System and method for cylinder deactivation in a high temperature hybrid control engine

Abstract

The embodiments described herein relate to systems and methods for cylinder deactivation in a compression ignition engine. The engine described herein may include N cylinders, where N is an integer of at least 2, and each cylinder includes an inner surface, a piston disposed and configured to move within each 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 a compression ignition engine includes injecting fuel into each combustion chamber, combusting substantially all of the fuel in the compression ignition engine, monitoring the load of the compression ignition engine, and deactivating one of the N cylinders when the load decreases to less than (N−1) / N×FL, where FL is the full load at a given engine speed.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to and the benefit of U.S. Provisional Application No. 63 / 049,763, filed on July 9, 2020, entitled “SYSTEM AND METHOD FOR CYLINDER DETENTION: MAINTAINING STOICHIOMETRIC AIR-FUEL RATIO IN A HEAVY DUTY ENGINE,” the entire disclosure of which is incorporated herein by reference. Technical Field

[0003] The present disclosure relates to methods and apparatus for controlling an internal combustion engine capable of using a variety of non-conventional fuels in a direct injection, compression ignition, high temperature engine. Background Art

[0004] Internal combustion engine pollutant standards are strictly regulated by agencies including the Environmental Protection Agency (EPA). Although engines are equipped with aftertreatment systems to treat standard pollutants (such as three-way catalytic converters, selective catalytic reduction systems, etc.) to reduce carbon monoxide (CO), hydrocarbons (HC) and nitrogen oxides (NO x ) levels, the way the engine is operated affects the "engine emissions", i.e. the emissions levels from the engine itself and before the aftertreatment systems. Engine exhaust emission levels can be affected by factors such as the engine air-fuel ratio, peak combustion temperature and exhaust dilution. Therefore, for the engine, precise control of factors such as air-fuel ratio, thermal management and exhaust gas utilization is very important for pollutant management. Summary of the invention

[0005] Embodiments described herein relate to systems and methods for cylinder deactivation in a compression ignition engine. The engine described herein may include N cylinders, where N is an integer of at least 2, each cylinder including an inner surface, a piston disposed and configured to move in each 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 a compression ignition engine includes injecting fuel into each combustion chamber, burning substantially all of the fuel in the compression ignition engine, monitoring the engine load of the compression ignition engine, and deactivating one of the N cylinders when the load decreases to less than (N-1) / N×FL, where FL is the full load at a given engine speed. In some embodiments, the fuel may meet stoichiometric conditions relative to the amount of intake air entering each combustion chamber. In some embodiments, the air-fuel ratio may be lean relative to the amount of intake air entering each combustion chamber. In some embodiments, the method may also include recirculating a portion of the exhaust gas from the exhaust port back to the combustion chamber via the intake port. In some embodiments, the compression ignition engine may include a three-way catalytic converter, and the three-way catalytic converter may reduce CO, HC, and NO xIn some embodiments, deactivating a cylinder may include closing an intake valve of the cylinder, closing an exhaust valve of the cylinder, and / or deactivating a fuel injector fluidly coupled to the cylinder. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Figure 1 Particulate matter (soot) emission measurements for diesel and methanol are shown as a function of equivalence ratio.

[0007] Figure 2 Particulate matter emission measurements for methanol and ethanol are shown as a function of equivalence ratio.

[0008] Figure 3 is a block diagram of a compression ignition engine with a cylinder deactivation system according to an embodiment.

[0009] Figure 4 is a block diagram of a method of operating a compression ignition engine with a cylinder deactivation system according to an embodiment.

[0010] Figure 5 A visual representation of the equivalent load achieved using only exhaust gas holding and only cylinder deactivation is shown.

[0011] Figure 6 A visual representation of reducing load from 100%, deactivating one cylinder at a time of a four cylinder engine, increasing EGR dilution in the active cylinders until the next deactivation threshold is reached is shown. DETAILED DESCRIPTION

[0012] Embodiments described herein relate to systems and methods for managing compression ignition (CI) engine operation, including cylinder deactivation (CDA). To meet the needs of the art, CDA is used to reduce the effective displacement of a direct injection, compression ignition multi-cylinder engine during partial load operation. During CDA, selected cylinders in the multi-cylinder engine are deactivated by the system, thereby reducing the effective displacement of the engine. The deactivated cylinders do not provide any power, so the remaining (working) cylinders are operated at a correspondingly higher load. Therefore, the amount of exhaust gas retention (EGR) used for intake dilution at low loads is reduced by CDA compared to using exhaust gas retention (EGR) alone to control engine output. By reducing the level of EGR required for load control, CDA minimizes the potential harmful effects of EGR on the stability of the combustion process and combustion efficiency. The fuel injector that injects into each working cylinder can be controlled by the ECU to inject an amount that meets stoichiometric conditions relative to the amount of fresh air in that cylinder. Therefore, the engine can be operated at a stoichiometric mixture, allowing the use of a conventional three-way catalytic converter to control CO, HC and NO x. In some embodiments, the fuel injector that injects into each working cylinder may satisfy a non-stoichiometric condition with respect to the amount of air in that cylinder. In some embodiments, the engine may be operated using dilution, temperature, or other means to reduce engine standard emissions. In some embodiments, the fuel injector that injects into each working cylinder may satisfy a fuel rich condition with respect to the amount of air in that cylinder. In some embodiments, the fuel injector that injects into each working cylinder may satisfy a fuel lean condition with respect to the amount of air in that cylinder.

[0013] In some embodiments, CDA is achieved by deactivating the intake and exhaust valves of deactivated cylinders in a multi-cylinder engine. A similar effect can be achieved by keeping one or more valves open throughout the cycle (if the geometry allows).

[0014] Precise control of the air-fuel ratio of the engine can be achieved by closed-loop control of the air-fuel ratio by the engine control unit (ECU). The ECU can use feedback from the exhaust oxygen sensor to adjust the amount of fuel delivered to keep the air-fuel ratio near the stoichiometric level (φ=1). In some embodiments, oxygen sensor feedback can be used to keep the air-fuel ratio near the non-stoichiometric level. The oxygen sensor can be installed upstream of the catalytic converter or other after-treatment device. A second oxygen sensor can be installed downstream of the catalytic converter or other after-treatment device to further improve the accuracy of the air-fuel ratio control.

[0015] Modern closed-loop controlled three-way catalytic converters are relatively simple, inexpensive, and reliable. However, commercial diesel engines typically operate with lean fuel mixtures throughout their operating range. Therefore, diesel engines are not usually equipped with a closed-loop controlled three-way catalytic converter to control CO, HC, and NO. x Conventional three-way catalytic converters. The low combustion efficiency of diesel engines under stoichiometric conditions can lead to poor fuel economy and excessive emissions of particulate matter (such as soot). To avoid the formation of excessive soot, the air-fuel ratio of heavy-duty diesel engines is usually maintained above 25:1, and the corresponding fuel-air equivalence ratio (φ≈0.6) is much lower than the stoichiometric equivalence ratio of 1. Therefore, operating with a stoichiometric strategy and controlling emissions through a three-way catalytic converter is not usually an option for diesel engines. Due to the lean stoichiometry, CO, HC, soot and NO x It is usually controlled by a diesel oxidation catalyst (DOC), a diesel particulate filter (DPF) and selective catalytic reduction (SCR).

[0016] In addition, if their poor ignition properties (except DME) can be overcome, low-carbon and / or oxygenated fuels (including but not limited to alcohols (such as methanol and ethanol), liquefied natural gas (LNG), propane, ammonia, hydrogen (H 2The inherent low soot emissions of methyl ether (Methyl Ether (DME)) make it an ideal choice for stoichiometric combustion in a direct injection compression ignition engine. Methods and apparatus for achieving consistent autoignition of such fuels in a heavy-duty direct injection compression ignition engine using a high temperature combustion strategy are described in U.S. Patent No. 9,903,262 filed on April 6, 2015 (the "'262 Patent"), entitled "Stoichiometric High Temperature Direct Injection Compression Ignition Engine," the disclosure of which is incorporated herein by reference in its entirety. Figure 1 Experimentally measured soot emissions for diesel and methanol fuels as a function of equivalence ratio are shown (see the '262 patent). Diesel engine operation at equivalence ratios greater than about 0.6 typically results in impractically high levels of soot. In contrast, emissions from operation with methanol are close to zero over the same equivalence ratio range. Figure 2 Shown from Figure 1 Soot emissions from methanol and ethanol for the same engine. Both methanol and ethanol can be directly injected at high fuel loads under stoichiometric conditions while keeping soot levels well below current regulatory limits. Similarly, fuels such as DME, LNG, propane, and H 2 The fuel can be directly injected, and the fuel load reaches the stoichiometric conditions without forming soot exceeding the current regulations.

[0017] In addition to strict lean diesel operation (limiting maximum fuel / air ratio due to soot formation) and tight stoichiometric operation, the low soot characteristics of low carbon and / or oxygenated fuels (as listed above) provide the opportunity to operate at richer operating conditions than diesel, but the overall lean air / fuel ratio remains. This allows engine tuning for low criteria pollutants, such as reducing NO emissions from the engine. x , without limiting the formation of soot that would otherwise impede such operation of an engine operating on diesel or diesel-like fuels. In these cases, emission control devices such as a diesel oxidation catalyst (DOC) and / or a selective catalytic reduction (SCR) may be used for standard pollutant control, but the size and complexity of these devices may be reduced, and a diesel particulate filter (DPF) may be omitted. Alternatively, low engine standard emissions may allow the engine to achieve lower emissions than would be possible with diesel, even in an overall lean burn scenario.

