SE512728C2 - Method and apparatus for controlling a diesel engine during gearing - Google Patents

Abstract

A method and an arrangement for controlling the speed of an engine (10) of a heavy vehicle during gear changing in a mechanical gearbox (12, 13, 14) in cases where a manually operable clutch (11) is incorporated in the driveline between the engine and the gearbox are distinguished by the fact: that running parameter data of the vehicle are observed and recorded, that breaking of the driveline upon disengagement of the clutch (11) is detected and a first signal indicative thereof is generated, that a gear signal indicating the intended gear position is generated, that a desired engine speed intended to prevail upon completion of the gear change is determined, in response to the first signal, on the basis of said running parameter data and the gear signal, and that a control signal is generated which acts upon the engine control system so that the engine speed is adjusted towards said desired speed.

Description

10 15 20 25 30 - 512 728 In addition, excessive clutch wear entails an additional cost for clutch replacements as well as significant extra costs for the vehicle's downtime. PURPOSE OF THE INVENTION It is an object of the present invention to eliminate or alleviate the problems of the prior art. This object is achieved in a method and a device of the kind mentioned in the introduction by the features stated in the characterizing parts of claims 1 and 2, respectively. 6.

This obtains by simple means that the undesired difference in speed between the clutch halves in connection with disengagement and reconnection is avoided, whereby the loads on and wear of the clutch can be significantly reduced as well as the corresponding load of other components in the driveline. As further advantages can be mentioned simplified driving of a vehicle, which is equipped in accordance with the invention as well as increased comfort, which is thus particularly noticeable in passenger transport buses but also has significance for other types of heavy vehicles.

With regard to the indication of the layout of the connection, it can be mentioned that sensors for emitting such signals are previously known, which, however, are conventionally arranged to e.g. communicate with a cruise control and / or enable the conversion of a possible split gearbox. However, such conventional sensors can be used in the invention.

The invention is applicable to both purely mechanical gearboxes with mechanical linkage and to servo-assisted gearboxes. The gearbox in question comprises a main gearbox and also possibly a split and / or a range gearbox or the like.

Systems for controlling the engine speed are known in advance and will not be described here.

Recently, advanced control systems have been developed which adapt the engine speed to the input speed of a gearbox unit, based on a number of sensors, which are located at different places in the driveline. However, these systems are applied in such a way that the clutch is not used during normal running, and that the speed adjustment is designed to be so accurate that a gear shift can be initiated directly without affecting the clutch. In the system according to the present invention, however, the speed adjustment or speed maintenance of the motor is initiated by the driver influencing a completely manual or a servo-assisted clutch, but that the clutch is otherwise used in a conventional manner. The advantage of the present invention is thus that the speed difference arising in the conventional systems is avoided and thus also the problems present therewith.

The driving data that may be considered for observation and registration are, among other things. a. vehicle speed, engine speed, gearbox output speed, accelerator (accelerator position) and present gear position. Depending on the application, the system may be arranged to observe some or possibly all of these driving parameters in order to generate relevant signals to be used in the engine control when the driver makes the clutch. In addition, it is sensed which gear position the driver intends to shift to. This can be achieved in different ways in different applications and can apply to the rearrangements in all sub-gearboxes included in the gearbox, for example: split, main, range gearboxes, or in one or two of these. Thus, as an example, the invention is easily applicable to a two-part gearbox containing split and main gearbox when rearranging only the split gearbox by means of a common actuator arranged as a movable collar on the gear lever. In this case, displacing the collar in one direction to rearrange the split gearbox.

Regarding insertions of a main gearbox with joy-stick control (for example Scania's Comfort Shift), there are already systems for predicting which gear the driver intends to engage. Namely, the lever is locked with a solenoid lock until the sensor in the gearbox has acknowledged that the gear is rearranged. Such a system is easily expandable to work according to the invention, since the signals relevant to the invention are easily accessible and can be used for the motor control. Other types of gearbox controls can also be relatively easily fitted with equipment to enable the system to get an indication of which gear the driver intends to load. As an example by means of sensors at the gear lever, in the linkage or t.o.m. in the gearbox itself. 5 10 15 20 25 30 »512 728 Further advantages are obtained by the features of the other claims and will be described in the following.

DESCRIPTION OF THE DRAWINGS The invention will now be described in more detail with reference to exemplary embodiments and with reference to the accompanying drawings, in which: Fig. 1 schematically shows a fate diagram of a method according to the invention, and Fig. 2 schematically shows the control system including a system according to the invention .

DESCRIPTION OF EMBODIMENTS I fi g l thus shows a fl diagram of a method according to a method according to the invention, wherein position 1 refers to the start of the sequence. Position 2 indicates observation of driving parameters such as vehicle speed, engine speed, speed of the gearbox output shaft, accelerator (accelerator pedal position) and present gear position, and position 3 refers to detection of interruptions in the driveline, in the form of e.g. disconnection of a lamella coupling and generating and emitting a first signal, which is indicative thereof. Position 4 refers to an indication of the driver's intended gear position for the current part or parts of the vehicle's gearbox and 5 refers to a position for calculating a desired engine speed for the intended gear position based on currently observed driving parameters, of which by means of stored data regarding input resp. output speed for each gear combination an equivalent speed can be easily calculated for each gear combination and for each speed on the output shaft. Furthermore, a control signal is generated and emitted, which describes said desired motor speed, which control signal is emitted to a system for controlling the motor. Position 6 refers to the actuation of the engine control system on the engine to obtain the desired engine speed, such as a balanced application of gas to reach the desired speed. 7 refers to the detection of reconnected driveline and 8, finally, refers to the end of the sequence.

