Engine
The engine design addresses pumping losses and efficiency reduction at low loads by using separate intake and exhaust pipes with a three-way valve and control system to manage fuel supply and discharge, ensuring reduced pumping losses and catalyst efficiency.
Patent Information
- Application Number
- JP2024110134
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2024-07-09
- Publication Date
- 2026-01-22
AI Technical Summary
Existing engines face increased pumping losses and efficiency reduction at low loads due to throttling the intake throttle valve, and implementing complex mechanisms to stop intake and exhaust valves is costly and complex.
The engine design includes separate intake and exhaust pipes for different cylinders, a three-way valve, and a control device to manage fuel supply and valve switching, allowing direct discharge of air from unfueled cylinders without passing through the three-way catalyst, thereby reducing pumping losses and maintaining catalyst efficiency.
This approach reduces pumping losses and eliminates the need for complex mechanisms, while maintaining the purification capacity of the three-way catalyst by avoiding direct mixing of air from unfueled cylinders with exhaust gas.
Smart Images
Figure 2026010340000001_ABST
Abstract
Description
[Technical Field]
[0001] The present disclosure relates to engines. [Background technology]
[0002] A typical engine has pistons connected to a crankshaft via connecting rods, cylinders in which the pistons reciprocate, intake pipes connected to the cylinders and each having an intake throttle valve, exhaust pipes connected to the cylinders, intake valves that open and close the connection from the intake pipe to the cylinder, and exhaust valves that open and close the connection from the cylinder to the exhaust pipe. Fuel is mixed with the intake air or injected directly into the cylinders. The amount of air flowing in is adjusted by opening and closing the intake throttle valve.
[0003] In addition, a three-way catalyst is installed in the exhaust pipe to purify the hydrocarbons (HC), carbon monoxide (CO), and nitrogen oxides (NOx) contained in the engine's exhaust gas. In order for the three-way catalyst to efficiently oxidize and reduce the exhaust gas, the engine must be operated at a theoretical air-fuel ratio (stoichiometry), where the fuel is completely burned and there is no excess oxygen. Summary of the Invention [Problem to be solved by the invention]
[0004] When the engine is operated at a low load, such as when driving at a constant speed on a highway or idling, throttling the intake throttle valve increases pumping loss and reduces efficiency. Furthermore, if the intake and exhaust valves of some cylinders are stopped from opening and closing, pumping loss can be reduced because there is no need to close the intake throttle valve significantly, but this requires the installation of a complex mechanism (such as a variable valve mechanism) to stop the intake and exhaust valves of some cylinders from opening and closing, which increases the number of parts and costs.
[0005] The present disclosure aims to provide an engine that can reduce pumping losses when the engine is operated at low load and that does not require a complex mechanism for stopping the opening and closing of the intake valves and exhaust valves. [Means for solving the problem]
[0006] The engine of the present disclosure includes a cylinder block having a plurality of cylinders, an intake pipe that takes in air from the outside, an intake throttle valve provided in the intake pipe, a first intake pipe branching from the intake pipe to take in air into some of the plurality of cylinders, a second intake pipe branching from the intake pipe to take in air into some of the other cylinders, a second exhaust pipe connected to some of the other cylinders and having a three-way catalyst installed midway, a first exhaust pipe connected to some of the cylinders and connected to the second exhaust pipe at the outlet side of the three-way catalyst, and a front exhaust pipe. The exhaust system includes a three-way valve provided midway through the first exhaust pipe, a connecting pipe branching from the three-way valve and connecting to a portion of the second exhaust pipe upstream of the three-way catalyst, a fuel supply device that supplies fuel to the plurality of cylinders, and a control device that controls the fuel supply device and the three-way valve, wherein the control device connects the three-way valve from the upstream side to the downstream side of the first exhaust pipe when stopping fuel supply to some of the cylinders, and connects the three-way valve from the upstream side of the first exhaust pipe to the connecting pipe when supplying fuel to some of the cylinders. [Effects of the Invention]
[0007] According to the present disclosure, when the engine is operated at low load, the fuel supply to some of the cylinders is stopped and the air supplied to those cylinders is discharged directly to the outside without passing through the three-way catalyst, thereby reducing pumping losses, eliminating the need to provide a complex mechanism for stopping the opening and closing of the intake valves and exhaust valves, and also preventing a decrease in the purification capacity of the three-way catalyst because the exhaust gas discharged from the cylinders that are not inactive is not mixed with the air discharged from the cylinders that are not inactive. [Brief explanation of the drawings]
[0008] [Figure 1] 1 illustrates an engine of the present disclosure; FIG. DETAILED DESCRIPTION OF THE INVENTION
[0009] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. Note that each of the embodiments described below represents a specific example of the present disclosure. Therefore, the components, the arrangement positions and connection forms of the components, etc. shown in the following embodiments are merely examples and are not intended to limit the present disclosure. Furthermore, among the components in the following embodiments, components not recited in independent claims will be described as optional components.