[0018] Most internal combustion engines also operate at a variety of loads. In most gasoline engines, power output (i.e. load) is controlled by regulating the amount of air entering the cylinders using a throttle. In contrast, engine load control in a diesel engine is achieved by adjusting the amount of fuel rather than throttling air, which results in a change in the air-fuel ratio across the load range.

[0019] Many engines, both SI and CI, use EGR to reduce NOx produced during combustion.x The triatomic nature of the combustion products (CO2, H2O) present in the exhaust can modulate the combustion process and reduce peak combustion temperatures. In many engines, it is desirable to use higher levels of EGR to reduce engine-out NO x levels, but there are also practical limits on the amount of EGR that can be used.

[0020] The direct injection compression ignition engine described in the '262 patent replaces a portion of the fresh charge with EGR in order to regulate the power output of the engine for part load operation without deviating from the overall stoichiometric air-fuel ratio. The ECU controls the fuel injectors to deliver a stoichiometric amount of fuel relative to the intake air mass. This strategy allows unthrottled, stoichiometric operation over most of the engine speed-load map while minimizing exhaust pollutants using a closed-loop controlled three-way catalytic converter.

[0021] Large displacement, multi-cylinder, heavy-duty engines typically use only a fraction of their maximum power during light load operation. The EGR-diluted stoichiometric combustion strategy for low load operation uses higher and higher EGR levels as the load demand on the engine becomes lower and lower. Similarly, diesel operation uses increased excess air at reduced loads. In other words, an EGR-diluted stoichiometric engine uses EGR for dilution, while a diesel engine uses primarily excess air for dilution, with a small amount of EGR used to reduce NO x emission.

[0022] Typically, the chemical properties of different fuels limit the amount of EGR that can be used, as does the choice of combustion mode. For example, in spark-ignition (SI) engines, both methanol and ethanol are more tolerant of EGR than gasoline. The EGR tolerance of a given combustion system can also be improved by using high in-cylinder turbulence, elevated temperatures, and increased compression ratios. However, in practice, EGR dilution operation is often limited by deterioration in combustion stability, incomplete combustion, or soot formation. More specifically, as the level of EGR increases in SI engines or the combustion efficiency (i.e., fuel conversion) decreases in CI engines, the greater the statistical variation in pressure, power output, and other characteristics from one cycle to another, the less reliable the EGR dilution combustion. Soot is formed when diesel and diesel-like fuels are used in a mixture-controlled combustion mode, and soot formation generally increases with increasing EGR levels. In addition, the amount of EGR that can be used before combustion becomes unstable decreases as engine load decreases because less energy is available to maintain rapid and efficient combustion. Complementary strategies that can work in conjunction with EGR to control the output and engine emission levels of the pure fuel, direct injection, compression ignition internal combustion engine of the '262 patent help address these issues.

[0023] Another limitation on the amount of EGR that may be used is soot formation - diesel fuel and other diesel-like molecules require sufficient excess air to avoid excessive soot formation during mixed controlled combustion in CI engines. Fuels such as ethanol, methanol, DME or other oxygenated or small molecule fuels may allow higher levels of EGR to be used without high soot generation. In this way, the characteristics of the fuel allow the engine to operate at lower engine standard emissions than using soot-generating fuels such as diesel.

[0024] Even in the internal combustion engine of the '262 patent, combustion stability and / or combustion efficiency decreases as EGR dilution increases. The relevant physics involves the mixing of fuel with the air / EGR mixture so that fuel molecules and fuel fragments meet and react with oxygen molecules. If mixing is achieved, sufficient thermal energy is also required to carry out these reactions. At lighter loads, the fuel energy is lower due to the reduced amount of fuel. This reduces the exhaust temperature. Therefore, since the high temperature combustion cycle depends on the exhaust temperature of the previous cycle, there may be challenges in maintaining sufficient thermal energy to ignite the low cetane fuel described herein. Even if sufficient thermal energy can be maintained, or even thermal energy can be applied from an external source (such as a heater), the dilution of the air / EGR mixture into which the fuel is injected slows the combustion reaction by reducing the probability of collision between oxygen and fuel molecules. This is because some collisions will occur between the fuel and the inert EGR components. Therefore, there are practical limitations to using EGR dilution to maintain stoichiometric conditions over the entire load range of engine operation.

[0025] In addition to in-cylinder phenomena during the combustion process, the mechanism of recirculating exhaust gas can also be limited to a certain extent. In some cases, for EGR to circulate from the exhaust manifold through the pipe connected to the engine's intake manifold, a pressure differential must exist and the exhaust pressure must be sufficiently higher than the intake manifold pressure to promote sufficient mass to circulate through the EGR loop. This is usually achieved by adjusting the exhaust back pressure applied by the turbocharger relative to the intake compressor. Beyond a certain level of EGR circulation, the circulation of large mass from the exhaust back to the intake can become inefficient, resulting in reduced system performance or less than optimal fuel economy.

[0026] In some embodiments, a large amount of exhaust gas recirculation can be achieved using an EGR pump or blower, which can overcome the lack or inadequacy of the pressure gradient from exhaust to intake. For some applications, this may be too high a level of complexity, and the in-cylinder restrictions on the maximum EGR ratio still apply.

[0027] The embodiments described herein can address the challenges of combustion stability, combustion efficiency, and / or circulating large amounts of EGR. With respect to these three issues, the first limit reached will define the threshold for maximum EGR before the other two become limiting. The first limit encountered depends on the operating point, the specific engine, the fuel selection, the combustion mode, and / or several other factors.

[0028] Compression ignition engines operating with low-soot fuels are described in more detail in U.S. Patent Publication No. 2021 / 0054777 (the '777 publication), entitled “Cold Starting of High Octane Fuels in a Diesel Engine Architecture,” filed on November 9, 2020, and International Patent Application No. PCT / US2021 / 019930 (the '930 publication), entitled “Fuel Agnostic Compression Ignition Engine,” filed on February 26, 2021, the disclosures of which are generally incorporated herein.

[0029] The embodiments described herein include a synergistic combination of engine load control strategies for direct injection, compression ignition, multi-cylinder heavy-duty engines. The method and apparatus described in the '262 patent can create conditions in the combustion chamber (i.e., inside the cylinder) suitable for auto-ignition of alcohols (e.g., methanol and ethanol). The inherent low soot formation characteristics of alcohol fuels enable direct injection at high fuel loads or higher EGR dilutions than diesel fuel can withstand. The ECU can command the fuel injector to deliver a certain amount of fuel relative to the commanded load, and the EGR valve or EGR control device can deliver a desired level of exhaust gas to mix with the intake air. This strategy allows unthrottled operation at a desired EGR load and air-fuel ratio on most engine speed load maps, thereby controlling exhaust pollutants emitted by the engine. In other words, in addition to the freedom already provided by using small molecule fuels, the load control strategy described herein allows additional degrees of freedom (engine displacement) when adjusting the engine, namely, not being restricted by soot.

[0030] According to this strategy, the high EGR levels required to achieve light load operation in a large displacement, multi-cylinder heavy-duty engine may result in reduced combustion stability and / or combustion efficiency. The embodiments described herein extend the low load limit using a hybrid engine load control strategy that combines variable engine displacement with EGR dilution operation to maintain stable operation of the active cylinders and a desired EGR dilution level or air-fuel ratio to reduce engine emissions.

[0031] CDA, used in conjunction with controlled EGR and fueling, can facilitate movement around the engine load map while maintaining a desired EGR dilution or air-fuel ratio. A more traditional application of CDA is to keep exhaust temperatures higher by operating fewer cylinders at higher loads to maintain equivalent power output. This can be used to keep exhaust aftertreatment systems hot. Innovations in control strategies can allow for more continuous load changes while maintaining high exhaust temperatures, or avoid throttling in SI engines. The benefits of maintaining a desired level of EGR dilution or air-fuel ratio through CDA include meeting stringent emissions standards and low engine emissions. This can be done in conjunction with adjacent innovations such as advanced controls, or in the absence of these innovations. Advanced control is described in more detail in U.S. Patent No. 7,954,474, entitled “Internal Combustion Engine Control for Improved Fuel Efficiency,” filed on November 9, 2009 (“the '474 patent”) and U.S. Patent No. 8,511,281, entitled “Skip Fire Engine Control,” filed on July 9, 2010 (“the '281 patent”), the entire contents of which are incorporated herein by reference. Advantages described herein include using CDA on a diesel type engine to control the dilution level or air-fuel ratio.

