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Development of Diesel Hybrid Vehicle Braking Systems

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Development of Diesel Hybrid Vehicle Braking Systems Challenge A: A more and more energy efficient railway Development of Diesel hybrid vehicle braking systems Atsushi TANIMOTO, Makoto KOBAYASHI, Yoshinori KODAMA, Hidemi YANO West Japan Railway Company, Osaka, Japan Keywords Hybrid, Diesel vehicle, Regenerative brake, braking system Abstract In West Japan Railway Company “JR West”, braking systems of diesel vehicle consist of pneumatic brake, engine brake. Regenerative brake and engine brake act because the diesel hybrid vehicle is directly connected of an engine and an induction motor. Therefore, we developed new diesel hybrid vehicle braking systems cooperated with pneumatic brake and regenerative brake and engine brake. Diesel hybrid vehicle braking systems developed by authors allowed smooth braking with small longitudinal vibration acceleration of the body. 1. Introduction Railway vehicle is environment friendlier than a car. However, we is dedicating to energy saving of the railway vehicle to improve the environment friendly of superiority and an economy further. In particular, energy consumed per car-kilometer of the diesel vehicle is more than an electric vehicle because a diesel vehicle cannot use regenerative brake. Thereby, necessity of energy saving of the diesel vehicle is high. Accordingly, we developed the diesel hybrid vehicle that used a lithium-ion battery based on a conventional diesel vehicle. The diesel hybrid vehicle developed by authors was selected in a series-hybrid system to connect directly an induction motor with an engine. Regenerative brake and engine brake act because a series-hybrid system is directly connected of the engine and the induction motor. Therefore, authors developed new diesel hybrid vehicle braking systems cooperated with pneumatic brake and regenerative brake and engine brake. In this paper, it reports on the result of test run executed to confirm control performance of new diesel hybrid braking systems for a series-hybrid system and state of operation of pneumatic brake, regenerative brake, and engine brake. Concept of diesel hybrid vehicle braking systems (1) Conventional diesel vehicle braking systems Figure 1 shows hardware configuration of conventional diesel vehicle braking systems. Hardware of conventional diesel vehicle braking systems consists of wheel tread brakes, the engine. All wheels were equipped with wheel tread brakes controlled with a pneumatic brake unit. Bogies were equipped with two types of a power bogie and a trailer. Due to the power bogie directly connected to the engine, the power bogie can acts pneumatic brake and engine brake. The trailer can acts the only pneumatic Challenge A: A more and more energy efficient railway brake. Figure 2 shows distributions of a braking force when the brake operates to the diesel vehicle. Required braking force in Fig.2 is a braking force command from a brake controller in driver’s cab. Pneumatic brake (Trailer) in Fig.2 is a braking force controlled with the pneumatic brake unit. Pneumatic brake (Power bogie) in Fig.2 is a braking force controlled with the pneumatic brake unit. Engine brake in Fig.2 is a braking force controlled with the engine. All required braking force can be covered by the pneumatic braking force. However, in case of all required braking force covered by the pneumatic braking force, wear out of brake shoe lining of wheel tread brakes increases. Thereby it is necessary to reduce the pneumatic braking force. Accordingly, because the engine braking force controlled with the engine, the increasing braking force is decreased from the pneumatic braking force. All required braking force covered by the pneumatic braking force because the diesel vehicle cannot use engine brake at the gear shifting. The required braking force which operated the brake controller is constant regardless of transport speed of a train. Pneumatic brake unit Induction motor Engine Transmission Trailer Power bogie Fig.1 Hardware configuration (conventional diesel vehicle braking systems) Braking start Stop Required braking force Engine brake Engine brake Pneumatic brake ( Power bogie ) Braking force Braking Pneumatic brake ( Trailer ) Gearshift 4th Gearshift 3rd Neutral Train speed Train Ｔｉｍｅ Fig.2 Proportion of braking force (conventional diesel vehicle braking systems) (2) Diesel hybrid vehicle braking systems The diesel hybrid vehicle composed based on the brake system of a conventional diesel vehicle. The induction motor directly connected to the engine so that the diesel hybrid vehicle absorbs regenerative energy. Challenge A: A more and more energy efficient railway 2. Hybrid System Hardware configuration (power transmission systems) Figure 3(a), (b) shows conventional system configuration