Patent Application
20110106414
The present disclosure relates to an engine having an electronically controlled engine starting method, and more particularly to an electronically controlled starting method to provide lubrication to engine components before the engine operates at normal operating speeds.
Many modern diesel engines contain fuel injection systems that allow the engine to start at low ambient temperatures without starting aids. When an engine is started, a lag time exists until a sufficient amount of engine oil circulates to lubricate engine components such as crankshaft bearings, connecting rod bearings, and turbocharger bearings. The lag time between engine starting and circulation of engine oil sufficient to lubricate engine components increases when ambient temperature is lower, particularly when engine oil has a larger viscosity number. The lag in sufficient lubrication to lubricate engine components may result in damage to components of the engine, including the turbocharger. In order to limit or prevent this type of damage, an oil with a lower viscosity number may be used, such that the oil flows better at low ambient temperatures, or an engine may be provided with a block heater, or an oil heater, that warms the engine, including the oil, allowing the oil to circulate more effectively at low ambient temperatures. However, the use of oil with a lower viscosity number, an engine block heater, or an oil heater all require a vehicle operator to take action. Therefore, a need exists for an engine having an electronically controlled starting method that sufficiently lubricates engine components.
According to one process, a method of starting an engine is provided. A starter is initiated to impart a first engine speed to a crankshaft of the engine. Fuel injects at a first rate into at least one cylinder of the engine. Fuel in the at least one cylinder of the engine combusts to operate the engine at generally the first speed imparted to the crankshaft of the engine by the starter until a predetermined oil pressure develops within the engine.
According to another process, a method of electronically controlling starting of an internal combustion engine is provided. The engine has an electronic control module, an oil pressure sensor, a starter, at least one cylinder, and at least one fuel injector. The method initiates a starter to start an engine. Fuel is injected at a first fuel injection rate with a fuel injector into at least one cylinder upon initiating the starter. The first fuel injection rate operates the engine at a speed generally equal to the engine speed provided by the starter. An output signal of an oil pressure sensor is generated indicative of engine oil pressure. The output signal of the oil pressure sensor is transmitted to an electronic control module. Oil pressure indicated by the output signal of the oil pressure sensor is compared to at least a first predetermined value stored in a memory of the electronic control module. At least a second fuel injection rate signal is transmitted to the fuel injector when the output of the oil pressure sensor is more than the at least a first predetermined value stored in the memory of the electronic control module. The second fuel injection rate signal corresponds to a second fuel injection rate greater than the first fuel injection rate. The second fuel injection rate allows the engine to operate at an engine speed greater than the engine speed provided by the starter.
According to a further process, a method of operating an engine is provided. The engine has an electronic control module with a memory, an oil pressure sensor, at least one cylinder, a starter, and at least one fuel injector. The method generates an output signal of an oil pressure sensor indicative of engine oil pressure. The output signal of the oil pressure sensor is transmitted to an electronic control module. The oil pressure indicated by the output signal of the oil pressure sensor is compared to at least a first predetermined value stored in a memory of the electronic control module. A first fuel injection rate signal is transmitted to a fuel injector when the output of the oil pressure sensor is less than the at least a first predetermined value stored in the memory of the electronic control module. The first fuel injection rate signal corresponds to a first fuel injection rate that causes the engine to operate at a first engine speed generally equal to an engine speed provided by a starter.
The ECM has a memory containing at least one oil pressure threshold value. The ECM compares the output signal of the oil pressure sensor to the at least one oil pressure threshold value at block 22. If the output signal of the oil pressure sensor is less than the at least one oil pressure threshold value, the process returns to block 16, where fuel is injected at the first rate to operate the engine so that the crankshaft turns at the first speed. However, if the output signal of the oil pressure is above the threshold value, the ECM initiates the fuel injector to inject fuel into the cylinder of the engine at a second rate that is higher than the first rate, as shown at block 24. The second rate of fuel injection is adapted to operate the engine such that the crankshaft turns at a second speed that is faster than the first speed.
Turning now to
An oil pressure sensor generates an oil pressure output signal at block 38 that is transmitted to an ECM at block 40. The ECM compares the oil pressure output signal with at least a first predetermined value stored in a memory in electrical communication with the ECM, as shown at block 42. As shown at block 44, if the oil pressure is not above the at least a first predetermined value, the method reverts back to block 38 and continues to compare the oil pressure sensor signal to the first predetermined value. However, if the oil pressure is above the at least a first predetermined value, fuel is injected at a second rate that is greater than the first rate to increase the rotational speed of the crankshaft of the engine, as shown at block 46. The fuel may be injected at the second rate in response to a second fuel injection rate signal being transmitted either directly or indirectly to the fuel injector.
After fuel has been injected at the second rate, the oil pressure signal is compared to a second predetermined value as shown at block 48. If the oil pressure signal is above the second predetermined value, fuel continues to be injected at the second rate. If the oil pressure signal is less than the second predetermined value, the method allows control of the speed of the crank to be controlled by the user, as shown at block 50. Preventing a user from operating the engine at a speed the user desires if the oil pressure is above the second predetermined value reduces the chances that the engine may be damaged if the engine is operating in a very cold ambient temperature before the oil has a chance to warm up. Thus, the method 30 shown in
It is additionally contemplated that the first predetermined value stored in a memory in communication with the ECM that the oil pressure signal is compared to is temperature dependent. For instance, it is contemplated that lower ambient temperatures will have higher first predetermined values than higher ambient temperatures, as colder oil is less viscous.
It is additionally contemplated that an engine will only be run for a limited time period at the first speed that is generally equal to the speed provided by the starter. If the oil pressure does not reach the first predetermined value by the end of that limited time period, the engine is shut down, and an error code is generated by the ECM that indicates low oil pressure.
It is still further contemplated that operating the engine at a speed generally equal to the speed of the starter may not require fuel to be injected into every cylinder of an engine having a plurality of cylinders. For instance, it is contemplated that every other cylinder of an engine having a plurality of cylinders would be fired. Firing every other cylinder may reduce complications from torsional vibrations generated by operating an engine at very low speeds.