[0032] Figure 3is a block diagram of a compression ignition engine 300 with a cylinder deactivation system according to an embodiment. As shown in the figure, the compression ignition engine 300 includes cylinders 310a, 310b (collectively referred to as cylinders 310), intake valves 312a, 312b (collectively referred to as intake valves 312), exhaust valves 314a, 314b (collectively referred to as exhaust valves 314), fuel injectors 320a, 320b (collectively referred to as fuel injectors 320), an ECU 330, and a cylinder deactivation system (CDA system) 340. As shown in the figure, solid lines represent physical or fluid connections, while dashed lines represent virtual connections or communications between devices. In some embodiments, the engine displacement of the compression ignition engine 300 may be at least about 0.5 L, at least about 1 L, at least about 2 L, at least about 3 L, at least about 4 L, at least about 5 L, at least about 6 L, at least about 7 L, at least about 8 L, at least about 9 L, at least about 10 L, at least about 11 L, at least about 12 L, at least about 13 L, at least about 14 L, at least about 15 L, at least about 16 L, at least about 17 L, at least about 18 L, at least about 19 L, at least about 20 L, at least about 25 L, at least about 30 L, at least about 35 L, at least about 40 L, at least about 45 L, at least about 50 L, at least about 55 L, at least about 60 L, at least about 65 L, at least about 70 L, at least about 75 L, at least about 80 L, at least about 85 L, at least about 90 L, or at least about 95 L. In some embodiments, the engine displacement of the compression ignition engine 300 may be no greater than about 100 L, no greater than about 95 L, no greater than about 90 L, no greater than about 85 L, no greater than about 80 L, no greater than about 75 L, no greater than about 70 L, no greater than about 65 L, no greater than about 60 L, no greater than about 55 L, no greater than about 50 L, no greater than about 45 L, no greater than about 40 L, no greater than about 35 L, no greater than about 30 L, no greater than about 50 L, no greater than about 65 L, no greater than about 6 ... The engine displacements may be as follows: about 20 L, no greater than about 19 L, no greater than about 18 L, no greater than about 17 L, no greater than about 16 L, no greater than about 15 L, no greater than about 14 L, no greater than about 13 L, no greater than about 12 L, no greater than about 11 L, no greater than about 10 L, no greater than about 9 L, no greater than about 8 L, no greater than about 7 L, no greater than about 6 L, no greater than about 5 L, no greater than about 4 L, no greater than about 3 L, no greater than about 2 L, or no greater than about 1 L. Combinations of the above engine displacements are also possible (e.g., at least about 0.5 L and no greater than about 100 L or at least about 2 L and no greater than about 10 L or at least about 19 L and no greater than about 95 L), including all values ​​and ranges therebetween.In some embodiments, the engine displacement of the compression ignition engine 300 can be about 0.5L, about 1L, about 2L, about 3L, about 4L, about 5L, about 6L, about 7L, about 8L, about 9L, about 10L, about 11L, about 12L, about 13L, about 14L, about 15L, about 16L, about 17L, about 18L, about 19L, about 20L, about 25L, about 30L, about 35L, about 40L, about 45L, about 50L, about 55L, about 60L, about 65L, about 70L, about 75L, about 80L, about 85L, about 90L, about 95L, or about 100L.

[0033] In some embodiments, the compression ignition engine 300 may include a four-stroke engine. In some embodiments, the compression ignition engine 300 may include a two-stroke engine. In some embodiments, the compression ignition engine 300 may include a five-stroke engine. In some embodiments, the compression ignition engine 300 may include a six-stroke engine.

[0034] As shown, cylinder 310 includes intake valve 312 and exhaust valve 314. In some embodiments, each cylinder 310 may include an inner surface, a cylinder head surface, and / or a piston disposed in each cylinder 310. In some embodiments, the inner surface, the cylinder head surface, the piston, the intake valve 312, and the exhaust valve 314 may form a combustion chamber.

[0035] As shown, an intake valve 312 and an exhaust valve 314 are included in each cylinder 310. The intake valve 312 may cover an intake port (not shown), and the intake valve 312 may open to expose the intake port (i.e., to allow fluid to flow through the intake port). The exhaust valve 314 may cover an exhaust port (not shown), and the exhaust valve 314 may open to expose the exhaust port (i.e., to allow fluid to flow through the exhaust port). In some embodiments, one or more cylinders 310 may not have an intake valve 312 and an exhaust valve 314, and may only include an intake port and an exhaust port. As a non-limiting example of such an embodiment, a two-stroke engine may not have an intake valve and / or an exhaust valve.

[0036] As shown, the compression ignition engine 300 includes 2 cylinders 310. In some embodiments, the compression ignition engine 300 may include 1 cylinder, 3 cylinders, 4 cylinders, 5 cylinders, 6 cylinders, 7 cylinders, 8 cylinders, 9 cylinders, 10 cylinders, 11 cylinders, 12 cylinders, 13 cylinders, 14 cylinders, 15 cylinders, 16 cylinders, 17 cylinders, 18 cylinders, 19 cylinders, 20 cylinders, 21 cylinders, 22 cylinders, 23 cylinders, 24 cylinders, 25 cylinders, 26 cylinders, 27 cylinders, 28 cylinders, 29 cylinders, 30 cylinders, 31 cylinders, or 32 cylinders, including all values ​​and ranges therebetween.

[0037] In some embodiments, the cylinders 310 may each include a plurality of pistons. In some embodiments, the cylinders 310 may include pistons in an opposed piston configuration. In some embodiments, the cylinders 310 may be implemented in a split single engine design. In some embodiments, one or more of the cylinders 310 may include an ignition assist device. In some embodiments, one or more of the cylinders 310 may include a spark plug disposed therein for spark assisted compression ignition. In some embodiments, one or more of the cylinders 310 may include a glow plug. In some embodiments, one or more of the cylinders 310 may include a plasma heating device. Ignition assist devices are further described in the '777 publication.

[0038] In some embodiments, the intake valve 312 and the exhaust valve 314 can be opened and closed by a variable valve timing (VVT) scheme. In some embodiments, the VVT ​​scheme can be implemented during the transition phase of the compression ignition engine 300. For example, when the compression ignition engine is switching between cold start and steady state operation, the VVT ​​scheme can be implemented. Further implementations of the VVT ​​scheme are described in the '777 publication.

[0039] In some embodiments, one or more fuel injectors 320 may be disposed directly in cylinder 310. In some embodiments, one or more fuel injectors 320 may be disposed external to cylinder 310. In some embodiments, one or more fuel injectors 320 may be disposed in an intake port (not shown) of a compression ignition engine. In some embodiments, the fuel injector 320 may inject a volume of fuel at an injection pressure of at least about 800 bar (absolute), at least about 900 bar, at least about 1000 bar, at least about 1100 bar, at least about 1200 bar, at least about 1300 bar, at least about 1400 bar, at least about 1500 bar, at least about 1600 bar, at least about 1700 bar, at least about 1800 bar, at least about 1900 bar, at least about 2000 bar, at least about 2100 bar, at least about 2200 bar, at least about 2300 bar, at least about 2400 bar, at least about 2500 bar, at least about 2600 bar, at least about 2700 bar, at least about 2800 bar, or at least about 2900 bar. In some embodiments, fuel injector 320 may inject a volume of fuel at an injection pressure no greater than about 3000 bar, no greater than about 2900 bar, no greater than about 2800 bar, no greater than about 2700 bar, no greater than about 2600 bar, no greater than about 2500 bar, no greater than about 2400 bar, no greater than about 2300 bar, no greater than about 2200 bar, no greater than about 2100 bar, no greater than about 2000 bar, no greater than about 1900 bar, no greater than about 1800 bar, no greater than about 1700 bar, no greater than about 1600 bar, no greater than about 1500 bar, no greater than about 1400 bar, no greater than about 1300 bar, no greater than about 1200 bar, no greater than about 1100 bar, no greater than about 1000 bar, or no greater than about 900 bar.

[0040] Combinations of the above injection pressures are also possible (e.g., at least about 800 bar and not more than about 3000 bar or at least about 1200 bar and not more than about 2000 bar), including all values ​​and ranges therebetween. In some embodiments, fuel injector 320 can inject a volume of fuel at an injection pressure of about 800 bar, about 900 bar, about 1000 bar, about 1100 bar, about 1200 bar, about 1300 bar, about 1400 bar, about 1500 bar, about 1600 bar, about 1700 bar, about 1800 bar, about 1900 bar, about 2000 bar, about 2100 bar, about 2200 bar, about 2300 bar, about 2400 bar, about 2500 bar, about 2600 bar, about 2700 bar, about 2800 bar, about 2900 bar, or about 3000 bar.

