BR112020017829A2 - AUTOMATIC COMMAND PROCESS FOR CHANGING STATES IN A MOTORPULSOR GROUP - Google Patents

Abstract

abstract automatic command process change of states of a powertrain automatic process command of changes of state of a powertrain (gmp) composed of a thermal motor coupled to an automatic transmission with at least one cutting clutch between the engine and wheels of a vehicle, by exchanging inter-system instructions between an engine computer (ecm) and a transmission computer (atcu), with a view to leaving a normal travel mode by cutting the engine on approaching the stop, or opening the clutch in order to enter a free-wheel travel mode with the engine running, characterized by the fact that the inter-system instructions exchanged include making a cut of the engine, of a part in normal travel at high speed when the accelerator pedal is relaxed with the foot on the brake and, on the other hand, when traveling freely with the accelerator and brake pedals relaxed.

Description

"PROCESS OF AUTOMATIC COMMAND OF CHANGES IN STATES OF A MOTORPULSOR GROUP"

[001] The invention relates to the automatic control of powertrain groups (GMP) of an automotive vehicle already having a “normal” mode, a “sailing idle” (or “sailing idle”) mode and a function of cutting and automatic restart of the thermal engine, called “start and stop”.

[002] More precisely, it has as its object a process of automatic command of changes of state, of a powerplant composed of a thermal motor coupled to an automatic transmission having at least one cutting clutch between the motor and the wheels of a vehicle, by exchanging inter-system instructions between an engine computer and a transmission computer, with a view to leaving a normal travel mode by cutting the engine on approaching the stop, or opening the clutch in order to enter a free-wheel travel mode with the engine running.

[003] The “Stop and Start” function allows the engine to be stopped at 0 km / h, with the foot on the brake. The purpose of the engine idling, or “sailing idle”, is to disengage the transmission from the engine in order to have a freewheeling vehicle with an engine at idle speed.

[004] By publication FR 3 030 423, a process for automatically controlling an automotive vehicle is known for switching from a "normal" mode to a "freewheeling" mode. The vehicle in question has an engine capable of supplying torque to the driving wheels, by means of an automatically controlled clutch. The driving wheels of the vehicle are coupled to the engine by the clutch in "normal" mode, or decoupled from it in "freewheel" mode. According to this process, a transition phase is chronologically interposed between the “normal” mode and the “free wheel” mode. During this period, the engine speed is automatically controlled so that the clutch-driven shaft rotates at the same speed as its steering tree, without transmitting torque to the wheels before opening the clutch, instead of being placed directly in its slow running.

[005] This transition period allows to avoid bumping, during the opening of the clutch, or if a brake causes the return to the “normal” mode by abruptly closing the clutch. Furthermore, the triggering of this transition step is delayed, if the request for the change to free wheel intervenes when the gearbox is in a state of change.

[006] In this process, the exchange of information and instructions between the engine computer and that of an automatic transmission, ensures the desired coherence between the behavior of the engine on the one hand and that of the gearbox with its clutch, on the other side, in order to generate the transitions between a “normal” mode and a “idle sailing” freewheel mode, where the engine is placed on its idle speed.

[007] If, in addition, the possibility of cutting the engine in "normal" or "free wheel" mode is introduced, the coherence between the behavior of the engine and that of the transmission is more complex to establish. New GMP states must be generated. The exchange of new inter-system requests between the engine and the transmission is necessary to ensure a good level of performance and service, in terms of speeds, bumps and vibrations felt.

[008] The purpose of the present invention is to build a new exchange of inter-system information within the GMP, which allows to reduce fuel consumption, as well as CO2 emissions, thanks to the extension of the “Stop and Start” and “sailing modes idle ”, by other modes of operation.

[009] For this purpose, it provides that the inter-system instructions include making a cut of the engine, on the one hand in normal displacement at high speed during the relaxation of the accelerator pedal with the foot on the brake and, for on the other hand, when traveling in freewheel with the accelerator and brake pedals relaxed.

[010] Preferably, the sending of inter-system information from the ECM to the ATCU, includes a request for the preparation of the automatic transmission in the opening of the clutch and in the management of the motor torque, the request for free-wheel movement with the motor turning on its idle speed, and the request for free-wheel travel with the engine cut.

