JPH0192523A - Variable volume type after-cooler - Google Patents

Abstract

PURPOSE:To aim at enhancing the performance of an engine by providing a plurality of air-cooled after-coolers and a plurality of valves for controlling the cooling capacities of the after-coolers in accordance with an operating condition of the engine which incorporates a turbo-charger, so that the after- coolers are always operated appropriately. CONSTITUTION:Two after-coolers 71, 72 and two valves 6, 9 for controlling the cooling capacities of the after-coolers 71, 72, respectively, are disposed between an engine 1 and a turbo-charger 2. The cooling capacities of the after- coolers 71, 72 are changed in accordance with the operating condition of the engine by opening and closing the valves 6, 9 so as to adjust the cross-sectional areas of the after-coolers 71, 72. For example, the valves 6, 9 are opened so as to allow intake-air to flow therethrough in order to aim at lowering the temperature of intake-air, at enhancing the durability of thermally loading components and so forth. Meanwhile the valves 6, 9 are closed so as to allow intake-air to flow only through one after-cooler 71 so as to prevent intake-air from being excessively cooled.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention secures optimal operating conditions by controlling the cooling capacity of an air-cooled aftercooler in a turbocharged engine, thereby improving engine performance and durability. The present invention relates to a variable capacity aftercooler that improves.

(Prior art) As a means of increasing engine output, an air-cooled aftercooler is installed to lower the intake air temperature and increase the air density. It is determined by the intake air flow rate, the allowable limit temperature of each part of the engine, etc.

(Problem to be solved by the invention) Figure 4 is an intake and exhaust line diagram of a conventional engine equipped with an aftercooler, where air is transferred from air cleaner 3 (filtration) to turbocharger 2 (@included, pressure feeding) to aftercooler 7 (cooling). ) → Engine 1 (combustion) → Turbocharger 2 (driven by exhaust)
→ It flows through muffler 8 (silence) and is discharged. As shown in Figure 3, the air temperature from the engine air cleaner to the cylinder head inlet becomes quite high due to the heat of compression, so an aftercooler is installed to cool the intake air so that the temperature of the piston and other parts does not exceed allowable values. However, if the aftercooler cooling capacity is constant, depending on the engine operating condition,
For example, if the internal volume of the aftercooler is too large, it will take time to compress the air during sudden acceleration, which will extend the acceleration time and worsen the exhaust color. Furthermore, when starting cold or operating in a cold region, the intake air becomes overcooled, which is unfavorable in terms of engine durability. On the other hand, when the cooling capacity is low, the cooling effect at maximum output is reduced, the intake air temperature rises, and an overheating state occurs, which significantly impairs the durability of heat-loaded parts such as pistons.

(Means and actions for solving problems) Therefore,
The present invention utilizes a plurality of air-cooled aftercoolers and valves to control the cooling capacity of the aftercooler according to engine operating conditions, thereby ensuring optimal operating conditions, improving engine performance and durability, and solving the conventional problems. It is a solution.

(Example) The details of the present invention will be explained below with reference to Examples.

FIG. 1(a) is a supply/exhaust line diagram showing one embodiment of the present invention, and FIG. 1(b) is a three-dimensional perspective view thereof.

In the engine 1 equipped with the turbocharger 2, two air-cooled aftercoolers 7-1.7. and a valve 6.9 for controlling these cooling capacities. The radiator 4 and fan 5 are arranged in the conventional manner.

In this configuration, when the engine 1 is operated, the intake air taken in from the air cleaner 3 is compressed by the action of the turbocharger 2, and the air density can be increased. However, since the intake air temperature is quite high, the valve 6.9 is opened to increase the passage area of the air-cooled aftercooler to cool the intake air. Conversely, when operating in a cold region, use valve 6.9.
close to prevent overcooling of the intake air.

Further, even during sudden acceleration, the valve 6.9 is closed to reduce the internal volume of the aftercooler, thereby reducing time loss due to air compression, improving transient characteristics, and shortening acceleration time.

As described above, by opening and closing the valves 6.9, the passage areas of the air-cooled aftercoolers 7-+ and 74 can be adjusted, and the cooling capacity of the aftercoolers can be changed according to the operating conditions of the engine.

The opening and closing of the valve is as shown in Fig. 2 (a), (b), and (c).
This is done by capturing the operating status of the engine or work equipment as an electrical signal and turning a solenoid valve on and off. That is, the second
Figure (a) shows a system that detects the engine speed and the amount of rack operation and switches the use of the air-cooled aftercooler to one or two depending on the combination. At present, when the amount of throttle movement becomes large, an electric signal is output. Figure 2 (C) shows when the degree of decrease in work machine hydraulic pressure (P) exceeds a certain amount (d p
/d When the load decreases at t) an electrical signal is output.

(Effects of the invention) At maximum output, the valve is opened to allow intake air to pass through multiple air-cooled aftercoolers, lowering the intake air temperature sufficiently, increasing output and improving the durability of heat-loaded parts, resulting in cold starting and When operating in cold regions, during sudden acceleration, or in low load ranges, by closing the valve and allowing intake air to pass through only one air-cooled aftercooler, it is possible to prevent the engine inlet temperature from overcooling, thereby reducing warm air during startup. Helps reduce operating time, improve engine transient characteristics and reduce acceleration time.

[Brief explanation of the drawing]

FIG. 1(a) is an intake and exhaust route diagram of the present invention. FIG. 1(b) is a three-dimensional perspective view of FIG. 1(a). FIGS. 2(a), 2(b), and 2(C) are explanatory diagrams of the valve operating system. FIG. 3 is a diagram showing the relationship between the intake stroke and intake air temperature of a conventional engine equipped with a turbocharger. Figure 4 is an intake and exhaust line diagram of a conventional engine equipped with an aftercooler. 1...Engine body 2...Turbocharger 3
...Air cleaner 4...Radiator 5...Fan 6...Valve 7...Air-cooled aftercooler 7-I...Air-cooled aftercooler V. 7-t...Air-cooled aftercooler■2

Claims (1)

[Claims] 1. A variable capacity aftercooler for a turbocharged engine, comprising a plurality of air-cooled aftercoolers and a valve that controls the cooling capacity of the air-cooled aftercoolers according to operating conditions of the engine.