[0041] As shown, the ECU 330 is virtually connected to the fuel injector 320, the intake valve 312, the exhaust valve 314, and the CDA system 340, and can control the fuel injector 320, the intake valve 312, the exhaust valve 314, and the CDA system 340. In some embodiments, the ECU 330 can adjust the air-fuel ratio based on the oxygen reading in the exhaust flow. In some embodiments, the ECU 330 can maintain a stoichiometric ratio of fuel and air. In some embodiments, the ECU 330 can maintain a non-stoichiometric ratio of fuel and air. In some embodiments, the ECU 330 can reduce or increase the pressure of the fuel injector 320. In some embodiments, the ECU 330 can modify the opening timing of the intake valve 312 and / or the exhaust valve 314 (for example, using a VVT scheme). In some embodiments, the ECU 330 can modify the closing timing of the intake valve 312 and / or the exhaust valve 314. In some embodiments, the ECU 330 can control the implementation of the EGR strategy. In some embodiments, the ECU 330 can control the amount of exhaust gas that is redirected back to the intake of the compression ignition engine 300. In other words, the ECU 330 may control a recirculation path (not shown) that may separate a portion of the exhaust gas so that the portion of the exhaust gas is redirected. In some embodiments, the ECU 330 may communicate with an oxygen sensor (not shown) that measures the oxygen content in the exhaust gas. In some embodiments, the ECU 330 may communicate with the recirculation path and adjust the amount of exhaust gas recirculated based on the oxygen content sensed by the oxygen sensor. In some embodiments, the fuel and air supplied to the compression ignition engine 300 may be maintained at a lean ratio based on the oxygen content sensed by the oxygen sensor. In some embodiments, the compression ignition engine 300 may include an oxygen sensor but not a catalytic converter.

[0042] In some embodiments, the fuel injector 320 may include a closed-loop controlled fuel injector. In some embodiments, the compression ignition engine 300 may include an EGR path. In some embodiments, the closed-loop controlled fuel injector and EGR path may maintain precise control of thermal management and combustion dilution in the compression ignition engine 300. In some embodiments, the closed-loop controlled fuel injector and EGR path may minimize standard pollutants leaving the compression ignition engine 300. In some embodiments, the engine may be equipped with a three-way catalytic converter. The closed-loop controlled fuel injector, EGR path, and three-way catalytic converter may reduce CO, hydrocarbons, and NO x of exhaust emissions.

[0043] As shown, the CDA system 340 is virtually connected to the ECU 330 and is mechanically and / or fluidically coupled to the intake valve 312 and the exhaust valve 314. In some embodiments, the CDA system 340 may exist as a controller or control system independent of the ECU 330. In some embodiments, the CDA system 340 may include CDA hardware and a CDA control module. The CDA hardware may be in physical contact, hydraulic contact, and / or communication with the intake valve 312 and the exhaust valve 314. In some embodiments, the CDA hardware may be in physical contact, hydraulic contact, and / or communication with the fuel injector 320. The CDA control module may communicate and / or contact with the intake valve 312, the exhaust valve 314, and the fuel injector 320. In some embodiments, the CDA system 340 may deactivate the intake valve 312 and / or the exhaust valve 314 of one or more cylinders 310. In some embodiments, the ECU 330 may deactivate the fuel injector 320 of one or more cylinders 310. In some embodiments, the CDA system 340 may deactivate one of the intake valves 312 and / or one of the exhaust valves 314 when the engine load of the compression ignition engine 300 decreases to less than or equal to (N-1) / N×FL, where N is the number of cylinders in the compression ignition engine 300 and FL is the full load at the engine speed of the compression ignition engine 300. In some embodiments, the ECU 330 may deactivate one of the fuel injectors 320 when the engine load of the compression ignition engine 300 decreases to less than or equal to (N-1) / N×FL. For example, if the compression ignition engine 300 has 4 cylinders 310, the CDA system 340 may deactivate one of the cylinders 310 when the engine load decreases to less than or equal to 75% of the full load. In some embodiments, FL may be defined by the manufacturer. In some embodiments, FL may be defined by calibration or modification performed by a user. In other words, FL may be a calibrated value based on adjustments applied by a user to the compression ignition engine 300. In some embodiments, FL may be defined by the total displacement of the compression ignition engine 300. In some embodiments, FL may be defined by the physical limitations of the compression ignition engine 300, such as peak pressure. In some embodiments, FL may be defined by the physical limitations of the compression ignition engine 300 multiplied by a safety factor (e.g., 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, 0.95, including all values ​​and ranges therebetween). In some embodiments, FL may be the maximum power output required by a user or device.

[0044] In some embodiments, the compression ignition engine 300 may include a boost device (not shown). In some embodiments, the compression ignition engine 300 may include an intake manifold (not shown) that is fluidly coupled to the intake valve 312 and the boost device. In some embodiments, the boost device may increase the pressure in the intake manifold. In some embodiments, the boost device may include a turbocharger, a supercharger, and / or a turbo compound device. In some embodiments, the CDA system 340 may operate based on a load requested by the driver (e.g., by the position of the accelerator pedal). In some embodiments, the CDA controller 340 may operate based on a recommended load. In some embodiments, the CDA system 340 may re-enable cylinders based on a load requested by the driver. In some embodiments, the CDA system 340 may re-enable cylinders based on a command load. In some embodiments, the CDA system 340 may re-enable cylinders to guide the compression ignition engine 300 from a lower load to a higher load.

[0045] Figure 4 A method 400 of operating a compression ignition engine according to one embodiment is shown. As shown, the method 400 includes injecting fuel into each combustion chamber of the compression ignition engine in step 401, combusting the fuel in each combustion chamber in step 402, recirculating a portion of the exhaust gas from the exhaust valve to each combustion chamber in step 403, monitoring the load operation of the compression ignition engine in step 404, and deactivating cylinders when the engine load decreases in step 405. In some embodiments, the method 400 may also include deactivating additional cylinders when the engine load further decreases in step 406. In some embodiments, the method 400 may include reactivating cylinders in step 407.

[0046] Step 401 includes injecting fuel into each combustion chamber. In certain embodiments, the piston, the cylinder head surface, the intake valve and the exhaust valve of the cylinder can define the combustion chamber. In certain embodiments, the fuel can include a fuel (e.g., methane, methanol) having 1 carbon atom per molecule. In certain embodiments, the fuel can be free of carbon atoms (e.g., hydrogen). In certain embodiments, the fuel can be at least about 1 carbon atom per molecule, at least about 2 carbon atoms per molecule, at least 3 carbon atoms per molecule, at least about 4 carbon atoms per molecule, at least about 5 carbon atoms per molecule, at least 6 carbon atoms per molecule, at least about 7 carbon atoms per molecule, at least about 8 carbon atoms per molecule or at least about 9 carbon atoms per molecule. In some embodiments, the fuel may be no more than about 10 carbon atoms per molecule, no more than about 9 carbon atoms per molecule, no more than about 8 carbon atoms per molecule, no more than about 7 carbon atoms per molecule, no more than about 6 carbon atoms per molecule, no more than about 5 carbon atoms per molecule, no more than about 4 carbon atoms per molecule, no more than about 3 carbon atoms per molecule, or no less than about 2 carbon atoms per molecule. Combinations of the above carbon atom numbers per molecule are also possible (e.g., at least about 1 carbon atom per molecule and no more than about 10 carbon atoms per molecule or at least 1 carbon-carbon atom per molecule and no more than about 3 carbon atoms per molecule), including all values ​​and ranges therebetween. In some embodiments, the fuel may be about 1 carbon atom per molecule, about 2 carbon atoms per molecule, about 3 carbon atoms per molecule, about 4 carbon atoms per molecule, about 5 carbon atoms per molecule, about 6 carbon atoms per molecule, about 7 carbon atoms per molecule, about 8 carbon atoms per molecule, about 9 carbon atoms per molecule, or about 10 carbon atoms per molecule.

[0047] In some embodiments, the cetane number of the fuel may be at least about -10, at least about -5, at least about 0, at least about 5, at least about 10, at least about 15, at least about 20, at least about 25, at least about 30, or at least about 35. In some embodiments, the cetane number of the fuel may be no more than about 40, no more than about 35, no more than about 30, no more than about 25, no more than about 20, no more than about 15, no more than about 10, no more than about 5, no more than about 0, or no more than about -5. Combinations of the above cetane numbers of the fuel are also possible (e.g., at least about -10 and no more than about 40 or at least about 10 and no more than 20), including all values ​​and ranges therebetween. In some embodiments, the cetane number of the fuel may be about -10, about -5, about 0, about 5, about 10, about 15, about 20, about 25, about 30, about 35, or about 40.

[0048] In certain embodiments, fuel may include naphtha, gasoline, ethanol, butanol, propanol, ethanol, methanol, gasoline / ethanol mixture, gasoline / methanol mixture, methanol / ethanol mixture, denatured alcohol, aqueous alcohol, gaseous hydrocarbons, natural gas, methane, ethane, propane, butane, hexane, alternative fuels, hydrogen, ammonia, synthesis gas and / or CO. In certain embodiments, fuel may have a small amount of additives that cause a significant change in cetane number. In certain embodiments, fuel may include an additive that causes a significant change in cetane number, the additive being less than about 5000ppm, less than about 4000ppm, less than about 3000ppm, less than about 2000ppm, less than about 1000ppm, less than about 900ppm, less than about 800ppm, less than about 700ppm, less than about 600ppm or less than about 500ppm by weight. In certain embodiments, fuel may be substantially free of the additive that causes a significant change in cetane number.