[011] Other features and advantages of the present invention will appear clearly from the following description of a non-limiting modality thereof, with reference to the attached drawings, in which:

[012] Figure 1 regroups the state of the GMP,

[013] Figure 2 describes the function of “coasting stop high speed”,

[014] Figure 3 shows the inter-system exchanges associated with this function,

[015] Figure 4 describes the function “sailing stop”, or “freewheel with motor stopped” and

[016] Figure 5 shows the inter-system information associated with this function.

[017] The automatic command of changes of states, illustrated in figure 1, involves a powertrain (GMP) composed of a thermal motor coupled to an automatic transmission having at least one cutting clutch between the motor and the gear wheels. a vehicle. The automatic command of these state changes is made by exchanging inter-system instructions between a motor computer (ECM) and a transmission computer (ATCU). These changes allow to leave a normal travel mode, cutting the engine when approaching the stop, or opening the clutch in order to enter a free-wheel travel mode with the engine turning. This displacement currently called “sailing idle” takes place with the engine rotating at its idle speed.

[018] Figure 1 also shows new functions introduced to extend the exchange of information between GMP inter-systems, generating a “normal” mode and a “idling idle” or “sailing idle” mode. These two modes are associated with other states, intermediate or complementary, allowing to combine the advantages of the freewheel function and the eventual cut of the motor. A new function, called “coasting stop high speed”, for “high speed stop” is planned. From the “normal” mode, it allows the engine to stop at approximately 20 km / h, when the accelerator pedal is relaxed, with the foot on the brake. In these circumstances, the engine from the engine to the engine to save fuel.

[019] The diagram also indicates two other states where the engine can be cut: - automatic engine stop when the vehicle is stopped, or "auto stop" linked to the automatic stop and restart function of the engine at stop ("stop and start ”), for example below 5 km / h, and - a new free-wheel drive, with this time the engine cut off, called“ sailing stop ”.

[020] An intermediate state, of free-wheeling or "entry sailing" is foreseen to change from "normal" mode, to one or the other of the two free-wheeling modes "sailing stop" or "sailing idle". Finally, you can switch to normal mode from the two free-wheel modes.

[021] To ensure a better start, when the engine is automatically cut (whether it is in “auto stop”, “coasting stop high speed” or “sailing stop” mode), the automatic transmission must have been « pre-engaged »in the optimal ratio. This is a function of the type of motor stop requested. This is the reason why it is necessary to extend the exchange of information between systems, placing in place a specific “system” between the engine computer (ECM) and that of the automatic transmission (ATCU).

[022] According to the invention, the inter-system instructions exchanged include making a cut of the engine, on the one hand, at normal displacement at high speed during the relaxation of the accelerator pedal with the foot on the brake and, for on the other hand, when traveling in freewheel with the accelerator and brake pedals relaxed.

[023] The sending of inter-system information from the ECM to the ATCU now includes a request for the preparation of the automatic transmission in the opening of the clutch and in the management of the engine torque, the request for free-wheel travel with the engine rotating at idle and the request for free wheeling with the engine cut.

[024] The entry and exit of the “coasting stop high speed” mode, or “high speed braking stop”, from the “normal” mode, are illustrated by figure 2. This function corresponds to a motor stop about 20 km / h, with the accelerator pedal relaxed and the foot on the brake. It allows the engine to stop, for the purpose of a higher fuel gain. The use case in question is, for example, the arrival over an obstacle or an event (red light type, roundabout), where the driver relaxes the accelerator and starts to brake. The figure shows the evolution in time of the position of the accelerator pedal, engine speed, clutch and GMP coordinator. According to the invention, the request for authorization to cut the engine at high speed to idle the vehicle in idle with the engine cut, is sent by the ECM to ATCU, when the engine is in idle, with the accelerator pedal completely relaxed and the brake pedal supported.

[025] In order to ensure a later restart in the best conditions, the automatic transmission must pre-engage the optimum ratio according to the type of engine stop requested, "auto stop", "coasting stop high speed" or "sailing stop". A specific “inter-system”, summarized in figure 3, is put in place between the ECM and ATCU for the transition between the “normal” mode and the “coasting stop high speed” mode. The ECM sends the request «ICE_StartStopStatus» to ATCU, to express its desire to stop the engine. ATCU sends, in return, an «AT__StartStopMode» message to the ECM, to respond positively to this request when the transmission is correctly predisposed. With reference to figure 2, the request “ICE_StartStopStatus” is sent on date tl, with the accelerator pedal completely relaxed, the brake pedal supported and the engine idling. The ATCU “AT_StartStopMode” authorization is sent to the engine on date t2, when the transmission is predisposed for the next restart of the engine. In short, the request for authorization to cut the engine at high speed for a stop at high speed is sent by the ECM to ATCU, when the engine is idling, with the accelerator pedal completely relaxed and the brake pedal supported .