[0010] Furthermore, each drawing is a schematic diagram and is not necessarily an exact illustration. In each drawing, the same reference numerals are used to denote substantially the same components, and redundant explanations may be omitted or simplified.
[0011] 1 is a diagram showing an engine according to an embodiment of the present disclosure. A cylinder block 10 is formed with, for example, six cylinders 2-1, 2-2, 2-3, 2-4, 2-5, and 2-6 (hereinafter sometimes collectively referred to as cylinders 2).
[0012] An intake pipe 11 that takes in air to cylinder 2 branches into a first intake pipe 12 and a second intake pipe 13. The first intake pipe 12 further branches into three, a first branch intake pipe 14, and the second intake pipe 13 branches into three, a second branch intake pipe 15, which are connected to cylinders 2-1, 2-2, 2-3, 2-4, 2-5, and 2-6, respectively. A fuel supply device 23 is provided in each of the second branch intake pipes 15. An intake throttle valve 37 is provided midway along the intake pipe 11, and its opening is adjusted by a control device 40.
[0013] A first branch exhaust pipe 16 is connected to each of cylinders 2-1, 2-2, and 2-3, and a second branch exhaust pipe 17 is connected to each of cylinders 2-4, 2-5, and 2-6. The first branch exhaust pipe 16 is connected to a first exhaust pipe 18, and the second branch exhaust pipe 17 is connected to a second exhaust pipe 19.
[0014] A three-way catalyst 20 is provided in the second exhaust pipe 19, and the outlet side of the three-way catalyst 20 is connected to an exhaust pipe 21. The first exhaust pipe 18 is connected to the exhaust pipe 21 on the outlet side of the three-way catalyst 20. A three-way valve 22 is provided midway through the first exhaust pipe 18, and the three-way valve 22 and the second exhaust pipe 19 are connected by a connecting pipe 41.
[0015] The three-way valve 22 is switched by the control device 40 between a first state in which the upstream side of the first exhaust pipe 18 (the first branch exhaust pipe 16 side) communicates with the connecting pipe 41, and a second state in which the upstream side of the first exhaust pipe 18 (the first branch exhaust pipe 16 side) communicates with the downstream side (the outlet side of the three-way catalyst 20).
[0016] A first EGR pipe 31 is connected between the first exhaust pipe 18 and the first intake pipe 12, and a second EGR pipe 32 is connected between the second exhaust pipe 19 and the second intake pipe 13. A first EGR valve 34 is provided in the first EGR pipe 31, and a second EGR valve 35 is provided in the second EGR pipe 32, each of which is driven to open and close by a control device 40. In addition, an EGR cooler 33 is provided in the first EGR pipe 31 and the second EGR pipe 32.
[0017] Next, the operation of the engine in the embodiment of the present disclosure will be described. When operating under high load, such as during acceleration or uphill driving, fuel is supplied from the fuel supply device 23 to all cylinders 2-1, 2-2, 2-3, 2-4, 2-5, and 2-6, the three-way valve 22 connects the upstream side of the first exhaust pipe 18 (the first branch exhaust pipe 16 side) with the connecting pipe 41, and the first EGR valve 34 and the second EGR valve 35 are opened. As a result, exhaust gas emitted from all cylinders 2 is purified by the three-way catalyst 20. In addition, the exhaust gas is mixed with the intake air of all cylinders 2, suppressing NOx emissions and improving fuel economy.
