, it is also possible that an additional safety function should kick in, which prevents the current from being switched on when the timer reassumes the correct position, or first when a control function has been run which verifies that no moisture has penetrated.

In the embodiment with the position sensor, the active mode is entered directly when the timer is connected to the electricity receptacle of the block heater and is switched on. The skilled person will appreciate that the function magnetic/magnetic field generating unit + magnetic field sensor and position sensor, respectively, can constitute complementary solutions.

In the active mode, the timer can calculate a starting time for switching on electrical power to the block heater based on the indicated stopping time Si and the temperature T (⁰C) of the environment. A temperature sensor 20 will continuously measure the temperature of the environment, which is further is registered by a time control means comprising the microprocessor 22. The environment can for example correspond to a garage or an outdoor environment, depending on the location of the parking lot. Based on the indicated temperature and on the selected stopping time, the time control means continuously calculates a starting time So for switching-on of electrical power to the block heater. The calculated time required for warming up a connected car is called a time window S and comprises a certain period of time immediately before the actual stopping time, at least 60 minutes and at the most 4 hours. The method implies that a possible change in weather is compensated by changing the calculated time window accordingly. The block heater is activated for a longer period of time at cold weather, and a shorter period of time at warmer weather. The following formula is used for calculating the time window taktiv:

t_aktiv=-7.2 x T + 60, where takiiv is the time in minutes,

T - is the temperature of the environment as measured in degrees Centigrade.

The timer is interlocked to calculate a time window according to the formula within a temperature interval from 0 ⁰C down to -25 ⁰C. At temperatures of 0 ⁰C and above, a time window of 60 minutes is obtained. It is appreciated that at even higher temperatures, e.g. 10 ⁰C, an even shorter period of time is sufficient and the timer can of course be interlocked also to indicate a shorter time window, but in order to also provide the comfort of a warmed-up passenger compartment, the smallest active time has been set to 60 minutes. At a temperature of -25 ⁰C and below, a time window of 4 hours is obtained. In the table below, examples of the length of the time window relative to the ambient temperature at some different temperatures are given:

Table 1, Len th of time window at different tem eratures

The skilled person will appreciate that the formula for calculating the length of the time window at different temperatures can be changed in dependence upon different parameters, e.g. motor size and maximum time window. If an even more energy saving embodiment than above, but with otherwise unchanged parameters, is desired, the timer can be interlocked to allow a shorter maximum time window, e.g. 3 hours at a temperature of -25 ⁰C and below, In that case, the formula for calculating the time window and the length of the time window at different temperatures instead becomes:

W=-4.8 x T + 60

Table 2, Length of time window at different temperatures., energy saving regulation The time control means can of course be adjusted to instead detect ambient temperature and to calculate the time window in a non-continuous manner, e.g, once each tenth minute or as seen appropriate.

At the point in time for calculated stalling time, that is to say at the beginning of the time window, the timer switches on electrical power to the female connector 8, which activates the block heater connected to the timer. When the stopping time has been reached, the timer switches off the electrical power. The user can drive away with a warmed-up motor.

The timer also comprises a function for temporarily moving the stopping time without changing the preset stopping time, This can be utilized when the user e.g. plans to work overtime, or to leave earlier than normal. The stopping time is moved in steps, e.g. of 15 minutes, up to a maximum of 3 hours, whereupon the sequence starts over again from the initially preset time. The movement of stopping time displaces the entire time window for the subsequent heating of the motor.

If the user should forget to pull out the block heater cable before departure, the positioning of the female connector and the fact that timer is movably suspended contribute to cause the block heater cable to be pulled out of the timer without any risk of the timer casing being damaged. This last-mentioned function ensures that no current- carrying components are exposed.

Fig. 3 shows an example of use of a timer according to the invention. A car 14 is parked in a parking lot at which a conventional block heater post 23 is available. A suspension device (not shown) for an inventive timer is mounted on the block heater post. A timer 1 is freely suspended on said suspension device, and a male connector being part of a block heater cable 17 is connected to the female connector 8 of said timer.