[026] The “sailing stop” function illustrated by figure 4, corresponds to an extension of the “sailing idle”, cutting the engine to optimize consumption, once the automatic transmission is decoupled from the engine. The request for authorization to cut the engine to enter the free wheel travel phase, is sent by the ECM to ATCU in the absence of braking. To ensure the “sailing stop” function, a specific inter- system, summarized in figure 5, is placed between ECM and ATCU. The ECM sends its wish to free-wheel to ATCU, by means of a request entitled «ECM_SailingRequest». It sends a request for authorization to stop the engine by another request entitled «ICE_StartStopStatus». After that, ATCU authorizes the engine to stop with the message “AT_StartStopMode”, and the passage to free, with the message “AT_ SailingRequest”.

[027] The use case covered by this example is as follows. On date t0, the driver relaxes the accelerator, without braking. On date t1, the ECM expresses its willingness to enter a free wheel. On date t2, the transmission clutch is fully opened. On date t3, the accelerator pedal is fully relaxed, and the engine is idling. The request for authorization to cut the engine takes place on date t4. It is granted by ATCU on date t5. The authorization to cut the engine to enter the phase of free-wheel travel with the engine cut given by the ATCU to the ECM, after which the engine speed goes down to its idle speed. On date t6, the engine is cut. The GMP is in «sailing stop» mode.

[028] The «ECM_SailingRequest» inter-system, which reflects the engine's desire to put the GMP in free wheel (engine free wheel request) may already contain the following states and requests: - the normal nominal mode: «normal driving », - the request to prepare for automatic transmission at the opening of the clutch and the management of the engine torque:« entry sailing », - the state of the open clutch and the engine rotating at idle:« sailing idle ».

[029] Introducing the possibility to cut the engine in free wheel, the invention adds to this inter-system, the "sailing stop" state where the vehicle moves with the clutch open and the engine stopped. According to the invention, the information sent by the ECM to the ATCU includes a request to prepare the transmission in order to predispose to running in freewheel with a cut engine.

[030] The invention does not lead to evolution of the inter-systems «AT_SailingRequest» which already contains the states and requests: - «sailing» authorized, - Inhibition of the «entry sailing» phase, - Inhibition of the «entry sailing» to «sailing passage »Temporary, - Request for departure from« sailing », - Prohibition of departure of« sailing ».

[031] In contrast, the "AT_StartStopMode" inter-systems evolves by adding two additional states, which are related to the authorization to cut the engine during normal braking at around 20 km / h "coasting entry allowed" and to cut it in free wheel without braking «sailing stop allowed».

[032] The three existing states, without the new functions can be: - Torque transmitted by the automatic transmission: «normal operation», - Automatic transmission predisposed to the engine stop at 0 km / h: «stop auto allowed», and - Return of automatic transmission with the understanding of engine stopped ("running down").

[033] In these states, two new states are added from now on: - Automatic transmission predisposed to «high speed stopping stop»: «coasting entry allowed», and - Automatic transmission predisposed to stopping the engine in free wheel (stop between 30 and 130 km / h): "Sailing stop allowed".

[034] The inter-system «ICE_StartStopStatus» to transmit the type of stop requested to ATCU, can already contain the following states (in addition to the cut off engine status):

1. In an initialization phase, before the motor autonomy: - a nominal mode, where the motor is autonomous «Engine running», - a preparation mode for stopping the motor by closing the «anticipation stop» throttle, - a preparation at the engine stop «begin stop», - closing the throttle and cutting the injection «end stop»

2. In an engine stop phase: - the start engine of the reflex start type (engine speed <starting device speed threshold), - the restart of the injection engine by injection relaunch, the decelerated engine of the engine stalled ', - the engine decelerated with preparation at the' anticipation star 'start, - the engine driven by the starter with authorized injection under' starting 'conditions.