[0018] On the other hand, when the engine is operated under low load, such as during low-speed driving or idling, fuel supply to some of the cylinders 2-1, 2-2, and 2-3 is stopped, the three-way valve 22 connects the upstream side (the side of the first branch exhaust pipe 16) of the first exhaust pipe 18 with the downstream side (the outlet side of the three-way catalyst 20), and the first EGR valve 34 is closed. At this time, the opening of the intake throttle valve 37 is adjusted to send air to all of the cylinders 2, and the second EGR valve 35 is open. This prevents the intake throttle valve from being significantly throttled, reducing pumping loss. Furthermore, the air supplied to some of the cylinders 2-1, 2-2, and 2-3 does not pass through the three-way catalyst 20, so the air does not mix with the exhaust gas emitted from the other cylinders 2-4, 2-5, and 2-6, allowing the three-way catalyst to efficiently purify the exhaust gas.
[0019] In other words, when the engine is operated at low load, simply stopping the fuel supply to some cylinders without throttling the intake throttle valve or stopping the opening and closing of the intake and exhaust valves reduces pumping loss and eliminates the need for a complex mechanism such as a variable valve mechanism, but the air supplied to the cylinders to which fuel supply has been stopped is sent to the three-way catalyst along with exhaust gas from the other cylinders to which fuel supply has not been stopped, reducing the purification capacity of the three-way catalyst. However, according to the present disclosure, the air supplied to the cylinders to which fuel supply has been stopped is discharged directly to the outside without passing through the three-way catalyst, so the purification capacity of the three-way catalyst is not reduced.
[0020] Therefore, according to the present disclosure, when the engine is operated at low load, the fuel supply to some of the cylinders is stopped and the air supplied to those cylinders is discharged directly to the outside without passing through the three-way catalyst, thereby reducing pumping loss, eliminating the need to provide a complex mechanism for stopping the opening and closing of the intake valves and exhaust valves, and preventing a decrease in the purification capacity of the three-way catalyst.
[0021] Although the present disclosure has been described above in accordance with the embodiments, the present disclosure is not limited to the above embodiments. For example, the number of cylinders in the engine and the number of cylinders to be stopped can be designed as appropriate. Fuel may be supplied to the cylinders by either port injection or direct injection. Also, a turbocharger may be provided between the intake pipe and the exhaust pipe. [Industrial Applicability]
[0022] The present disclosure is suitably applicable to gasoline engines, natural gas engines, and the like. [Explanation of symbols]
[0023] 1 engine 2-cylinder 10 Cylinder block 11 Intake pipe 20 Three-way catalyst 21 Exhaust pipe 22 Three-way valve 37 Intake throttle valve 41 Connecting pipe
Claims
1. a cylinder block having a plurality of cylinders; An intake pipe that takes in air from the outside, an intake throttle valve provided in the intake pipe; a first intake pipe branching from the intake pipe and supplying air to some of the plurality of cylinders; a second intake pipe branching from the intake pipe and supplying air to another part of the plurality of cylinders; a second exhaust pipe connected to the other part of the cylinders and having a three-way catalyst provided therein; a first exhaust pipe connected to the part of the cylinders and connected to the second exhaust pipe at an outlet side of the three-way catalyst; a three-way valve provided midway along the first exhaust pipe; a connecting pipe branching from the three-way valve and connected to a portion of the second exhaust pipe upstream of the three-way catalyst; a fuel supply device that supplies fuel to the plurality of cylinders; a control device that controls the fuel supply device and the three-way valve; and the control device, when stopping fuel supply to the partial cylinders, causes the three-way valve to communicate from the upstream side to the downstream side of the first exhaust pipe, and when supplying fuel to the partial cylinders, causes the three-way valve to communicate from the upstream side of the first exhaust pipe to the connecting pipe. engine.
2. a first EGR pipe branching from a portion of the first exhaust pipe upstream of the three-way valve and connected to the first intake pipe; a first EGR valve provided in the first EGR pipe; a second EGR pipe branching off from a portion of the second exhaust pipe upstream of a portion where the connecting pipe is connected to the second intake pipe, and connecting to the second intake pipe; a second EGR valve provided in the second EGR pipe; an EGR cooler that cools the first EGR pipe and the second EGR pipe; and the control device closes the first EGR valve when stopping fuel supply to the part of the cylinders.
10. The engine of claim 1.