Systems and methods of cylinder deactivation in high-temperature mixing-controlled engines
Embodiments described herein relate to systems and methods of cylinder deactivation in compression-ignition engines. An engine described herein can include N cylinders, with N being an integer of at least 2, with each cylinder including an inner surface, a piston disposed and configured to move in each cylinder of the N cylinders, an intake port, an exhaust port, and a fuel injector. The piston and the inner surface define a combustion chamber. A method of operating the compression ignition engine includes injecting a fuel into each of the combustion chambers, combusting substantially all of the fuel in the compression ignition engine, monitoring engine load of the compression ignition engine, and deactivating a cylinder of the N cylinders upon a decrease in load to less than (N−1)/N×FL, wherein FL is a full load at a given engine speed.
1 . A method of operating a compression ignition engine, the compression ignition engine including N cylinders, N being an integer of at least 2, each of the N cylinders having an inner surface, a piston disposed and configured to move in each cylinder of the N cylinders, an intake port, an exhaust port, an intake valve configured to allow and/or block fluid flow through the intake port, an exhaust valve configured to allow and/or block fluid flow through the exhaust port, and a fuel injector, the piston and the inner surface defining a combustion chamber, the method comprising:
injecting a fuel into each of the combustion chambers, the fuel having a cetane number of less than about 40, the fuel substantially free of additives that result in a substantial change in cetane number;
combusting substantially all of the fuel in the compression ignition engine; and
deactivating a cylinder by deactivating motion of the intake valve and exhaust valve before deactivating the fuel injector in order to trap combustion products rather than air and maintain overall stoichiometric air/fuel ratio in the cylinder.
2 . The method of claim 1 , further comprising:
monitoring engine load of the compression ignition engine; and
deactivating a cylinder of the N cylinders.
3 . The method of claim 2 , wherein the deactivating a cylinder of the N cylinders is upon a decrease in engine load to less than (N−1)/N×FL, FL being a full load at a given speed.
4 . The method of claim 3 , further comprising:
igniting the fuel via compression ignition in the compression ignition engine.
5 . The method of claim 4 , wherein the compression ignition engine further includes an engine control unit (ECU), the ECU comprising ECU hardware and in communication with an exhaust oxygen sensor.
6 . The method of claim 4 , wherein an exhaust aftertreatment control device controls CO, HC, soot, and/or NO x emissions via at least one of a diesel oxidation catalyst, selective catalytic reduction, or a three-way catalyst.
7 . The method of claim 1 , wherein the compression ignition engine further includes an exhaust aftertreatment control device.
8 . The method of claim 1 , wherein the deactivating is via a cylinder deactivation (CDA) system, the CDA system comprising CDA hardware and a CDA control module in communication and/or contact with the intake valves, the exhaust valves, and the fuel injectors.
9 . The method of claim 5 , wherein the ECU adjusts an amount of exhaust recirculated based on an oxygen content sensed by the exhaust oxygen sensor.
10 . The method of claim 1 , wherein the air/fuel ratio is lean with respect to an intake air quantity entering each of the combustion chambers.
11 . The method of claim 1 , further comprising:
recirculating a portion of exhaust from the exhaust port back into the combustion chambers via the intake port.
12 . The method of claim 1 , wherein the fuel has an octane rating of at least about 100.
13 . The method of claim 1 , wherein the deactivating increases engine load for each cylinder in response to the cylinders in the compression ignition engine operating outside of a prescribed load range.
14 . The method of claim 1 , further comprising:
reducing a flow rate of air into the combustion chambers to maintain a desired air-fuel ratio.