Fig, 4 shows a timer 1 according to one embodiment of the invention, wherein said timer 1 is suspended substantially vertically on a suspension device 24. The suspension device is most simply constituted of a conventional hook made of a magnetic material which generates the magnetic field which can be sensed by the magnetic field sensor, Preferably, however, the suspension device is given a design which allows a stable mounting on a block heater post, at the same time as the suspension device can accommodate a magnetic/magnetic field generating unit which can be sensed by the magnetic field sensor of the timer when the timer is suspended on the suspension device correctly. It is appreciated that the magnetic field generating unit of the holder is selected so that it is compatible with the magnetic field sensor of the timer, i.e. generates a magnetic field with a magnetic field strength which is adapted to the purpose.

Accordingly, by means of providing a timer to a user, the owner of a block heater post, e.g. an employer, can ensure himself/herself of an efficient utilization of the electricity and thereby minimize unnecessary withdrawal of electricity. If the timer comprises a magnetic field sensor, a suspension device with a magnetic unit is provided, which magnetic field sensor, if a timer is correctly positioned on said suspension device, sends a signal to that effect to the microprocessor which, in its turn, controls a relay to a closed position. The utilization of the timer preferably requires some kind of log in. It can for example be a pin code which the individual user chooses or is given, or a code which can be common for employees at a workplace. In order to stimulate the user to use the timer, private use can be encouraged by providing an additional suspension device which the user installs at home, i.e. a win-win situation. It is appreciated that owners of electrical connections, who already control the withdrawal of electricity e.g. by means of a time limitation, achieve additional advantages by means of the inventive timer, since unnecessary withdrawal of electricity is eliminated owing to the temperature control. Furthermore, it is conceivable to permanently provide a power post with a timer by locking the cover, when the timer has been connected to the electrical outlet in the post, so that access to the connectors is prevented and the user has to connect via the timer.

The invention also relates to a device for upgrading existing block heater posts with an earth fault breaker. This normally requires that an intervention is made in the apparatus cabinet on the block heater post, something which is expensive and requires renewed certification/inspection, or is possibly not even allowed by the electrical safety board. The applicant has solved this problem, and at the same time an adequate storage of the timer in connection with the block heater post is provided. The applicant has designed a lockable timer cabinet (not shown), comprising an earth fault breaker, which is intended to be connected to an existing block heater post. Electricity to a block heater can then be withdrawn from this timer cabinet. The timer cabinet, most simply in the form of a box with a lockable cover being lockable and sealed against penetrating moisture, is adapted to be mountable on the block heater post, alternatively to be placed in another suitable way close to the block heater post. From the timer cabinet runs a mains supply cable and, at its end, there is a male connector intended to be connected to the female connector of the block heater post, whereupon the cover on the block heater post can be folded down and locked/sealed by the owner in the intended way. Inside the timer cabinet, there is a female connector and an earth fault breaker which disconnects the current thereto in case of an earth fault. Inside the cabinet, there is also a holder for an inventive timer. In the bottom of the cabinet, there is an opening for the mains supply cable from the timer to the block heater receptacle of the vehicle. Preferably, also this opening is sealed in order to prevent moisture penetration into the cabinet.

When the owner of a vehicle arrives at the parking lot close to the block heater post, he/she will thus have to suspend his/her timer in the timer cabinet and to connect his/her timer to the female connector therein, instead of in the electrical outlet of the block heater post. Because the timer cabinet is lockable, a protected and theft-proof suspension of the timer is provided. Furthermore, the advantage that all withdrawal of electricity has to pass via the timer cabinet and the earth fault breaker therein is achieved.

