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EP-4737701-A1 - METHOD AND SYSTEM OF CONTROLLING CYLINDER ACTIVATION AND DEACTIVATION IN AN INTERNAL COMBUSTION ENGINE

EP4737701A1EP 4737701 A1EP4737701 A1EP 4737701A1EP-4737701-A1

Abstract

The present invention relates to a method (1) of controlling cylinder activation and deactivation in an internal combustion engine of a vehicle, said method comprising the steps of: - detecting an engine motoring condition (2); - deactivating all the engine cylinders (3) when said motoring condition is detected; - re-activating (4) at least one of the engine cylinders if: • a high load request to the internal combustion engine approaching is predicted (5), and/or • the speed of an internal combustion engine turbine drops below a predetermined turbine speed threshold (6). The present invention further relates to a system of controlling cylinder activation and deactivation in an internal combustion engine, comprising a control unit configured to perform the steps of said method.

Inventors

  • BORG, JONATHAN

Assignees

  • FPT Industrial S.p.A.

Dates

Publication Date
20260506
Application Date
20251031

Claims (14)

  1. A method (1) of controlling cylinder activation and deactivation in an internal combustion engine of a vehicle, said method comprising the steps of: - detecting an engine motoring condition (2); - deactivating all the engine cylinders (3) in response to a detection of the motoring condition; - re-activating (4) at least one of the engine cylin-derswhen at least one of the following conditions is verified: • Prediction of a high load request to the internal combustion engine approaching (5), wherein said high load exceeds a predetermined load threshold, • Detection that a current speed value of an internal combustion engine turbine drops below a predetermined turbine speed threshold (6).
  2. Method (1) according to claim 1, wherein said motoring condition corresponds to a condition wherein the vehicle inertia motors the engine and the engine runs, connected to the vehicle transmission, with zero fuel consumption.
  3. Method (1) according to claim 1 or 2, wherein the prediction of the high load request to the internal combustion engine approaching is based on at least one of: - signals coming from a radar and/or a vision system and/or other sensors of the vehicle; - information provided by a cartographic navigation system; - information from a Vehicle-to-Vehicle, and/or from a Vehicle-to-Infrastructure system.
  4. Method (1) according to the preceding claim, wherein the information provided by the cartographic navigation system comprises at least one of: actual position of the vehicle, upcoming road conditions, real-time traffic information, topographical information, presence and status of traffic lights, speed limits in a path to be followed.
  5. Method (1) according to claim 3 or 4, wherein the vision system of the vehicle is configured to detect traffic lights status.
  6. Method (1) according to any of the preceding claims, wherein the high load request to the internal combustion engine approaching is predicted in a fixed or calibratable short-term time horizon.
  7. Method (1) according to any of the preceding claims, wherein said predetermined turbine speed threshold is settable to at least two different values, each corresponding to a respective different drive mode.
  8. Method (1) according to any of the preceding claims, wherein, following the step of deactivating all the engine cylinders (3), if a complete stop of the vehicle is predicted, the turbine predetermined speed threshold is set to zero to maintain all the cylinders deactivated.
  9. Method (1) according to any of the preceding claims, wherein, following the step of deactivating all the engine cylinders (3), if an engine acceleration value is predicted which is below a first predetermined acceleration threshold, at least some cylinders are reactivated when the turbine speed drops below said turbine predetermined speed threshold value.
  10. Method (1) according to any of the preceding claims, wherein, following the step of deactivating all the engine cylinders (3), if an engine acceleration is predicted which exceeded a second predetermined acceleration threshold, at least some cylinders are reactivated irrespective of the turbine speed dropping below the turbine predetermined speed threshold.
  11. A system of controlling cylinder activation and deactivation in an internal combustion engine, comprising a control unit configured to perform the steps of the method according to any of the preceding claims.
  12. System according to the preceding claim, wherein the control unit comprises an Advanced Driver-Assistance System (ADAS) configured to predict said high load request to the internal combustion engine approaching.
  13. Diesel engine comprising a controlling system according to claim 11 or 12.
  14. Vehicle comprising a diesel engine according to the preceding claim.