[0049] In some embodiments, the fuel may include additives for other purposes that do not result in a significant change in the cetane number (e.g., lubricity additives). In some embodiments, the fuel may include additives that do not result in a significant change in the cetane number, less than about 5000 ppm, less than about 4000 ppm, less than about 3000 ppm, less than about 2000 ppm, less than about 1000 ppm, less than about 900 ppm, less than about 800 ppm, less than about 700 ppm, less than about 600 ppm, or less than about 500 ppm by weight. In some embodiments, the fuel may be substantially free of additives that do not result in a significant change in the cetane number. In some embodiments, the fuel may include an additive that does not result in a significant change in cetane number, at least about 50 ppm, at least about 100 ppm, at least about 200 ppm, at least about 300 ppm, at least about 400 ppm, at least about 500 ppm, at least about 600 ppm, at least about 700 ppm, at least about 800 ppm, at least about 900 ppm, at least about 1000 ppm, at least about 2000 ppm, at least about 3000 ppm, or at least about 4000 ppm. Combinations of the above ranges of additives that do not result in a significant change in cetane number (e.g., at least about 50 ppm and not more than about 5000 ppm or at least about 1000 ppm and not more than about 4000 ppm) are possible, including all values ​​and ranges therebetween. In some embodiments, the fuel may include an additive that does not result in a significant change in cetane number, wherein the additive is about 50 ppm, about 100 ppm, about 200 ppm, about 300 ppm, about 400 ppm, about 500 ppm, about 600 ppm, about 700 ppm, about 800 ppm, about 900 ppm, about 1000 ppm, about 2000 ppm, about 3000 ppm, about 4000 ppm, or about 5000 ppm.

[0050] In some embodiments, the octane number of the fuel (i.e., calculated by the (RON+MON) / 2 method) may be at least about 50, at least about 55, at least about 60, at least about 65, at least about 70, at least about 75, at least about 80, at least about 85, at least about 90, at least about 95, at least about 100, at least about 105, at least about 110, at least about 115, at least about 120, at least about 125, at least about 130, at least about 135, at least about 140, or at least about 145. In some embodiments, the octane number of the fuel may be no greater than about 150, no greater than about 145, no greater than about 140, no greater than about 135, no greater than about 130, no greater than about 125, no greater than about 120, no greater than about 115, no greater than 110, no greater than 105, no greater than 100, no greater than 95, no greater than about 90, no greater than about 85, no greater than about 80, no greater than about 75, no greater than about 70, no greater than about 65, no greater than about 60, or no greater than about 55. Combinations of the above octane numbers are also possible (e.g., at least about 50 and no greater than about 150 or at least about 80 and no greater than about 120), including all values ​​and ranges therebetween. In some embodiments, the octane number of the fuel may be about 50, about 55, about 60, about 65, about 70, about 75, about 80, about 85, about 90, about 95, about 100, about 105, about 110, about 115, about 120, about 125, about 130, about 135, about 140, about 145, or about 150.

[0051] In some embodiments, the flash point of the fuel may be at least about 0° C., at least about 5° C., at least about 10° C., at least about 15° C., at least about 20° C., at least about 25° C., at least about 30° C., at least about 35° C., at least about 40° C., or at least about 45° C. In some embodiments, the flash point of the fuel may be no greater than about 50° C., no greater than about 45° C., no greater than about 40° C., no greater than about 35° C., no greater than about 30° C., no greater than about 25° C., no greater than about 20° C., no greater than about 15° C., no greater than about 10° C., or no greater than about 5° C. Combinations of the foregoing fuel flash points are also possible (e.g., at least about 0°C and no greater than about 50°C or at least about 10°C and no greater than about 40°C, including all values ​​and ranges therebetween. In some embodiments, the flash point of the fuel may be about 0°C, about 5°C, about 10°C, about 15°C, about 20°C, about 25°C, about 30°C, about 35°C, about 40°C, about 45°C, or about 50°C.

[0052] In some embodiments, multiple fuels may be injected in step 401. In some embodiments, the multiple fuels may be injected separately in step 401. In some embodiments, the multiple fuels may be injected as a mixture in step 401. In some embodiments, the fuels may be injected at any pressure or pressure range described for fuel injector 320, as described above with reference to FIG. Figure 3 described.

[0053] Step 402 includes burning fuel in each combustion chamber. This may include moving the piston from a bottom dead center (BDC) position to a top dead center (TDC) position to cause autoignition of the injected fuel. In some embodiments, the compression ratio formed by the movement of the piston from the BDC position to the TDC position may be at least about 10:1, at least about 11:1, at least about 12:1, at least about 13:1, at least about 14:1, at least about 15:1, at least about 16:1, at least approximately 17:1, at least approximately 18:1, at least about 19:1, at least about 20:1, at least about 21:1, at least about 22:1, at least about 23:1, at least about 24:1, at least about 25:1, at least about 26:1, at least about 27:1, at least about 28:1, or at least about 29:1. In some embodiments, the compression ratio formed by the movement of the piston from the BDC position to the TDC position may be no greater than about 30:1, no greater than about 29:1, no less than about 28:1, no greater than about 27:1, no greater than about 26:1, no greater than about 25:1, no greater than about 24:1, no greater than about 23:1, no greater than about 22:1, no greater than about 21:1, no greater than about 20:1, no greater than about 19:1, no greater than about 18:1, no greater than about 17:1, no greater than about 16:1, no greater than about 15:1, no greater than about 14:1, no greater than about 13:1, no greater than about 12:1, or no greater than about 11:1.

[0054] Combinations of the above compression ratios are also possible (e.g., at least about 10:1 and not more than about 30:1 or at least about 13:1 and not more than about 20:1), including all values ​​and ranges therebetween. In some embodiments, the compression ratio formed by the movement of the piston from the BDC position to the TDC position can be about 10:1, about 11:1, about 12:1, about 13:1, about 14:1, about 15:1, about 16:1, about 17:1, about 18:1, about 19:1, about 20:1, about 21:1, about 22:1, about 23:1, about 24:1, about 25:1, about 26:1, about 27:1, about 28:1, about 29:1, or about 30:1.

[0055] In some embodiments, burning the fuel at step 402 may include promoting combustion through an ignition aid (e.g., a spark plug, a glow plug, etc.). In some embodiments, step 402 may include burning substantially all of the fuel injected at step 401. In some embodiments, less than 50% of the volume of the fuel may be premixed with the volume of air at the start of combustion. In other words, the ignition of the volume of fuel may be a mixture controlled compression ignition or MCCI. In some embodiments, the volume of fuel that may be premixed with the volume of air at the start of combustion is at least about 5%, at least about 10%, at least about 15%, at least about 20%, at least about 25%, at least about 30%, at least about 35%, at least about 40%, or at least about 45%. In some embodiments, the volume of fuel that may be premixed with the volume of air at the start of combustion is no greater than about 50%, no greater than about 45%, no greater than about 40%, no greater than about 35%, no greater than about 30%, no greater than about 25%, no greater than about 20%, no greater than about 15%, or no greater than about 10%. Combinations of the above percentages of the volume of fuel premixed with the volume of air are also possible (e.g., at least about 5% and not more than about 50% or at least about 10% and not more than about 40%), including all values ​​and ranges therebetween. In some embodiments, the volume of fuel premixed with the volume of air at the start of combustion may be about 5%, about 10%, about 15%, about 20%, about 25%, about 30%, about 35%, about 40%, about 45%, or about 50%. In some embodiments, the local equivalence ratio at various points within the combustion chamber may be at least about 1.5, at least about 2, at least about 3, at least about 4, at least about 5, at least about 6, at least about 7, at least about 8, at least about 9, or at least about 10, including all values ​​and ranges therebetween.

[0056] Optional step 403 includes recirculating a portion of the exhaust gas from the exhaust valve back to each active combustion chamber. In some embodiments, the recirculation may be via a recirculation path. In some embodiments, the initial EGR dilution may start from 0% or a desired baseline level (such as in a NO xIn some embodiments, the initial EGR dilution may be about 5%, about 10%, about 15%, about 20%, about 25%, about 30%, about 35%, or about 40%, including all values ​​and ranges therebetween. In some embodiments, the EGR dilution may be increased during operation of the compression ignition engine. In some embodiments, the EGR dilution may be increased during operation such that at least about 10%, at least about 20%, at least about 30%, at least about 40%, at least about 50%, at least about 60%, at least about 70%, or at least about 80% of the exhaust gas from the exhaust valve may be recirculated back to each active combustion chamber. In some embodiments, the EGR dilution may be increased during operation such that no more than about 90%, no more than about 80%, no more than about 70%, no more than about 60%, no more than about 50%, no more than about 40%, no more than about 30%, or no more than about 20% of the exhaust gas from the exhaust valve may be recirculated back to each active combustion chamber. Combinations of the above EGR percentages are also possible (e.g., at least about 10% and not more than about 90% or at least about 20% and not more than about 60%), including all values ​​and ranges therebetween. In some embodiments, the EGR dilution may be increased such that about 10%, about 20%, about 30%, about 40%, about 50%, about 60%, about 70%, about 80%, or about 90% of the exhaust gas from the exhaust valve may be recirculated back to each active combustion chamber. In some embodiments, the proportion of recirculated exhaust gas may be equal or approximately equal between the combustion chambers. In some embodiments, the recirculation amount may be based on the amount of oxygen sensed in the exhaust gas.

