SE507435C2 - Procedure and arrangement for accelerating the heating of the vehicle engine in a retarded vehicle - Google Patents

Abstract

A heating function which, when switched on, allows simultaneous retarder braking and throttle, is used to accelerate heating of a motor vehicle equipped with a hydraulic retarder (2). Normally the retarder is controlled by an electrical system which incorporates a blocking function preventing the retarder from performing braking work whilst the engine is being throttled. But because of the heating function incorporated in the retarder control unit the retarder can be used to increase the engine load to accelerate its heating. The braking work perfomed by the retarder is cooled by the engine coolant, which is thereby heated and further accelerates the heating.

Description

10 15 20 25 30 35 507 435 operating parameters, so that the engine always works optimally with consideration of current operating parameters and the driver's wishes.

Among these, by means of various sensors, continuously monitored and sensed operating parameters can be mentioned the accelerator pedal position, the charge air pressure in the engine, coolant temperature, engine speed, vehicle speed respectively the one desired by the driver and by means of the vehicle's automatic constant speed set constant travel speed.

The fuel injection control system connected in this way different sensors thus contain information about the current vehicle operating license. This information can also be used for others computer-based control systems included in the vehicle, such as control systems for vehicle retarder. The retarder's control system is usually on its own conventionally designed to optimally control the retarder in depending on different operating parameters. The retarder's control system is available for example, programmed barriers that prevent the retarder from is activated at the same time as the driver affects the throttle. Such a driving style with simultaneous acceleration and brake activation is not normally appropriate.

Object of the invention The object of the invention is to be able to use the hydraulic the retarder at a motor vehicle to accelerate engine warm-up.

You want to be able to engage it as a hydrodynamic brake functioning retarder already in connection with the start-up of the vehicle, in order to utilize the retarded power developed during braking as soon as possible to provide heating of the coolant in the engine cooling system.

This heating is then obtained partly due to the engine now forced to work with increased load due to the retarder braking effect, which increases the heat developed during combustion, partly due to the braking effect that the retarder "brakes away" and which thereby resulting in heating of the retarder's hydraulic oil whose heat absorbed by the engine coolant via one between the retarder hydraulic oil and coolant effective heat exchanger.

Such driving with simultaneous braking by means of the retarder and 10 15 20 25 30 35 507 435 however, as explained above, throttle is not normally possible with one modern diesel engine with electrically controlled retarder.

Disclosure of the invention However, this problem can be solved, and the above-mentioned object is thereby achieved, on the procedure and arrangement of the kind initially indicated also involves taking the characterizing part of claim 1 specified measures respectively that the arrangement is designed according to The characterizing part of claim 7.

Further developments of the procedure are set out in the dependent claims 2- And further developments of the arrangement of the dependent claims 8- 9.

The basic idea of the invention is thus that through the proposed the procedure and the arrangement, respectively, cancel the locking function against driving with simultaneous acceleration and deceleration braking, which is available built into the computer-controlled retarder control system This allows the retarder equipped to perform braking work at the same time as the engine is given throttle, thereby increasing the load on the engine and heating of the engine coolant is accelerated, partly by the increased load on the engine and partly by absorbing heat from the retarder hyd raulvätska.

The vehicle's engine heating function by utilizing heat which the retarder develops when performing braking work involves in other words that the operation of the accelerator pedal (accelerator) is prevented from disable or disconnect the retarder. This allows the vehicle engine and the retarder "runs" simultaneously (i.e. the engine operates under throttle at the same time as the reta rder performs braking work) which results in fast heating of the coolant in the vehicle's cooling system, and thus fast heating of the engine, as well as heating of the vehicle passenger compartment as this in turn is heated by the engine coolant.

An additional advantage of fast engine heating is a faster achieving its operating temperature and a corresponding faster 10 15 20 25 30 35 507 435 reducing its exhaust emissions. Diesel engines emit at cold starts and during heating so-called white smoke and a rapid heating reduces the inconveniences hereby faster.

The abolition of the said locking function against driving at the same time braking by means of the retarder and throttle can suitably be done by man, when the vehicle engine is started, simultaneously activates a special heating function. This can be activated by means of a manual actuable actuator, for example a special button, and this button can advantageously be combined with an already existing control associated with the retarder's control system. The use of an already existing one controls have the advantage that no additional components are required, and the modification may be limited to software in the retarder control system.

Brief description of the drawings The invention will now be further elucidated and explained reference to an arrangement shown in the drawings for carrying out the method according to the invention.