Description

Technical field of the invention The present invention relates to the field of thermal management of an internal combustion engine, in particular a diesel engine, during motoring of a vehicle, such as, for example, a heavy-duty truck. The present invention, for example, can be applied in internal combustion engines provided with a turbocharger, such as a turbo-diesel engine. Prior art Cylinder Deactivation (in brief, CDA) in vehicles equipped with a multi-cylinder internal combustion engine, is a known technique where a combination of cylinders is disabled when the full power of the engine is not required. CDA can be used, for example, under motoring conditions, namely, when the engine is driven by the inertia of the vehicle. This generally improves engine efficiency and fuel economy. With specific reference to diesel engines, CDA results in airflow reductions, which, in turn, generally result in higher exhaust gas temperatures and lower exhaust flow rates. This reduction in air flow is achieved by controlling at least the intake valves of deactivated cylinders in order to remain closed during the deactivation. Preferably, the exhaust valves of the same group of cylinders are also controlled to remain closed during the deactivation. Considering the very stringent emission limits, this is beneficial for the after-treatment system, which must work in a predetermined temperature range and, accordingly, is prevented from being cooled. In known CDA systems used during motoring in engines with a turbocharger, most but not all of the cylinders (e.g. 3 out of 6 cylinders) are deactivated, in the sense that fuel injection and the opening of at least the intake valves of the deactivated cylinders are inhibited. The deactivation of all the cylinders is avoided due to the impact on the subsequent load transient when more load is requested (for example in case of a necessary overtake or in case of an uphill road after a motoring condition). In fact, if all cylinders were deactivated, the turbine of the turbocharger would eventually spin down to rest and, at the next request of load, the load transient would be very slow and sluggish due to a large turbo-lag. On the other hand, running in motoring conditions with all cylinders deactivated, in principle, would be beneficial due to the complete elimination of exhaust mass flow and, consequently, the maximum reduction in the cooling of the after-treatment system, with a consequent improvement in the fuel consumption. Additionally, the deactivation of all the cylinders would result in the elimination of increased engine noise and vibration which is typically associated with cylinder deactivation. Finally, the deactivation of all the cylinders would result in a minimal torque, resulting in reduction of fuel consumption due to improved vehicle rolling resistance. Summary of the invention Therefore, it is an object of the present invention to provide a method and a system of controlling the activation and deactivation of cylinders in an internal combustion engine, in particular under motoring conditions, such that the benefits of the deactivation of all the cylinders are obtained with a substantial limitation of the above-mentioned drawbacks in the load transient after cylinder deactivation. This and other objects are achieved by a method of controlling the activation and deactivation of cylinders in an internal combustion engine according to the claim 1 and a system of controlling the activation and deactivation of cylinders in an internal combustion engine according to the claim 11. The Applicant has found that utilising an all-cylinder deactivation during motoring and then switching back some of the cylinders to active mode either based on a turbine speed threshold (in the case the engine is provided with a turbocharger) and/or based on the prediction of an upcoming load transient, optimizes the reduction of the after-treatment system temperatures, and maximises the benefits of motoring at minimal motoring torque with minimal engine vibrations. It should be clear that the two conditions are simultaneously monitored, but when at least one of the two conditions is verified the cylinder activation is executed. The dependent claims define possible advantageous embodiments of the invention. Brief description of the figures To better understand the invention and appreciate its advantages, some of its non-limiting exemplary embodiments will be described below, referring to the attached figures, in which: figure 1 shows a flowchart of exemplary steps of a method of controlling activation and deactivation of cylinders of an internal combustion engine according to an embodiment of the present invention. Detailed description of the invention With reference to the figure 1, exemplary steps of a method 1 of controlling activation and deactivation of cylinders of an internal combustion engine, in particular a diesel engine, of a vehicle, such as, for example a heavy-duty truck, are depict