and hybrid system configuration. Conventional system consists of the engine, a hydraulic transmission, “constant speed unit”CSU”” which can take out constant rotational frequency from the engine, and three phase alternator. In contrast the hybrid diesel vehicle system consists of the engine, a transmission, the induction motor directly connected to the engine, a traction inverter, a static inverter and battery. The induction motor serves both as generator and motor for hybrid. This system enables to do the function of the hybrid systems such as regenerative brake, idle reduction, auxiliary power supply, and motor assist in power running. In addition, because the induction motor directly connected to the engine, we can start the engine by using battery electricity, traction inverter and the induction motor. As a result this hybrid system can omit a cell motor and battery for start engine. (a) Conventional system (b)Hybrid system Fig.3 Power transmission systems configuration Hardware configuration (braking systems) Figure 4(a), (b), (c), (d), and (e) shows hardware configuration of diesel hybrid vehicle braking systems. Hardware of diesel hybrid vehicle braking systems consists of wheel tread brakes, the engine, and the induction motor. All wheels were equipped with the wheel tread brake controlled with the pneumatic brake unit. The bogies were equipped with two types of the power bogie and the trailer. Due to the power bogie directly connected to the engine, the power bogie can acts pneumatic brake and engine brake, regenerative brake. The trailer can acts the only pneumatic brake. By cooperated with pneumatic brake and regenerative brake and engine brake, diesel hybrid vehicle braking systems developed by authors allowed smooth braking with small longitudinal vibration acceleration of the body. Challenge A: A more and more energy efficient railway Pneumatic brake unit Induction motor Traction Static Inverter Battery Engine Inverter Transmission Trailer Power bogie (a) Braking systems (b) Trailer (c) Motor (d) Engine (e) Power bogie Fig.4 Hardware configuration (diesel hybrid vehicle braking systems) Software configuration (braking systems) Figure 5(a) shows software configuration of diesel hybrid vehicle braking systems. Software of diesel hybrid vehicle braking systems consists of the pneumatic brake unit, a transmission control device, a regenerative brake control device, a brake control device which can control these devices and units. The pneumatic brake unit acts wheel tread brakes by controlling step relay valve by a braking force command from the brake control device. The transmission control device acts engine brake by controlling a transmission by a brake command from the brake control device. The regenerative brake control device acts regenerative brake by controlling a traction inverter by a braking force command from the brake control device. Additionally, the regenerative brake control device sends the brake control device the engine braking force operated from engine rotational speeds and the regenerative braking force. The brake control device gain the required braking force by controlling the pneumatic brake unit, the transmission control device, and the regenerative brake device. Similar to conventional diesel vehicle braking systems, the required braking force which operated the brake controller is constant regardless of transport speed of a train. Figure 5(b) shows distributions of the pneumatic braking force, the regenerative braking force, and the engine braking force from the brake start to the stop of the diesel hybrid vehicle. The regenerative braking force in Fig. 5(b) is a braking force controlled with a traction inverter. Diesel hybrid vehicle braking systems is controlling a braking force by adjusting the pneumatic braking force. The brake control device operates insufficient braking force from the required braking force, the regenerative braking force, and the engine braking force, and the brake control device sends the pneumatic brake unit this insufficient braking force. However, due to the response delay of the pneumatic brake, diesel hybrid vehicle braking systems can smooth braking by considering the response of the pneumatic brake. Challenge A: A more and more energy efficient railway Driver：brake operation Brake control device Braking force Braking Brake Transmission Braking force -command -force -command -information -command Regenerative Transmission Pneumatic brake control control device brake unit device Braking Gearshift Braking Induction motor Traction Inverter Static Inverter Battery Engine braking Pneumatic brake Regenerative brake (a) Software configuration Braking start Required braking force Stop Engine brake Engine brake Engine brake Engine brake Regenerative Regenerative Regenerative Regenerative brake brake brake brake Pneumatic brake (
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