[0057] Step 404 includes monitoring the load operation of the compression ignition engine, and step 405 includes deactivating cylinders when the engine load decreases. In some embodiments, moving from high load to low load using CDA and EGR together may include starting from a maximum desired load point and decreasing the load. In some embodiments, the maximum desired load point may coincide with the initial EGR dilution. The first opportunity for CDA is reached when the desired load decreases from a maximum value to a load less than or equal to (N-1) / N×FL at a given RPM. At this point, step 405 includes deactivating cylinders. In some embodiments, deactivating cylinders at step 405 may be in response to cylinders of the compression ignition engine operating outside a specified or desired load range. For example, a user may specify that, in a four-cylinder engine, each cylinder operates between 65% and 90% of the FL of that cylinder. When the load in at least one cylinder decreases below 65%, one of the four cylinders may be deactivated, a higher load may be imposed on each of the remaining cylinders, and the load on each cylinder may be increased to within a specified range. In some embodiments, the air flow into each enabled cylinder may be reduced to maintain a desired air-fuel ratio. In some embodiments, deactivating cylinders may help maintain the air-fuel ratio in each cylinder, rather than having to adjust the air-fuel ratio in each cylinder in response to engine load. In some embodiments, deactivating cylinders may help maintain a desired air-fuel ratio in the cylinders. In some embodiments, deactivating cylinders may help maintain a substantially stoichiometric ratio in the cylinders. In some embodiments, deactivating cylinders may help maintain a rich air-fuel ratio in the cylinders. In some embodiments, deactivating cylinders may help maintain a lean air-fuel ratio in the cylinders.

[0058] In some embodiments, deactivating a cylinder at 405 may include closing an intake valve of the cylinder, closing an exhaust valve of the cylinder, and / or deactivating a fuel injector fluidically coupled to the cylinder. In some embodiments, deactivating a cylinder at 405 may include closing an intake port, closing an exhaust port, and / or deactivating a fuel injector fluidically coupled to the cylinder.

[0059] In some embodiments, deactivating the cylinder at step 405 may include deactivating movement of the intake and exhaust valves prior to deactivating the fuel injectors to trap combustion products other than air during deactivation. Such trapping helps maintain an overall stoichiometric air / fuel ratio in the cylinder for operation of the catalytic converter.

[0060] In addition to CDA, conventional recirculated EGR, and fuel controlled by the engine ECU, there are other enabling technologies that can be used in combination to improve the efficiency of CDA in diesel engine stoichiometric operation. In some embodiments, the boost level can be used to control load and stoichiometry. Increasing boost (i.e., increasing the pressure in the intake manifold, thereby increasing the pressure and density of the air entering the cylinder) allows more air to be drawn into the cylinder at a fixed displacement. In other words, additional fuel can be added to maintain stoichiometry. This can be done without EGR or with a constant baseline EGR level. Additionally, it can be used in combination with EGR and CDA to move across the load map while maintaining stoichiometry and maximizing brake thermal efficiency at each operating point. This can provide additional degrees of freedom for reducing load and maintaining the correct intake air mass. Increasing EGR, reducing boost, and / or deactivating cylinders helps to reduce load and maintain the correct intake air mass. In the absence of a device such as an EGR pump, recirculated EGR control and boost level are linked because the backpressure exerted by the turbocharger must be sufficient to move EGR from the exhaust side of the engine to the intake side. Thus, when the boost pressure (on the intake side) is high, a greater backpressure can provide the pressure differential. In some embodiments, method 400 can include complex boost / turbo configurations, including BorgWarner's "e-boost", electric boosting, and / or turbocompounding, all of which allow decoupling of turbine work from compressor work in a boosted engine configuration, thereby providing additional flexibility for system operation and optimization. In some embodiments, an EGR pump or other device can be used to move EGR from the exhaust to the intake in the absence of a pressure gradient or with an insufficient pressure gradient to drive the desired EGR flow, thereby largely decoupling the EGR flow from the exhaust and intake pressures.

[0061] The type of EGR that can be used in combination with CDA to vary the load is not limited to the conventional recirculated exhaust gas common in diesel engines. Exhaust gas dilution can be achieved by increasing the exhaust backpressure to increase the trapped residual, and VVT of the exhaust valve and / or intake valve can be used to trap or re-inhale exhaust gas to dilute the incoming air. In some embodiments, by holding the exhaust valve in the closed position, the burned fuel can be trapped in the combustion chamber.

[0062] In addition, the EGR dilution and boost intake control are not limited to the individual intake manifold pressure. VVT of the intake valves can also be used to vary the amount of air or air / EGR combination drawn into the combustion chamber during the intake stroke. This may be similar to the Miller cycle, or in the case of early exhaust valve closing, the intake valve can be opened later to maintain approximately symmetric valve timing with respect to TDC. Such strategies are described in the '777 disclosure. When the load is reduced, increasing the trapped EGR and / or reducing the intake valve timing can be used more and more until the CDA threshold is reached, allowing the valve timing to be reset. In the same way, CDA can avoid excessive EGR dilution and can also be used to avoid overly wide VVT requirements.

[0063] Step 406 is optional and includes deactivating additional cylinders when the engine load is further reduced. When one cylinder has been deactivated, as the load is further reduced, the total load can be reduced to below (N - 2) / N × FL (e.g., by EGR). At this point, a second cylinder can be deactivated, leaving the remaining N - 2 cylinders operating at full load. In some embodiments, when the engine load reaches appropriate conditions, the number of cylinders that can be deactivated can be 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, or 31, including all values and ranges therebetween.

[0064] Step 407 is optional and includes re - enabling cylinders. This can be in response to an increase in the engine load. In other words, when the desired load at a given RPM increases from less than (N - 1) / N × FL to greater than or equal to (N - 1) / N × FL, the cylinders can be re - enabled. This may include re - enabling the intake valves, exhaust valves, and / or fuel injectors. In some embodiments, the re - enabling of cylinders can be based on an engine load close to the value of (N - 1) / N × FL. In some embodiments, the re - enabling of cylinders can be based on an engine load that reaches about 80%, about 85%, about 90%, about 95%, about 96%, about 97%, about 98%, or about 99% of (N - 1) / N × FL, including all values and ranges therebetween. In some embodiments, the re - enabling of cylinders can be based on a recommended load. In some embodiments, the re - enabling of cylinders can be based on the position of the throttle pedal. In some embodiments, the re - enabling of cylinders can be performed to navigate a compression - ignition engine from a lower load to a higher load.

[0065] Figure 5 A visual representation of equivalent loads achieved using only EGR and only CDA is shown. Figure 5A four-cylinder engine is shown, but the strategy can be used for any number of cylinders. The shaded regions represent the load fraction of the cylinders compared to full load. This roughly corresponds to the cylinder displacement used for intake, neglecting the minimum EGR base level that may be required for simplicity in this example. The non-shaded regions represent the portion of the cylinder volume composed of EGR and deactivated cylinders. In some embodiments, deactivating a cylinder may include pausing fuel injection to the cylinder.

[0066] Figure 6 A graphical representation is shown of reducing load from 100%, deactivating one cylinder of a four-cylinder engine at a time, and increasing the EGR dilution in the active cylinders until the next deactivation threshold is reached. When one cylinder has been deactivated, as the load is further reduced, the EGR dilution in the remaining working cylinders will increase until the total load is reduced below ((N - 2) / N) × FL. At this point, a second cylinder can be deactivated, leaving the remaining N - 2 cylinders operating at full load. In a manner similar to the way the EGR dilution shows a sawtooth shape in Figure 6 , valve timing can be similarly used while reducing load to increase the trapped EGR and / or reduce the intake until a CDA threshold is reached to allow resetting of the valve timing. In the same way, CDA can avoid excessive EGR dilution and can also be used to avoid overly wide VVT requirements.

[0067] In some embodiments, the engine can employ the strategies described herein in parallel. While each of these methods can be used independently, their combination is within the scope of this disclosure.

[0068] The various concepts can be embodied as one or more methods, with at least one example provided. The actions performed as part of a method can be ordered in any suitable way. Thus, embodiments can be constructed in which the actions are performed in a different order than shown, which can include performing some actions simultaneously, even if shown as sequential actions in the illustrative embodiments. In other words, it should be understood that these features are not necessarily limited to a particular order of execution, but can be performed by any number of threads, processes, services, servers, etc. serially, asynchronously, concurrently, in parallel, simultaneously, synchronously, etc. in a manner consistent with this disclosure. Thus, some of these features may be mutually contradictory as they cannot appear in a single embodiment simultaneously. Similarly, some features apply to one aspect of the innovation and not to others.

[0069] In addition, the present disclosure may include other innovations not currently described. The applicant reserves all rights to such innovations, including the rights to implement such innovations, file additional applications therefor, continue applications, continue-part applications, divisional applications, etc. Accordingly, it should be understood that the advantages, embodiments, examples, functions, features, logics, operations, organizations, structures, topologies, and / or other aspects of the present disclosure should not be considered as limitations to the present disclosure defined by the embodiments or limitations to equivalents of the embodiments. Depending on the specific expectations and / or features of individual and / or enterprise users, database configurations and / or relational models, data types, data transmissions, and / or network frameworks, syntactic structures, etc., various embodiments of the technologies disclosed herein may be implemented in ways that achieve a great deal of flexibility and customization as described herein.

