US-12617511-B2 - Outboard motor and marine vessel

US12617511B2US 12617511 B2US12617511 B2US 12617511B2US-12617511-B2

Abstract

An outboard motor includes an engine, a fuel pump to draw fuel into an outboard motor body from a fuel tank installed on a hull, a temporary storage tank to temporarily store the fuel drawn into the outboard motor body by the fuel pump, a fuel injector to inject the fuel stored in the temporary storage tank into the engine, a temperature sensor on the temporary storage tank to detect a temperature of the fuel stored in the temporary storage tank, and a controller configured or programmed to perform a control to limit an engine speed to no more than a predetermined upper limit rotation speed based on a detection result of the temperature sensor while the engine is running.

Inventors

Yosuke Kato
Masaya OISHI
Masashi Nonaka
Shintaro Aoyagi

Assignees

YAMAHA HATSUDOKI KABUSHIKI KAISHA

Dates

Publication Date: 20260505
Application Date: 20231006
Priority Date: 20221018

Claims (20)

1 . An outboard motor comprising: an engine; a fuel pump to draw fuel into an outboard motor body from a fuel tank installed on a hull; a temporary storage tank to temporarily store the fuel drawn into the outboard motor body by the fuel pump; a fuel injector to inject the fuel stored in the temporary storage tank into the engine; a temperature sensor on the temporary storage tank to detect a temperature of the fuel stored in the temporary storage tank; and a controller configured or programmed to perform a control to limit an engine speed to no more than a predetermined upper limit rotation speed based on a detection result of the temperature sensor while the engine is running.
2 . The outboard motor according to claim 1 , wherein the controller is configured or programmed to perform a control to limit the engine speed to no more than the upper limit rotation speed when the temperature of the fuel detected by the temperature sensor is equal to or higher than a threshold temperature.
3 . The outboard motor according to claim 2 , wherein the controller is configured or programmed to perform a control to decrease the upper limit rotation speed as the temperature of the fuel increases to the threshold temperature or above.
4 . The outboard motor according to claim 3 , wherein the controller is configured or programmed to perform a control to maintain the upper limit rotation speed at a constant minimum upper limit rotation speed, smaller than the upper limit rotation speed at which the fuel is at the threshold temperature when the temperature of the fuel is equal to or higher than an upper limit temperature higher than the threshold temperature.
5 . The outboard motor according to claim 2 , wherein the controller is configured or programmed to limit the engine speed to no more than the upper limit rotation speed, and cancel a limitation on the engine speed being the upper limit rotation speed when the temperature of the fuel detected by the temperature sensor becomes lower than the threshold temperature.
6 . The outboard motor according to claim 5 , wherein the controller is configured or programmed to cancel the limitation on the engine speed being the upper limit rotation speed when the temperature of the fuel detected by the temperature sensor becomes lower than the threshold temperature and the engine speed becomes equal to or lower than a predetermined cancel rotation speed lower than the upper limit rotation speed.
7 . The outboard motor according to claim 1 , wherein the controller is configured or programmed to cancel a limitation on the engine speed being the upper limit rotation speed when a predetermined period of time has elapsed since a start of the limitation on the engine speed being the upper limit rotation speed.
8 . The outboard motor according to claim 1 , further comprising: a notifier to notify a user that a limitation on the engine speed being the upper limit rotation speed has started when the limitation by the upper limit rotation speed has started.
9 . The outboard motor according to claim 8 , further comprising: a manual pump between the fuel tank and the temporary storage tank to be manually driven to deliver the fuel from the fuel tank into the temporary storage tank; wherein the notifier includes a display to display a predetermined message to prompt the user to manually drive the manual pump when the limitation on the engine speed being the upper limit rotation speed continues without being canceled.
10 . The outboard motor according to claim 1 , wherein the temperature sensor is in contact with an outer surface of the temporary storage tank to detect the temperature of the fuel via the outer surface.
11 . The outboard motor according to claim 10 , wherein the temperature sensor is on a lower side of the temporary storage tank in contact with the outer surface of the temporary storage tank.
12 . The outboard motor according to claim 3 , wherein the controller is configured or programmed to perform a control to change the upper limit rotation speed to within an engine speed range including at least a portion of a range of about 4,000 rpm or more and about 6,000 rpm or less.
13 . A marine vessel comprising: a hull; and an outboard motor installed on the hull; wherein the outboard motor includes: an engine; a fuel pump to draw fuel into an outboard motor body from a fuel tank installed on the hull; a temporary storage tank to temporarily store the fuel drawn into the outboard motor body by the fuel pump; a fuel injector to inject the fuel stored in the temporary storage tank into the engine; a temperature sensor on the temporary storage tank to detect a temperature of the fuel stored in the temporary storage tank; and a controller configured or programmed to perform a control to limit an engine speed to no more than a predetermined upper limit rotation speed based on a detection result of the temperature sensor while the engine is running.
14 . The marine vessel according to claim 13 , wherein the controller is configured or programmed to perform a control to limit the engine speed to no more than the upper limit rotation speed when the temperature of the fuel detected by the temperature sensor is equal to or higher than a threshold temperature.
15 . The marine vessel according to claim 14 , wherein the controller is configured or programmed to perform a control to decrease the upper limit rotation speed as the temperature of the fuel increases to the threshold temperature or above.
16 . The marine vessel according to claim 15 , wherein the controller is configured or programmed to perform a control to maintain the upper limit rotation speed at a constant minimum upper limit rotation speed, value smaller than the upper limit rotation speed at which the fuel is at the threshold temperature when the temperature of the fuel is equal to or higher than an upper limit temperature higher than the threshold temperature.
17 . The marine vessel according to claim 14 , wherein the controller is configured or programmed to limit the engine speed to no more than the upper limit rotation speed, and cancel a limitation on the engine speed being the upper limit rotation speed when the temperature of the fuel detected by the temperature sensor becomes lower than the threshold temperature.
18 . The marine vessel according to claim 17 , wherein the controller is configured or programmed to cancel the limitation on the engine speed being the upper limit rotation speed when the temperature of the fuel detected by the temperature sensor becomes lower than the threshold temperature and the engine speed becomes equal to or lower than a predetermined cancel rotation speed lower than the upper limit rotation speed.
19 . The marine vessel according to claim 13 , wherein the controller is configured or programmed to cancel a limitation on the engine speed being the upper limit rotation speed when a predetermined period of time has elapsed since a start of the limitation on the engine speed being the upper limit rotation speed.
20 . The marine vessel according to claim 13 , wherein the outboard motor further includes a notifier to notify a user that a limitation on the engine speed being the upper limit rotation speed has started when the limitation by the upper limit rotation speed has started.

