JPS5855346B2 - Diesel engine starting aid - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an auxiliary device for improving startability when starting a diesel engine.

Traditionally, it has been used as a starting aid for diesel engines in cold weather.
Devices using intake air heating are widely known.

As this intake air heating device, a combustion type heater is known, which heats intake air by dropping fuel onto a red-hot electric heater to combust the fuel.

Furthermore, when the engine is started, the engine speed is low, so the amount of air taken in is small.

Therefore, a large amount of intake oxygen is consumed by the combustion type heater, and the amount of oxygen in each cylinder of one engine tends to be insufficient.

For this reason, sufficient combustion does not take place in the combustion chamber of the engine.
In some cases, engine startability deteriorated.

Further, if the amount of fuel supplied to the combustion heater is reduced to such an extent that the oxygen concentration within the cylinder is not insufficient, there is a risk that the ignition of the heater flame may be delayed or the flame may be blown out.

The present invention aims to improve this, and improves starting problems caused by lack of oxygen to the cylinders of the engine in an intake air heating device using a combustion heater, and provides a starting assist device for a diesel engine that prevents the heater frame from being blown out. The purpose is to provide.

The present invention provides a starting assist device for a diesel engine that heats the intake air by operating a combustion heater in the intake air at the time of starting.
The apparatus further comprises an oxygen detection means attached to an intake system between the combustion heater and the cylinder of the engine, and a means for controlling fuel supply to the combustion heater according to the output of the oxygen detection means. Features.

Next, embodiments will be described based on the drawings.

The figure is a configuration diagram of an apparatus according to an embodiment of the present invention.

In the figure, 1 is a fuel injection pump, 2 is a feed pump, and 3 is a filter.

Fuel in a fuel tank (not shown) is sent to a filter 3 by a feed pump 2, filtered through, and supplied to a fuel injection pump 1.

Then, by the plunger of the injection pump 1, the nozzle
Although the fuel is being fed under pressure to the holder 4, overflowing fuel is returned to a fuel tank (not shown) via a return pipe 5.

Also, the vibro branched from the return pipe 5.

It is connected to a combustion type heater 9 attached to an intake pipe 8 via a solenoid valve 7.

A part of the fuel that overflowed from the fuel injection pump 1 is
It flows into the branched vibro to the extent that a slight pressure of 0.1 to 0.4 to 9/crA is applied to the electromagnetic valve 7 and is supplied to the combustion heater 9 so as to ooze out.

The solenoid valve 7 is an opening/closing solenoid valve that supplies this fuel to the combustion heater 9.

The combustion type heater 9 is preheated and cranking is started to start one engine, and at the same time, the electromagnetic valve 7 is opened and fuel is supplied to the combustion type heater 9.

An oxygen sensor 10 is attached to an intake pipe 8 extending from a mounting portion of the combustion heater 9 to a cylinder of an engine (not shown) so as to be in contact with intake air.

This oxygen sensor 10 is for detecting the oxygen concentration in intake air and controlling the oxygen concentration by electrical means.

This oxygen sensor is a known oxygen concentration battery type ZrO sensor.
A 2-system 02 sensor or an adsorption type conductivity change type metal oxide semiconductor sensor is preferred.

In particular, with the ZrO2-based 02 sensor, when the oxygen concentration falls below a certain value, its electromotive force rapidly changes from small to large, producing a noticeable signal.

In addition, the response time is very short, ranging from several m5 ec to several 100 m5 ec, and it can withstand high-temperature use of 4000 to 900°C, and the output characteristics of the sensor hardly change depending on the temperature. This sensor is preferably installed in a combustion-type intake air heating device to detect and control the amount of oxygen in the intake air.

The detection output of this oxygen sensor 10 is given to a control circuit 11 and amplified.

The control circuit 11 is configured to deliver an output and open the relay switch 12 only when the input signal to the control circuit 11 rises above a certain value.

One end of this relay switch 12 is connected to a power source 14 via a starter switch 13.

On the other hand, the other end of the relay switch 12 is connected to the electromagnetic valve 7 described above.

When starting a diesel engine, the starter switch 12
When , the relay switch 12 closes and the solenoid valve 7 opens.

Therefore, the fuel is supplied to the heated combustion heater 9, and the intake air is heated.

However, at the stage when ignition begins within the cylinders of the engine, it is preferable that the air sucked into the cylinders has a large amount of oxygen.

At this stage, when the oxygen sensor 10 detects an oxygen concentration below a certain value, the output of the control circuit 11 opens the relay switch 12, thereby closing the solenoid valve 7, and during cranking, the combustion type heater It is possible to cut fuel to 9.

As a result, the oxygen in the intake air is not consumed by the combustion heater 9, so that the amount of air necessary for ignition is sucked into the cylinders of the engine.

In the above embodiment, a case has been described in which the fuel to the combustion type heater is cut, but it is also possible to control the opening of the solenoid valve to be narrowed depending on the output of the oxygen sensor.

As described above, the starting assist device of the present invention can improve starting failures due to lack of oxygen in the cylinders when starting a diesel engine that uses a combustion heater as an intake air heating device.

In addition, since the amount of fuel supplied to the combustion heater can be automatically controlled according to the output of the oxygen sensor, proper combustion of the heater can be achieved in proportion to the amount of intake air and the flame of the heater. There is no risk of ignition delay or blowout.

[Brief explanation of drawings]

The figure is a configuration diagram of an apparatus according to an embodiment of the present invention. 1...Fuel injection pump, 2...Feed pump, 3...Filter, 4°...
Nozzle holder, 5...Return pipe, 6...
... Branch pipe, 7... Solenoid valve, 8...
...Intake pipe, 9...Combustion type heater, 10°°
...Oxygen sensor, 11...Control circuit, 12.
... Relay switch, 13 ... Starter switch, 14 ... Power supply.

Claims (1)

[Claims] 1. A starting assist device for a diesel engine that heats the intake air by operating a combustion heater in the intake air during startup, which includes an oxygen detection means installed in the intake system between the combustion heater and the engine cylinder, and an oxygen detection means installed in the intake system between the combustion heater and the cylinder of the engine. A starting assist device for a diesel engine, comprising means for controlling fuel supply to the combustion type heater according to the output of the means.