15 . A method of operating a compression ignition engine, the compression ignition engine including a plurality of cylinders, each of the plurality of cylinders having an inner surface, a piston disposed and configured to move in the engine cylinder, an intake port, an exhaust port, and a fuel injector, the piston, the inner surface, the intake port, and the exhaust port defining a combustion chamber, the method comprising:
injecting a fuel into each of the combustion chambers, the fuel having a cetane number of less than about 40, the fuel substantially free of additives that result in a substantial change in cetane number;
igniting the fuel via compression ignition in the compression ignition engine;
combusting substantially all of the fuel in the compression ignition engine;
monitoring engine load of the compression ignition engine;
setting a predetermined load value; and
deactivating at least one cylinder of the plurality of cylinders upon a decrease in engine load to less than the predetermined load value.
16 . The method of claim 15 , wherein each of the plurality of cylinders has an intake valve configured to allow and/or block fluid flow through the intake port, and an exhaust valve configured to allow and/or block fluid flow through the exhaust port.
17 . The method of claim 16 , wherein deactivating at least one cylinder includes deactivating motion of the intake valve and exhaust valve before deactivating the fuel injector in order to trap combustion products rather than air and maintain overall stoichiometric air/fuel ration in the cylinder.
18 . The method of claim 17 , wherein the fuel satisfies a stoichiometric condition with respect to an intake air quantity entering each of the combustion chambers.
19 . The method of claim 18 , wherein the compression ignition engine further includes an exhaust aftertreatment control device, and the exhaust aftertreatment control device controls CO, HC, soot, and/or NO x emissions via at least one of a diesel oxidation catalyst, selective catalytic reduction, or a three-way catalyst.
20 . The method of claim 17 , further comprising:
recirculating a portion of exhaust from the exhaust ports back into the combustion chambers via the intake ports.
21 . The method of claim 17 , wherein the predetermined load value is calculated as (N−D)/N×FL, wherein N is the number of cylinders in the compression ignition engine, D is the number of cylinders deactivated, and FL is a full load at a given engine speed.
22 . The method of claim 17 , further comprising:
re-activating the cylinder to navigate from lower load to higher load.
23 . The method of claim 17 , wherein the fuel has no more than about 3 carbon atoms per molecule.
24 . The method of claim 17 wherein the fuel includes at least one of methanol, ethanol, propanol, butanol, gasoline/ethanol mixtures, gasoline/methanol mixtures, methanol/ethanol mixtures, denatured alcohol, hydrous alcohol, dimethyl ether, ammonia, hydrogen, propane, or natural gas.
25 . A compression ignition engine, comprising:
a plurality of N cylinders, each of the N cylinders including:
an inner surface;
a piston disposed and configured to move in the engine cylinder;
an intake port;
an exhaust port;
and
a fuel injector fluidically coupled to each of the N cylinders, the piston and the inner surface, defining a combustion chamber;
a fuel supply fluidically coupled to the fuel injector, the fuel supply configured to contain a fuel having a cetane number of less than about 40, the fuel substantially free of additives that result in a substantial change in cetane number;
an engine control unit (ECU) in communication with each of the fuel injectors, the ECU configured to deliver a quantity of a fuel to each of the cylinders; and
a cylinder deactivation (CDA) control module configured to deactivate D cylinders from the N cylinders when an engine load in the compression ignition engine decreases below (N−D)/N×FL,
wherein FL is a full load at a given engine speed,
wherein N is an integer of at least 2, and
wherein D is an integer of at least 1.
26 . The compression ignition engine of claim 25 , further comprising:
an intake valve configured to allow and/or block fluid flow through the intake port; and
an exhaust valve configured to allow and/or block fluid flow through the exhaust port.
27 . The compression ignition engine of claim 26 , wherein the CDA is configured to deactivate motion of the intake valve and the exhaust valve.
28 . The compression ignition engine of claim 26 , wherein the CDA is configured to maintain overall stoichiometric air/fuel ratio in the cylinder.
29 . The compression ignition engine of claim 26 , wherein the CDA is configured to deactivate motion of the intake valve and the exhaust valve before deactivating the fuel injector during a period of deactivation and maintain overall stoichiometric air/fuel ratio in the cylinder.