Description

CROSS REFERENCE TO RELATED APPLICATIONS This application claims the benefit of priority to Japanese Patent Application No. 2022-166931 filed on Oct. 18, 2022. The entire contents of this application are hereby incorporated herein by reference. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an outboard motor and a marine vessel. 2. Description of the Related Art An outboard motor and a marine vessel each including a temporary storage tank connected to a fuel injector are known in general. Such an outboard motor and a marine vessel are disclosed in Japanese Patent Laid-Open No. 2001-132573, for example. Japanese Patent Laid-Open No. 2001-132573 discloses an outboard motor including a low-pressure fuel pump to pump fuel from a fuel tank installed on a hull, a temporary storage tank installed in the vicinity of an engine, and a temperature sensor and a high-pressure fuel pump installed on and in the temporary storage tank. Fuel is supplied from the fuel tank to the temporary storage tank by the low-pressure fuel pump, and the temporary storage tank delivers the fuel to an injection nozzle by the high-pressure fuel pump. The temperature sensor detects the temperature of the fuel in the temporary storage tank. The outboard motor further includes a controller to control driving of the high-pressure fuel pump when the engine is started based on the detected value of the temperature sensor during stopping of the engine. Although not clearly described in Japanese Patent Laid-Open No. 2001-132573, in the outboard motor field it is known in general that while the engine is running the fuel in the temporary storage tank vaporizes due to an excessive increase in the temperature of the fuel in the temporary storage tank caused by an increase in the temperature of the engine. In such a case, a pressure in the temporary storage tank increases, and it becomes difficult to pump fuel from the fuel tank to the temporary storage tank. In other words, a so-called vapor lock occurs. Consequently, a decrease in an engine speed not intended or desired by a user may occur due to insufficient fuel supply. When such an issue is considered in the outboard motor disclosed in Japanese Patent Laid-Open No. 2001-132573, the controller controls driving of the high-pressure fuel pump when the engine is started, not while the engine is running, and thus the issue in a state in which the engine is running as described above is not resolved. Therefore, even in the outboard motor disclosed in Japanese Patent Laid-Open No. 2001-132573, when the temperature of the fuel in the temporary storage tank increases, it becomes difficult to pump fuel from the fuel tank to the temporary storage tank, and there is concern that a decrease in the engine speed not intended or desired by the user may occur. Thus, improvement is required. SUMMARY OF THE INVENTION Preferred embodiments of the present invention provide outboard motors and marine vessels that each reduce or prevent decreases in engine speeds not intended or desired by users caused by insufficient fuel supplies to temporary storage tanks due to the difficulty in pumping fuel from fuel tanks to the temporary storage tanks caused by vaporization of the fuel in the temporary storage tanks while engines are running. An outboard motor according to a preferred embodiment of the present invention includes an engine, a fuel pump to draw fuel into an outboard motor body from a fuel tank installed on a hull, a temporary storage tank to temporarily store the fuel drawn into the outboard motor body by the fuel pump, a fuel injector to inject the fuel stored in the temporary storage tank into the engine, a temperature sensor on the temporary storage tank to detect a temperature of the fuel stored in the temporary storage tank, and a controller configured or programmed to perform a control to limit an engine speed to no more than a predetermined upper limit rotation speed based on a detection result of the temperature sensor while the engine is running. An outboard motor according to a preferred embodiment of the present invention includes a controller configured or programmed to perform a control to limit the engine speed to no more than the predetermined upper limit rotation speed based on the detection result of the temperature sensor operable to detect the temperature of the fuel stored in the temporary storage tank while the engine is running. Accordingly, the engine speed is limited to the predetermined upper limit rotation speed based on the temperature of the fuel in the temporary storage tank detected by the temperature sensor, and thus an excessive increase in the temperature of the engine is prevented. Thus, the fuel in the temporary storage tank is prevented from reaching a temperature at which it evaporates due to an excessive increase in the temperature of the engine. Furthermore, the engine speed is limited to no more than the predetermined upper limit rotatio