[0070] All definitions defined and used herein shall be understood to control dictionary definitions, definitions in incorporated-by-reference documents, and / or ordinary meanings of defined terms.

[0071] As used herein, in a particular embodiment, when preceding a numerical value, the terms "about" or "approximately" mean a range of the value plus or minus 10%. In cases where a range of values is provided, it should be understood that unless the context clearly dictates otherwise, each intervening value between the upper and lower limits of that range and any other stated or intervening value therein to each tenth of the lower limit unit is included in the present disclosure. The upper and lower limits of these smaller ranges may independently be included in the smaller ranges, which are also included in the present disclosure, but are not limited to any specifically excluded limit of the stated range. If the stated range includes one or both of the limits, ranges excluding one or both of them are also included in the present disclosure.

[0072] The phrase "and / or" used in this specification and embodiments shall be understood to refer to "one or both" of the elements so combined, i.e., elements that exist in combination in some cases and separately in other cases. Multiple elements listed with "and / or" shall be interpreted in the same way, i.e., "one or more" elements so combined. Except for the elements specifically identified by the "and / or" clause, other elements may optionally exist, whether or not related to those specifically identified. Thus, as a non-limiting example, in one embodiment, when used in conjunction with open-ended language such as "comprising", a reference to "A and / or B" may refer only to A (optionally including elements other than B); in another embodiment, only to B (optionally including elements other than A); in yet another embodiment, it refers to both A and B (optionally including other elements); and so on.

[0073] As used in this specification and the examples, "or" shall be understood to have the same meaning as "and / or" as defined above. For example, when separating items in a list, "or" or "and / or" shall be interpreted as inclusive, i.e., including at least one, but also more than one of the elements or list, as well as optionally additional unlisted items. Only terms explicitly indicating the contrary, such as "only one" or "exactly one", or when used in the examples, "consisting of" will refer to including exactly one of the elements in a list of one or more elements. Generally, the term "or" as used herein shall be interpreted as indicating exclusive alternation (i.e., "one or the other, but not both") only when preceded by an exclusive term, such as "one of", "only one of", "just one of". "Consisting essentially of" when used in the examples shall have the ordinary meaning used in the field of patent law.

[0074] As used herein in the specification and the examples, the phrase "at least one", referring to a list of one or more elements, shall be understood to mean at least one element selected from any one or more of the elements in the list of elements, but not necessarily including at least one of each specifically listed element in the list of elements, and not excluding any combination of the elements in the list. This definition also allows for the optional presence of elements outside of the specifically identified elements in the list of elements referred to by the phrase "at least one", whether or not related to those specifically identified elements. Thus, as a non-limiting example, in one embodiment, "at least one of A and B" (or equivalently, "at least one of A or B", or equivalently "at least one of A and / or B") may refer to at least one, optionally including more than one, of A, without B (and optionally including elements other than B); in another embodiment, it is at least one, optionally including more than one, of B, without A (and optionally including elements other than A); in yet another embodiment, it is at least one, optionally including more than one, of A, and at least one, optionally including less than one, of B (and optionally including other elements); and so on.

[0075] As used herein, "fuel" may refer to any material capable of undergoing an exothermic chemical reaction with an intake mixture, regardless of the cetane number of the fuel. This may include fuels and mixtures of naphtha, gasoline, alcohol fuels (including butanol, propanol, ethanol, and methanol), gaseous hydrocarbons (including natural gas, methane, ethane, propane, butane, hexane, etc.), and alternative fuels such as hydrogen, ammonia, dimethyl ether (DME), syngas, CO, etc.

[0076] As used herein, "plume" may refer to a large quantity of fuel diffusing from an injection point, which may entrain or mix with an air volume as the air volume moves in space and / or time during a fuel injection event.

[0077] As used herein, "combustion efficiency" may refer to the degree to which air and fuel are burned sufficiently to form complete combustion products. As a non-limiting example, the lower heating value (LHV) of the fuel (such as ethanol, methanol, etc.) and the combustion products (such as CO 2 、H 2 O, etc.) can be used to calculate the combustion efficiency as described below:

[0078]

[0079] Where:

[0080] η combustion is the combustion efficiency;

[0081] LHV products is the LHV (MJ / kg) of the combustion products;

[0082] mass products is the mass (kg) of the combustion products;

[0083] LHV fuel is the LHV (MJ / kg) of the fuel; and

[0084] mass fuel is the mass (kg) of the fuel.

[0085] As used herein, "efficiency", "thermal efficiency", or "LHV efficiency" may refer to the conversion of fuel energy into mechanical work, calculated as follows:

[0086]

[0087] Where:

[0088] Η is the efficiency;

[0089] Work is the amount of mechanical work achieved (J), which can be the indicated work calculated based on the pressure in the engine cylinder, or the brake work, where the work is measured at the point where the rotating shaft enters the transmission or generator from the engine (i.e., "brake thermal efficiency");

[0090] LHV fuel is the LHV (J / kg) of the fuel; and

[0091] mass fuel is the mass (kg) of the fuel.

[0092] As used herein, the numerical definition of "crank angle" or "engine crank angle" should be understood as the crank angle relative to a fixed point in the engine cycle (as described for a four-stroke engine in Table 1 below). In other words, in a four-stroke engine, when the piston is at the TDC position between the exhaust stroke and the intake stroke, the engine crank angle is 0° (or 720°). When the piston is at the TDC position between the compression stroke and the expansion stroke, the engine crank angle is 360°. When the piston is at the BDC position between the expansion stroke and the exhaust stroke, the engine crank angle is 540°. When the piston is at the BDC position between the intake stroke and the compression stroke, the engine crank angle is 180°. Negative numbers can also be used to describe the crank angle relative to the TDC position between the exhaust stroke and the intake stroke. That is, 540° can also be described as -180°, 360° can also be described as -360°, and 180° can also be described as -540°.

[0093] Table 1. Crank Angle Description of Four-Stroke Engine

[0094]

[0095] In some embodiments, the term "immediately before ignition" or "just before ignition" may refer to the time point when the engine crank angle (in a four-stroke engine) is about 300°, about 305°, about 310°, about 315°, about 320°, about 325°, about 330°, about 335°, about 340°, about 345°, about 350°, about 355°, about 360°, about 365°, about 370°, about 375°, or about 380°, including all values and ranges therebetween. Similarly, "immediately before ignition" or "just before ignition" can be used to refer to the crank angle before and after TDC combustion in a two-stroke, five-stroke, or six-stroke engine.

[0096] In some embodiments, the term "immediately before ignition" or "just before ignition" may refer to the time point before the time when 5% fuel heat release is observed to occur. In other words, when a measurable pressure deviation can be detected to indicate that exothermic fuel oxidation is occurring, the fuel can be considered to have ignited.

[0097] In some embodiments, the term "immediately before ignition" or "just before ignition" may refer to the time point at about 1 degree crank angle, about 2 degree crank angle, about 3 degree crank angle, about 4 degree crank angle, about 5 degree crank angle, about 6 degree crank angle, about 7 degree crank angle, about 8 degree crank angle, about 9 degree crank angle, about 10 degree crank angle, about 11 degree crank angle, about 12 degree crank angle, about 13 degree crank angle, about 14 degree crank angle, about 15 degree crank angle, about 16 degree crank angle, about 17 degree crank angle, about 18 degree crank angle, about 19 degree crank angle, or about 20 degree crank angle before ignition, including all values and ranges therebetween.

[0098] In some embodiments, the term "immediately before fuel injection" or "just before fuel injection" may refer to a point in time that is about 1 degree of crank angle, about 2 degrees of crank angle, about 3 degrees of crank angle, about 4 degrees of crank angle, about 5 degrees of crank angle, about 6 degrees of crank angle, about 7 degrees of crank angle, about 8 degrees of crank angle, about 9 degrees of crank angle, about 10 degrees of crank angle, about 11 degrees of crank angle, about 12 degrees of crank angle, about 13 degrees of crank angle, about 14 degrees of crank angle, about 15 degrees of crank angle, about 16 degrees of crank angle, about 17 degrees of crank angle, about 18 degrees of crank angle, about 19 degrees of crank angle, or about 20 degrees of crank angle before fuel injection, including all values and ranges therebetween.

[0099] In some embodiments, the term "valve closed" (e.g., "intake valve closed" or "exhaust valve closed") may refer to a point in time at which the valve has traveled a threshold distance from the valve seat (i.e., 0.1 mm valve lift). In some embodiments, the term "valve open" (e.g., "intake valve open" or "exhaust valve open") may refer to a point in time at which the valve has traveled a threshold distance from the valve seat (i.e., 0.1 mm valve lift).

[0100] In embodiments, and in the foregoing specification, all transitional phrases such as "comprising," "including," "carrying," "having," "containing," "involving," "holding," "constituting," etc., are to be understood to be open-ended, i.e., to mean including but not limited to. According to the provisions of Section 2111.03 of the Manual of Patent Examining Procedure of the United States Patent and Trademark Office, only the transitional phrases "consisting of" and "consisting essentially of" are closed or semi-closed transitional phrases, respectively.