[035] According to the invention, «ICE_StartStopStatus» can also contain: - the sending of requests for the preparation of the automatic transmission (TA) in order to prepare for a cut-off freewheel: «warn sailing stop», - the sending preparation requests sent to a TA, in order to predispose to a high speed breakdown: “warn coasting”, - sending preparation requests to a TA in order to prepare for an engine shutdown at a stop, or an engine stop cut at low speeds: «warn stop» in the case of a transmission with double clutch, - sending preparation requests to a TA to prepare for an engine stop («stop auto» or «coasting stop high speed»): « Warn Stop ', in the case of a variable-speed transmission.

[036] In summary, the requests sent by the ECM to ATCU now include: - a request to prepare the transmission for predisposing, at high speed, to a halted stop, - a request for preparing the transmission to predispose, at low speed , to a braked stop, - a request to prepare the transmission to prepare for an engine stop.

[037] The invention can be applied without changes in the technical definitions of the GMP.

It applies to different types of transmissions, including dual-clutch transmissions (DCT for “Dual Clutch Transmission) and CVT (continuously variable transmission” type drives), while it can also be extended to clutch driven architectures. type "e-clutch" (controlled clutch) .The creation of new inter-systems allows an optimum predisposition of the automatic transmission.

By informing her of the desire to leave free-wheel mode, she ensures a good service provided by NVM "Noise Vibrations Harshness", minimizing jolts, as well as speeding the closing of the clutch and improving the start of the vehicle.

Claims (10)

1. Process of automatic command of changes of state of a powerplant (GMP) composed of a thermal engine coupled to an automatic transmission having at least one cutting clutch between the engine and the wheels of a vehicle, by exchanging inter-system instructions between an engine computer (ECM) and a transmission computer (ATCU), with a view to leaving a normal travel mode by cutting the engine on approaching the stop, or opening the clutch in order to enter a mode of free-wheel travel with the engine running, characterized by the fact that the inter-system instructions exchanged include cutting the engine, from a part in normal travel at high speed when the accelerator pedal is relaxed with the foot on the brake and , on the other hand, when traveling in freewheel with the accelerator and brake pedals relaxed. 2. Process of automatic command of changes of states according to claim 1, characterized by the fact that the sending of inter-system information from the ECM to the ATCU includes a request to prepare the automatic transmission in the opening of the clutch and in the management of the engine torque, the request for free-wheel travel with the engine rotating on idle, and the request for free-wheel travel with the engine cut. 3. Process of automatic command of changes of states according to claim 1 or 2, characterized by the fact that the sending of information from the ATCU to the ECM includes authorization to enter the high-speed stop phase or in phase of free-wheel travel with the engine cut. 4. Process of automatic command of changes of state according to claim 1, 2 or 3, characterized by the fact that the information sent by the ECM to the ATCU includes a request for the preparation of the transmission in freewheeling cut engine. 5. Process of automatic command of changes of states according to one of the preceding claims, characterized by the fact that the information sent by the ECM to the ATCU includes a request to prepare the transmission, at high speed, at a stopped stop. 6. Process of automatic command of changes of states according to one of the preceding claims, characterized by the fact that it includes a request to prepare the transmission, at low speed, for a braked stop. 7. Process of automatic command of changes of states according to one of the preceding claims, characterized by the fact that it includes a request to prepare the transmission, when the engine is stopped. 8. Process of automatic command of changes of states according to one of the preceding claims, characterized by the fact that the request for authorization to cut the engine at high speed for a stopped stop is sent by the ECM to the ATCU, when the engine it is on idle, with the accelerator pedal completely relaxed and the brake pedal supported. 9. Process of automatic command of changes of states according to one of the preceding claims, characterized by the fact that the request for authorization to cut the engine to enter the phase of free-wheel travel, is sent by the ECM to the ATCU in the absence braking. 10. Process of automatic command of changes of states according to one of the preceding claims, characterized by the fact that the authorization to cut the engine to enter the phase of free-wheel travel with the engine cut, is given by the ATCU to the ECM after the engine speed went down at idle. Stop Stunted engine stop Speed <5hmh Driving speed> 7hmh normal free wheel entry Freewheel Freewheel Engine stopped engine idling depressed accelerator pedal relaxed brake pedal depressed Petition 870200110925, of 9/1/2020, p. 25/37 rpm engine idling speed open clutch status closed GMP Coordinator Normal driving clutch input engine stop input engine stop restart relaxed brake pedal depressed relaxed accelerator pedal Petition 870200110925, of 9/1/2020, p. 26/37 engine idling speed open clutch status closed Coordinator Normal driving GMP freewheel idling idling input engine idling restart engine idling engine idling