Dongfeng Honda: Four Measures Will Be Adopted to Solve the Problem of Increasing the Liquid Level of CR-V

Recently, Dongfeng Honda held a briefing session on CR-V recall in Shenzhen. At the meeting, Xia Mu, general manager of Dongfeng Honda Automobile Co., Ltd. and Guan Taisong, chief of service technology department, explained the recall.

Dongfeng Honda Motor Co., Ltd. General Manager Natsume also stated at the briefing that after receiving the feedback of the first CR-V oil level rise at the end of last year, Dongfeng Honda organized various projects including the Honda Institute of Technology. The party’s technical experts are the first to carry out diagnostics, assessments, and tests on the actual vehicles in the field and go all out to solve the problems.

In the past five months, Dongfeng has always been rigorous, and has conducted rigorous and repeated tests and re-verifications to ensure that the final solution is effective and effective. In the end, the National Market Supervision Administration issued a recall announcement on May 16 and was formally implemented on May 22. At the same time, CR-V also resumed sales.

Regarding the recall technology, Guan Taisong, the service technology section manager of Dongfeng Honda Automobile Co., Ltd. pointed out that when the engine is working, part of the fuel is attached to the inner wall of the cylinder. During the piston movement, a small amount of fuel will be pumped into the crankcase engine oil, causing the liquid level. Increased. The crankcase ventilation system of the engine solves this problem. After the engine water temperature rises, the fuel mixed with the oil will enter the combustion chamber through the ventilation system to burn again. All the engines are designed through this principle. If the amount of fuel injected is greater than the amount of evaporation, the oil level will increase. When the outside temperature is low, the engine warm-up time will be longer and the liquid level will rise more significantly.

This recall corresponds to solving the problem of increasing oil consumption from reducing fuel inflow and increasing evaporation. In general, there are four aspects of the policy: First, the FI-ECU software upgrades, adjusted the fuel injection, reduce the amount of intrusion. Secondly, optimizing fuel injection timing and delaying ignition time promote mixture combustion, and then increase combustion injection pressure to promote atomization.

The next three policies are basically the same, to speed up the engine warming at low temperatures and promote evaporation. Replacement of the air conditioning control unit, the main strategy is to adjust the time the coolant flows to the heater, and promote the rapid increase in water temperature, after the low temperature start three minutes before closing the water will open. TCU software upgrade strategy is to change the engine speed during the process of low temperature to promote the increase of water temperature.

In the end, the replacement of the sewage pipe assembly mainly changed the path to the CVT radiator coolant and promoted the increase of the water temperature. The first of the four measures is to reduce the fuel inflow, followed by the increase in fuel evaporation.

Guan Taisong also pointed out that the FI-ECU software upgrade uses a higher fuel injection pressure at low temperatures. After the recall, the pressure will be higher, and at the same time, the fuel injection and ignition timing will be optimized to promote the full combustion of the mixture. With the same amount of fuel injected, the lower the fuel pressure and the longer the injection time, the easier it is for the injected fuel to adhere to the cylinder wall. After the pressure is increased, the injection time will be shorter, and the droplets of injected fuel will be smaller at high pressure, making it easier. Mix with air and burn better, so as to reduce the effect of fuel intrusion.

Guan Taisong also introduced that the reason why car air conditioners can heat is to rely on the engine coolant flow to the heater under the dashboard inside the fan blowing hot air for heating the vehicle, replace the air conditioning control unit to change the control unit inside the control logic, New control logic has been added to shut down the flow of coolant from the engine to the heated air core in the first three minutes of low temperature start-up to reduce heat loss and promote engine water temperature. Tests have shown that changes in the temperature of the engine before and after the countermeasure are still very obvious.

In addition, a new control logic is added to the car software. When the temperature is low, the engine speed is increased during the exercise and the water temperature rises. The new control software will detect the ambient temperature and engine temperature of the outside world when the engine starts. If the low temperature environment is judged when starting, it will increase the engine speed during running. As the temperature rises, the speed will decrease, and after reaching normal temperature, the speed will return to normal speed. If this does not work at normal temperatures, it will travel at its original speed. The engine speed in the previous driving period during the warm-up process is slightly increased. This increase will not affect the vehicle's power performance, nor will it affect the driving feel. Driving will not feel any change, and there will not be any change in vehicle acceleration. Through the increase of the speed, the engine water temperature will be increased to promote the evaporation of fuel.

The last measure, the replacement of the sewage pipe assembly. Before the countermeasure, the water flow is directly connected to the engine. Whenever the water flows to the radiator, the flow direction is adjusted to the front of the thermostat after the countermeasure. When the engine temperature is low, The coolant is in a small circulation state. When the thermostat is in the closed state, it will not flow in, reducing the heat loss of the coolant, and thus promoting the engine's lift; when the operating temperature is reached, the thermostat will open and turn to the coolant. The circulation, at which time the coolant flows into the radiator, provides heat for the CVT. Changes in flow direction will not affect the cooling effect of the power system, because the engine is working normally in most cases, but changes in flow direction at low temperatures do not affect the heat dissipation performance. However, the heat loss of the engine coolant decreases, the engine temperature rises faster, and the temperature changes on the right and the front can be seen. By increasing the temperature, the evaporation of the fuel in the engine oil is increased.

The above four strategies, on the one hand, to reduce the amount of fuel intrusion, and the other to promote the evaporation, so that a balance between the two, which can inhibit the increase in the oil level. This is the effect of the four projects recalled and the four projects.

At the same time, Guan Taisong also made detailed introduction to the current recall progress, he said. In addition to the four measures just mentioned, the recall will address the problem of increased oil level, and will provide free maintenance for the owner’s vehicle when recalled. In order to allow owners to use their cars at ease, they provide lifelong repair services for the main engine parts.

At the same time, Dongfeng Honda promised that during the use of the car, if the engine oil level increases to a certain degree, the engine failure indicator will light up and cause damage to the engine crankshaft, damage to the oil pump, damage to the piston liner, and damage to the camshaft. The owner vehicle replaces the engine assembly.

Guan Taisong also stated that the recall time and the number of projects are relatively large. The time spent by each vehicle is relatively long. At this stage, the special shop is mainly responsible for recalling the vehicles of the scheduled owners according to their own operational capabilities. From May 22 to today, A total of nearly 20,000 vehicle owners have implemented recalls in 9 days, accounting for 15% of the total recalls.