For the drawing figures, Fig. 1 shows in a very schematic way the essential parts of the invention for a control arrangement of the engine warm - up function of a diesel - powered vehicle with a retarder system set up to accelerate engine heating. IN Fig. 2 shows in block diagram form a flow chart for engine heating function.

Description of embodiment Fig. 1 schematically shows an arrangement which enables acceleration of the heating of a diesel engine in a motor vehicle fitted with a connectable hydraulic retarder 2 that can be used either as hydrodynamic auxiliary brake for vehicle deceleration, or as aids for accelerating the heating of the vehicle engine. Themselves the vehicle engine is shown in Fig. 1 only in the form of one driven by the vehicle engine motor shaft 4 which via a clutch 6 supplies the motor power to a gearbox 8. The driving force is then transmitted from the output shaft 10 of the gearbox 10 15 20 25 30 35 507 435 in a conventional manner to the subsequent parts not shown here vehicle driveline. A hydraulic retarder 2 is further connected to one oil sump 12, an accumulator 14 and an oil cooler 16.

Activation (on) and deactivation (disconnection) of the retarder 2 is electrically controlled by a computer-based control unit 18 which is standing in connection with the retarder 2 via a signal line 20. It is known that a such control unit 18 comprises a locking function which prevents the retarder can be activated at the same time as the engine is given throttle.

The locking function also means that in the event that the retarder is connected in this way this is automatically disconnected as soon as throttle is applied. It showed the arrangement is thus to a significant extent normally included in one with retarder provided vehicle, but is also used in accordance with this invention for to enable the retarder to be activated when starting the vehicle engine in order to by means of it bring about an increase of the engine load as well at throttle and thereby accelerate the heating of the coolant in the engine's regular cooling system. The activation of this heating function is done by canceling the locking function against driving with simultaneous retarder braking and accelerator that is built into the retarder's computer-controlled control system.

For the control of the retarder 2, both when driving with the heating function activated or not activated, must the computer 18 become aware of a number of relevant control parameters.

Information about these control parameters is obtained by the computer 18 via signal lines from i.a. the units and sensors shown in Fig. 1.

The control system for the retarder 2 works in close collaboration with the control system for the engine's electronically controlled fuel injection. l practice is designed these two control systems as separate units, but because of their intimate collaboration, they have in Figure 1 been integrated in the control unit 18.

The controls operated by the driver, such as the clutch pedal 22, the brake pedal 24 and the accelerator pedal 26, are of course controls whose action on the operation of the vehicle and the engine are significant in this context. To these pedals are therefore connected here not further shown actuators as via signal lines 28, 30 and 32, respectively, emit state signals to the control unit 18. One engine speed sensor 48 and one 10 15 20 25 30 35 507 435 coolant temperature sensors 50 are also via signal lines 49 and 51, respectively connected to the control unit 18. Since it is an electric control system, the control unit 18 is also connected via a line 34 a switch 36 whose switching on causes the system to be switched on electricity supply. This switch 36 can be conveniently operated with the ignition key.

The abolition of the above-mentioned locking function against driving at the same time acceleration and braking with the retarder take place at the shown the arrangement by switching on a heating function, which is stored in the control unit 18. Activation of the heating function can take place automatically at start-up or with the help of a special control. In this For example, activation takes place in accordance with the following. Retarderns control unit 18 comprises a function known per se for constant speed keeping which, when activated, ensures that the vehicle is braked at a constant speed, for example when driving downhill. The activation of this constant cruise control function takes place with the help of one that can be activated by the driver control switch 38. In this example, this is used control switch 38 also for activating the heating function.

An advantage of this is that this component is already available and the modification required is limited to the control unit 18 software. The heating function is then switched on simultaneous activation of the control switch 38 and start of the motor.

The control unit 18 comprises software that detects this simultaneously activation of the control switch 38 and the start switch 36. At activation of only the control switch 38 this functions as intended only for activating the constant speed function.

In the embodiment shown, the control switch 38 can be actuated via a control button mounted in the outer free end of a hand lever 40 whose position setting, an actuator 42 operates via the needle line 44 and the computer 18 controls the activation of the retarder 2. The figure shows five pieces alternative setting modes for the hand lever 40. These modes are denoted 0, 1, 2, 3 and 4, respectively, and correspond to incremental increases braking torques effected by means of the retarder 2. These braking torques can for the positions 1, 2, 3 and 4 of the hand lever, for example be 500 Nm, 1000 Nm, 2000 Nm and 3000 Nm respectively. 10 15 20 25 30 35 507 435 In the alternative embodiment where a special control is used to to switch on the heating function, no simultaneous activation of is required the starter switch 36, without connection takes place by means of the control directly, regardless of whether the engine is switched on or not. In the second alternative the embodiment where the heating function is activated automatically at start, this is conveniently done at the same time as the system is energized by means of the ignition key.