[0101] While specific embodiments of the present disclosure have been outlined above, many alternatives, modifications, and variations will be apparent to those skilled in the art. Accordingly, the embodiments described herein are intended to be illustrative and not limiting. Various changes may be made without departing from the spirit and scope of the present disclosure. Where the above-described methods and steps indicate specific events occurring in a particular order, those of ordinary skill in the art having the benefit of the present disclosure will recognize that the order of the specific steps may be modified and that such modifications are within the variations of the invention. Additionally, when possible, certain steps may be performed concurrently in parallel processes as well as in the order described above. Embodiments have been specifically shown and described, but it should be understood that various changes may be made in form and detail.

Claims

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 within each of the N cylinders, an intake port, an exhaust port, an intake valve, an exhaust valve, and a fuel injector, the intake valve being configured to permit and / or block fluid flow through the intake port, the exhaust valve being configured to permit and / or block fluid flow through the exhaust port, the piston and the inner surface defining a combustion chamber, the method comprising: injecting fuel into each combustion chamber, the fuel having a cetane number less than 40 and being substantially free of additives that cause a significant change in the cetane number; igniting the fuel by compression ignition in the compression ignition engine; burning substantially all of the fuel in the compression ignition engine; monitoring the engine load of the compression ignition engine; and when the engine load decreases to less than (N - 1) / N×FL, deactivating one of the N cylinders, deactivating the cylinder including deactivating the movement of the intake valve and the exhaust valve before deactivating the fuel injector so as to trap combustion products rather than air and maintain the overall stoichiometric air-fuel ratio in the enabled cylinders, and wherein FL is the full load at a given engine speed.

2. The method according to claim 1, wherein, The compression ignition engine further includes a three-way catalytic converter configured to reduce emissions of CO, hydrocarbons, and NO x .

3. The method according to claim 1 or 2, wherein, deactivating the cylinder includes at least one of the following: closing the intake valve of the cylinder, closing the exhaust valve of the cylinder, or deactivating the fuel injector fluidly coupled to the cylinder.

4. The method according to claim 1 or 2, wherein, the deactivation is performed by a cylinder deactivation system, the cylinder deactivation system including cylinder deactivation hardware and a cylinder deactivation control module in communication with and / or in contact with the intake valve, the exhaust valve, and the fuel injector.

5. The method according to claim 1, wherein, the fuel satisfies stoichiometric conditions with respect to the intake air quantity entering each combustion chamber.

6. The method according to claim 1, wherein, the overall stoichiometric air-fuel ratio is lean with respect to the intake air quantity entering each combustion chamber.

7. The method according to claim 1, further comprising: recirculating a portion of the exhaust gas from the exhaust port back to the combustion chamber via the intake port.

8. The method according to claim 1, wherein, N is at least 3 and the cylinder is the first cylinder, the method further comprising: when the engine load decreases to less than (N - 2) / N×FL, deactivating a second one of the N cylinders.

9. The method according to claim 1, wherein, the compression ignition engine further includes a supercharging device, the method further comprising: applying pressure to the intake air via the supercharging device.

10. The method according to claim 9, wherein, the supercharging device includes a turbocharger, a supercharger, and / or a turbocompound device.

11. The method according to claim 1, further comprising: re-enabling the cylinder according to a recommended load.

12. The method according to claim 1, wherein the fuel has an octane number of at least 100.

13. The method according to claim 1, wherein, Each molecule of the fuel has no more than 3 carbon atoms.

14. The method according to claim 1, wherein, the fuel includes at least one of methanol, ethanol, propanol, butanol, gasoline / ethanol mixture, gasoline / methanol mixture, ethanol / methanol mixture, denatured alcohol, hydrous alcohol, dimethyl ether, ammonia, hydrogen, propane or natural gas.

15. The method according to claim 1, wherein, the deactivation increases the engine load of each cylinder in response to the cylinder in the compression ignition engine operating outside a specified load range.

16. The method according to claim 1, further comprising: Reducing the air flow into the combustion chamber to maintain a desired air-fuel ratio.

17. The method according to claim 1, wherein, the deactivation maintains a substantially stoichiometric ratio in the combustion chamber.

18. A method of operating a compression ignition engine, the compression ignition engine including a plurality of cylinders, each cylinder of the plurality of cylinders having an inner surface, a piston disposed and configured to move within the engine cylinder, an intake port, an exhaust port, an intake valve, an exhaust valve and a fuel injector, the intake valve being configured to allow and / or block fluid flow through the intake port, the exhaust valve being configured to allow and / or block fluid flow through the exhaust port, the piston, the inner surface, the intake port and the exhaust port defining a combustion chamber, the method comprising: Injecting fuel into each combustion chamber, the fuel having a cetane number less than 40 and being substantially free of additives that cause a significant change in the cetane number; Igniting the fuel by compression ignition in the compression ignition engine; Burning substantially all of the fuel in the compression ignition engine; Monitoring the engine load of the compression ignition engine; Setting a predetermined load value; and When the engine load drops below the predetermined load value, deactivating at least one of the plurality of cylinders, wherein deactivating the at least one cylinder includes deactivating the movement of the intake valve and the exhaust valve before deactivating the fuel injector so as to trap combustion products rather than air and maintain the overall stoichiometric air-fuel ratio in the enabled cylinders.

19. The method according to claim 18, wherein, deactivating the cylinder includes at least one of the following: closing the intake valve of the cylinder, closing the exhaust valve of the cylinder or deactivating the fuel injector fluidly coupled to the cylinder.

20. The method according to claim 18 or 19, wherein, the fuel satisfies stoichiometric conditions relative to the intake air amount entering each combustion chamber.

21. The method according to claim 18, further comprising: Recirculating a portion of the exhaust gas from the exhaust port back to the combustion chamber via the intake port.

22. The method according to claim 18, wherein, the predetermined load value is calculated as (N - D) / N × FL, where N is the number of cylinders in the compression ignition engine, D is the number of deactivated cylinders and FL is the full load at a given engine speed.

23. The method according to claim 18, further comprising: Re-enabling the cylinder to navigate from a lower load to a higher load.

24. The method according to claim 18, wherein, the compression ignition engine further includes a supercharging device, and the method further includes: Pressure is applied to the intake air via a supercharging device.

25. The method according to claim 18, wherein, the fuel has an octane number of at least 100.

26. The method according to claim 18, wherein, the fuel has no more than 3 carbon atoms per molecule.

27. The method according to claim 18, wherein, the fuel includes at least one of methanol, ethanol, propanol, butanol, gasoline / ethanol mixture, gasoline / methanol mixture, methanol / ethanol mixture, denatured alcohol, hydrous alcohol, dimethyl ether, ammonia, hydrogen, propane or natural gas.

28. A compression ignition engine, comprising: N cylinders, each of the N cylinders comprising: an inner surface; a piston, the piston being arranged and configured to move within the engine cylinder; 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 fluidly coupled to each of the N cylinders, the piston and the inner surface defining a combustion chamber; a fuel supply device fluidly coupled to the fuel injector, the fuel supply device being configured to hold fuel having a cetane number less than 40 and substantially free of additives that cause a significant change in the cetane number; an engine control unit ECU in communication with each fuel injector, the ECU being configured to deliver a quantity of fuel to each cylinder; and a cylinder deactivation (CDA) control module configured to deactivate D of the N cylinders when the engine load in the compression ignition engine drops below (N - D) / N × FL, the cylinder deactivation control module being configured to deactivate the movement of the intake valve and the exhaust valve before deactivating the fuel injector during cylinder deactivation in order to trap combustion products rather than air and maintain the overall stoichiometric air-fuel ratio in the enabled cylinders, where FL is the full load at a given engine speed, where N is an integer of at least 2, and where D is an integer of at least 1.

29. The compression ignition engine according to claim 28, wherein, the fuel injector includes a closed-loop controlled fuel injector, and the compression ignition engine further includes a three-way catalytic converter and an EGR path, Wherein the closed-loop controlled fuel injector, the EGR path, and the three-way catalytic converter are configured to reduce the exhaust emissions of CO, hydrocarbons, and NO x from the exhaust gas.

30. The compression ignition engine according to claim 28 or 29, wherein, the ECU is configured to deliver a stoichiometric quantity of fuel to each of the cylinders.

31. The compression ignition engine according to claim 28, further comprising: an oxygen sensor configured to measure the oxygen content in the exhaust gas stream leaving the cylinder via the exhaust port.

32. The compression ignition engine according to claim 29, wherein, the fuel injector includes a closed-loop controlled fuel injector, wherein the closed-loop controlled fuel injector and the EGR path are configured to maintain precise control of thermal management and combustion dilution and minimize the standard pollutants leaving the compression ignition engine.

33. The compression ignition engine according to claim 28, wherein, N is at least 3 and D is at least 2.

34. The compression ignition engine according to claim 28, wherein, N is at least 4 and D is at least 3.

35. The compression ignition engine according to claim 28, further comprising an intake manifold fluidly coupled to the intake port and a supercharging device configured to increase the pressure in the intake manifold.

36. The compression ignition engine according to claim 35, wherein, the supercharging device includes a turbocharger, a supercharger, and / or a turbocompounding device.

37. The compression ignition engine according to claim 28, wherein, the cylinder deactivation control module operates based on the position of the accelerator pedal.

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