Control system and method for limiting engine torque based on engine oil pressure and engine oil temperature data

1. A compression ignition engine comprising:

engine cylinders within which combustion occurs to operate the engine;

an intake system for introducing charge air into the engine cylinders;

a fueling system for introducing fuel into the engine cylinders to combust with the charge air;

an exhaust system through which exhaust gas resulting from combustion of fuel in the engine cylinders exits;

a lubrication system for delivering lubrication under pressure to certain engine components;

a control system for comparing engine speed data representing engine speed to an engine speed threshold above which the engine is considered to be running, for comparing engine temperature data representing temperature of the engine to an engine temperature threshold, for starting a first timer once engine speed data has become greater than the engine speed threshold, for starting a second timer once engine speed data has become greater than the engine speed threshold and engine oil pressure data representing pressure of lubrication in the lubrication system has become greater than an engine oil pressure threshold, and for causing engine torque to be limited to an engine torque limit until the first to occur of: engine temperature data exceeding the engine temperature threshold, the first timer having timed to a time that is a function of engine temperature, and the second timer having timed to a time that is a function of engine temperature, wherein the control system comprises a latch function that is selectively operable to a set state and a reset state and that is operated from the reset state to the set state when engine speed data becomes greater than the engine speed threshold, and the first timer commences timing when the latch function is operated from the reset state to the set state.

2. A compression ignition engine as set forth in claim 1 in which engine temperature data is sourced from an engine oil temperature sensor and engine oil pressure data is sourced from an engine oil pressure sensor.

3. A compression ignition engine as set forth in claim 2 further comprising an accelerator pedal that is operated to accelerate the engine and an accelerator position sensor operated by the accelerator pedal for issuing to the control system a torque request that is a function of accelerator pedal position, and in which the control system, when limiting engine torque, is effective to limit any torque request from the accelerator position sensor that would cause the engine torque limit to be exceeded.

4. A compression ignition engine as set forth in claim 3 in which the control system conjunctively acts on both the intake system and the fueling system to limit both charge air and fueling when limiting engine torque.

5. A compression ignition engine as set forth in claim 1 in which the control system comprises a compare function for comparing the engine oil pressure data to the engine oil pressure threshold, and in which the second timer commences timing upon concurrence of the latch function being in the set state and the compare function disclosing that the engine oil pressure data has become greater than the engine oil pressure threshold.

6. A compression ignition engine as set forth in claim 5 in which the latch function is operated from the set state to the reset state when the engine is turned off.

7. A compression ignition engine as set forth in claim 1 in which the control system comprises a first look-up table from which the engine temperature data selects the time that is a function of engine temperature to which the first timer times, and a second look-up table from which the engine temperature data selects the time that is a function of engine temperature to which the second timer times.

8. A compression ignition engine as set forth in claim 1 in which the control system comprises an input for selectively allowing and disallowing engine torque to be limited to the engine torque limit.

9. A compression ignition engine as set forth in claim 1 in which the control system comprises a first fault input for disallowing engine torque to be limited to the engine torque limit when engine temperature data is indicated to be potentially faulty, and a second fault input for disallowing engine torque to be limited to the engine torque limit when engine oil pressure data is indicated to be potentially faulty.

10. A compression ignition engine as set forth in claim 1 in which an engine component to which the lubrication system delivers lubrication under pressure comprises a turbocharger comprising a turbine through which exhaust gas exiting through the exhaust system passes and a compressor operated by the turbine through which air that has entered the intake system passes to create the charge air.

11. A compression ignition engine as set forth in claim 1 in which the control system ceases causing engine torque to be limited to the engine torque limit upon the first to occur of: engine temperature data exceeding the engine temperature threshold, the first timer having timed to a time that is a function of engine temperature, and the second timer having timed to a time that is a function of engine temperature.

12. A method of limiting engine torque produced by a compression ignition engine that comprises engine cylinders within which combustion occurs to operate the engine; an intake system for introducing charge air into the engine cylinders; a fueling system for introducing fuel into the engine cylinders to combust with the charge air; an exhaust system through which exhaust gas resulting from combustion of fuel in the engine cylinders exits; a lubrication system for delivering lubrication under pressure to certain engine components; and a control system, the method comprising:

comparing engine speed data representing engine speed to an engine speed threshold above which the engine is considered to be running, comparing engine temperature data representing engine temperature to an engine temperature threshold, starting a first timer once engine speed data has become greater than the engine speed threshold, starting a second timer once engine speed data has become greater than the engine speed threshold and engine oil pressure data representing pressure of lubrication in the lubrication system has become greater than an engine oil pressure threshold, and causing engine torque to be limited to an engine torque limit until the first to occur of: engine temperature data exceeding the engine temperature threshold, the first timer having timed to a time that is a function of engine temperature, and the second timer having timed to a time that is a function of engine temperature, operating a latch function from a reset state to a set state when engine speed data becomes greater than the engine speed threshold, and starting the first timer when the latch function is operated from the reset state to the set state.

13. A method as set forth in claim 12 comprising sourcing engine temperature data from an engine oil temperature sensor and sourcing engine oil pressure data from an engine oil pressure sensor.

14. A method as set forth in claim 13 further comprising operating an accelerator pedal to accelerate the engine, issuing a torque request that is a function of accelerator pedal position from an accelerator position sensor operated by the accelerator pedal, and limiting engine torque by limiting any torque request from the accelerator position sensor that would cause the engine torque limit to be exceeded.

15. A method as set forth in claim 14 comprising conjunctively acting on both the intake system and the fueling system to limit both charge air and fueling when limiting engine torque.

16. A method as set forth in claim 12 comprising comparing engine oil pressure data to an engine oil pressure threshold, and starting the second timer upon concurrence of the latch function being in the set state and the engine oil pressure data becoming greater than the engine oil pressure threshold.

17. A method as set forth in claim 16 comprising operating the latch function from the set state to the reset state when the engine is turned off.

18. A method as set forth in claim 12 comprising using engine temperature data to select from a first look-up table the time that is a function of engine temperature to which the first timer times, and using engine oil pressure data to select from a second look-up table the time that is a function of engine temperature to which the second timer times.

19. A method as set forth in claim 12 comprising selectively allowing and disallowing engine torque to be limited to the engine torque limit.

20. A method as set forth in claim 12 comprising disallowing engine torque to be limited to the engine torque limit when engine temperature data is indicated to be potentially faulty, and disallowing engine torque to be limited to the engine torque limit when engine oil pressure data is indicated to be potentially faulty.

21. A method as set forth in claim 12 comprising causing engine torque to cease being limited to an engine torque limit upon the first to occur of: engine temperature data exceeding the engine temperature threshold, the first timer having timed to a time that is a function of engine temperature, and the second timer having timed to a time that is a function of engine temperature.