There is suitably an indicator 53 on the engine dashboard, which shows when the heating function is switched on. This indicator can for example, consists of a lamp _ The connection and disconnection of the one effected by the retarder 2 the engine heating function will now be illustrated by means of that in Fig. 2 showed the flow chart.

The flow chart comprises six consecutive pieces function blocks 52, 54, S6, 58, 60, 62. In the top block 52 it is determined whether there is any voltage surge happened in the system, i.e. if the system's power supply is connected through switching on the ignition switch 36, which is the case if the ignition key has been turned to the power-on mode. The system simultaneously detects if the control switch 38 is activated, i.e. if its control button is If so, the next step in the heating function follows, namely, that indicated in block 54 according to which sensing is done to clarify if the coolant temperature is below 70 ° C. About the answer to the question in block 52, on the other hand, is "No", so the preparations for activation of the heating function immediately. Likewise about coolant temperature exceeds 70 ° C (and the answer to the question in block 54) thus "No"), the preparations for activating the heating function immediately. If the answer to the question in block 54, on the other hand, is "Yes", then the following, i block 56 indicated namely the activation of the heating function. This means that the locking function against 10 15 20 25 30 35 507 435 simultaneous deceleration braking and engine throttle are switched off.

The retarder can thus be equipped to brake with the torque that corresponds to the position of the hand lever 40, at the same time the accelerator pedal 26 can used in a conventional way to regulate the engine's throttle. l it In the event that the retarder is not equipped to brake, no activation takes place either of the retarder and the heating function are not used. When the retarder has been switched on, the one specified in the following block 58 is started the coolant temperature monitoring. As long as this one coolant temperature is below a predetermined value, preferably the value corresponding to normal engine operating temperature and which in this example is 85 ° C, so the heating function is kept switched on, but as soon as the coolant temperature reaches or exceeds 85 ° C (meaning that the desired engine heating has completed), then follows the next step specified in block 60, namely that the heating function is switched off which leads to the procedure according to the invention is completed, as indicated in block 62. This means also that the delay function of the retarder is reactivated.

In summary, it can be said that an activation of heating The operation function means that actuation of the accelerator pedal 26, as in throttle by depressing the accelerator pedal, does not disengage retarder 2, but instead allows the engine and retarder to operate at the same time in order to thereby achieve an acceleration of the engine heating through both the engine's own increased heat generation and the heat development generated by the deceleration braking, which cooperates to a rapid heating of the coolant in the engine cooling system, and thus to a rapid warm-up of the engine itself and thus also of the vehicle compartment space.

The implementation of the method according to the invention has been described above by an account of the function of it controlled by the computer 18 activation of the heating function .As a complement to this shall now finally be reported on how the driver proceeds to implement the method according to the invention, i.e. when he wants to use the heating function to accelerate with the help of the retarder the heating of the vehicle engine. To accomplish this, proceed the driver suitably as follows: 10 15 20 25 30 35 507 435 1. If the vehicle engine is already running, the driver starts to switch off the engine and the ignition. 2. Then the operator activates the control switch 38 through pressing its control button and holding it down location. 3. The driver then switches on the ignition and starts the engine by means of the ignition key, so that the power switch 36 is activated at the same time as the control switch 38 is activated. 4. The engine must then idle for a few seconds, for example for three seconds. 5. Then the driver deactivates the control switch 38 by release the control button so far. 6. The driver then starts the vehicle with a suitable throttle by depressing the accelerator pedal 26 so that the vehicle picks up speed. 7. The driver then starts at the first best suitable opportunity one braking using the retarder 2 which is activated by the hand lever 40 is set to the desired braking torque position at the same time as the throttle is increased by depressing the accelerator pedal 26. The one developed by the retarder the heat output (which helps to raise the coolant temperature) is determined of the position in which the hand lever 40 is set (see Fig. 1), i.e. of the set the braking torque of the retarder. 8. When the vehicle engine has reached the desired operating temperature, i.e. when the coolant temperature reached a predetermined value, so disconnected the heating function. However, this happens automatically and requires therefore no special effort on the part of the driver.