The invention also relates to a method for heating a motor of a motor vehicle and to the use of an inventive timer when regulating withdrawal of electricity from an electrical outlet, preferably at a block heater post. The method comprises the steps of detecting a point in time (Sj)₅ i.e. stopping time, when said motor is desired to be warmed up, detecting a temperature (T) in the environment where the vehicle is located, calculating a time window (t_aktj_V), i.e. the time required to warm up the motor, from the prevailing temperature, calculating a starting time for switching on electrical power (So) to a block heater in said motor vehicle, based on said stopping time and said time window, and supplying a block heater in said vehicle with electricity at said point in time for switching on electrical power. Furthermore, the method also comprises the step of switching off the electricity supply to said block heater at said stopping time.

ALTERNATIVE EMBODIMENTS The invention is not limited by what has been described above, but can be varied within the scope of the following claims. For instance, it is appreciated that the described timer does not need to be specifically intended for use together with a block heater, but also in other contexts where it is convenient to regulate the withdrawal of electricity in dependence upon the prevailing temperature. For example, in certain cases it might be convenient to have a room or a house warmed up at a certain time, which could be accomplished by means of said timer connected to an electrical heating element or the like. It is further appreciated that the timer can be used at an air-conditioner, when it is desired to have a space cooled down at a certain point in time. The skilled person will appreciate that, depending on the field of application, the time control means in the timer is provided with an adapted formula for calculating a correct time window for the desired action. Furthermore, it is appreciated that, within the scope of the inventive thought, the components included in the timer can be varied. Of course, other electronic and/or electro-mechanical components can be used. As an example, it can be mentioned that the transformer 15 can be constituted of a switched mains unit instead which meets new regulations on current consumption in stand-by mode. The position sensor can be constituted of other types than the one described above, e.g. be resistive, inductive, capacitive, of accelerator type, inclinometer type, gyroscopic or semiconductor type. The same applies to the magnetic field sensor, which e.g. can be mechanical of the heavy-element type, or IC-circuit-based of the Hall effect switch-type.

It is conceivable to arrange the timer in close vicinity of a public parking lot, which thereby could also provide a possibility for withdrawal of electricity for block heaters. A system of this kind would provide a possibility to reduce emissions due to cold startups, which otherwise are difficult to avoid. Because the car driver pays for parking for a certain period of time, a stopping time, i.e. an expected time of departure, is obtained. The car driver can then choose to also pay a fee for withdrawal of electricity to his/her block heater and to plug his/her block heater cable into the timer which, in the way described above, ensures that the motor of the car is warmed up when the parking time expires, In a similar way, a possibility to "fill up" electricity can be provided for electric vehicles and hybrid vehicles, which could mean that special filling stations for these vehicles are not needed. The skilled person will appreciate that if the timer is to be used for hybrid vehicles, the microprocessor has to be provided with special software for this having a calculation formula adapted thereto. In order not to overload the block heater post, power will have to be supplied during a longer period of time, so that the battery of the car can be charged before warming up the motor,

It is appreciated that the timer can be given a different shape than the one described here, but it should be so designed that the female connector is protected against penetrating dampness. The suspension device and the lug on the timer can of course be varied. For example, suspension devices adapted in shape, of male/female attachment type, can be used. If the safety function with a magnetic detection is not demanded, it is appreciated that the timer can be provided with an attachment of another kind instead, for example a lug for suspending the timer on one of the viechle's side mirrors. Furthermore, it is appreciated that the timer can be placed in a holder protecting against dampness and moisture. Such an embodiment probably implies that the timer will be fixedly positioned, wherein the safety function with shutting off the current when the timer is inclined is not required. Furthermore, it is appreciated that the invention encompasses equivalent solutions for the above-mentioned function with the position sensor. The position sensor can e.g. be adapted to send a signal to the time control means, if the angle of the female connector exceeds the preset angle, which instead disconnects the electricity supply to the female connector.

The skilled person will further appreciate that it is conceivable to integrate a timer with a block heater cable. For example, the timer can constitute an integrated unit of the female connector of the block heater cable, i.e. the connector which is connected to the block heater receptacle of the car. This would probably require that the block heater receptacle of the car is designed for withstanding the turning torque caused by the weight of the timer. It is of course appreciated that the timer can be made smaller and be designed in a way reducing the turning torque. Furthermore, the block heater cable can be fixedly connected to the timer, which nonetheless comprises an attachment or some form of suspension device allowing the timer to be suspended in the way described previously. The skilled person will also appreciate that the timer can constitute an integrated part of the timer cabinet but that this implies that the private electricity saving which the owner of a mobile timer can be offered cannot be achieved.