Figure 2 schematically shows the control system 9, which suitably comprises both a system according to the invention integrated in or connected to the normal engine control system. 16 refers to a memory for registration of driving parameters and speed modes for different gears, etc., which is relevant in connection with the present invention. In the driveline, the engine is denoted by 10, the clutch with the ll _ 512 728 _ which can be manually actuated by the driver via a clutch pedal and the gearbox in this example three-part with 12, 13 and 14 with respect to split, main and range gearbox, while an output speed sensor is denoted by 15. 17 refers to the final gear. The gearbox is thus a mechanical gearbox with a number of specific steps (gears) which the driver can select by means of a gear selector, for example in the form of a gear lever which directly or via the servo means rearranges the gears in the gearbox. The figure shows that the control system communicates with the engine, with the clutch, with the sensor 15 for the output shaft and with the memory 16. It can also communicate with the gearbox, which is indicated by dashed lines. Overall, the invention achieves significantly simpler driving, which means that a vehicle equipped according to the invention can also be driven by an untrained driver so that in practice very advanced steps can be achieved in a very simple manner.

Significant cost reduction due to reduced maintenance can be expected. An important advantage of the invention is that the system is inexpensive and can be applied to vehicles which have been chosen by the driver to be as cheap as possible for minimized driving cost, and which are not equipped with sophisticated but expensive automatic transmission systems. Another part is that the driver does not have to hesitate to put in a more optimal gear, as the gear becomes much less problematic, some improved driving economy should therefore be expected.

The changeover times can also be shortened. Since the system allows full throttle shifting, driving with the system engaged can be said to mean a "performance driving period", whereby more efficient driving at high loads can be achieved. For example, the system may be connected as such a performance driving node when the driver depresses the clutch pedal cra 70% 25 The system also results in reduced noise as the idle speed is reduced when shifting during performance driving.

The invention can be varied within the scope of the claims, and as stated above, it is also applicable to e.g. only one of a number of partial gearboxes.

Claims (10)

10 15 20 25 - 512 728 PATENT REQUIREMENTS Method for controlling the engine speed of an engine (10) of a heavy vehicle when shifting a mechanical gearbox (12, 13, 14), wherein a manually actuable clutch (1 1) is included in the driveline between the engine and the gearbox, characterized by -that driving parameter data for the operation is observed and recorded, -that interruption in the driveline when laying out the clutch (11) is detected and a first signal, indicative thereof, is generated, -that a gear signal from the gearbox or its actuators is indicated, indicating which gear the driver intends to load -that a desired engine speed, which is to prevail at the end of the shift, is determined, initiated by the first signal, and based on said travel parameter data and from the gear signal, and -that a control signal is generated, which affects the engine control so that the engine speed is controlled at said desired speed. Method according to claim 1, characterized in that said driving parameter data is taken from the group consisting of: vehicle speed, engine speed, speed of the gearbox output shaft, throttle and the present gear position (s) in the gearbox. Method according to Claim 1 or 2, characterized in that the gear ratio is a nerve gear ratio and that the engine speed is increased in a controlled manner. Method according to Claim 1 or 2, characterized in that the gear ratio is a gear ratio and that the engine speed is reduced in a controlled manner. Method according to Claim 1 or 2, characterized in that the system is switched on when the driver makes the clutch, provided that the throttle is at least approximately 70%. 10 15 20 25 _ 512 728 Device for controlling the engine speed of an engine (10) of a heavy vehicle when shifting a mechanical gearbox (12,13,14), wherein a manually actuable clutch (1 1) is included in the driveline between the engine and the gearbox, characterized by a control system (9), which is arranged to observe and record the driving parameter data for the operation, - means for detecting interruptions in the driveline when laying out the clutch and for generating a first signal, indicative thereof, - means for detecting new intended by the driver gear position and generating a gear signal indicating this position, -that the control system (9), initiated by said first signal, is arranged to determine a desired engine speed, which should prevail at the end of the gear, based on said driving parameter data and the gear signal, and -that the control system ( 9) is arranged to generate a control signal, which is arranged to influence the motor control so that the motor speed is controlled towards said desired speed. Device according to claim 6, characterized in that said driving parameter data are taken from the group consisting of: vehicle speed, engine speed, the speed of the gearbox output shaft, throttle and the present gear position (s) in the gearbox. Device according to Claim 6 or 7, characterized in that the gear ratio is a nerve gear ratio and that the engine speed is arranged to increase in a controlled manner. Device according to Claim 6 or 7, characterized in that the gear ratio is an upshift and that the engine speed is arranged to be reduced in a controlled manner. Device according to claim 6 or 7, characterized by means for engaging the system when the driver is laying the coupling, provided that the throttle is at least about 70%.