It is assumed that when there is a need to accelerate heating of the vehicle's passenger compartment also activates the driver's compartment at the appropriate time the vehicle's air conditioning system for heating the ventilation air which added to the vehicle's passenger compartment. Heat for this is taken from the engine 10 507 435 10 15 20 25 30 35 coolant via a heat exchanger in a conventional manner.

The entire heating process takes place - after it has been initiated by the driver - with by means of the control system for the retarder shown in Fig. 1. The most important the component of this system is, of course, that of microcomputer technology based control unit 18. The adoption of the control laws that enable the implementation of the method according to the invention should be in practice be able to do so through an appropriate modification of the software included in retarder control system 18. Alternatively, it may require the program control be arranged in a separate control unit This descriptive example has essentially dealt only with the function when the heating function is activated. Of course, the control unit 18 and the described arrangement designed to at others operating conditions when the heating function is not activated work in a conventional manner to control the retarder and the engine. In such a case is the locking function built into the control unit is active and about the driver thereby activating the accelerator pedal automatically disengages braking with the retarder (provided the retarder is activated).

The description has been intended for an advantageous embodiment in which the diesel engine fuel injection is electrically controlled. l simpler and alternative embodiments of the invention, the fuel injection may be controlled mechanically, which, however, requires that such an arrangement be supplemented with the components required to be able to detect current operating parameters.

Claims (7)

10 15 20 25 30 35 11 507 435 Patent claims A method for accelerating the heating of a motor vehicle equipped with a hydraulic retarder (2), the retarder consisting of a hydrodynamic auxiliary brake which is controlled under the influence of an electric control unit (18) depending on various operating parameters, which control unit comprises a locking function which prevents driving with simultaneous braking with the retarder (2) and engine throttle, whereby the retarder's hydraulic fluid is cooled by the engine coolant, characterized in that a heating function is activated so that the retarder's (2) locking function is created, after which the retarder is equipped to perform braking work. on the engine is increased and heating of the engine coolant is accelerated, partly by the increased load on the engine and partly by absorbing heat from the retarder's hydraulic fluid. Method according to claim 1, characterized in that the heating function is activated by holding an operating switch (38) belonging to the retarder control unit (18), advantageously a switch included in a constant speed function for the retarder (2), in activated position, e.g. by holding down the control button of the switch (38) while starting the engine. Method according to Claim 1, characterized in that the heating function is activated by activating a special control switch belonging to the retarder control unit (18). Method according to Claim 1, 2 or 3, characterized in that after the vehicle has been accelerated to a suitable driving speed, the retarder (2) is equipped to perform braking work, under simultaneous throttle, by setting a suitable braking torque value for the retarder by means of a special control ( 40), for example a hand lever, wherein the setting position of the control determines the heating effect thus developed by the braking of the retarder which is used for heating the coolant. 10 15 20 25 30 35 12 507 435 Method according to claim 1 or 2, characterized in that the heating function is activated by first bringing the control switch (38) into the activated position, after which the motor starting circuit is closed and the motor is started while maintaining the control switch (38) activated, and only when the motor has started and operated for at least a few seconds, the control switch (38) is deactivated, after which the motor vehicle is accelerated by accelerator, and then the vehicle is braked by setting a suitable braking torque value for the retarder (2) by means of a special control (40). 6. A method according to any one of claims 1-5, characterized in that the retarder (2) is switched off automatically when the temperature of the engine coolant has reached a predetermined value, preferably the value corresponding to normal engine tear temperature and that the locking function of the control unit (18) is reintroduced. Arrangement for accelerating the heating of a motor vehicle equipped with a hydraulic retarder (2), the retarder consisting of a hydrodynamic auxiliary brake which is controlled under the influence of an electric control unit (18) depending on various operating parameters, which control unit (18) comprises a locking function which prevents driving with simultaneous braking with the retarder (2) and engine throttle and that the hydraulic fluid of the retarder (2) is cooled by the engine coolant, characterized in that the control unit (18) comprises a heating function which deactivates the locking function, and that the control unit is connected to a control (40) by means of which the braking action of the retarder can be manually equipped at the same time as the throttle is given to the engine. Arrangement according to claim 7, characterized in that the control unit (18) is connected to a control switch (38) activatable by the driver for switching on the heating function, and a start switch (36), and that the control unit (18) comprises a detection circuit which at the same time detected actuation of the control switch (38) and the start switch (36) activates switching on of the heating function. Arrangement according to claim 7, characterized in that the control switch (38) is included in a constant speed circuit for the retarder. Arrangement according to Claim 7 or 8, characterized in that the control switch (38) is arranged on a hand control (40) for regulating the braking action of the retarder (2).