Furthermore, it is appreciated that the disclosed design of said control buttons 3-6 should be regarded as exemplary only. It is conceivable that setting of stopping time and real-time clock can have separate control buttons, or that the control can take place by means of a touch pad or the like,

Claims

1. A microprocessor-controlled timer (1), adapted to control a mains power supply comprising a temperature sensor (20), characterized in that said temperature sensor is adapted to detect ambient temperature (T), and that said timer comprises a control device adapted to activate a mains power supply in dependence upon temperature (T) indicated by the temperature sensor (20).

2. The microprocessor-controlled timer according to claim 1, characterized in that said control device comprises a time control means, which can be set to switch off the electricity supply at a predetermined stopping time (Si) .

3. The microprocessor-controlled timer according to claim 2, characterized in that said time control means is adapted to calculate a time window (ta_kϋv) from the set stopping time (Si), based on the temperature (T) indicated by said temperature sensor (20), wherein said time window comprises the time immediately before the predetermined stopping time.

4. The microprocessor-controlled timer according to claim 3, characterized in that it activates mains power supply at a point in time corresponding to the beginning of said calculated time window.

5. The microprocessor-controlled timer according to claim 2_S characterized in that said time control means comprises a software adapted to calculate the time window for heating a motor, preferably a motor of a passenger car.

6. The microprocessor-controlled timer according to claim ^characterized in that it is adapted to be placed on a suspension device (24) in close vicinity of a parking lot with access to an electrical outlet.

7. The microprocessor-controlled timer according to claim 6, characterized in that said suspension device (24) comprises a unit generating a magnetic field, and that the timer comprises a magnetic field sensor (21) which senses the magnetic field if the timer is correctly positioned on said suspension device and sends a signal to that effect to said time control means, whereby an electricity supply to a female connector 8 of said timer is enabled.

8. The microprocessor-controlled timer according to claim ^characterized in that said timer comprises a position sensor (17) which senses whether the female connector 8 of the timer is directed substantially vertically downward and sends a signal to that effect to said time control means, whereby the electricity supply to said female connector 8 of the timer is enabled.

9. The microprocessor-controlled timer according to claim 2, characterized in that utilization of said timer requires some kind of identification, preferably in the form of a personal pin code, for enabling setting and/or selection of stopping time (S₁) to be made.

10. A method for heating a motor of a motor vehicle, comprising the steps of:

a) detecting a point in time (Si), i.e. stopping time, when said motor is desired to be warmed up, b) detecting a temperature (T) in the environment where the vehicle is located, c) calculating a time window (t_akti_v) , i-^e- the time required to warm up the motor, from the prevailing temperature,. d) calculating a starting time for switching on electrical power (So) to a block heater in said motor vehicle, based on said stopping time and said time window, e) supplying a block heater in said vehicle with electricity at said point in time for switching on electrical power.

11. The method for heating a motor of a motor vehicle according to claim 10, characterized in that it also comprises the step of: i) switching off the electricity supply to said block heater at said stopping time.

12. The method for heating a motor of a motor vehicle according to claim 10, characterized in that said time window comprises a continuous period immediately before said stopping time.

13. A use of a timer according to any one of the claims 1-9 for regulating withdrawal of electricity from an electrical outlet, preferably at a block heater post (23).

14. A timer cabinet, comprising a compartment in which a holder for a timer according to any one of claims 1-9, a female connector for electrical connection of said timer to an electrical grid, an earth fault breaker, and a mains supply cable, are arranged.

15. The timer cabinet according to claim 15,characterized in that said holder comprises a magnetic and/or magnetic field generating unit, which is arranged to interact with a magnetic field sensor in said timer when said timer is placed on said holder.